Direct evidence for self-annihilation of antiphase domains in GaAs/Si heterostructures

The nature and behavior of antiphase boundaries in GaAs/Si heterostructures using GaP, GaP/GaAsP, and GaAsP/GaAs strained-layer superlattices as intermediate layers have been studied by transmission electron microscopy. The antiphase domains are found to be very complicated three-dimensional polygons consisting of several subboundaries in different orientations. Self-annihilation of antiphase domains during crystal growth of GaAs on (001) 0.4° off or (001) 2° off Si substrates is directly observed for the first time through plan-view and cross-sectional observations. Based on these findings, a mechanism of annihilation of these domains is presented.