Study On A Power Device Which Has High Voltage And High Transient

As an emerging technology,power electronics technology is capable of converting and processing electrical energy,and is widely used in high-power power transformation and management.Its smooth implementation depends on power electronic systems with different functions.The key to these systems is power semiconductor devices.MOS control thyristor(MCT)is a voltage controlled bipolar device.It is widely used in the field of power electronic devices because of its advantages of reduced on-state voltage,large conduction current,small conduction loss,and fast switching speed.The demand for MOS-controlled thyristors has increased rapidly with the development of environmental engineering,mineral exploration,and biological industries.However,the whole technical level of domestic MCT is not yet mature,and the chip design is relatively weak.In this paper,we design a high transient MCT with 4000 V through the study of the relevant electrical characteristics.The main work is as follows:(1)The development of power electronics and power devices as well as the development history of MCTs and the research status at home and abroad are briefly introduced.Then,the structure,working principle,static and dynamic characteristics of thyristors and MCTs are described in detail.Based on the analysis,and put forward the methods for improving the withstand voltage and conduction characteristics of the devices,which provide a theoretical basis for the design of the following devices.In addition,when selecting the device parameters,it is necessary to pay attention to the compromise between withstand voltage capability and turn-on characteristics.(2)Completed the structure optimization design of 4000 V MCT.The two parts of the cell and the junction are optimized.Cell part: the device structure parameters such as device wafer thickness,gate length,device area,junction depth and doping concentration in P-well and N-well regions are determined by requirements for blocking voltage and transient current,respectively.Terminal section: firstly,several commonly used junction termination technologies are introduced,and then design a junction termination structure that meets the withstand voltage requirements by combining these technologies with the existing working conditions.Through the simulation tool to determine the process of the device manufacturing process;at the last,complete layout drawing according to the results of the design of cell and junction terminal.(3)Test device related electrical parameters: The forward blocking voltage of the device exceeds 4000 V,the forward voltage is 5V at 10 A and the threshold voltage is approximately 6V.When the power supply voltage is 3500 V,the peak transient current of the device exceeds 5000 A,and the current increase rate is about 40KA/?s.The device has a high blocking voltage,reducing the size of the discharge capacitance,which is conducive to the miniaturization of the device;in addition,the device has a high transient current,which can avoid multiple devices in series and simplify the circuit when the transient current is consistent.