Elastically strained InGaAsP films grown by LPE and conception of stress-induced supercooling

Abstract

The pseudomorphic InGaAsP films with elastic strains up to 1% are grown on GaAs substrates of (111)B orientation by liquid phase epitaxy (LPE). The evolution of morphology with an increase of elastic strain in the films is analysed. A new mechanism of elastic strain relaxation during InGaAsP film growth is discovered. It consists in the appearance of unstrained islands in the InGaAsP strained film and their lateral spreading till they come together. The fundamental limit of elastic strains to about 1% in the InGaAsP films grown by LPE is connected with the stress-induced supercooling that appears and increases with the stresses in the film and, at last, compensates the initial supercooling of the liquid. The time required for the growth of the elastically strained films does not exceed a few seconds. At longer duration of the growth unstrained parts of the film spread laterally and cover the whole surface of the substrate with a highly mismatched unstrained layer of poor crystal quality. [Russian Text Ignored].