The impact of the initial surface reconstruction on heteroepitaxial film growth and defect formation

Abstract

While it is well known that growth conditions such as temperature greatly affect defect incorporation in thin films, less is known about the direct effects of the surface reconstruction. In this work, we examine the effect of the initial surface reconstruction on defect incorporation in GaSb/GaAs(001) lattice mismatched films. The stress built up in GaSb films grown on As-terminated and Sb-terminated GaAs was monitored during film growth and shows that the total relaxation is similar in both films along the [110], but lower on the Sb-terminated surface along the . These differences can be understood by examining the ability for the two surface terminations to accommodate strain. The resulting films show that the density of 3D islands is lower for the Sb-terminated surfaces, and that lattice mismatch strain is further accommodated by a 5° tilt. In contrast, the As-terminated surface contains both stacking faults and misfit dislocations. These results demonstrate the possibility to engineer specific defects into films by controlling the starting surface of film growth.