Modeling And Research Of Self-heating Characteristics Of High Power SiC Devices

The new generation of new semiconductor material silicon carbide(SiC),due to its superior physical properties such as a larger forbidden band width,higher critical breakdown electric field,and higher electron mobility than the previous two generations of semiconductor materials,makes SiC It has shown unique advantages in the application of high temperature,high frequency and high power circuits.It has become the focus of the semiconductor industry.In order to take full advantage of these advantages,accurate SiC device models play an important role in computer-aided circuit design and simulation.Since power SiC devices are prone to self-heating under high power conditions,it is extremely important to establish accurate models of SiC power devices.Unlike the previous two generations of semiconductor materials,simply relying on the models of traditional Si and GaAs devices is not enough to describe the external characteristics of SiC devices.The SiC device needs to be modeled according to the characteristics of the device itself.The main work of this article is:Firstly,it introduces the unique advantages of SiC materials in the current semiconductor industry and combines the advantages of new generation semiconductor devices with SiC power devices.It describes the historical development process and research status of SiC power devices and device modeling.Importance for current power electronics design and practical applications.Introduced the device’s physical structure,process flow,working mode,and focused on the physical parameters affected by temperature.Then introduced the main methods of device modeling and several important large-signal empirical models,and selected a method to measure the accuracy of device models.Then,the Spice model of SiC power device is established according to the device data sheet.This method is simple and easy to implement with high accuracy,and it can also avoid a lot of calculations.The establishment of the model mainly includes several important parts:core channel and internal resistance,body diode and internal voltage source current source.Then validate the model with Pspice simulation software.Secondly,the device will be affected by the external environment during operation,and the electrical characteristics will change greatly with temperature.Especially when the device is operated at high temperature and high power,the self-heating effect becomes an inevitable factor,so it is necessary to An accurate temperature model to describe the electrical characteristics of the device under self-heating effects.In this paper,the I-V characteristics of SiC power devices at 25°C are tested.Based on the correlation between the physical characteristics of the internal structure of the device and the temperature,each physical base that is greatly affected by temperature is modeled.The temperature coefficient of the parameter is determined by the construction method of the physical base level(carrier velocity saturation)theory and mathematical function fitting(hyperbolic tangent function),and finally the drain-source current temperature variation model of the SiC device is established.Finally,the accuracy of the self-heating simulation was verified by comparing the measured results with the simulation results and the traditional Angelov model.