STRUCTURAL STUDIES OF DIAMOND THIN-FILMS GROWN FROM DC ARC PLASMA

Diamond thin films grown from a dc-arc discharge in CH4/H-2 mixtures o n Si wafers were examined by transmission electron microscopy and Rama n spectroscopy. This deposition method provides good diamond crystalli nity at high CH4 concentrations (3%-9%). Seeding the substrate with 5 nm diamond particles at a density of 2 x 10(12) cm(-1) followed by arg on laser irradiation to reduce their agglomeration gives, just after s tarting deposition, a density of growth centers of 10(10) cm(-2). At 3 % CH4 concentration the film grows with almost perfect crystallites. R icher CH4 mixtures (5% and 9%) produce crystallites with twins and sta cking faults. An amorphous 20-70 nm SiC interlayer is present at these CH4 concentrations, which was not observed at 3% CH4. Amorphous sp(3) - and sp(2)-bonded carbon was detected by Raman spectroscopy at all CH 4 concentrations and correlated with TEM data.