Greg M. Swain, Michigan State University
Jean-Charles Arnault, Commissariat Energie Atomique (CEA/Saclay)
Chia Liang Cheng, National Dong Hwa University
Milos Nesladek, IMOMEC division of IMEC
Oliver A. Williams, Cardiff University
Symposium Support Advanced Diamond Technologies, Inc.
Applied Diamond, Inc.
Cline Innovations LLC
Fraunhofer USA CCL
Seki Diamond Systems
S3: Electronic Devices and Applications
Monday PM, December 02, 2013
Hynes, Level 2, Room 204
2:30 AM - *S3.01
Metal Oxide Semiconductor Structure Using Oxygen-Terminated Diamond
Julien Pernot 1 2 G. Chicot 1 A. Marechal 1 E. Gheeraert 1 P. Muret 1
1CNRS and Universitamp;#233; Joseph Fourier Grenoble Cedex 9 France2Institut Universitaire de France Paris FranceShow Abstract
The high breakdown electric field, the elevated mobility and the outstanding thermal conductivity make diamond the ultimate semiconductor for high power and high frequency applications. Intensive works and important progresses have been done recently in the field of substrate fabrication, epilayer growth and doping control. Unfortunately, the high serial resistance of the low-doped active layer generally limits diamond devices performances. Indeed, the high ionization energy of diamond dopants gives rise to a low ionization rate and so a high serial resistance. Today, the minimization of such resistance is one of the main issue for diamond devices fabrication. One way to overcome this problem is to perform electronic device based on electron or hole channel created by field effect, like Metal Oxide Semiconductor Field Effect Transistor (MOSFET).
In this context, we fabricated a diamond Metal Oxide Semiconductor (MOS) structure with aluminum oxide as insulator and pminus;type (100) mono-cristalline diamond as semiconductor. We investigated the samples by capacitance voltage and current voltage measurements. It will be shown that the dielectric aluminum oxide, deposited by atomic layer deposition on an oxygenated diamond surface at low temperature, gives a clean interface with diamond . The capacitance voltage measurements demonstrate that accumulation, depletion and deep depletion regimes can be controlled by the bias voltage. A MOS band diagram will be proposed and discussed. These results will be compared to other works recently reported in the literature [2,3] and discussed in terms of potentiality for diamond based MOSFET.
 G. Chicot et al. “Metal oxide semiconductor structure using oxygen-terminated diamond”, Appl Phys Lett, 102, 242108 (2013)
 S. Cheng et al., “Integration of high-dielectric constant Ta2O5 oxides on diamond for power devices”, Appl Phys Lett 101, 232907 (2012).
 J.W. Liu et al., “Electrical characteristics of hydrogen-terminated diamond metal-oxide-semiconductor with atomic layer deposited HfO2 as gate dielectric,” Appl. Phys. Lett., 102, 112910 (2013).
3:00 AM - S3.02
Photo Assisted Electron Field Emission Behavior of Sulfur-Doped Nano-Crystalline Diamond
Frank Mendoza 1 Vladimir Makarov 1 Brad Weiner 2 Gerardo Morell 1
1University of Puerto Rico, Rio Piedras Campus San Juan, PR USA2University of Puerto Rico, Rio Piedras Campus San Juan, PR USAShow Abstract
Photosensitivity properties of sulfur-doped nano- (NCD) crystalline diamond films on (100) silicon substrates haven been investigated by Field Emission (FE) trough of photo-induced electrons (PE) with weak visible light. The structure and composition of these diamond materials were characterized by Raman spectroscopy, X- ray Diffraction (XRD) pattern and scanning electron microscopy. The UV sensitivity and time response was studied on NCD surfaces using a steady state broad UV excitation source and UV laser. In our study, we demonstrate that NCD have high sensitivity in the ultraviolet region, linear response in a broad intensity, no dependence of the fluency intensity at short time response. The electron emission intensity, increasing with the electric field applied is increased. The fact that the emission can be controlled by different electric field values allows the possibility to easily switch electrical currents at room temperature.
3:15 AM - S3.03
Nanodiamond Foil Product for H-Stripping to Support Spallation Neutron Source (SNS) and Related Applications
Ratnakar Vispute 1 Henry Kurt Ermer 1 Phillip Sinsky 1 Andrew Seiser 1 Lance Robinson 1 Robert W. Shaw 2
1Blue Wave Semiconductors, Inc. Baltimore USA2Oak Ridge National Laboratory Oak Ridge USAShow Abstract
Thin diamond foils are needed in many particle accelerator operations relevant to nuclear and atomic physics experiments. Particularly, the nanodiamond form is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness, and therefore, it is considered as a potential material for ion beam stripping foils. A small set of foils must be able to survive the typically 6 month operation period of the SNS, without the need for costly shutdowns and repairs. A nanodiamond foil about the size of a postage stamp is critical to the production of neutrons at the SNS and similar sources in US laboratories and around the world.
We are investigating nanocrystalline, polycrystalline, and their admixture films fabricated using a hot filament chemical vapor deposition system. Process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, plasma biasing, substrate to filament distance, filament temperature, carburization conditions, and filament geometry are optimized to achieve high purity diamond films without significant heavy metal contamination. An in-situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of diamond thin film materials. The integrated LRI in the HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. By knowing the wavelength of the laser and by knowing the refractive index of the film, growth rate and film thickness can be determined. This helps to monitor accurately the targeted 350 micro-g/cm2 thickness of the nanodiamond foil to be manufactured for the spallation neutron source. Using LRI integrated HFCVD, we correlated several important growth parameters of poly and nanodiamond films including the seeding process. Our LRI results clearly indicated that the seeding procedure strongly affects initial growth stages of diamond film through the early onset of oscillations. As the film starts to grow the laser reflectance decreases, until the nucleation layer is continuous on the substrate. After that laser reflectance starts to increase and oscillations can be measured. SEM measurements were conducted to confirm the in-situ film thickness measurements using LRI. Using this approach, a nanodiamond foil product is under development. The process parameters are also optimized for thermal and intrinsic stress management to fabricate free standing thin foils with minimal curling during irradiation. An optimization process removes pinholes to the lowest possible density in the foils. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging damaging the foils. The results will be presented in the light of development of a nanodiamond foil product that will be able to withstand a few MW of beam power.
3:30 AM - S3.04
Revolutionarily Enhanced Dielectric Strength of an ALD-Al2O3 Film Annealed at a High Temperature
Tatsuya Saito 1 Kazuhiro Kuruma 1 Akira Daicho 1 Atsushi Hiraiwa 1 Hiroshi Kawarada 1
1Waseda Univ. Tokyo JapanShow Abstract
Two-dimensional hole gas (2DHG), which is induced on a hydrogen-terminated diamond surface, is promising as a drift layer of diamond field-effect transistors (FETs), and is effectively protected against its environment being covered with an Al2O3 film formed by an atomic-layer-deposition (ALD) method with an H2O oxidant at 450°C . This film initially allowed a large leakage current, but we have recently succeeded in reducing the current, stacking the O3-oxidized Al2O3 on the H2O-oxidized one. However, the breakdown field only slightly improved contrary to expectation. Here, in order to solve this, we report the effect of high-temperature annealing on the dielectric strength of ALD-Al2O3.
The Al2O3 films in this study were formed 33-nm thick on p-type (100) Si substrates (0.002-0.004 Omega;cm) using the ALD method at 450°C with Trimethylaluminium and H2O as precursors. Next the films were annealed in Ar at 600-1100°C for an hour. The samples further received Ti/Au sputtering using a metal mask to form gate electrodes (2.5x10-3 - 5.6x10-3 cm2). The leakage current was measured applying a negative voltage to the gate according to the operation condition of diamond 2DHG-FETs. In this study, we used Si instead of diamond as a substrate material as aforementioned, because of the ease of back ohmic contact. However, note that the results obtained here apply equally to diamond substrates under this polarity of biasing.
The high-temperature annealing not only reduced the leakage current but also improved the breakdown field. This improvement was more marked for a higher temperature, and the sample annealed at 1100°C exhibited a dielectric strength of as high as 18MV/cm, which is twice the reported value . Because X-ray diffraction patterns did not show a trace of crystallized Al2O3, this revolutionarily high dielectric strength might be simply ascribed to Al2O3 densification, which was caused by the high temperature annealing. The problem is that the breakdown field was widely distributed among the samples, only some of which exhibited the aforementioned high value. The suppression of defective samples and the reduction of annealing temperature are a remaining challenge.
To conclude, we found out that, being annealed in Ar at 1100°C, the ALD-Al2O3 film potentially has a breakdown field as high as 18MV/cm, which is twice the conventional value. Presently, however, there are many defective samples that fall short of the best samples. Solving this problem and reducing the annealing temperature, the ALD-Al2O3 film will drastically enhance the breakdown voltage not only of diamond 2DHG-FETs but of other wide-bandgap semiconductor devices.
NB. This study was supported by research grants from ALCA (JST).
 A. Hiraiwa, A. Daicho, H. Kawarada, et al., J. Appl. Phys. 112 (2012) 124504.
 A. C. Kozen, M. A. Schroeder, K. D. Osborn, C. J. Lobb, and G. W. Rubloff, Appl. Phys. Lett. 102 (2013) 173501.
3:45 AM - S3.05
Characterizations of Vertical Diamond Schottky Diodes Fabricated on MPACVD Heavily Boron Doped Substrates
David Eon 1 Aboulaye Traore 1 Pierre Muret 1 Julien Pernot 1 Amine Boussadi 2 Jocelyn Achard 2 Alix Gicquel 2
1Institut Namp;#233;el Grenoble France2Laboratoire des Sciences des Procamp;#233;damp;#233;s et des Matamp;#233;riaux Villetaneuse FranceShow Abstract
Diamond is now well-known for its exceptional properties that make it the ultimate semiconductor in particular in the field of power electronic devices. This is illustrated by the recent increase in the number of publications describing the fabrication and characterization of elementary "all-diamond" components. Nevertheless, these works are mainly related, with a few exceptions , to coplanar or pseudo-vertical components. Even if the characteristics in terms of breakdown voltage are promising [2,3], in the area of high energy devices, the reverse characteristics are not enough. It is also of prime interest to ensure high current flow in forward bias which is only compatible with a large cross-section component, i.e. in vertical configuration  as it is usually done in the case of more conventional semiconductors such as silicon, silicon carbide or even gallium nitride . Obviously, the development of such components is conditioned by the availability of heavily-doped diamond substrates (doping level around 1E20 cm-3) with a thickness allowing mechanical handling which has been recently achieved by microwave plasma assisted chemical vapour deposition (MPACVD), this technique allowing having good doping homogeneity that cannot be ensured at such doping level with High Pressure High Temperature substrates.
In this paper, starting from heavily boron doped substrates grown by MPACVD, vertical Schottky diodes have been fabricated. Then, a homoepitaxial growth of thin p-layer is performed on a reactor dedicated to low doped diamond. The Schottky contacts have been obtained by evaporation of aluminum, and gold. The vertical component is characterized by ellipsometry, cathodoluminescence, and optical profilometer to determined thickness layer, dopant concentration and surface roughness. Finally, Voltage-Current behavior is carried out. Our preliminary results show a high rectification ratio, higher than 9 orders of magnitude with a low reverse current (1e-10 A). This first demonstration of vertical diode in diamond can help encapsulation and pave the way to electronic power devices.
 R. Kumaresan, H. Umezawa and S. Shikata, Diam. Relat. Mat. 19, 1324 (2010).
 P.-N. Volpe, P. Muret, J. Pernot, F. Omnès, T. Teraji, F. Jomard, D. Planson, P. Brosselard, N. Dheilly, B. Vergne and S. Scharnholtz, Phys. Stat. Sol. (a) 207, 2088 (2010).
 J. E. Butler, M. W. Geis, K. E. Krohn, J. Lawless, S. Deneault, T. M. Lyszczarz, D. Flechtner and R. Wright, Semiconductor Science and Technology 18, S67 (2003).
 J. Achard, F. Silva, R. Issaoui, O. Brinza, A. Tallaire, H. Schneider, K. Isoird, H. Ding, S. Kone, M. A. Pinault, F. Jomard and A. Gicquel, Diam. Relat. Mater. 20, 145 (2011).
 Toyota gears up HEMTs for hybrid electric vehicles, Compound Semiconductor 17, 6, 18 (2011).
 B. N. Mavrin, V. N. Denisov, D. M. Popova, E. A. Skryleva, M. S. Kuznetsov, S. A. Nosukhin, S. A. Terentiev and V. D. Blank, Physics Letters A 372, 3914 (2008).
4:30 AM - S3.06
Doped Diamond Negative Ion Sources
Franz A Koeck 1 Jeff Sharp 2 Robert J Nemanich 1
1Arizona State University Tempe USA2Subsidiary of II-VI Inc. Dallas USAShow Abstract
Negative ion sources find applicability in materials science, accelerator physics and fusion research. Our research focuses on the direct conversion of heat to electricity which utilizes negative ions to enhance a thermionic electron emission current to increase conversion efficiency. Generation of negative ions scattered from a surface is described by the Saha-Langmuir formalism which relates the ion yield to the surface work function, its temperature and the affinity level of the scattered particle. Practical ion yields are generated when the value of the particle&’s affinity level approaches the work function of the surface. For a diamond based negative ion source the value of the negative electron affinity and the magnitude of the band bending will also affect ion generation efficiency. Single crystal nitrogen - doped diamond has been utilized as a negative ion source for atomic hydrogen. The deep single substitutional states of 1.7 eV with a concentration of about 3.5 x 10-19 cm-3 establishes upward band bending, which, in conjunction with the NEA, significantly affects the ionization phenomenon. We have measured ionization of atomic hydrogen (affinity level of 0.75 eV) scattered from a hydrogenated, N-doped single crystal diamond surface in various temperature regimes. Here, an electron from a populated state in the diamond tunnels to the hydrogen affinity level if the states are energetically aligned. For the N-doped diamond a thermionic work function of about 2.6 eV was derived by a fit to the Richardson-Dushman relation. The ionization results indicate that at low temperatures < 750K no significant hydrogen ionization occurs. In a medium surface temperature regime from sim;750K to sim;950K ionization becomes more pronounced but deviates from the Saha-Langmuir relation. At elevated temperatures > 950K an exponential temperature dependence of the ionization current is observed as is described by the Saha-Langmuir formalism. We will discuss the ionization phenomenon in terms of dopant level, negative electron affinity and band bending and will compare results to surface ionization from a phosphorus doped, shallow donor diamond film. We will also elaborate on its application in direct energy conversion.
This research is supported by the Office of Naval Research.
4:45 AM - S3.07
Photo Induced Electron Emission from Phosphorus Doped Diamond Films
Tianyin Sun 1 Wiebke Janssen 2 3 Franz A.M. Koeck 1 Ken Haenen 2 3 Robert J. Nemanich 1
1Arizona State University Tempe USA2Hasselt University Diepenbeek Belgium3IMEC vzw Diepenbeek BelgiumShow Abstract
Diamond films can obtain a negative electron affinity (NEA) surface after hydrogen termination. With n-type doping, this leads to a low effective work function, and efficient thermionic electron emission has been observed from these diamond films. Photo-induced electron emission from nitrogen doped diamond films with visible light illumination has also been reported by our group. Phosphorus doping is found to provide the lowest known work function of any non-cesiated material, yet remains mostly unstudied. The focus of this work is the photo-induced emission from phosphorus doped nanocrystalline diamond (NCD) films. The P-doped NCD films have been grown by microwave plasma enhanced chemical vapor deposition (MPCVD) on different substrate materials (silicon or molybdenum), using phosphine as an in-situ dopant gas. In situ laser reflectance interferometry indicates a typical diamond film thickness of 200 to 350 nm. The photo-induced emission spectra have been collected with a hemispherical electron analyzer at elevated temperatures. A Xe arc lamp with associated bandpass filters provides photon illumination from 320 to 600 nm. The results show a low work function of 1.8 to 3 eV, and the photo-induced emission intensity presents a strong temperature dependence, which may be characteristic of Photon Enhanced Thermionic Emission (PETE). The results indicate potential application in concentrated solar energy conversion devices.
This research is supported by the Office of Naval Research through grant # N00014-10-1-0540, and by the EU FP7 through the Marie Curie ITN “MATCON” (PITNGA-2009-238201).
5:00 AM - S3.08
Practical Considerations in the Modeling of Thermionic Energy Converters
Matthew D. Brown 1 Tianyin Sun 1 Joshua R. Smith 1 Franz A.M. Koeck 1 Robert J. Nemanich 1
1Arizona State University Tempe USAShow Abstract
Low work function nitrogen-doped diamond films have demonstrated thermionic emission at temperatures less than 500 degree C, motivating the use of the films as electrodes in thermionic energy converters (TECs). Recently, our group has obtained significant enhancement of diamond-based TEC efficiency through a molecule-mediated charge transfer mechanism. We have built up a base of Python code in an attempt to explain these results. This endeavor has involved determining and modeling many practical sources of inefficiency in the converter so as to isolate the effects of molecular charge transfer, including black-body radiation from the electrodes and internal resistance of the device. The limiting factors on efficiency appear to be electronic heat and black-body losses. The model provides an approach for improving the designs of TEC devices. Future work will include the enhancement of thermionic emission through photon illumination.
This research is supported by the Office of Naval Research under grant # N00014-10-1-0540.
5:15 AM - S3.09
400deg;C Operation and High Breakdown Characteristic of Hydrogen-Terminated Diamond MOSFETs with Al2O3 Passivation
Hidetoshi Tsuboi 1 Tomoya Naruo 1 Akira Daicho 1 Tatsuya Saito 1 Dechen Xu 1 Tetsuya Yamada 1 Kazuhiro Kuruma 1 Atsushi Hiraiwa 1 Hiroshi Kawarada 1
1Waseda University Tokyo JapanShow Abstract
Diamond has a unique property that holes are accumulated densely on a carbon-hydrogen bond (C-H bond) surface. Using the property based on C-H surface, we have developed high performance field-effect transistors (FET) so far [1,2]. Since the H-termination effect is affected by a surrounding environment (surface adsorbate, high temperature, etc.), passivation technology [3,4] has been investigated. We have recently developed an advanced passivation for the surface p-type conduction operated at high temperature (~500°C)  using atomic layer deposition (ALD) Al2O3 film formed at 450°C. Here, we applied this passiviation for metal-oxide-semiconductor (MOS) FETs. The electrical properties C-H bond diamond MOSFETs were evaluated at high temperature up to 400°C. Two types of channel with different boron concentration were prepared in the following MOS fabrication process. Source-drain electrode are formed by Ti/Au on undoped (B<1016cm-3) and lightly boron-doped (B~1017cm-3) homoepitaxial layer on (001) diamond. Both layers were C-H bonded by remote plasma. The Al2O3 passivation film also employed as gate insulator was deposited by ALD utilizing ozone and H2O as oxidant at 450°C . Al gate electrode was formed for on the Al2O3 gate insulator. In drain current (IDS) - drain voltage (VDS) characteristics such as pinch-off, on resistance and transconductance, the two types of MOSFETs on undoped and lightly doped diamond shows very similar properties at 400°C in vacuum. However, drain leakage current of lightly boron doped FET is much higher than that of undoped FET. In undoped FET, the on-off ratio is 109, 105, and 103 at room temperature, 300°C, and 400°C, respectively. From the activation energy of the leakage current, the leakage path in undoped FET is not due to the residual boron as acceptor, but nitrogen as deep donor or device isolation by oxygen terminated area. It can be highly decreased by purer diamond and perfect device isolation. The breakdown characteristic of MOSFETs at the temperature from 25°C in vacuum we evaluated VDS : 275V. This result is higher than the highest breakdown voltage of diamond FET reported so far . Stable performance at 400°C comparable to SiC or GaN FETs has been achieved using H-terminated diamond MOSFETs.
[Acknowledgment] This research was supported by research grants from ALCA (JST).
 H.Kawarada Surf. Sci. Rep. 26 (1996) 205.
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 M.Kasu et al. APEX 5 (2012) 025701.
 A.Hiraiwa, H.Kawarada et al., J. Appl. Phys. 112 (2012) 124504.
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5:30 AM - S3.10
Anomalous Electric Conduction at Al-First AlN/Diamond Interface Formed by Molecular Beam Epitaxy
Wako Ono 1 Yuki Yokoyama 1 Daiki Utsunomiya 1 Tomohiro Hakamata 1 Atsushi Hiraiwa 1 Hiroshi Kawarada 1
1Waseda University Tokyo JapanShow Abstract
1.Al-first AlN on diamond (111) to get N polarity
AlN/diamond structure is an ideal system to form 2-dimensional hole gas because of a large valence band offset at the AlN/diamond interface. This structure is promising to control holes in diamond by the AlN polarity. As to the spontaneous (intrinsic) polarization of AlN, N polarity (C-Al bonds at the interface) induces more holes at diamond side than Al polarity (C-N at the interface) does. We deposited AlN by Molecular Beam Epitaxy (MBE) alternately supplying N radicals and Al atoms. Alternately supplying starting from Al (Al-first) may realize N polarity (C-Al at the interface). In this study, we deposited Al-first AlN on diamond to get C-Al bonds and investigated the AlN crystallinity and the electric properties of the AlN/diamond interface.
2.Alternative supply of Al and N on diamond and in-situ observation by RHEED
After depositing a homoepitaxial layer on a (111)-diamond substrate (Ib), an AlN was deposited by MBE alternately supplying N radicals and Al atoms. We observed diffraction pattern from [10-1] direction of diamond (111) surface in-situ. By pre-heating, diamond surface caused surface reconstruction 2×1 structure. The pattern emerged immediately after deposition start is derived from AlN phase. The pattern of Al-first AlN shows no substantial difference from that of N-first AlN.
3.Properties of Al-first AlN/diamond interface
From XRD pole figure measurements of AlN 101 asymmetry reflection, for N-first AlN, 6 fold rotation symmetry spots were observed in the AlN films. By contrast, for Al-first AlN, AlN 101 reflection is arc indicating that AlN crystal has rotational distribution.
Sheet resistivity using the van der Pauw method
We measured the resistance of 5 Al-first samples. The sheet resistivity RS of the H-terminated diamond surface were originally ~10kOmega;/sq. After the Al-first AlN deposition, RS of the AlN/diamond system were distributed between 1kOmega;/sq-10kOmega;/sq, which were very low resistivity ever reported at AlN/diamond interface. As to the low resistivity, one possibility is that H-terminated diamond surface produced by the small of residual gas such as water molecules and AlN layer show acceptor-like behavior. The second is that the polarization of the AlN film induces the p-type conduction expected in the spontaneous polarization by N polarity. The third is due to the 2×1 diamond (111) surface with partially π-bonded chain having high conductivity like graphene. We are now investigating which is the case.
We successfully deposited Al-first AlN on diamond (111). The Al-first AlN shows rotational crystal distribution. The sheet resistance RS of the interface is reproducibly obtained in 1kOmega;/sq-10kOmega;/sq. Although the conducting mechanism is still open question, the relatively high conductive layer might be used as a channel of diamond FET operated in a harsh environment.
This study was supported by research grants from ALCA (JST).
5:45 AM - S3.11
Large Area Schottky Diamond Diodes for High Power and Fast Switching Applications
Vitaly Bormashov 1 2 Alexander Volkov 1 Sergey Tarelkin 1 Sergey Terentiev 1 Sergey Buga 1 2 Dmitry Teteruk 1 Mikhail Kuznetsov 1 Vladimir Blank 1 2
1Technological Institute for Superhard and Novel Carbon Materials Troitsk Russian Federation2Moscow Institute of Physics and Technology Moscow Russian FederationShow Abstract
In spite of significant progress in diamond electronics typical diamond-based devices are not suitable for power applications due to low forward current in several hundreds of milliamps. This value is limited by a quality of large area diamond crystals.
In this work large area diamond Schottky diodes were produced and investigated. We used IIb HPHT diamond plates cut to 5×5×0.3 mm3 size with boron content about 1018 cm-3 as a p+ substrates. The doping level of substrate was limited by abrupt degradation of crystal quality during subsequent increase of boron concentration. We paid a special attention to quality of plates because the presence of extended structural defects in substrate affects strongly on the quality of CVD-grown films. Only defect-free plates were selected by the X-ray topography method.
Low doped 20 mu;m thick diamond film was grown on substrates by MP-CVD. For precise boron doping of this p- layer we used laser ablation of the high purity boron sample in hydrogen supply gas line. After surface preparation ohmic contact (Ti/Pt/Au) was made at the bottom of p+ substrate and Schottky contact (Pt) was made at the top of p- layer. To decrease the electrical field enhancement in contact edge we used field plate termination technique with 2 mu;m thick dielectric (Al2O3) layer.
Produced diamond Schottky diodes had good electrical characteristics. The forward current was 5 A (31 A/cm2) at bias 7V. Current was limited by serial resistance of substrate that has significant resistivity 5 Ohm×cm at RT. The reverse leakage current was less than 100 mu;A (0.6 mA/cm2) at 600V blocking voltage. The maximum value of breakdown voltage was slightly above 1000V. The reverse recovery time was 5 ns. Stability tests showed capability of diodes in a wide temperature range and under the influence of harsh impacts including high radiation doses.
S4: Poster Session
Greg M. Swain
Monday PM, December 02, 2013
Hynes, Level 1, Hall B
9:00 AM - S4.01
Laser Reflectance Interferometry for In-Situ Growth Monitoring and Characterization of Polydiamond, Nanodiamond, Graphene, and CNTs
Ratnakar Vispute 1 Henry Kurt Ermer 1 Phillip Sinsky 1 Andrew Seiser 1 Lance Robinson 1 Gary Harris 2
1Blue Wave Semiconductors, Inc. Baltimore USA2Howard University NW Washington USAShow Abstract
Laser reflectance interferometry tool (LRI) is developed for in-situ measurement of the growth characteristics of carbon based thin films materials. LRI tool integrated with hot-filament CVD (HFCVD) was used to grow films of diamond, nanodiamond, graphene, and thermal-CVD was used for carbon nano tubes (CNTs). LRI allows the in-situ measurement of the growth rate and the surface roughness of the samples as they were grown. This process provides real time information into the growth of films and can quickly illustrate growth features. The in-situ measurements allow for quick determination of the effectiveness of initial diamond seeding of the films. By knowing the wavelength of the laser and by knowing the refractive index of the diamond film, growth rate and film thickness can be determined.
Using LRI integrated HFCVD; growth parameters of poly and nanodiamond films were correlated such as seeding process and optimization, CH4 concentration, negative biasing, filament temperature, and Ar/H2 ratio on nanodiamond growth. LRI results clearly indicate that seeding procedure strongly affects initial growth stages of diamond film through early start of oscillations. As the film starts to grow the laser reflectance decreases, until nucleation layer is continuous on the substrate. After that laser reflectance starts to increase and oscillations can be measured. Since the time from peak to peak is used to measure the growth rate of the sample, LRI can be used to determine how growth parameters affect the growth rate and surface morphology of the deposited sample. Filament temperature had the greatest effect on the growth rate of diamond samples. Increasing CH4/H2 flow decreased time to nucleation, but had little effect on the growth rate once the film had nucleated. Increasing CH4 concentration increased the growth rate. SEM measurements were conducted to confirm the in-situ film thickness measurements using LRI.
LRI is also used for characterization of combustion of carbon materials. The materials tested were CNTs, polycrystalline diamond, and nanodiamond films heated in air. Each phase of carbon form (polydiamond, nanodiamond, CNTs) has it its own characteristic behavior. The characteristic onset combustion temperature strongly depends on the form of the carbon (sp3 vs. sp2). The LRI for polydiamond has constant reflectance until it decreases at 700°C. Raman spectroscopy showed this was due to the destruction of the sp2 bond but that the diamond (sp3) counterpart remained intact. CNTs and nanodiamond both showed constant laser reflection until total destruction of the carbon films. CNTs were completely and combusted at 660°C, nanodiamond at 740°C, indicated by a strong change in reflectivity. These results will be presented in the light of laser reflectivity monitoring tool integrated with Blue Wave HFCVD or other CVD or PVD techniques used for monitoring growth and characterization of carbon and related optical thin film and coating materials.
9:00 AM - S4.02
Autocorrelation Function Analysis - A Novel Method for the Evaluation of the Lateral Grain Size Distribution of the B-Doped Nanodiamond Crystallites from AFM Topographies
Ladislav Fekete 1 Vaclav Petrak 1 Katerina Kusova 1 Irena Kratochvilova 1
1Academy of Sciences of the Czech Republic Prague Czech RepublicShow Abstract
Boron-doped diamond is a promising material for electronic devices due to its attractive electrical properties, namely wide bandgap, high thermal conductivity, high breakdown electric field and high carrier mobility. However, the crucial step before the fabrication of electronic devices is to understand all of the parameters which influence the fabrication process. Whereas single-crystal diamond devices are well-suited for understanding the basic principles, nanodiamond films attract more attention for large-scale applications. Nanodiamond films, in comparison to the single-crystal diamond, consist of large number of small crystallites, whose properties can have strong influence on the electrical properties. One of the basic parameters is the size of the crystallites, which can be well visualized using the AFM microscope.
The distribution of sizes is one of the basic characteristics of nanoparticles. The knowledge of the lateral grain size distribution has potential to shed light on growth mechanisms or charge transport and electric properties in diamond films. Here, we propose a novel way to determine the lateral distribution of sizes from AFM topographies. Our algorithm is based on the autocorrelation function and can be applied both on topographies containing spatially separated and densely packed nanoparticles as well as on topographies of polycrystalline B-doped diamond films. As no manual treatment is required, this algorithm can be easily automatable for batch processing.
The grain size distributions obtained by the autocorrelation algorithm will be confronted with the most precize but very slow manualy obtained histogram of the lateral grain sizes and an excelent agreement of the both methods will be presented.
9:00 AM - S4.03
The Optimization of P-Type Transparent Electrode Using Boron-Doped Nanodiamond
Mitsuyasu Koga 1 Taisuke Kageura 1 Yukihiro Shintani 1 Masataka Hasegawa 2 Atsushi Hiraiwa 1 Hiroshi Kawarada 1
1Waseda University Tokyo Japan2National Institute of Advanced Industrial and Technology (AIST) Tsukuba JapanShow Abstract
In harsh environment, a diamond has many advantages superior to other materials, such as its high thermal conductivity, hardness, high conductivity, and high transparency. Since an excellent p-type conductivity and high optical transmittance are both required for photovoltaic and electroluminescence devices for an efficient hole injection in p-n junctions, a novel p-type nature obtained by boron doping in diamond endows this semiconductor with promising transparent electronics applications. In our previous study, we showed a p-type transparent conductor having a sheet resistance less than 300Omega;/Sq with 70% transparency. The samples were made by a methane (CH4) concentration of 3% on heavily boron-doped nanocrystalline diamond (NCD) on quartz [1.2]. However, it is necessary to obtain a higher transparent with the same or lower sheet resistance for practical uses. Here, we report the optimization of p-type conducting films using boron-doped NCD (B-NCD). B-NCD layers were deposited on the undoped NCD film/quartz substrate. First, undoped NCD films on quartz which was achieved at a low temperature (300-400degreeC). Next, the B-NCD layer was deposited by the MPCVD system using trimethyl boron (TMB) as the doping gas at 80 Torr in 700-800degreeC. This work was carried out in CH4 1-3% together with [B]/[C] ratio of 3000-10000ppm. As a result, the B-NCD layers retain their optical transparency in 80-90% with a low resistance less than 500-2000Omega;/Sq at a CH4 concentration being 1-1.5% together with [B]/[C] ratio of 3000-10000ppm. The top data is an optical transmittance higher than 80% together with a low sheet resistance less than 500Omega;/Sq. It is important to mention that a low sheet resistance can be obtained at a thinner B-NCD layer with higher boron concentration. The optical transmittance of B-NCD layer is better than that of solution-processed grapheme with the same sheet resistance. In the present case, the transmittance decrease is due to the increased thickness of B-NCD layers. Secondary Ion Mass Spectrometry (SIMS) showed that Boron concentration is higher than 1021 cm-3 at the outermost surface of the B-NCD layer. This conclusion is similar to the boron-concentration from metallic concentration in the range 3x1020 - 1x1021 cm-3. In the present case, 30-50% of boron atoms are present inside the grains, occupying substitutional sites and being electrically active. Therefore, B-NCD films indicate an optical transmittance obtain stably-higher 90%. It is an obvious trade-off relationship can be obtained between high optical transmittance and low sheet resistance. If you raise an optical transmittance, B-NCD must be thin film together with boron concentration being higher than 5x1021cm-3.
 X.Wang, H.Kawarada et al. (Submitted)
 Tsugawa, Hasegawa et al Phys. Rev. B 2010, 82, 125460-125468
 Kawano, Ishiwata, Kawarada, Phys. Rev. B 82, 085318 (2010)
9:00 AM - S4.05
Hydrogen Termination of Phosphorous Co-Doped Nanocrystalline Diamond and Its Implication on N-Type Doping
Adam Khan 1 Anirudha V. Sumant 2
1AKHAN Technologies, Inc. Hoffman Estates USA2Argonne National Laboratory Argonne USAShow Abstract
Achieving n-type doping in diamond with high electron mobility and concentration still remains among the final and most challenging problems in diamond materials research, preventing highly promising diamond electronic and optoelectronic device demonstrations. Having a negative electron affinity, n-type diamond is also ideally suited for low-field electron emission. Considerable efforts have been made toward fabricating n-type diamond, only very recently however, were n-type diamond films obtained in the absence of a high degree of crystallographic distortion where crystalline pitting is a known carrier scattering mechanism in diamond. Aside from crystal pitting, other defect structures in diamond are known to be detrimental to carrier mobility and electronic characteristics such as the dangling bond defect structure associated with three-fold coordinated diamond. In connection with experimental reports, hydrogen is believed to deactivate donor phosphorous through passivation of carriers and is further believed to be a source of crystallographic distortion. Therefore, the interaction between hydrogen, phosphorous, and the NCD surface is an important study towards the realization of practical n-type diamond. Motivated by our recent success, we explore the effect of hydrogen termination on phosphorous doping through various analysis techniques. We demonstrate successful h-termination, a first for experimental reports involving donor Phosphorous. In the absence of significant levels of defect density, we demonstrate excellent hall mobility. These results are promising towards the development of next generation high performance diamond electronics.
9:00 AM - S4.06
Incorporation of Silver to Microcrystalline Diamond in Fabrication of Bactericidal Materials
Khaled Mohamed Habiba 1 3 Zuania Cordero 3 4 Rafael Velazquez Vicente 1 3 Barbara Avalos 3 4 Olga Medina 2 3 Javier A. Avalos Sanchez 2 3 Gerardo Morell 1 3
1University of Puerto Rico- Rio Piedras Campus San Juan USA2University of Puerto Rico -Bayamon Campus Bayamon USA3Institute for Functional Nanomaterials San Juan USA4University of Puerto Rico -Rio Piedras Campus San Juan USAShow Abstract
Nosocomial infections are expensive and responsible for millions of deaths per year. To decrease this problem innovative microcrystalline diamond films with silver nanoparticles incorporated were successfully elaborated, characterized chemically and physically, and tested for antibacterial capacity. Recent studies demonstrated that pure silver films are more effective antibacterial agents compared to microcrystalline diamond films. The incorporation of silver nanoparticles to the microcrystalline diamond films yielded a significant improvement in its antibacterial properties. In order to perform the bacterial characterization of these MCD-Ag films, a rigorous protocol for bacterial culture was executed and the development of the bacterial populations was assessed through growth curves and absorbance measurements with an Ultraviolet-visible Spectrophotometer. Furthermore, the technique of Bacterial Transfer was used to conduct a temporal quantitative analysis of the MCD-Ag bacterial inhibition properties resulting in zero bacterial growth within 24 hours. Additionally, Scanning Electron Microscope (SEM) spectroscopy allowed us to obtain imaging of the colonial behavior of the P. Aeruginosa on the surfaces of the MCD-Ag films. The elaboration of the ground-breaking MCD-Ag films was achieved via the technique of Hot Filament Chemical Vapor Deposition. The chemical and physical characteristics of the MCD-Ag films were assayed through Transmission Electron Microscopy (TEM) and Raman Spectroscopy.
9:00 AM - S4.07
A Study of the Behavior of Voltage-Current Curves for the Prototype Interface of a Bacterial Biofilm on Microcrystalline and Nanocrystalline Diamond Films
Barbara Avalos Sanchez 3 4 Zuania Cordero 3 4 Khaled Mohamed Habiba 1 3 Rafael Velazquez Vicente 1 3 Olga Medina 2 3 Javier A. Avalos Sanchez 2 3 Gerardo Morell 1 3
1University of Puerto Rico- Rio Piedras Campus San Juan USA2University of Puerto Rico -Bayamon Campus Bayamon USA3Institute for Functional Nanomaterials San Juan USA4University of Puerto Rico -Rio Piedras Campus San Juan USAShow Abstract
The National Institutes of Health USA reported that 60% of all microbial infections are caused by biofilms, due to microbial presence on the surfaces of implants in the human body and in surgery tools. The medical industry can benefit greatly from coatings designed to reduce the bacterial viability on implants and medical tools. In the present work, we have evaluated the response to the electric current generated by a biofilm formed by bacteria that can be either gram negative or positive on the surface of microcrystalline (MCD) and nanocrystalline (NCD) diamond. The preliminary results demonstrated a change in the effective resistance of NCD and MCD material when a biofilm is formed on its surface. Furthermore, an oscillating behavior was observed in the curves of electric current versus voltage due to the presence of a bacterial strain droplet on the surface of MCD and NCD starting at 1.6 V and ranging from 0.2 V - 4.0V, similar to RC electric circuit. These studies are focused on the hypothesis of the mechanism of bacterial inhibition most accepted that involves an electrostatic relationship between the organism and the substrate in contact. The voltage-current measurements were taken with modified contact angle equipment, elaborated in the laboratory. Other studies of characterization were done using the Scanning Electron Microscope, Atomic Force Microscope, and Raman Spectroscopy. These studies allow us to infer that the formation of biofilm on biomedical instruments can alter their electrical response, thus providing misleading results, which can be prejudicial for patient diagnosis.
9:00 AM - S4.08
Simultaneous Detection of Toxic Metal Ion Using Samarium Hexacyanoferrate Nanoparticles Modified Diamond Nanowires Electrode as an Electro-Chemical Sensor
Shalini Jayakumar 1 Sankaran Jothiramalingam Kamatchi 1 Lee Young Chi 1 Tai Hwa Nyan 1 Lin I-Nan 2
1National Tsing Hua University Hsinchu Taiwan2Tamkang University New-Taipei TaiwanShow Abstract
Heavy metal pollution, caused by the waste streams of metal plating facilities, mining operations, and tanneries are not biodegradable and tend to accumulate in living organisms, causing various diseases and disorders to the nervous, immune, reproductive and gastrointestinal systems. Electrochemical method is one of the most favorable techniques for the simultaneous determination of environmental pollutants because of its low cost, high sensitivity and easy operation. Here, we explore diamond nanowire (DNW) electrode for a chemical sensing application by employing an electrochemical technique. The DNW electrode has been synthesized on silicon substrate by N2-based microwave plasma enhanced chemical vapor deposition. Further, diamond nanowire (DNW) electrode explored for the electrochemical deposition of samarium hexacyanoferrate  (SmHCF) as electroactive materials for chemical sensors. The DNW electrode has been synthesized on silicon substrate by N2-based microwave plasma enhanced chemical vapor deposition. The SmHCF deposited on the surface of the DNW electrode by potential cycling from +0.8 to -0.2 V. The SmHCF found to grow on the surface of the DNW electrode with each potential cycle, as revealed by the change of peak currents with each cycle. A well-separated voltammetric peaks for the simultaneous detection of Cd2+, Pb2+, Hg2+, Cu2+, and Zn2+ toxic metal ions are obtained using SmHCF/DNW electrodes in differential pulse voltammetry measurements. Consequently, the DNW electrode with large surface area , good chemical stability, and SmHCF makes the electrode an efficient chemical sensor.
Keywords: N2 incorporated diamond nanowire electrode, Samarium hexacyanoferrate, Cyclic voltammetry, Differential pulse voltammetry, Heavy metal ion.
 Ibrahim A. Darwish and Diane A. Blake, Anal. Chem. 74 (2002) 52-58
 Ping Wu, Shan Lu, Chenxin Cai, Journal of Electroanalytical Chemistry, 569 (2004) 143-150
 Jayakumar Shalini, Kamatchi Jothiramalingam Sankaran, Chung-Li Dong, Chi-Young Lee, Nyan-Hwa Tai and I-Nan Lin, Nanoscale, 5 (2013) 1159-1167
9:00 AM - S4.09
Electrochemical Oxygen Demand Measurement Using Diamond Electrode
Yusuke Tamura 1 Takeshi Kondo 1 2 3 Tatsuo Aikawa 1 Takeshi Watanabe 4 Yasuaki Einaga 4 5 Makoto Yuasa 1 2 3
1Tokyo University of Science Noda Japan2Tokyo University of Science Noda Japan3JST ACT-C Noda Japan4Keio University Hiyoshi Japan5JST-CREST Hiyoshi JapanShow Abstract
Chemical oxygen demand (COD) is used widely as an indication of organic pollution level in water. Conventional titration method for COD measurement has some drawbacks including production of additional waste, and thus development of electrochemical method is desired. Diamond electrode (or boron-doped diamond, BDD electrode) has wide potential window and is stable to electrolysis at high potentials. In this study, organic compounds were oxidized at high potentials with BDD electrode, and electrochemical oxygen demand (ECOD) was calculated from the anodic charge.
Constant potential of +2.5 V vs. Ag/AgCl was applied to stirred 0.1 M Na2SO4 and complete electrolysis of organic samples was performed until the current decreased down to the background level. The amount of electric charge was then calculated to ECOD. The estimated ECOD was compared with COD measured with simple COD meter and total-organic-carbon (TOC) analyzer.
Result and discussion
Highly positive potential (+2.5 V vs. Ag/AgCl) was applied to the aqueous electrolyte using BDD electrode, and a sample aliquot containing 300 nmol of potassium hydrogen phthalate was added. The anodic current increased as the sample was added, and the current decreased down to the background level. The anodic charge for the electrolysis was calculated from the integration of the background-subtracted current to be 0.81 C. Since oxidation with 1 mol of O2 corresponds to electrochemical oxidation with 4 mol of electron, ECOD can be evaluated to be 16.8 mg/L, which is close to the theoretical COD value (17.4 mg/L). This method was found to be valid for other organic compounds, and thus can be useful for a simple and accurate indication of water pollution level.
9:00 AM - S4.10
Platinum Nanoparticle-Embedded Porous Diamond Spherical Particles for a Stable Catalyst
Takuji Morimura 1 Takeshi Kondo 1 2 3 Tatsuo Aikawa 1 Makoto Yuasa 1 2 3
1Tokyo University of Science Noda Japan2Tokyo University of Science Noda Japan3JST ACT-C Noda JapanShow Abstract
Platinum nanoparticle (PtNP) catalysts are usually supported on substrates such as alumina in order to improve the performance. However, when catalysts are used under high temperature for a long time, PtNP agglomerates strongly (sintering) on the support, and the catalytic activity decreases. Recently, for a stable catalyst, PtNP@SiO2 coreminus;shell nanocatalysts, where a PtNP is covered with mesoporous silica, has been reported. In this study, we embedded PtNP into a micrometer-sized porous diamond spherical particle (PDSP), and produced a catalyst with high stability to sintering.
The PtNPs were distributed and were fixed in the spherical particle consisting of a diamond nanoparticle (DNP) aggregate formed by spray drying of an aqueous suspension containing DNP, PtNP and polyethylene glycol as a binder. After removal of the binder by thermal oxidation in air at 300°C, diamond was grown with microwave-plasma-assisted chemical vapor deposition method on the particle surface to improve the strength of the particle. After thermal oxidation in air at 425°C to remove graphitic impurities, platinum nanoparticle-embedded diamond spherical particles (PtNP@PDSP) was obtained. The catalytic activities of the catalysts were tested by dehydrogenation reaction of cyclohexane. The mixture of PtNP@PDSP and cyclohexane were refluxed at 180°C for 150 min, and benzene produced was determined with UV-vis spectroscopy.
Result and discussion
Scanning electron microscopy images showed that the PtNP@PDSP were micrometer-sized spherical particles. Nitrogen gas adsorption isotherms of the PtNP@PDSP showed curves with hystereses in the high pressure region, which indicates the presence of mesopores. Scanning transmission electron microscopy images showed that the PtNPs remained dispersed even after heat treatment. Generation of benzene was not detected when the dehydrogenation reaction of cyclohexane was performed without any catalyst or with PDSP. On the other hand, since generation of benzene was detected when the PtNP@PDSP was used, it was found that the PtNP@PDSP has catalytic activity to the reaction.
9:00 AM - S4.12
Electrical Properties of Boron Doped CVD Diamond after Plasma Cleaning Probed by Capacitance-Voltage Profiling
Luana Santos Araujo 1 Olivia Berengue 2 Mauramp;#237;cio Baldan 3 Neidenei Ferreira 3 Joamp;#227;o Moro 4 Adenilson Chiquito 1
1Universidade Federal de Samp;#227;o Carlos Samp;#227;o Carlos Brazil2Universidade Estadual Jamp;#250;lio de Mesquita Filho Guaratinguetamp;#225; Brazil3LAS/INPE Samp;#227;o Josamp;#233; dos Campos Brazil4Instituto Federal de Educaamp;#231;amp;#227;o, Ciamp;#234;ncia e Tecnologia de Samp;#227;o Paulo Braganamp;#231;a Paulista BrazilShow Abstract
The semiconducting properties of diamond make it a material of large interest for fabrication of active electronic devices. Doped films grown by chemical vapor techniques (CVD) were shown to be useful to development of new devices like gas sensors or radiation detectors. In order to produce a reliable device the charge density at the active regions of the device should be well determined. This work is aimed on investigating the distribution of the Boron in diamond films (single and multilayered).using the capacitance-voltage profiling technique. The as grown CVD diamond usually has hydrogenated surfaces that behave as a p-type semiconductor, and these surfaces must be removed. We observed that a conventional cleaning solution based on H2SO2/K2CrO4 lead to unexpected results: our p-doped samples exhibited an electrical n-type behavior. Seeking for a more efficient treatment the samples were then exposed to an oxygen plasma (150W @ 100mbar) before making electrical contacts. A significant difference between the capacitance-voltage curves of the films before and after the treatment was observed confirming the efficiency of the plasma treatment. Also capacitance-voltage data provided us with the doping profile of the samples as expected for a p-type boron doped CVD diamond.
9:00 AM - S4.13
Nanodiamond Enhanced Polyaniline Film for Electrochemical Cholesterol Biosensing
Pedro Villalba 1 4 Manoj K Ram 2 Venkat Bhethanabotla 1 2 Ashok Kumar 3 2
1University of South Florida Tampa USA2University of South Florida Tampa USA3University of South Florida Tampa USA4Universidad del Norte Barranquilla ColombiaShow Abstract
Early and accurate detection of life threatening physiological indicators are key aspects for the treatment of many diseases. The cholesterol, for an example, has been reported to associate with coronary heart problems, cerebral thrombosis, and atherosclerosis. Methods such as colorimetric approach and high-pressure liquid chromatography have been previously reported for highly specific and robust cholesterol quantification; however, these methods do not meet the important aspect requirement of high selectivity at low cost.
In this research work, we have synthetized different ratios of nanodiamond (ND)-polyaniline (PANI) based conducting composite on imprinted platinum electrodes, and later thoroughly studied for electrochemical biosensing applications. Attempts are made to vary the ND-to-aniline monomer ratio for optimal electroactive surface using comparative studies based on electrochemical response and roughness measurements. Cyclic voltammetry and Atomic Force Microscope (AFM) measurements have demonstrated that the inclusion of ND particles yields to an increment in the active surface area, which promote a higher electron exchange rate at the electrode surface. Choline oxidase (Chx) and acetylcholinesterase (AChE) enzyme were co-immobilized into the surface using covalent binding. The synthetized structures were analyzed under dynamic as well as steady state condition using electrochemical techniques. Phosphate buffer saline (PBS) containing different concentrations of cholesterol were examined to obtain the calibration curve. Also, robustness of the biosensing structure was tested using cholesterol-free PBS buffer and PBS containing analytes different than cholesterol.
9:00 AM - S4.14
Surface Treatments Effects for NO2 Gas Responsivity of p-Type Surface Conductive Layer on Diamond Films
Kenichi Haruta 1 Hideki Kimura 2 Masafumi Chiba 3
1Grad. School of Tokai Univ. Hiratsuka Japan2Tokai Univ. Hiratsuka Japan3Tokai Univ. Numazu JapanShow Abstract
Nitrogen dioxide (NO2) is one of air pollution gasses, so that the emission of is regulated. In recent years, the demand for a better gas sensor has been increase from the view point of environment conservation. The sensor material was required having the environment resistance, since the NO2 was corrosive gas and its source was usually high temperature. In generally, the diamond is an isolator. However, p-type surface conductive layer (PSCL) is formed on it, when NO2 was adsorbed on crystal surface terminated by hydrogen. The conductance of the PSCL depends on NO2 concentration in atmosphere. In addition, as the diamond has high chemical stability and heat resistance, the application to a gas sensor was expected. In this study, to improve in NO2 responsivity of PSCL, the surface treatments for the diamond films have been carried out, and its effects have been considered.
The poly-crystalline diamond films were deposited on Si substrate by hot-filament chemical vapor deposition (CVD) method and were used for samples. At first, the changes in conductance of the PSCL by atmospheric gases were measured using diamonds before treatment. The NO2 diluted with nitrogen by 12ppm and pure N2 were used for atmospheric gases. As the surface treatments, after the oxygen plasma irradiation for 10 minutes, the hydrogen annealing for 10 to 90 minutes at 900 °C to the diamond films was applied. Then the conductance was measured again. In addition, the surface hydrogen density of treated diamond films was measured by using elastic recoil detection analysis (ERDA).
The responsivity of the conductance by change in atmospheric gas was compared with before and after surface treatment. As a result, it was confirmed that the NO2 adsorption became faster than before treatment, by increase in hydrogen annealing time. On the other hands, the surface hydrogen densities of the treated diamond films were varied with annealing time, and it was considered that the adsorption rate was influenced by the surface hydrogen density. The desorption of NO2 also became faster than before treatments. Since the weak correlation with annealing time, that was affected by the oxygen plasma irradiation. It found out that surface treatment in this study was effective for improvement in responsivity as the gas sensor.
9:00 AM - S4.15
Morphological Changes in Gamma Irradiated Red Blood Cells Tracked by AFM and Nanodiamond Bio-Labeled Raman Micro Spectroscopy
Karla Santacruz-Gomez 1 Beatriz Castaneda 1 Diego Soto-Puebla 2 Rodrigo Melendrez 2 Marcelino Barboza-Flores 2 Martin Pedroza 2
1Universidad de Sonora Hermosillo Mexico2Universidad de Sonora Hermosillo MexicoShow Abstract
Gamma irradiation is a standard method to prepare blood for transfusion and for reduce the risk of Graft-versus-Host-Disease. Most prediction models are based in both counts and viability of lymphocytes after radiation exposure (around 25 Gy). However, the remained cells in blood tissue are not considered and then, important changes in red blood cells (RBC) may interfere with the recovery process in the affected patient. RBC changes include membrane deformation as we presented in our AFM study. In particular, when the depletion of RBC is altered as consequence of radiation dose, the oxygen transportation capacity is compromised. We report, how this RBC oxygen state with Raman spectroscopy using a nanodiamond as a biolabel. Two characteristic peaks were used to measure 1588 cm-1 for oxygenated RBC and 1640 cm-1 for deoxygenated. The ratio I1588/I1640 of these peaks diminished as radiation dose increased. This may indicate that gamma radiation introduced a deformability and loss of oxygen from RBC and should be considered in the irradiation blood protocols.
9:00 AM - S4.17
Thermoluminescent and Afterglow Properties in HPHT Diamond Crystals under Beta and Gamma Irradiation
Maria Gil-Tolano 1 Rodrigo Melendrez 2 Diego Soto-Puebla 2 Beatriz Castaneda 3 Marcelino Barboza-Flores 2 Martin Pedroza 2
1Universidad de Sonora Hermosillo Mexico2Universidad de Sonora Hermosillo Mexico3Universidad de Sonora Hermosillo MexicoShow Abstract
A study of the thermoluminescent (TL) and afterglow (AG) response of several commercial samples of synthetic HPHT type-Ib diamond crystals is reported. In previous works it has been reported that the TL glow curves of diamonds grown by HPHT techniques are non-reproducible. We obtained the TL and AG curves in "as grown" samples irradiated with 90Sr radiactive source (beta emission) and compared them after a stabilization procedure (SP) which includes a high gamma (60Co) dose irradiation of 500 kGy followed by a thermal treatment (TT) of 800°C for 1 hour in nitrogen atmosphere. After one SP cycle, the TL and AG have enhanced their dosimetric range of linearity of the response; between 0 and 1 Gy and around 2 Gy the TL signal has a saturation behavior. For 2 SP cycles the reproducibility of TL was improved and we obtained a 5% marginal error.
9:00 AM - S4.18
Wafer of Combined Single-Crystalline and Polycrystalline CVD Diamond for Diamond Electronics
Anatoly Vikharev 1 Aleksei Gorbachev 1 Mikhail Dukhnovsky 2 Anatoly Muchnikov 1 Aleksandra Ratnikova 2 Yuri Fedorov 2
1Institute of Applied Physics RAS Nizhny Novgorod Russian Federation2amp;#8220;Istokamp;#8221; Scientific and Industrial Enterprise Fryazino, Moscow Region Russian FederationShow Abstract
Single crystal CVD diamond has noticeable advantages over conventional semiconductor materials and allows devices with a higher operating temperature, electric power, and radiation resistance to be developed . However, one of the main factors preventing its wide application and the advent of diamond electronics is the small geometric dimensions of diamond substrates on which epitaxial growth occurs.
Currently, the technology for fabricating electronic devices on silicon is commercialized for substrates up to 300 mm in diameter . Recently, a Japanese team succeeded in fabrication of one inch mosaic crystal diamond wafers . However, the dimensions of these, although large, wafers are still far from the dimensions of silicon wafers. Nevertheless, it should be noted that polycrystalline diamond wafers 0.2 to 2 mm thick and 75 to 150 mm in diameter are successfully grown in some laboratories. The question arises: how can a single-crystal diamond of the dimensions presently achieved be used as a material for fabricating electronic devices in a large-scale technological process? In our opinion, one of the areas of such application can be as substrates of polycrystalline diamond with single-crystal diamond inclusions. Such combined diamond wafers will have a polycrystalline wafer diameter 75 to 150 mm and contain a large number of ingrown rectangular (or circular) small CVD diamond single crystals (as large as 5×5 mm or less). Processing lines which are already developed for silicon technology can be used to fabricate electronic devices on such 200-500 mu;m thick diamond wafers. To implement this approach, studies directed at fabricating the combined substrates under consideration are required.
In this paper, we present the results of a study in which two problems were solved. One problem is the fabrication of substrates in which single-crystalline and polycrystalline diamond form a single wafer. The other problem is wafer polishing and study of the epitaxial growth of diamond on combined substrates containing regions of polycrystalline and (100) single-crystalline CVD diamond. In experiments 2.45 GHz CVD reactor was used. During the experiments, we determined the conditions under which high-quality single-crystalline and polycrystalline diamond films are deposited. Also the conditions of combined substrate polishing by thermal etching were studied. At each experimental stage, the grown diamond was characterized by scanning electron microscopy (SEM) and Raman spectroscopy.
 CVD Diamond for Electronic Devices and Sensors, Edited by R.S. Sussmann (John Wiley & Sons, 2009).
 Laurent Bosson. Challenges range from 300-mm economies to new cost pressures and technical barriers. - Wafer News. Special Issue. 2005, July 11.
 H. Yamada, A. Chayahara, Y. Mokuno, N. Tsubouchi, S. Shikata, N. Fujimori. Diamond and Related Materials, 20, 616-619 (2011).
9:00 AM - S4.19
Exploring the Microstructure, Corrosion and Thermal Stability of DLC Films Deposited by High Power Impulse Magnetron Sputtering
Jin-Bao Wu 1 Jia-Jen Chang 1 Chao-Ying Chen 1 Ding-Shiang Wang 2 Hao-Wen Cheng 1 Ming-Sheng Leu 1 Shou-Yi Chang 2
1Materials Research Laboratories, Industrial Technology Research Institute Hsinchu Taiwan2Department of Materials Science and Engineering, National Chung Hsing University Taichung TaiwanShow Abstract
Diamond-like carbon (DLC) coatings have been deposited on Si(100) and stainless steel substrates by high power impulse magnetron sputtering (HIPIMS) system utilizing high peak cathode powers densities of 1260 W/cm2. Adherent deposits on substrates can be obtained through applying gradient Ti/TiC/DLC layers. A pulsed sputter current more than 120 A was generated on the C target in order to make DLC coatings have higher hardness and denser structure. The films properties were correlated with the growth conditions, including deposition partial pressure, duty cycle and pulsed sputter current apply to the target. The microstructure and hardness value of DLC films were analyzed by using X-ray photoelectron spectroscopy and nanoindenter. The experimental results show that the pulsed sputter current had strong influence on the hardness value of the DLC coatings. It has been observed that DLC films prepared by HIPIMS technology have the hardness value as high as 32 GPa. The corrosion behavior of DLC coatings was also studied in 0.5 M H2SO4 solution by using potentiodynamic polarization method. These results showed that DLC coatings on stainless steel exhibited excellent corrosion behavior especially in lower corrosion current which was less than 5×10-7 A/cm2. Furthermore, the thermal stability of the DLC films on Si substrate was evaluated by monitoring the sheet resistance as a function of treatment temperature (30 min). The results reveal that the DLC films can stabilize up to 400°C.
9:00 AM -
S4.04 TRANSFERRED TO S7.04
S1: Single Crystal Diamond Growth
Greg M. Swain
Monday AM, December 02, 2013
Hynes, Level 2, Room 204
9:30 AM -
Opening Remarks by Greg Swain
9:45 AM - *S1.01
Synthetic CVD Diamond - 25 Years on
D. J. Dodson 1 G. A. Scarsbrook 1 Daniel Twitchen 1 A. D. Wilson 1
1Element Six Santa Clara USAShow Abstract
Element Six first started its CVD diamond programme in 1988, twenty five years on this paper will review notable high and low points flagging some lessons learned. Notable recent trends in areas such as diamond quantum based and electrochemical sensing will be discussed. In addition it will summarize recent progress and challenges for microwave grown polycrystalline diamond as an enabling thermal substrate material for high power density rf electronics and optical windows for next generation EUV lithography.
10:15 AM - S1.02
Epitaxial Layer Growth on Single Crystal Diamond Substrates Using Pulsed MW PECVD Apparatus with Linear Antenna Delivery System
Andy Taylor 1 2 Ladislav Fekete 1 Vaclav Petrak 1 2 Milos Nesladek 3
1Institute of Physics, ASCR, v. v. i Prague Czech Republic2Czech Technical University Prague Czech Republic3IMOMEC, IMEC, Institute for Materials Research, University Hasselt Hasselt BelgiumShow Abstract
The wide range of applications of CVD diamond single crystals requires the possibility of mass production. Today, the growth of CVD homoepitaxial single crystal diamond (SCD) is prepared mainly by resonance cavity MW PECVD deposition which provides sufficiently high growth rates. This growth has been extensively studied in the past by many research groups [1 - 5]. Limiting factors are not only the substrate quality but also the homogeneity of the plasma over large area and the scalability. Finding a method for reproducible and reliable production of large number of SCD samples with the same characteristics (morphology, doping level, thicknesshellip;etc) remains a challenge.
In this study, we employ pulsed MW PECVD apparatus with linear antenna delivery system that is capable of producing a diffuse plasma over large areas using H2/CH4/CO2 gas mixtures. From previous studies it has been shown that nanocrystalline diamond (NCD) can be produced by this technique . However, by tuning the growth conditions, epitaxial growth conditions have been identified leading to significantly reduced secondary nucleation resulting in mosaic growth patterns.
Successful homoepitaxial growth was realized on (100) single crystal Ib high pressure high temperature synthetic diamond substrates. Samples were characterized using Raman spectroscopy, photoluminescence (PL), AFM and scanning electron microscopy.
 R Linares et al: Diamond and Related Materials 8 (1999) 909-915
 P Martineau et al: Gems & Gemology, 40 (1): 2-25 SPR (2004)
 G. Bogdan et al: phys. stat. sol. (a) 203, No. 12, 3063-3069 (2006)
 N Tranchant et al: Materials research society symposium proceedings, 956, 117-182 (2007)
 R Balmer et al: J. Phys.: Condens. Matter 21 (2009) 364221 (23pp)
 A. Taylor et al: Diamond & Related Materials 20 (2011) 613-615
10:30 AM - S1.03
Kinetic Monte Carlo Modelling of CVD Diamond Growth Processes - 2D and 3D Models
Paul William May 1 W. Jeff Rodgers 1 Neil L Allan 1 Jeremy N Harvey 1
1University of Bristol Bristol United KingdomShow Abstract
We previously reported the results from a 2-dimensional Monte Carlo simulation of diamond growth which models 300 atomic layers of diamond growth using a PC in around an hour. This simulation reproduced many of the features seen in as-grown CVD diamond, such as apparent step-edge growth, flat surfaces, and hillock formation, as well as correctly predicting growth rates of the order of a few mu;m/h.
We have spent the last 2 years refining this model, and in particular upgrading it to a full 3-dimensional model of the surface. We can now model the effects of addition to or etching from sidewalls, step-edges, corners, and vacancies. The results from these simulations will be compared with those from the simpler 2D model to assess which processes occurring on the growing diamond surface are important (i.e. determine the growth rate and or morphology) and so need to be understood in detail, and which processes are less important and can be approximated.
The nature of the critical nucleus in a true 3D system can now be determined for the first time using this model, as can other insights into the fundamental diamond growth processes occurring for a range of different deposition conditions.
11:30 AM - *S1.05
Progress on Single Crystal Diamond Growth and Its Application
Timothy Grotjohn 1 S. N. Demlow 1 N. Suwanmonkha 1
1Michigan State University East Lansing USAShow Abstract
Diamond is a unique material with exceptional properties, including high hardness, unmatched thermal conductivity, high electronic carrier mobility, high electric field breakdown, radiation hardness, biocompatibility, and unique chemical inertness. Despite these superb material properties, the full potential of diamond for numerous applications has not been realized because material of sufficient size and perfection has not been adequately available. Progress has been made over the past decade on the plasma-assisted chemical vapor deposition (PACVD) of single crystal diamond for numerous applications. This presentation will present recent progress of single crystal diamond PACVD, especially as the advances relate to electronic and optical applications. Two areas that will be discussed include (1) progress on improving the properties/quality of PACVD single crystal diamond and (2) progress on improving the PACVD process to increase substrate area, increase the deposition rate and reduce the cost of single crystal diamond. Progress at Michigan State University/Fraunhofer Center for Coatings and Laser Applications and progress around the world by other researchers will be discussed in this presentation.
Important quality factors for improving single crystal diamond for optical and electronic applications include growing the diamond while minimizing defects, controlling the incorporation of dopants with predictable uniformity and high dopant activation percentages for electronic applications, and processing the diamond with techniques to form devices while minimizing the formation of new defects. The objective is to get single crystal diamond for electronic applications that has the high electric field breakdown strength and high carrier mobilities possible with diamond. As diamond electronics looks to compete with other wide bandgap semiconductor materials, selected properties must be at or near the highest values possible with diamond.
The other challenge for single crystal diamond is producing substrates of sufficient size and quantity that the availability and price make it a reliable, easy to use, and competitive product. Progress on increasing growth rate, increasing substrate area and decreasing diamond synthesis cost will be discussed in this presentation.
S2: Heteroepitaxial Diamond Growth
Monday AM, December 02, 2013
Hynes, Level 2, Room 204
12:00 PM - *S2.01
Towards Single Crystal Diamond Wafers by Heteroepitaxy: Recent Progress, Further Challenges and Potential Applications
Matthias Schreck 1 Stefan Gsell 1 Martin Fischer 1 Christian Stehl 1 Christolph Mieskes 1 Andre Sartori 1
1Univesity of Augsburg Augsburg GermanyShow Abstract
Devices for high end applications which make use of diamond&’s unique physical properties typically require single crystals in order to guarantee that the extreme material properties are not deteriorated by the presence of grain boundaries. In order to synthesize samples with single crystal quality and technologically relevant wafer size dimensions two major concepts are currently explored. Both use chemical vapor deposition (CVD). The first is based on homoepitaxy using substrates grown by the high pressure high temperature (HPHT) technique and applying cloning and tiling steps. In the second approach heteroepitaxial growth is performed on foreign substrates. Amongst all substrates for which generation of epitaxially aligned diamond grains has been shown experimentally, iridium has turned out to be unique since it facilitates unrivaled alignment of the grains.
In this talk the recent progress of diamond heteroepitaxy on iridium layers will be reviewed. All work has been performed on Ir/YSZ/Si with on-axis or off-axis Si(001) and Si(111) substrates. The major defects that have to be considered can be distinguished according to their dimensionality, i.e. 2D, 1D and 0D. Two-dimensional grain boundaries are present only during the first 10-30 µm of film growth forming a closed network that separates individual mosaic blocks. After their dissolution the defect structure is dominated by 1D threading dislocations which appear as individual defects or gathered in groups. Their initial density above 1010 cm-2 decreases continuously by several orders of magnitude during film growth up to 1000 µm thickness. This decrease and the concomitant reduction in microstrain as deduced from Raman line width measurements follow simple mathematic laws. In addition it will be shown that dislocations crucially control the formation of intrinsic stress of both signs during film growth. Among the structural / chemical zero-dimens