TEM structure investigations of low-temperature MBE grown InAlAs layers on InP substrate

摘要

The real crystal structure of In(sub 0.52)Al(sub 0.48)As layers grown on InP substrate as a function of the growth temperature (between 150(degree)C and 450(degree)C) was investigated. Following structural/electrical analysis were applied to the samples: transmission electron microscopy (TEM) , x-ray diffraction and particle induced x-ray emission (PIXE). In the temperature range between 200(degree)C and 450(degree)C good epitaxial growth of InAlAs layers can be achieved with a low density of dislocations and stacking faults. Ordering of group-III elements on (111) planes was observed for these layers. Structure models of such ordered domains are discussed. At growth temperatures below 300(degree)C additional As ((approx)2%) is incorporated in the lattice. Growth at temperatures below 200(degree)C leads to the formation of pyramidal defects with As grains in their cores. As-grown as well as annealed InAlAs layers show a nearly constant, high electrical resistance (10(sup 6)--10(sup 7)(Omega)cm) in the whole temperature range.