Influence of Sn incorporation and growth temperature on crystallinity of Ge1-xSnx layers heteroepitaxially grown on Ge(110) substrates

The influence of Sn incorporation and growth temperature on the crystalline structure of Ge and Ge1-xSnx layers epitaxially grown on Ge(110) substrates has been investigated. The homoepitaxial Ge layer on Ge(110) exhibits the defective structure which includes many stacking faults. In contrast, the incorporation of Sn effectively improves on the crystallinity of an epitaxial Ge layer on a Ge(110) substrate. We achieved a pseudomorphic Ge0.952Sn0.048 layer growth on Ge(110) without the introduction of stacking faults and Sn precipitation by lowering the growth temperature to 150 degrees C. This improvement is thought to be due to the reduction of the anisotropy in the surface reconstruction structure of Ge(110) with the Sn adsorption. We also found that the strain in the Ge1-xSnx layer with a Sn content of 7.8% on Ge(110) is relaxed preferentially along the [(1) over bar 10] direction during the growth. (C) 2013 Elsevier B.V. All rights reserved.