Research On The Mechanism Of IGBT Switch Surge And Improvement Of Turn-off Peak Voltage

Insulated Gate Bipolar Transistor(IGBT)is widely used in new energy vehicles and rail transit due to its advantages of high voltage and current endurance,high switching frequency,strong controllability and good reliability.Field-Stop IGBT(FS-IGBT)has become the mainstream design today because it has smaller switching losses.However,as the switching speed of the device becomes faster and faster,the effect of FS-IGBT on the voltage overshoot generated by the shutdown device will become more and more obvious,which not only lays hidden dangers for the reliability of the device,but also affects the entire system in serious cases.The purpose of this article is to improve the voltage overshoot and oscillation phenomenon generated by FS-IGBT devices during shutdown.This thesis is based on the background of 1200V/40 A trench gate FS-IGBT,When the bus voltage is 600 V and the gate resistance is 10Ω,the peak voltage generated during the turn-off period exceeds 1000 V,followed by more serious oscillation.By studying the mechanism of shutdown overshoot and optimizing the process,the peak voltage of the product was successfully reduced to less than 800 V under this test condition,and the subsequent oscillation phenomenon was greatly slowed down,and the expected purpose of the experiment was achieved.The arrangement of this article is as follows:1.The structural development process and working principle of IGBT devices are briefly introduced,and then the causes of overshoot generated in the switching stage of the device are explained,and the overshoot mechanism is analyzed.2.The device model is built through Sentaurus simulation software,and a series of parameter tests are performed on the built device model to ensure that it is the same as the actual product specification.By changing the bus voltage,load current,gate resistance,and the thickness of the drift region of the device in the test circuit,the influence trend of the change of these parameters on the voltage overshoot generated by the device during the turn-off period is observed.Finally,according to the simulation results,the improvement ideas are put forward.3.This thesis introduces the common processes in semiconductor manufacturing and briefly introduce some precautions in the tape-out process.Then,the tape-out results are analyzed and summarized to verify whether the experiment achieves the expected goal.