Sputtering effects in hexagonal silicon carbide

Abstract

Sputtering yields of α-SiC crystals in the energy range of argon ions from 1 to 2.5 keV as a function of substrate temperature were determined. For a normal incident beam the sputtering yield was in the range 0.45 – 0.71 for acceleration voltages of 1–2.6 keV. The temperature dependence of the sputtering yield was determined at 2 keV in the temperature range 20–1000 °C. A drop in sputtering yield was observed between 400 °C and 700 °C. Auger electron spectroscopy studies and computer simulation of Ar + sputtering as a function of the ion energy at room temperature showed changes in composition under argon sputtering, which were due to preferential sputtering of silicon. At room temperature sputtering led to the formation of a thin amorphized layer on the surface, observed by reflection high energy electron diffraction. At a substrate temperature of 200 °C a partial phase transition of the type GH → 3C was obtained, whereas at 400 °C a partial transition of the type 6H → 15R occurred. At higher substrate temperatures no changes in the polytype structure were observed. However, increasing temperatures led to a decrease and at higher temperatures to elimination of the amorphized fraction at the silicon carbide surface.