Abstract
Excess carrier lifetime in bulk 2-in. SiC wafers was measured by microwave photoconductivity decay (µ-PCD). The mapping technique was used to obtain the lifetime distribution in the entire wafer. We observed the birefringence image and X-ray topograph of the wafers in order to determine the structural defect distribution, and the net donor concentration distribution was also observed by capacitance–voltage measurements. By comparison of lifetime maps with the structural defect distribution, it was found that relatively long lifetime regions correspond to regions with high-density structural defects. The net donor concentration did not show a clear influence on the carrier lifetimes. We confirmed that surface recombination has a negligible effect on the carrier lifetimes, and therefore the lifetimes obtained from mapping measurements are mainly dominated by carrier recombination behavior in the bulk of the wafers.