InGaAs/GaAs应变异质结中的反常离子沟道效应

用5.8,3.0和1.2MeV的Li离子对用MBE制备的In_0.25Ga_0.75As/GaAs(100)异质结在(100)面中沿100]及110]轴进行角扫描。5.8MeV时,110]轴外延层与衬底沟道对准角的差值为0.90°,从而计算出其晶格失配度为1.62％。3.0MeV时,背散射角扫描谱出现了严重的不对称现象。若离子以1.2MeV入射,沟道对准角的差值及衬底沟道的半角宽大大地偏离实际值。本文对以上反常现象从物理机理上进行了分析,给出了这些反常离子沟道 关键词：

ANOMALOUS ION CHANNELING EFFECTS IN InGaAs/GaAs STRAINED HETEROJUNCTIONS

The 5.8, 3.0 and 1.2 MeV Li ions were used to study the MBEIn_0.25Ga_0.75As/GaAs (100) sample. Ion channeling angular scans about100] and 110] axes were carried out in the (100) plane.It is found that in the case of 5.8 MeV, the critical angle of the epilayer is almost the same as that of the substrate and the angle misalignment between them is 0.90° for axis 110] , corresponding to the misfit of sample being 1.62%, in good agreement with theoretical calculation. In the 3.0 MeV case, serious asymmetry have been observed in RBS/Channeling angular scan; in the 1.2 MeV case, the angular misalignment is reduced to 0.50° and the critical channeling angle of substrate is increased significantly. We have studied and discussed the physical mechanism of these anomalous phenomena in detail, and present a good interpretation of the experimental results.