Thermochemical process occurring in PLD-derived SiC films during vacuum annealing

Compositional change on the surface of PLD-derived SiC films during vacuum (10−3 Pa) annealing was investigated by using Fourier transform-infrared absorption (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements. The as-deposited film consisted of only a small amount of Si–C bonds, and was abundant in CC component. With an increase in annealing temperature from 800 to 950 °C, the amount of SiC bond increased, and the CC component decreased. The films were slightly oxidized by residual O2 at temperatures lower than 950 °C. When the temperature reached 1000 °C, the amount of SiC bond dropped sharply, accompanied by production of ∼72 at.% of SiSi bonds, which was surprisingly high. A model of SiC oxidation based on the loss of C atoms and the formation of SiSi bonds was adopted to explain the experimental results. The activation energy for SiC formation during vacuum annealing was 22.5±2.6 kcal/mol, as calculated from the FT-IR data.