Fabrication of nanogranular diamond films by MPJCVD system

Nanogranular diamond films have been prepared by microwave plasma jet chemical vapor deposition system (MPJCVD) with argon-rich (Ar/H2:90%) plasma. In this work, the plasma pre-carbonization (P.P.) pre-treatment was employed to obtain uniform and smooth (13.3 nm rms) diamond films with high nucleation density. The diamond films were fabricated in various Ar/H2 concentrations from 0% to 100% and fixed at CH4 concentration of 1%. It can be clearly observed that the grain size of diamond films changed from micrometer to nanometer scale and down to 5 nm at the concentration of 90% Ar/H2. The reason is due to the rise of C2 dimer in the plasma, which could be proved from the analysis of OES analysis.