Model Of Silicon Carbide Merged PiN Schottky(MPS) Diodes

The increasing demand for high efficiency,energy-saving and the progress of power electronics technology have put forward higher requirements for the performance of power semiconductor diodes.SiC MPS diodes combine the advantages of PiN diodes and Schottky diodes,such as the ability to withstand high reverse bias voltage,low voltage conduction,and good reverse recovery characteristics.This article will conduct research on SiC MPS diodesFirst of all,the structure and working principle of SBD diode,PiN diode and MPS diode are analyzed.Traditional MPS resistance model is only suitable for unipolar mode.This paper improves the existing MPS unipolar resistance model by adding the effect of temperature on conduction angle and carrier mobility.A carrier distribution model in the drift region under high injection conditions is established and applied to the solution of the bipolar mode resistance model.The accuracy of the resistance model was verified by comparing the model results with the test results,and the characteristics and main components of the resistance of the MPS diode were analyzed through the model resultsThe forward Ⅰ-Ⅴ characteristic model of MPS diode was established based on the resistance model.Through this model,the typical forward characteristic curve and surge current characteristic curve of MPS diode can be obtained,and the model results are verified.The existing reverse characteristic model of the MPS diode is based on the structure of the junction barrier Schottky diode.The structures of the two diodes are not same exactly,and the model cannot be applied completely.And the traditional reverse characteristic model does not consider the influence of the lateral electric field on the surface potential.In this paper,a two-dimensional Poisson equation is used to analyze the two-dimensional electric field distribution inside the MPS diode.A surface electric field model is established and applied to the solution of the MPS diode reverse characteristic model.The validity of the reverse characteristic model was verified by test results.Finally,the temperature-dependent characteristics,voltage characteristics of the reverse leakage current of the MPS diode,and the characteristics of the hot electron emission current and the tunneling current which are main components of MPS are analyzed.