FORMATION OF THE PRECURSOR FOR DIAMOND GROWTH BY IN-SITU DIRECT-CURRENT GLOW-DISCHARGE PRETREATMENT

A direct current (dc) glow discharge-surface interaction process for i n situ substrate surface pretreatment, for the promotion of diamond gr owth on mirror polished Si(100) is reported. A key step of the pretrea tment is a generation of a stable de-glow discharge between a grounded substrate and a positively biased electrode using a CH4/H-2 gas mixtu re. During this stage, no additional gas phase activation by a hot fil ament is carried out. For subsequent diamond deposition, the de-glow d ischarge is switched off and the standard hot filament CVD growth cond itions are applied. The nature of the deposits formed by the de-glow d ischarge process and after standard diamond deposition conditions, are investigated by Raman spectroscopy and high resolution scanning elect ron microscopy. It is found that the properties of the films, deposite d following the de-glow discharge pretreatment, strongly depend on the pretreatment conditions: methane concentration, substrate temperature , and pretreatment time. It is suggested that the nature of the diamon d precursor formed during the de-glow discharge pretreatment is simila r to that one observed after bias enhanced nucleation process. (C) 199 8 American Institute of Physics.