Planar lcub;110rcub; channeling measurements with 1ndash;2hyphen;MeV He+ions have been used to investigate strainedhyphen;layer structures of (100) GaAs/InxGa1minus;xAs/GaAs withx=0.07ndash;0.17. Beamhyphen;steering effects in the surface GaAs layer are observed to have a major influence on lcub;110rcub; planar angular scans carried out in the InxGa1minus;xAs layers resulting generally in a double or more complexhyphen;shaped angular dip. A simple computer simulation has been developed which determines the main features of the experimental angular scan data. Comparison of simulation and experimental data allows a reasonable determination of the kink angle thgr;Kbetween the lcub;110rcub; planes for the surface GaAs and underlying strained layer. Only in limiting cases is it possible to unequivocally determine thgr;Kfrom the experimental data alone. They are as follows: (i) when thgr;K=0; (ii) thgr;K2psgr;thinsp;pc(psgr;thinsp;pcis the critical angle for lcub;110rcub; planar channeling); and (iii) when the thicknesstof the top layer is thin (tLt;2d/psgr;thinsp;pc, wheredis the lcub;110rcub; interplanar spacing).
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