J Mater Sci Technol ›› 2012, Vol. 28 ›› Issue (2): 132-136.

Special Issue: 光电材料专辑

• Thin Film and Coatings • Previous Articles     Next Articles

High Hole Mobility of GaSb Relaxed Epilayer Grown on GaAs Substrate by MOCVD through Interfacial Misfit Dislocations Array

Wei Zhou1), Xiang Li1), Sujing Xia1), Jie Yang1), Wu Tang1), K.M. Lau2)   

  1. 1) State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
    2) Department of Electronic and Computer Engineering, Hong Kong University of Science & Technology, Hong Kong, China
  • Received:2011-07-06 Revised:2011-07-30 Online:2012-02-28 Published:2012-02-24
  • Contact: Wei Zhou
  • Supported by:

    the National Natural Science Foundation of China (Grant Nos. 51071038 and 60576007) and Program for New Century Excellent Talents in University (NCET-09-0265) and the Sichuan Province Science Foundation for Youths (No. 2010JQ0002)

Abstract: The structural property of GaSb epilayers grown on semi-insulator GaAs (001) substrate by metalorganic chemical vapor deposition (MOCVD) using Triethylgallium (TEGa) and trimethylantimony (TMSb), was investigated by variation of the Sb:Ga (V/III) ratio. An optimum V/III ratio of 1.4 was determined in our growth conditions. Using transmission electron microscopy (TEM), we found that there was an interfacial misfit dislocations (IMF) growth mode in our experiment, in which the large misfit strain between epilayer and substrate is relaxed by periodic 90 deg. IMF array at the hetero-epitaxial interface. The rms roughness of a 300 nm-thick GaSb layer is only 2.7 nm in a 10 μm×10 μm scan from atomic force microscopy (AFM) result. The best hole density and mobility of 300 nm GaSb epilayer are 5.27×106 cm-3(1.20×106) and 553 cm2?V−1?s−1 (2340) at RT (77 K) from Hall measurement, respectively. These results indicate that the IMF growth mode can be used in MOCVD epitaxial technology similar to molecular beam epitaxy (MBE) technology to produce
the thinner GaSb layer with low density of dislocations and other defects on GaAs substrate for the application of devices.

Key words: Interfacial misfit dislocations, Metalorganic chemical vapour deposition, Misfit dislocation, Hole mobility