AC vs. DC bias-enhanced nucleation of highly oriented diamond on silicon (100)

Bias-enhanced nucleation of highly oriented diamond on silicon (100) has been investigated in the context of bias type. The formation of aligned crystallites using conventional dc substrate biasing was facilitated by a preceding carburization. The optimum biasing conditions following a 1 h carburization involved a bias voltage of 2250 V and a stringent bias duration of 3-4 min which produced total nucleation densities of similar to1 X 10(10) cm(-2) and highly oriented diamond percentages of similar to50%. In comparison, the application of a 55-65 min ac substrate bias of 175 V-rms (+/-250 Vpeak-to-peak) resulted in a comparable percentage of oriented crystallites and similar crystallographic alignment. However, in this approach a precarburization was not found to be beneficial. This simplification in the processing of the oriented diamond was further aided by a broader bias duration window for producing the optimum combination of high total nucleation density and highly oriented diamond percentage. (C) 2001 The Electrochemical Society.