Growth of GaAs on Preferentially Etched GaAs Surfaces by Migration-Enhanced Epitaxy

The migration mechanism of surface adatoms during migration-enhanced epitaxy is quite different from that expected in conventional molecular beam epitaxy. This difference is clearly demonstrated in the cross-sectional views of GaAs layers grown on preferentially etched, undercut-mesa stripes. Definite crystal facets of (110) appear in the layers grown by migration-enhanced epitaxy, in contrast to the (111)B facets in the layers grown by molecular beam epitaxy. The migration mechanisms of these two growth methods are discussed in order to interpret the differences in the facetting characteristics.