Multi-technique characterisation of InAs-on-GaAs wafers with circular defect pattern

Abstract

The article presents the results of diameter mapping for circular-symmetric disturbance of homogeneity of epitaxially grown InAs (100) layers on GaAs substrates. The set of acceptors (beryllium) doped InAs epilayers was studied in order to evaluate the impact of Be doping on the 2-inch InAs-on-GaAs wafers quality. During the initial identification of size and shape of the circular pattern, non-destructive optical techniques were used, showing a 100% difference in average roughness between the wafer centre and its outer part. On the other hand, no volumetric (bulk) differences are detectable using Raman spectroscopy and high-resolution X-ray diffraction. The correlation between Be doping level and circular defect pattern surface area has been found.