Research On Ionizing Radiation Simulation And Hardness Of IGBT

IGBT(Insulated Gate Bipolar Transistor)has received extensive attention in the field of power electronic technology for its excellent frequency characteristics and control ability. IGBT is composed with MOSFET and BJT structure, so it not only has the advantages of forward voltage drop which BJT has, but also has the fast switching speed which MOSFET has. However, power devices are generally vulnerable to space environment. Ionizing irradiation may cause variable effect and bring about a negative influence on electrical characteristics of IGBTs.In the first part, this paper introduced the base theory of ion irradiation and the structure of several IGBTs. And the ways irradiation cause damage in IGBT was presented. What’s more, a way was introduced to simulate the main effects: SEE(Single Event Effect) and TID(Total ionizing dose) effect with TCAD software.In the second part, LET(Linear Energy Transfer) was introduced to simulate the damage SEE caused in IGBTs. Ionizing effect of IGBTs in blocking state was taken into account for this state is most sensitive to SEE. Then the re-distribution process of electron-hole pairs was described. Based on this theory, several kinds of IGBT were compared in the ability of anti-irradiation. Finally, LCLCR(Low Carrier Lifetime Control region) was considered to enhance the robustness of IGBTs in the irradiation environment. What’s more, the negative influence TID caused was simulated. It is confirmed that the charge in the gate oxide and the interface charge is the main reason to damage the devices.In the third part, the general method of designing a IGBT with expected blocking voltage and ideal dynamic performance was presented. A NPT-IGBT with blocking voltage over 1200 V was designed. Then, Single Event Effect and Total Dose Effect was studied about this IGBT. With the simulation results, it is obviously that the bilateral interleaving junction terminal achieved better performance. Also, the process flow and layout were accomplished in the last part.