Synthesis of High Density Nucleation of Nano-Crystalline Diamond Films on Non Carbon Affinity Substrates

Thin films of nano-crystalline diamond (NCD) were grown on c-Si (100) substrates using a gas mixture of methane (CH4) and hydrogen (H-2) by hot filament chemical vapor deposition technique. No special pretreatment of substrate for enhancement of nucleation center was employed. Films were prepared at low substrate temperature of 430-450 degrees C and a low chamber pressure of 2 mbar with varying CH4 gas concentration. The concentration of CH4 gas in the mixture of CH4 and H-2 was varied from similar to 10-70%. The growth rate for the diamond particles achieved was of the order of similar to 10 nm/min. Films were characterized using x-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM), which confirmed the growth of NCD. The grown films have both type of carbon bonding sp(3) as well as sp(2). The average particle size estimated by FESEM image was in the range of 50-200 nm. The nucleation density of the diamond particles as obtained from FESEM image was approximately 108(-)10(10) /cm(2), and it was found to increase with increasing CH4 gas concentration. The crystallite size estimated by XRD was similar to 21 nm.