AL-GA MONOLAYER LATERAL GROWTH OBSERVED INSITU BY SCANNING ELECTRON-MICROSCOPY

The characteristics of an Al-Ga top layer on AlGaAs and GaAs surfaces during alternate supply molecular beam epitaxy (MBE) growth are studied by in situ observation using a MBE scanning electron microscope (SEM) hybrid system. It is found that an Al-Ga alloy top layer has a pseudo-self-limiting nature. It is also found that the migration distance of Al-Ga atoms on an Al-Ga alloy top layer is as large as 10-mu-m. By utilizing these characteristics, a mu-m-scale Al-Ga monolayer lateral growth process is realized, and the lateral growth rate, about 1-mu-m/s, is observed. Comparison of this growth with migration-enhanced epitaxy is discussed.