Suppression of Three-Dimensional Pit Formation of InAs on GaSb(001) by Two-Step MBE

InAs heteroepitaxial growth on GaSb by molecular beam epitaxy was investigated. Pits tend to easily form on InAs surface at low temperature growth; however, they are suppressed by adding traces of Sb owing to its surfactant effect. We further investigated a method to eliminate pits without Sb irradiation for device applications. We found that as the growth temperature increased, size of the pits reduced. The pits were completely suppressed by applying a two-step low- and high-temperature InAs growth. Sb carryover from the underlying InAs was negligible and never contributed to the elimination of pits. Two factors seemed to be essential: (1) initial planar growth of InAs on GaSb favored at low temperature and (2) preference for a (001) plane rather than high-index crystal planes at high temperature.