The Effects of HCl Added to Chemical Vapor Deposition Source Gases for Producing a SiC X-Ray Mask Membrane

Abstract

The effects of adding HCl to the chemical vapor deposition source gases on the stress, optical transparency, and surface roughness of a SiC X-ray mask membrane were examined. It was found that the stress dependence on the source gas carbon-to-silicon ratio was changed by adding HCl, and that a SiC membrane with low stress and high optical transparency is obtainable by adjusting these parameters. The surface roughness was about 15 nm from peak to valley under a good condition. The X-ray diffraction results of the SiC membranes showed that the peak sharpness, which indicates the crystal qualities such as densities of various intrinsic defects and the size of each crystal grain, is related to the optical transparency, and that the crystal orientation parameter is related to the surface roughness.