The influence of low-temperature Ge seed layer on growth of high-quality Ge epilayer on Si(1 0 0) by ultrahigh vacuum chemical vapor deposition

High-quality Ge epilayer on Si(1 0 0) substrate with an inserted low-temperature Ge seed layer and a thin Si0.77Ge0.23 layer was grown by ultrahigh vacuum chemical vapor deposition. The epitaxial Ge layer with surface root-mean-square roughness of 0.7 nm and threading dislocation density of 5×105 cm−2 was obtained. The influence of low temperature Ge seed layer on the quality of Ge epilayer was investigated. We demonstrated that the relatively higher temperature (350 °C) for the growth of Ge seed layer significantly improved the crystal quality and the Hall hole mobility of the Ge epilayer.