Sb irradiation effect on growth of GaAs thin film on Si (111) substrate

We studied the effect of Sb4 irradiation on the growth of GaAs thin films on Si (111) substrates. GaAs thin films were grown by molecular beam epitaxy (MBE) system with As2 as a source. Sb4 was also supplied during the GaAs growth. We evaluated surface roughness with an atomic force microscope and crystallinity with an X-ray diffraction system. When GaAs is grown without Sb4 irradiation, crystallinity can be improved by subjecting it to high temperatures, although the surface becomes very rough. In contrast, GaAs grown with Sb4 irradiation showed both good crystallinity and a very flat surface. As the growth temperature increased, both crystallinity and surface flatness were improved, probably due to the enhanced migration with two-dimensional growth modes. Furthermore, plan-view observation with a transmission electron microscope (TEM) showed that Sb4 irradiation was very effective for reducing stacking faults. ► Effect of Sb4 irradiation on the growth of GaAs on Si (111) was studied. ► GaAs was grown by MBE with As2 as a source. ► Sb4 was also supplied during the GaAs growth. ► GaAs grown with Sb4 showed good crystallinity and a very flat surface. ► Under Sb4 irradiation, the GaAs growth mode seemed to become a 2D growth mode.