Sn-Guided Defect-Free GeSn Lateral Growth on Si by Molecular Beam Epitaxy
journal contributionposted on 06.08.2015, 00:00 by Dalin Zhang, Zhi Liu, Dongliang Zhang, Xu Zhang, Junying Zhang, Jun Zheng, Yuhua Zuo, Chunlai Xue, Chuanbo Li, Shunri Oda, Buwen Cheng, Qiming Wang
A new strategy to grow defect-free GeSn alloy matrixes (GSMs) on Si(111) substrates with the assistance of Sn is discussed. It is found that the compressive strain induced by a large lattice mismatch (>4.2%) in the GeSn–Si system is relaxed by introducing (111)-parallel planar dislocations at the GeSn/Si interface, while the upper part of the GSMs remained defect-free. The incorporation of Sn into Ge is investigated by both Raman spectra and selected area electron diffraction patterns. The Sn concentration varies approximately linearly against the epitaxial temperature and reaches 5.26% at 300 °C, which is considerably larger than the equilibrium value. The growth mechanism and morphological features are investigated systematically. The proposed method provides an easy technique to grow high-quality GeSn materials for Si-based photonics and microelectronics applications.