PLASMA-ASSISTED CHEMICAL VAPOR-DEPOSITION AND CHARACTERIZATION OF HIGH-QUALITY SILICON-OXIDE FILMS

High quality low temperature plasma silicon oxide films were deposited in a single-wafer chemical vapor deposition (CVD) system using very dilute silane (in helium) and nitrous oxide as reactant gases. Variations in the film's deposition rate, thickness uniformity, and refractive index were studied as a function of process parameters. The films were also characterized by Fourier transform IR spectroscopy, X-ray photoelectron spectroscopy, electron spin resonance, nuclear reaction analysis for hydrogen, metal-oxide-semiconductor electrical measurement, wet (10:1 buffered HF) and reactive ion etching with CF4 and CHF3 + CO2 gases. Overall, the qualities of plasma-deposited silicon oxide films are comparable with those of high temperature (700-800-degrees-C) thermal CVD oxide films and approaching those of thermally grown oxide. However, because of the effect of the initial transient state phenomenon during plasma deposition processing, thin gate quality plasma-enhanced CVD oxide films with low interface states can only be obtained on deposition upon thin oxide surfaces.