High Voltage Silicon Carbide Power Optimization Design And Experimental Research Of The Rectifier

Silicon carbide, a third generation semiconductor, becomes the best candidate to fabricate high power, high temperature and anti irradiation power device, for it enjoys a "four-high" characteristics, namely, high band gap, high electron saturation velocity, high thermal conductivity, high critical electric field.4H-SiC rectifiers such as SBD and JBS, have great potential in energy conversion applications. However,4H-SiC material gives full play to withstand high voltage, due to curve effect severely.Aimed at solving this problem, this paper achieves a new junction termination structure-multi-step etched JTE and the breakdown voltage of this device is1200V using this structure by means of reduce surface electric field theory(Resurf theory) and junction termination technology. The main contents of this paper are as follows:1. Structures of4H-SiC SBD and JBS power diodes are optimized. Relationships between electrical characteristics and device parameters such as the thickness and doping concentration of the drift region and the p+region, the length of the p+region are obtained.2. Junction termination structures of4H-SiC SBD and JBS power diodes are designed and optimized. Relationships between breakdown voltage and various junction termination structures (JTE, GR, FP etc.) are obtained.3. A new multi-step JTE junction termination structure which can reduce process difficulties is proposed in this paper. Experiments and tests are carried out with the result of breakdown voltage higher than1200V.