'Molecular Beam Epitaxial Growth, Characterization, and Devices of Modulated Semiconductor Structures'.

Download or read book 'Molecular Beam Epitaxial Growth, Characterization, and Devices of Modulated Semiconductor Structures'. written by Wen I. Wang and published by . This book was released on 1990 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Substrate stabilized metastable single crystal germanium (1-x) stannide (x) films can be grown by molecular beam epitaxy (MBE). We have grown for the first time single crystal Ge (1-x) Sn(x) alloys on lattice matched gallium antimonide (with x=0.5) and indium phosphides substrates up to a thickness of 0.3 micrometer. Reflection high energy electron diffraction (RHEED) observations and x-ray measurements show that even at very small lattice mismatch, single crystal Ge(1-x)Sn(x) films cannot be grown thicker than 0.3 micrometer. Our x-ray results suggest that the critical thickness of alpha-Sn and Ge(1-x)Sn(x) single crystal films is mainly determined by a phase transition mechanism, and the dislocation generation equivalent critical thickness is an overestimate. Under practical MBE growth conditions, it is very difficult to grow thick films, due to the sensitivity of the critical thickness to composition fluctuations. We have shown that even under an exact lattice match between substrate and film, the critical film thickness is limited. Keywords: Metastable alloys; Single crystals; Germanium; Antimony; X-Ray diffraction; Aluminum; Gallium; Tin; Surface structure; Infrared detectors. (jg).