Abnormal Impurity Distributions in High-Purity Epitaxial Silicon Layers

High-resistivity epitaxial ayers with carrier concentrations of the order of 1012-1013 atoms/cm 8 have been reproducibly grown on heavily Sb- or B-doped substrates. The epitaxial ayers so obtained have been used to observe the behavior of impurities during epitaxial growth. When the epitaxial growth is performed using an as-grown surface as the substrate, an abnormal peak in the impurity distribution appears near the substrate-epitaxial interface. The resistivity of the layers is found to increase by heat-treatment in a hydrogen atmosphere, which is probably due to the effect of defects. Similar epitaxial layers have also been obtained by pyrolysis of Sill4 and the carrier concentra-tions of these layers are found to have a considerably larger temperature dependence than the layers from SiCI~. It has been established that the carrier concentration of the epitaxial ayer is a function of the contamination from the substrate and the experimental apparatus. However, from the re-sults of the present investigation, it appears that the impurities adsorbed o