Correlation between the sign of strain and the surface morphology and defect structure of InAlAs grown on vicinal (111)BInP

The MBE growth of InAlAs layers on vicinal (111)BInP substrates, misoriente d by 1 degrees toward [(2) over bar 11], has been investigated. Scanning el ectron microscopy and atomic force microscopy revealed a dependence of InAl As surface morphology on the layer's strain type: a strong trend to excessi ve surface step bunching characterized the compressively strained layers wh ile much more regular surfaces, often with depressions, were observed on te nsilly strained layers. However, high resolution ii-ray diffraction suggest ed generally, a better crystalline structure for compressive layers and thi s was verified by transmission electron microscopy since twins and other de fects appear to nucleate easily on tensile layers. Our results indicate the significant influence of the sign of strain in the strain relaxation-defec t nucleation and adatom surface diffusion processes. (C) 1998 Elsevier Scie nce S.A. All rights reserved.