Bias enhanced nucleation of diamond on silicon (100) in a HFCVD system

A setup for bias enhanced nucleation inside a hot filament CVD system is described. It consists of a combination of two separate voltages for independent generation of ions in the gas phase as well as the acceleration of the ions toward the substrate surface. Using the bias current as a monitor for the dynamics of diamond nucleation, the pretreatment can be terminated at a definite condition and the diamond growth process can be continued under normal deposition conditions. With suitable deposition parameters we are able to obtain diamond nucleation on an entire 4" Si (100) substrate with a density of more than 10(9) cm(-2) as confirmed by secondary electron microscopy. Furthermore, the area of oriented diamond nucleation on a 4" Si wafer was investigated. Terminating the pretreatment at the threshold of the bias current rise leads to oriented nucleation of diamond. With the present homogeneity of the filament-substrate distance we are able to extend the area of oriented diamonds up to 50 cm(2). (C) 2002 Elsevier Science B.V. All rights reserved.