Effect of Si-Ge buffer layer for low-temperature Si epitaxial growth on Si substrate by rf plasma chemical vapor deposition

Abstract

Silicon epitaxial growth on the Si-Ge buffer layer at a low substrate temperature by the rf plasma chemical vapor deposition using SiH4 and GeH4 has been investigated. The electron Hall mobility of the homoepitaxial layer grown at 750 °C with a growth rate of 14 Å/sec coincides with that of bulk Si, but for a high growth rate of 33 Å/sec, the mobility was limited to within half the value of bulk Si. However, a small amount of Ge introduced in an initial stage of growth to form the Si-Ge buffer layer improved the crystalline quality of the ensuing Si epitaxial layer with a high growth rate. The electron Hall mobility of the Si layer grown on the Si-Ge buffer layer was a similar value of bulk Si in a low carrier concentration of 6×1015 cm−3. The crystalline quality of the grown Si layers was examined by the combination of Rutherford backscattering spectrometry and transmission electron microscopy.