1989 Fiscal Year Final Research Report Summary
Dynamical Observations of MBE Grown Thin Films by Ultrahigh Vacuum In-situ Electron Microscopy
| Project/Area Number |
63550543
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | Waseda University |
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Principal Investigator |
OSAKA Toshiaki Waseda University, School of Science and Engineering, 理工学部, 教授 (50112991)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Ultrahigh Vacuum In-situ Electron Microscopy / MBE Growth / Heteroepitaxial Growth / Surface Reconstructed Structure / Lattice Fitting |
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| Research Abstract |
We have studied homoepitaxial growth processes and surface reconstruction of InSb{111} using ultrahigh vacuum in-situ transmission electron microscopy (UHV in-situ TEM) combined with UHV in-situ reflection electron microscopy (REM). From the TEN observations for InSb(111)B and the REM observations for both reconstructed InSb(111)A and reconstructed InSb(111)B surfaces, the following results were obtained:
(1) When the incident fluxes(1:1) of Sb_4 and In_1 are impinged onto the InSb(111)B substrate, the respective molecules form homoepitaxially grown InSb films, leaving an excess molecule Sb^* which does not contribute to the formation of the InSb films. As a result, there exists a critical temperature(T_h) for the condensation of Sb^* molecules. Below T_h, the surface concentration of Sb^*(n_<sb*>) becomes higher than a critical concentration for the condensation (n^c_), SO that two phases (InSb+Sb) grow in a polycrystalline state. However, above T_h as n_<sb*> becomes lower than n^c_, InSb films grow with the 2x2 reconstructed surfaces. This critical temperature is defined as a homoepitaxial temperature. Quantitative interpretations of T_h were discussed.
(2) By using UHV in-situ REM, changes in the surface reconstructions of InSb(111)B and InSb(111) A were for the first time observed: for (111)B from the 2x2-Sb to the 3xl-In structure at 420ﾟC and for (111)A from the 2x6-Sb to the 2x2-In structure at 300ﾟC. The particles formed on the InSb(111)B and (111)A surface at 420ﾟC and 450ﾟC respectively, intensely affected the structural transformation in the InSb(111) surface. Also, the particle formed on the InSb(111)B-3xl-In substrate played an important role in spreading the (111)B-3x3-In region which appeared during the homoepitaxial growth of InSb(111)B.
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