Novel Structure Of Suppressing LIGBT Substrate Leakage Current

LIGBT devices are an important class of power devices, both because of its high input, small power control, simple drive circuit, high switching speed as same as MOSFET. At the same time it also has a high current density, the low saturation voltage drop, excellent current handling capability as same as bipolar power transistors, so LIGBT devices are widely used in a variety of power ICs and power electronics system. However in operating state, because of the conductivity modulation effect, a large number of anode holes injected into the drift region, part of the holes will continue inject into the substrate directly, resulting in severe leakage substrate currents, affect circuit performance. In order to reduce the leakage.substrate current.we propose two novel structure.(1)For the serious self-heating effect and low breakdown voltage,the layered SOI LIGBT was proposed the new structure introduced the windowing at middle and anode terminal of the buried oxide layer. By using the substrate to undertake voltage and the bulk silicon to conduct heat, the new structure improve the withstand voltage and reduce the self-heating effect.The simulation results show that the:the breakdown voltage of the new structure increase more than two times, the hot spot temperature drop more than 15 K, at the same time the leakage substrate current is only7×10-12A/μm, the switching speed basically unchanged.(2)For the complex process and current conduction ability of the first structure, the double channel SOI LIGBT was proposed. The new structure introduced double-gate and shorten the length of the buried oxide layer further. By increasing the conductive channel to improve the current conduction ability. The simulation results show that the:the breakdown voltage of the new structure is about 400 V, the saturation current density reached 3.7A/μm, at the same time the leakage substrate current is only 7×10-12A/μm, the switching speed basically unchanged.