Research On Short-circuit Characteristics Fof SiC MOSFET

Compared with traditional silicon(Si)materials,silicon carbide(SiC)has many excellent properties,such as wide bandgap,high intrinsic temperature,high breakdown field and high thermal conductivity.The development of SiC material manufacturing technology creates conditions for the industrialization of new semiconductor devices based on SiC material.Silicon carbide(SiC)MOSFET is one of the new wide bandgap(WBG)power semiconductor devices,compared with Si MOSFET or Si IGBT,SiC MOSFET has lower on-resistance,stronger resistance to high temperature and faster switching speed.However,due to its smaller chip area,higher current density and thinner gate oxide,the short-circuit reliability of SiC MOSFETs needs to be verified.Any semiconductor device must pass strict reliability tests before put into the large-scale operation,short-circuit robustness test is essential.The short-circuit test can help to obtain relevant data of devices' short-circuit capability,analyze the short-circuit characteristics under different operating conditions and provide key information for the design of driver circuit,fault protection circuit and application circuit.The short-circuit characteristics of SiC MOSFET is studied in this thesis and the work relies on the National Key Research and Development Project "High Voltage High Power SiC Materials,Devices and Its Application in Power Electronic Transformer" of Ministry of Science and Technology.Firstly.the basic short-circuit types of power semiconductor devices are introduced and a corresponding short-circuit test platform is designed based on the occurrence conditions,characteristics and driving requirements of each short-circuit types in this thesis.Then,the experimental tests of the first and second types of short-circuit of SiC MOSFET are carried out based on the LTspice short-circuit simulation of SiC MOSFET.The influence of different parameters on the short-circuit characteristics of the first and second types are studied.The short-circuit failure tests of SiC MOSFET are also conducted,by which the short-circuit failure modes and short-circuit capability are obtained and analysed.The results of this research help to get the basic short-circuit characteristics of SiC MOSFET and provide key parameters for design of its driver and protection circuit.