April 7 - 11, 2025
Seattle, Washington
Symposium Supporters
2025 MRS Spring Meeting & Exhibit
EL11.02.01

Growth of Hexagonal Boron Nitrides by MOCVD and Their Applications

When and Where

Apr 8, 2025
10:30am - 11:00am
Summit, Level 4, Room 435

Presenter(s)

Co-Author(s)

Jong Kyu Kim1,Seokho Moon1,Jiye Kim1,Jaesub Song1,Semi Im1,Jawon Kim1

Pohang University of Science and Technology1

Abstract

Jong Kyu Kim1,Seokho Moon1,Jiye Kim1,Jaesub Song1,Semi Im1,Jawon Kim1

Pohang University of Science and Technology1
Hexagonal boron nitride (h-BN), an insulating two-dimensional layered material, has recently attracted a great attention due to its fascinating optical, electrical, and thermal properties, and promising applications across the fields of photonics, quantum optics, and electronics. However, mechanically exfoliated bulk h-BN and h-BN films grown on catalytic metal substrates have been mainly used to study the fundamental properties, lacking in scalability for practical implementation of h-BN. Here, we present a scalable approach for growing high-quality h-BN on various substrates, including Si and epitaxial III-Nitrides, via metal-organic chemical vapor deposition (MOCVD), and its various electronics and photonics applications.
For implementation of wafer-scale h-BN films into current state-of-the-art Si-based microelectronics technology, we demonstrate the conformal growth of sp2 hybridized few-layer h-BN over an array of Si-based nanotrenches with 45 nm pitch and the aspect ratio of ~ 7:1. Surface-sensitive near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory calculations reveal that the B-O bonds formed on the non-catalytic SiO2 surface act as nucleation sites for the formation of mixed sp2-and sp3-hybridized BON2 and BN3, facilitating the conformal growth of sp2-hybridized h-BN with excellent step coverage.
In addition, we demonstrate the scalable use of uniform h-BN van der Waals passivation layer on a 2-inch AlGaN/GaN high-electron mobility transistor (HEMT) wafer via MOCVD. The resulting HEMTs demonstrated outstanding radio-frequency (rf) performance, with fT and fMAX values reacing 28 and 88 GHz, respectively. Structural, spectroscopic, and theoretical analyses revealed an atomically sharp heterointerface between the h-BN layer and the AlGaN surface, underscoring the potential of h-BN for advanced device passivation. We believe that these results can provide a broad avenue for the implementation of fascinating 2D materials for current state-of-the-art microelectronics technology.
As a demonstration of an active electronic component, we fabricated an analog switching memristor using an MOCVD-grown h-BN memristive layer suspended on GaN nanocones for artificial neural network applications. Our unique h-BN on GaN nanocone heterostructure exhibits analog switching behavior with high endurance and low operation voltage. Consecutive conductive atomic force microscopy measurements reveal gradual formation of multiple nano-filaments, leading to a reduced Joule heating and a significant increase in device endurance, evidenced by a decrease in cycle-to-cycle conductance variation from 59% to 8%. This improvement enables linear and symmetric synaptic weight updates, achieving a high accuracy of 97.1% in MNIST handwritten digit recognition task simulation.
In addition to electronics applications, leveraging the unique properties of h-BN, our recent results demonstrate its potential in deep ultraviolet optoelectronics and quantum emitters. We report the development of an h-BN/GaN heterostruture photodetector, exhibiting high responsivity and selectivity in the deep ultraviolet range. Furthermore, using MOCVD, we have successfully incorporated carbon into the h-BN matrix, resulting in enhanced structural and optical properties and advancing the scalable fabrication of h-BN-based quantum devices. These advancements underscore the versatility of h-BN and provide a strategic pathway for its implementation in advanced photonic and quantum technologies.

Keywords

epitaxy

Symposium Organizers

Robert Kaplar, Sandia National Laboratories
Filip Tuomisto, University of Helsinki
Motoaki Iwaya, Meijo University
Sriram Krishnamoorthy, University of California, Santa Barbara

Symposium Support

Silver
Taiyo Nippon Sanso

Session Chairs

Motoaki Iwaya
Jong Kyu Kim

In this Session