Study On Temperature-dependence Of Static And Dynamic Characteristics Of Silicon Carbide MOSFET

Even though the technologies with silicon(Si)-based power devices are mature,inherent material restrictions limit their performance in high voltage,high power,high switching frequency and high temperature applications.Thus wide bandgap(WBG)power devices like silicon carbide(SiC)are becoming more attractive and SiC have the potential to replace Si in the near future within certain application areas.SiC has many superior properties compared to Si,like higher critical electrical field,relatively high electron mobility,and higher thermal conductivity.SiC has the potential to be operated at much higher temperature(>300?)and its temperature sensitivity is much lower than Si device.With the wide application of power electronic devices in harsh environment,the operation ability of SiC MOSFET in high temperature environment has been paid more and more attention.The Temperature 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.In this paper,theoretical research and experimental verification are combined to analyze the Temperature dependence characteristics of the static and dynamic characteristics of SiC MOSFETs from room temperature to 200?.Then the high temperature gate bias experiment of SiC MOSFET is designed to study the stability of the static characteristic parameters after a long time of high temperature gate bias,and to evaluate the reliability of gate oxide layer.The results show that although SiC MOSFETs have very sensitive temperature characteristics,they still have good electrical properties at high temperatures of 200?,and devices have the extremely low leakage current,good ability of blocking and lower conduction resistance compared with the Si.The total switching loss of SiC MOSFET is not sensitive to temperature.In addition,after a long time of high temperature gate bias,except for the threshold voltage forward drift,other static characteristic parameters have excellent stability.