Research On SiC MOSFET Junction Temperature Measurement Method And Power Cycle Online Temperature Measurement Equipment

Silicon carbide(SiC)devices have the advantages of wide band gap,high breakdown electric field and good thermal conductivity,and are especially suitable for high temperature,high pressure and high power conditions.In recent years,with the rapid development of new energy vehicles,aerospace and artificial intelligence and other technical fields,the performance requirements for semiconductor devices in the industry have also increased,and SiC-based power devices have gradually been widely used.With the development of power electronics technology,while putting forward higher requirements for device performance,its reliability requirements are also increasing.According to the Arrhennis model,when the junction temperature of a semiconductor device rises by 10°C,its life is about half reduced.Therefore,the junction temperature is the key to the reliability of the semiconductor device.Due to the many defects in the gate oxide growth of SiC material,its electrical parameters are not repeatable before and after the gate switch.As a result,the existing thermal resistance and junction temperature detection equipment(such as PHASE11 or T3,etc.)cannot be used for SiC MOSFET(silicon carbide metal).Oxide field effect transistors,SiC Metal Oxide Semiconductor Field Effect Transistor)devices and modules are accurately measured.This paper takes SiC MOSFET as the research object,mainly based on the electrical method to study the junction temperature measurement method of SiC MOSFET's discrete devices and modules,and builds an on-line temperature measurement experiment platform for SiC MOSFET power cycle.This article mainly completed the following research content:1.The junction temperature measurement method of SiC MOSFET discrete device is studied.The electrical method is selected as the junction temperature measurement method,and the most suitable temperature-sensitive electrical parameters are found by studying the influence of its structure and interface state traps on electrical parameters.Because the interface state traps existing at the interface of SiC and Si O₂ will cause the electrical parameters to drift,which makes the electrical temperature measurement inaccurate.Therefore,the study analyzed the influence of traps on some electrical parameters,explained the mechanism of traps'influence on parameters,and explored and studied the temperature-sensitive electrical parameters to avoid the effects of traps.The SiC MOSFET parasitic body diode source-drain diode voltage drop V_SD was used as the temperature sensitivity.Electrical parameters,and studied its repeatability,stability and temperature sensitivity.2.The junction temperature measurement method of SiC MOSFET module is studied.The electrical method is selected as the junction temperature measurement method,and the parasitic body diode voltage drop V_SD and the conduction voltage drop V_DS of the SiC MOSFET are respectively used as the temperature-sensitive electrical parameters for the junction temperature measurement of two SiC MOSFET modules with different internal structures.Since the SiC MOSFET module also has interface state traps,the influence of traps on temperature-sensitive electrical parameters and the repeatability of parameters are studied,and how to shield the traps to ensure the accuracy of temperature-sensitive electrical parameters temperature measurement.3.Researched on-line temperature measurement of SiC MOSFET power cycle experiment,and tried to build an experimental platform.In turn,the formulation of the platform design plan,the establishment of the temperature calibration curve library during the heating process and the cooling process in the power cycle process,the software design,the circuit design of the power cycle platform and the PCB production.Among them,the conduction voltage drop V_DS under high current and the parasitic body diode conduction voltage drop V_SD under small current are selected as the temperature-sensitive electrical parameters of real-time junction temperature measurement,so as to realize online temperature measurement in the whole process of power cycle,and through soft Hardware cooperative control realizes online temperature measurement of SiC MOSFET power cycle experiment.