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Title: Thin SiGe virtual substrates for Ge heterostructures integration on silicon

The possibility to reduce the thickness of the SiGe virtual substrate, required for the integration of Ge heterostructures on Si, without heavily affecting the crystal quality is becoming fundamental in several applications. In this work, we present 1 μm thick Si{sub 1−x}Ge{sub x} buffers (with x > 0.7) having different designs which could be suitable for applications requiring a thin virtual substrate. The rationale is to reduce the lattice mismatch at the interface with the Si substrate by introducing composition steps and/or partial grading. The relatively low growth temperature (475 °C) makes this approach appealing for complementary metal-oxide-semiconductor integration. For all the investigated designs, a reduction of the threading dislocation density compared to constant composition Si{sub 1−x}Ge{sub x} layers was observed. The best buffer in terms of defects reduction was used as a virtual substrate for the deposition of a Ge/SiGe multiple quantum well structure. Room temperature optical absorption and photoluminescence analysis performed on nominally identical quantum wells grown on both a thick graded virtual substrate and the selected thin buffer demonstrates a comparable optical quality, confirming the effectiveness of the proposed approach.
Authors:
; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. L-NESS, Dipartimento di Fisica, Politecnico di Milano–Polo Territoriale di Como, Via Anzani 42, I-22100 Como (Italy)
  2. L-NESS, Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, via Cozzi 53, I-20126 Milano (Italy)
  3. Electron Microscopy ETH Zurich, ETH Zurich, Auguste-Piccard-Hof 1, CH-8093 Zurich (Switzerland)
  4. School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)
Publication Date:
OSTI Identifier:
22277944
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COMPARATIVE EVALUATIONS; CRYSTAL LATTICES; CRYSTALS; DISLOCATIONS; GERMANIUM; GERMANIUM SILICIDES; HETEROJUNCTIONS; INTERFACES; LAYERS; OXIDES; PHOTOLUMINESCENCE; QUANTUM WELLS; SEMICONDUCTOR MATERIALS; SILICON; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K