Growth of Nitrogen-Incorporated Diamond Films Using Hot-Filament Chemical Vapor Deposition Technique

Abstract

Micro- and nanocrystalline diamond (MNCD) films were deposited on silicon substrates by hot-filament chemical vapor deposition (HF-CVD) at chamber pressure of 22.5 torr for 20 hours. The total mass flow rate was 300 sccm (3 Vol.% CH4), while the nitrogen gas flow rate was varied from 0.04 to 0.64 sccm corresponding to 0.8 to 12.8% of H2+CH4 mixture. The resulting films were characterized by X-Ray Diffraction (XRD), Raman Spectra, Scanning Electron Microscope (SEM) and four point probe van der Pauw method to analyze and measure the structure, quality, morphology and resistivity of the deposited films, respectively. Results show that the grain size increases at low concentration of nitrogen, while it decreases for high concentration of nitrogen and the fact is probably the formation of atomic nitrogen N° near filament surface and its inward diffusion on the surface of growing film. Resistivity decreases continuously due to formation of C—H bonds in a trans-polyacetylene structure along with diamond film, which leads to change surface morphology. By increasing nitrogen content enhance distortion along [111] direction of the resulting films.