Highly Conductive Nanocrystalline Diamond Films and Electronic Metallization Scheme

By using a methane and hydrogen process gas mixture in an appropriate hot-filament CVD process without further dopant, high electrical conductivity of over 100 S/cm has been achieved in nanocrystalline diamond films deposited on silicon single-crystalline substrates. Furthermore, it was found that an oxygen reactive-ion etching process (O-RIE) can improve the diamond film surface's electron affinity, thus reducing the specific contact resistance. The reduction of the specific contact resistance by a factor of up to 16 was realized by the oxygen ion etching process, down to 6x10-6 omega cm2. We provide a qualitative explanation for the mechanism behind the contact resistance reduction in terms of the electron affinity of the diamond surface. With the aid of XPS, AFM, and surface wetting measurements, we confirmed that a higher surface electron affinity is responsible for the lower specific contact resistance of the oxygen-terminated nanocrystalline diamond films.

Automated summary

The high electrical conductivity of over 100 S/cm was achieved in nanocrystalline diamond films deposited on silicon single-crystalline substrates by using a methane and hydrogen process gas mixture in an appropriate hot-filament CVD process without further dopant. Oxygen reactive-ion etching process was found to improve the diamond film surface's electron affinity, leading to a reduction in specific contact resistance. The mechanism behind the contact resistance reduction was explained qualitatively in terms of the electron affinity of the diamond surface, confirmed through XPS, AFM, and surface wetting measurements.