Estimation of Epitaxial Temperature Using X-Ray Diffraction for Si Films Grown on (100) Si by Molecular Beam Epitaxy

Abstract

Silicon films were grown at low temperatures (≤350°C) by solid-source molecular beam epitaxy (MBE). The films were characterized using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and atomic force microscopy (AFM). A single-crystalline silicon homoepitaxial layer was obtained at the substrate temperature of 350°C. The thickness of the layer was about 0.4 µm and the growth rate was about 1 Å/s. The crystallinity of the silicon films was discussed by comparing the results of RHEED and XRD measurements. The method for estimating the epitaxial temperature using X-ray diffraction is discussed. At a temperature between 200°C and 250°C, the silicon film changed from a small-grain amorphouslike polycrystalline film to a larger-grain mosaiclike polycrystalline film. Single-crystalline silicon was homoepitaxially grown on (100) Si at a critical temperature which existed between 300°C and 350°C.