(111)A基板上のInAs/GaAsヘテロエピタキシ(<小特集>ヘテロエピタキシーと界面構造制御)

概要

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A comparison has been made of the surface morphology of thin InAs films grown on GaAs (001) and (111)A substrates by molecular beam epitaxy using in-situ reflection high energy electron diffraction and ex-situ atomic force microscopy. InAs growth on (001) surface proceeds via the Stranski-Krastanov mechanism, with three dimensional island formation beginning at the critical layer thickness. In contrast, InAs on (111)A surface showed a two-dimensional growth mode, independent of detailed growth conditions. The strain relaxation in the InAs/GaAs (111) A heteroepitaxy has been studied on an atomic scale by scanning tunneling microscopy. The coalescence of small islands and the formation of a dislocation network were identified. The atomic displacement around the threading segments and the strain fields induced by the misfit dislocations were both identified . We also compare the electrical properties of InAs thin films embedded in GaAs layers grown on (111)A and (001) substrates. A major improvement in Hall mobility through the use of (111)A substrates was confirmed. Self-consistent calculation assuming interface Fermi level pinning produces resulted in a good agreement with the experimental results. The use of a novel index substrate like GaAs (111)A plane provides the opportunity of fabricating a wide range of high quality heterostructures.
日本結晶成長学会の論文
1998-03-30