Measurement of nonuniform bowing in GaN/sapphire epi-wafers and subsequent stress analysis by using a theoretical model

Abstract

We present our approach to measure the profile of nonuniformly bent GaN epi-wafers grown on sapphire substrates. By using a laser displacement sensor, the position of the epi-wafer is accurately measured and mapped. From the measured profile data, analysis of stress distributions over the nonuniformly bent wafer is performed by using a theoretical model. We show the result of theoretical analysis of how the stress tensors distribute over a wafer. The estimated stress tensors are related with optical properties such as photoluminescence of the wafer. © 2011 SPIE.