Comparison Of Defects In GaAs Epilayers Grown On Si by MBE and OMCVD: As-Grown And After Rapid Thermal Annealing (RTA)

Abstract

GaAs layers grown on silicon by molecular beam epitaxy (MBE) and organometallic chemical vapor deposition (OMCVD) have been characterized using transmission electron microscopy (cross-section and plan view) and high-resolution electron microscopy. The nature of defects in the GaAs layers has been analyzed as a function of growth technique. The type, density and distribution of dislocations was virtually the same in both samples, however the MBE sample also had a high density of planar defects (twins and microtwins). The effect of rapid thermal annealing (RTA) on the defect density and nature has also been studied for both growth techniques. RTA leads to a decrease in the dislocation density in the near surface region and eliminates virtually all the twins and microtwins in the MBE sample.