Growth of low-defect density Ino(0.25)Gao(0.75)As on GaAs by molecular beam epitaxy

The growth parameters of In(0.25)Ga(0.75)AS grown on GaAs by molecular beam epitaxy were investigated. Low substrate temperatures coupled with lower g rowth rates and low arsenic overpressures were explored and the correspondi ng threading dislocation densities were determined using transmission elect ron microscopy. Threading dislocation densities in layers much thicker than the critical thickness were found to be as low as 1x10(7) cm(-2) using opt imal growth conditions. In addition, the critical thickness of the ternary alloy was estimated. The evolution of the misfit dislocations and threading dislocations was also examined as a function of epilayer thickness. (C) 20 00 American Vacuum Society. [S0734-211X(00)13306-2].