Effects of low-temperature Si buffer layer thickness on the growth of SiGe by molecular beam epitaxy
Journal
Journal of Applied Physics
Journal Volume
92
Journal Issue
11
Pages
6880-6885
Date Issued
2002
Author(s)
CHIEH-HSIUNG KUAN
Lee, S.W.
Chen, H.C.
Chen, L.J.
Peng, Y.H.
Kuan, C.H.
Cheng, H.H.
CHIEH-HSIUNG KUAN
Abstract
The thickness of a low-temperature silicon (LT-Si) buffer layer has been found to affect the growth of a SiGe overlayer significantly. 300-nm-thick Si0.7Ge0.3 films were grown on 50- to 300-nm-thick LT-Si buffer layers at 450 °C by solid-source molecular beam epitaxy. The threading dislocation density was found to decrease with the thickness of the LT-Si buffer in the thickness range of 50–200 nm. The density remains at the same low level when the thickness was increased from 200 to 300 nm. A relatively dense misfit dislocation network was observed to form at the SiGe/Si interface in samples with the LT-Si buffer layer thickness exceeding 200 nm. It is suggested that the presence of more point defects in the thicker LT-Si buffer layer is more effective to block the propagation of threading dislocations.
Type
journal article