Optimization And Characteristics Of Recessed Gate 4H-SiC Static Induction Transistor

Silicon carbide (SiC) is a very promising candidate for high temperature, high power, high frequency, and radiation hardness applications because of its superior properties such as wide band gap, high critical breakdown field, high thermal conductivity and high saturation electron drift velocity. In recent years, SiC has become a research focus in the field of semiconductors. And it has found widely application prospects in communications, transportation, energy and defense fields.Static Induction Transistor (SIT) based on 4H-SiC is studied in this paper. The advantages and some basic properties of SiC material are analyzed, DC characteristics of recessed gate SIT under the pentode-like mode, triode-like mode and bipolar mode are simulated respectively using TCAD software MEDICI. Furthermore, working mechanism of the device is described and the results are discussed.Simulation results show that either increasing channel doping concentration or reducing the channel length can increase the drain current. The device's gate-drain blocking voltage increases with the increase of the drift layer thickness and reduction of the concentration of drift layer. The device's gate-source breakdown voltage increases with the increase of the channel doping concentration and the channel width, and the reduction of the channel length.After analysis, it is to get a superior performance of the recessed gate 4H-SiC SIT model. In the model, the blocking voltage is about 2000V, the gate-source breakdown voltage is reached -66V, and its specific resistance is as small as 2 m?c m2.Because channel and the drift layer doping concentrations of SIT are small, impurities can be assumed completely ionized, thus incompletely ionized effect on the SIT can be ignored. In this paper, the temperature characteristics of the 4H-SiC SIT are also analyzed. The results show that the saturation drain current under pentode-like mode decreases with the increase of temperature above room temperature. Under triode-like mode, the blocking voltage decreases with the increase of temperature.