Migration-enhanced epitaxy of GaAs and AlGaAs

The principle and characteristics of migration-enhanced epitaxy are reviewed. Migration of surface adatoms along the surface is very important for growing high quality layers and atomically flat heterojunctions. In the migration-enhanced epitaxy of GaAs and AlGaAs, migration of surface Ga and Al atoms is enhanced even at low substrate temperatures by evaporating them onto a clean GaAs surface under an As-free or low As pressure atmosphere. Thus, high quality GaAs and AlGaAs layers and flat heterojunctions have been grown by this method. Migration-enhanced epitaxy has also proved useful in investigating atomic processes during epitaxial growth.