Influence of UTA-Si buffer layers on the growth of SiGe films analyzed by high resolution X-ray reciprocal space map

Abstract

The Si_1-xGe_x(x ≈ 0.25) films were grown on Si(001) substrate using ultra-thin amorphous Si(UTA-Si) buffer layers with thickness from 0∼30 Å by molecular beam epitaxy. The films were mainly characterized by a reciprocal space mapping performed on a high-resolution X-ray diffraction. It is shown that the smooth and relaxed SiGe alloy layers are obtained using UTA-Si buffer layers, without the necessity of using several microns of thick compositionally graded layers. The surface morphology and crystal quality of SiGe thin film can be improved obviously. The strains in both [001] and [110] directions were relaxed greatly depending on the thickness of UTA-Si. [DOI: 10.1380/ejssnt.2004.256]