Structural Study of Amorphous SiGe Alloy Films Using Extended X-Ray Absorption Fine Structure

Extended X-ray absorption fine structure (EXAFS) measurements were made on a-SiGe and a-SiGe:H prepared by rf-diode sputtering and glow discharge decomposition along with crystal line SiGe, c-SiGe, prepared by annealing the amorphous samples. The Fourier transforms of Ge K-edge EXAFS of c-SiGe prepared by annealing sputtered a-SiGe, a-SiGe:H and glow discharge a-SiGe:H resemble each other inshape. The Fourier transforms of Ge K-edge EXAFS of sputtered and glow discharge a-SiGe:H films are also quite similar to each other. On investigating EXAFS and X-ray absorption near edge structure, XANES, of c-SiGe, a-SiGe and a-SiGe:H, it is found that the disorder of the network structure in the SiGe alloy system increases in the order of c-SiGe, a-SiGe and a-SiGe:H.