Thermal stability and etching characteristics of electron beam deposited SiO and SiO2

We have studied the thermal stability and etching characteristics of electron beam deposited SiO and SiO2. Scanning electron microscopy, Auger, atomic form microscopy, and ellipsometry were used to analyze the surface morphology, roughness, and film composition as a function of annealing temperatures. Both SiO and SiO2 showed excellent thermal stability up to 400 degrees C anneal and refractive index, surface morphology and pattern edge definition of both films barely changed. For higher temperature anneal, based on Auger analysis results, the ratio of Si/O of SiO2 film stayed constant after 700 degrees C. However, the Si/O ratio of SiO film increased from 0,54 to 0.62 due to oxygen outdiffusion. Dry etch characteristics of SiO and SiO2 were investigated using SF6 and NF3 discharges in a Plasma Therm inductively coupled plasma system. Wet etches were performed using buffered HF and HF/H2O solutions. Dry etch rates of SiO2 were comparable with that of conventional plasma enhanced chemical vapor deposition SiO2. SiO2 etched faster than SiO under all etch conditions. (C) 2000 American Vacuum. Society. [S0734-211X(00)05301-4].