An improved method for large-area oriented nucleation of diamond during bias process via hot-filament chemical vapor deposition

Abstract

A hollow cathode technique has been applied as a new bias-enhanced nucleation (BEN) process prior to diamond growth in hot-filament chemical vapor deposition (HF-CVD). A large-area plasma is produced above a silicon substrate by glow discharge during the new BEN process from the beginning of the diacharge. A uniform nucleation over the substrate surface can be obtained even under the condition of lower bias voltage. The plasma sheath plays an important role for diamond nucleation. Diamond films are deposited by conventional HF-CVD after the new BEN pretreatment. Nomarski micrography has revealed that the uniformity of as-grown film pretreated by this method is improved. Scanning electron microscopy 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.