EXAFS study on poly-Si1−XGeX films prepared by reactive thermal CVD method

Extended X-ray absorption fine structure analyses were carried out on Si1−XGeX films of different thicknesses, prepared by the reactive thermal chemical vapor deposition (CVD) method. From a Rutherford backscattering measurement, the Ge fraction was found to be high near the substrate interface. The Ge coordination ratio, Ge–Ge bond length and Ge–Si bond length decreased with increasing film thickness. The Ge fraction dependences of these parameters were found to be different from the results of previous studies on Si1−XGeX films prepared by molecular beam epitaxy. Our results are considered to be caused by the local structure formation around the Ge atoms during the reactive thermal CVD process.