Spatial Inhomogeneities in Rapidly Thermal-Processed GaAs Wafer

Abstract

ABSTRACTThe spatial distributions of the midgap defect (EL2) concentration in semi-insulating liquid-encapsulated Czochralski GaAs wafers have been characterized by the contactless measurement of the optically injected carrier using reflectance microwave probe (RMP) method. The four-fold symmetrical distribution of EL2 in the (100) plane is observed in the 2 inch diameter GaAs wafer after rapid thermal processing(RTP). The deep level distribution in the RTP wafer corresponds to the crystallographic slip generation pattern obtained from x-ray topography. The correlation between the pattern of the redistributed EL2 concentration and the slip generation in the RTP wafer is suggested that the EL2 is produced by the large thermal stress during RTP. Furthermore, the distributions of EL2 center measured by the RMP method are compared with the dislocation patterns in undoped and In-doped GaAs wafers.