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

• Published in: Journal of materials science & technology Vol. 28; no. 2; pp. 132 - 136
• Main Authors: Zhou, Wei, Li, Xiang, Xia, Sujing, Yang, Jie, Tang, Wu, Lau, K.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2012
• Subjects: Arrays; Atomic force microscopy; Density; Dislocations; GaAs衬底; Gallium arsenide; Gallium arsenides; Hole mobility; Interfacial misfit dislocations; Metalorganic chemical vapour deposition; Misfit dislocation; MOCVD生长; Molecular beam epitaxy; Roughness; 化学气相沉积法; 半绝缘砷化镓; 国际货币基金组织; 失配位错; 锑化镓; 阵列; Interfacial misfit dislocations; Misfit dislocation; Hole mobility; Metalorganic chemical vapour deposition
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/S1005-0302(12)60033-4

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/Ill） ratio. An optimum V/Ill ratio of 1.4 was determined in our growth conditions. Using transmission electron microscopy （TEM）, we found that there was an interracial 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 10μm×10μm scan from atomic force microscopy （AFM） result. The best hole density and mobility of 300 nm GaSb epilayer are 5.27xi06 cm-3（1.20×106） and 553 cm2-V-l.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.