Excess Carrier Lifetimes in a Bulk p-type SiC Wafer Measured by the Microwave Photoconductivity Decay Method

摘要

Abstract We carried out mapping of the excess carrier lifetime for a bulk p-type 4H-SiC wafer by the microwave photoconductivity decay (μ-PCD) method, and we compared the lifetime map with structural defect distribution. Several small regions with short lifetimes compared with surrounding parts are found, and they correspond to regions with high-density structural defects. Excess carrier decay curves for this wafer show a slow component, which originates from minority carrier traps. From temperature dependence of the excess carrier decay curve, we found decrease of the time constant of the slow component with increasing temperature. We compared the activation energy of the time constant with that obtained from the numerical simulation, and concluded that the energy level for the minority carrier trap would be 125 meV from the conduction band.