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Title: Structural properties of relaxed thin film germanium layers grown by low temperature RF-PECVD epitaxy on Si and Ge (100) substrates

We report on unusual low temperature (175 °C) heteroepitaxial growth of germanium thin films using a standard radio-frequency plasma process. Spectroscopic ellipsometry and transmission electron microscopy (TEM) reveal a perfect crystalline quality of epitaxial germanium layers on (100) c-Ge wafers. In addition direct germanium crystal growth is achieved on (100) c-Si, despite 4.2% lattice mismatch. Defects rising from Ge/Si interface are mostly located within the first tens of nanometers, and threading dislocation density (TDD) values as low as 10{sup 6} cm{sup −2} are obtained. Misfit stress is released fast: residual strain of −0.4% is calculated from Moiré pattern analysis. Moreover we demonstrate a striking feature of low temperature plasma epitaxy, namely the fact that crystalline quality improves with thickness without epitaxy breakdown, as shown by TEM and depth profiling of surface TDD.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ; ; ;  [1] ;  [4]
  1. LPICM-CNRS, Ecole Polytechnique, 91128, Palaiseau (France)
  2. (France)
  3. (Italy)
  4. CNR-IMM, strada VIII n°5, zona industriale, 95121, Catania (Italy)
Publication Date:
OSTI Identifier:
22299864
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 7; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHEMICAL VAPOR DEPOSITION; DENSITY; DISLOCATIONS; ELLIPSOMETRY; EPITAXY; GERMANIUM; INTERFACES; PLASMA; STRAINS; STRESSES; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY