Formation of Ohmic Contacts to (001) Diamond with Nitrogen-Doped Nanocarbon Surface Layers

The electrical properties of Ohmic contacts (<i>i.e.,</i> the specific contact resistance) was investigated using the transfer length method (TLM). In this study, the TLM method was employed to analyze the properties of Ohmic contacts using a tri-layer stack of Ti/Pt/Au contacts on a nitrogen-doped n-type conducting nanocarbon (nanoC, (Patent No.: US 11,380,763 B2) epitaxial film grown on a (001) diamond substrate. Samples were annealed to monitor any changes in electrical conductivity and specific contact resistance values between the electrode and the nanoC layer were 8×10⁻⁵ Ωcm². This is significantly lower than previously reported values by almost two orders of magnitude. The improved contact resistivity was attributed to two factors. Firstly, the increased amount of nitrogen incorporation into the nanocarbon film enhanced the electrical conductivity. Nitrogen doping also introduced additional charge carriers, improving conduction properties in the nanocarbon layer. Secondly, the presence of electrically active defects in the film further contributed to the increase in conduction. These findings demonstrate the potential for improved Ohmic contacts in nanocarbon-based electronic devices, offering opportunities for enhanced performance.