Investigations of surface defects of GaAs grown by molecular beam epitaxy

Results of investigations of the macroscopic defects on GaAs surfaces grown by molecular beam epitaxy (MBE) as a function of growth parameters are presented. Special attention was paid to the growth parameter dependence of the density of various types of the defects on As-stabilised surfaces. It has been observed that different types of dominant defects can be generated alternately on the surface by adjusting the growth temperature and growth rate. We conclude that the out-diffusion of atoms from Ga droplets is a process of great importance on the epi-layer and is responsible for the oval defect changes. We also conclude that the size of the Ga droplets together with the distance over which Ga atoms are able to migrate on the surface will determine the size and type of the dominant defects.