DEPOSITION AND CHARACTERIZATION OF NANOCRYSTALLINE DIAMOND FILMS

Highly uniform, smooth nanocrystalline diamond films have been fabrica ted with a magnetoactive microwave chemical vapor deposition system. T he top and bottom magnet currents were 145 and 60 A, respectively, whi le the microwave power and substrate temperature were controlled at 15 00 W and 850-degrees-C, respectively during deposition. The total proc essing pressure was regulated at 40 Pa (300 mTorr) with gas-flow rates of 30 sccm of hydrogen, 2.4 sccm of methane, and 1 sccm of oxygen. Di amond films obtained under these conditions have grain sizes between 0 .1 and 0.3 mum, and a mean roughness of 14.95 nm. The growth rate is 0 .1 mum/h. Characterization techniques have involved x-ray diffraction, Raman spectroscopy, scanning electron microscopy, atomic force micros copy, and transmission electron microscopy. Both x-ray and electron di ffraction patterns show no evidence of graphitic phase. Although a hig h density of twins and stacking faults was revealed by high-resolution electron microscopy, compact diamond grains, and clean intergranular boundaries (no graphitic phase) were observed.