Silicon Surface Morphology after Annealing in Ambient Hydrogen Containing a Trace Amount of Hydrogen Halide Gas

Abstract

The semiconductor silicon substrate surface morphology was studied after annealing in ambient hydrogen containing a trace amount (ppm level) of hydrogen chloride gas and hydrogen fluoride gas at atmospheric pressure. The silicon substrate surface became significantly rough after the annealing at substrate temperatures higher than 1100 °C. The surface had many randomly-shaped deep pits without any crystalline orientation. In contrast, the silicon surface was still specular after annealing at 1000 °C with the root mean square roughness of ca. 0.2 nm. Hydrogen chloride gas and hydrogen fluoride gas at very low concentrations are considered to be inactive toward the silicon surface at temperatures lower than 1000 °C.