Analysis Of IE Effect And Characteristics Of 4.5kV IEGT

Injection Enhancement Gate Transistor (IEGT) was derived from Insulated Gate Bipolar Transistor (IGBT), which is firstly developed by Toshiba Corporation in 1994. IEGT devices can be used in power application fields due to the stronger current capacity. At present, some corporation, such as, Toshiba, Hitachi, Mitsubishi in Japan and ABB in Switzerland has been developing are the products, but IEGT is a blank in interiorly now.In this thesis, the structure feature, operation principle and characteristics of IEGT devices are systematically analyzed. The IE effects of Planar gate IEGT (P-IEGT), Trench gate IEGT (T-IEGT) and T-IEGT with barrier layer are studied by ISE simulator. The conducting, blocking and switching characteristics of IEGT at room and high temperature are simulated and the key structure parameters of the IEGT device are optimized. At last, the latch up effect of the P-IEGT device at high temperature is analyzed and high-voltage terminal structure of P-IEGT is designed. The main content is as follows:Firstly, the features and characterization parameters of IEGT are introduced. And the mechanism of the IE effects, and Safe Operating Area (SOA) of IEGT are analyzed.Secondly, the influences of structural parameters on IE effect of IEGT devices are studied. The results show that, with an increase of the gate length of P-IEGT, the IE effect enhances and finally trends to stabilization, on-state voltage drop reduces, and turn-off time increases. With increases of the trench depth and length of T-IEGT, it causes the stronger IE effect and the smaller on-state voltage drop. With the increase of barrier layer thickness and concentration of T-IEGT, it causes the stronger IE effect, and the lower on-state voltage drop.Thirdly, the characteristics of IEGT are simulated. The results show that, the key parameters, such as, the concentration and thickness of field stop layer, the thickness of collector, length of n+emitter and minority lifetime, have an important to the characteristics. The increases of the trench width and depth, and concentration of barrier layer of T-IEGT reduce the fall of the blocking voltage and the transfer of peak electric field, and the increase of input and output capacitance.Fourthly, the influences of high temperature on characteristics of IEGT are discussed. The results show that, with the increase of the temperature, blocking voltage increases and then falls, on-state voltage drop falls and then increases, and the latch-up current will be reduced significantly.Fifthly, the high voltage terminal structure of P-IEGT is designed. The results show that the combination of field ring and field plate can not only improve the surface breakdown voltage, but also save the surface area (?)rrier layer. If the field plates are placed between rings, it can achieve the better results.