Minority carrier lifetime measurement for N-type 4H-SiC by means of the microwave photoconductivity decay method

In order to understand the electrical property of N-type 4H-SiC better and evaluate its crystal quality, with laser technique and microwave photoconductivity measurement as a tool of the non-conductive and non-destructive characterization for semiconductors, the measurement principle was described and the experimental equipment was put forward. The dependence of the minority carrier lifetime on the excitation intensity was discussed. The results show that the changing of the laser pulse energy (i.e. the photon injection level) little affect the carrier lifetime of the specimen, its peak voltage is proportional to the excitation intensity. The method of carrier lifetime measurement is convenient and efficient and has a great significance for examination of the property of SiC material.