AN IMPROVED METHOD FOR LARGE-AREA ORIENTED NUCLEATION OF DIAMOND DURING BIAS PROCESS VIA HOT-FILAMENT CHEMICAL-VAPOR-DEPOSITION

A hollow cathode technique has been applied as a new bias-enhanced nuc leation (BEN) process prior to diamond growth in hot-filament chemical vapor deposition (HF-CVD). A large-area plasma is produced above a si licon substrate by glow discharge during the new BEN process from the beginning of the diacharge. A uniform nucleation over the substrate su rface can be obtained even under the condition of lower bias voltage. The plasma sheath plays an important role for diamond nucleation. Diam ond films are deposited by conventional HF-CVD after the new BEN pretr eatment. Nomarski micrography has revealed that the uniformity of as-g rown film pretreated by this method is improved. Scanning electron mic roscopy results have shown that the area of the oriented nucleation is enhanced considerably. The micro-Raman spectrum of as-grown film has shown a strong crystalline diamond peak at 1333 cm(-1). (C) 1997 Elsev ier Science S.A.