Surface roughness of strained In 0.1Ga 0.9As films grown on GaAs substrates by molecular beam epitaxy

Abstract

InGaAs layers of varying epilayer thickness grown at different temperatures on GaAs substrates by molecular beam epitaxy are analyzed by atomic force microscopy. This relatively new technique allows high resolution imaging and analysis of surface morphology and roughness of semiconducting materials. The surface roughness and morphology of InGaAs grown at substrate temperatures ranging from 450°C to 530°C are analyzed as the epilayer thickness is increased from 100 Å to 800 Å. Over an area of 100 microm 2, an abrupt increase in the surface roughness probably indicates an acceleration of surface roughening mechanisms related to the process of strain relaxation. At higher InGaAs thicknesses, surface corrugations were observed. The results indicate that thicker pseudomorphic InGaAs films on GaAs substrates can be grown at lower temperatures.