Design And Optimization Of Short Circuit Characteristics With 550V SOI-LIGBT Based On Thick SOI Technology In Intelligent Power Module

Recently, intelligent power module is widely used in air conditioners, industrial equipment and new energy vehicles due to its excellent dielectric isolation, high efficiency and high robust, etc. Silicon on insulator-lateral insulated gate bipolar transistor (SOI-LIGBT) is a basic attractive device in intelligent power module because SOI substrates can offer true dielectric isolation, small parasitic capacitance, low leakage current and high integration. However, as heat conductivity in BOX is much lower than in silicon, it will hinder the rapid transfer of heat, which easily lead to short-circuit failure. Therefore, the optimization of short-circuit characteristics of SOI-LIGBT is urgently needed.Based on the application requirements of intelligent power module, this thesis aims to discuss the short-circuit failure mechanism in detail and finish the structure design and layout design of the new device respectively. Firstly, this thesis determines the type of short-circuit failure of the conventional device is advanced thermal failure near the bird region caused by excess concentrated electric field and current. Then, a simple self-heating model based on RC thermal circuit which accounts for the temperature rise in short-circuit conditions is developed and the factors including main device dimensions and doping concentrations that affect short-circuit failure are obtained. Additionally, a new structure called Carrier Storage Trench Snake-LIGBT (CSTS-LIGBT) is proposed, which features trench snake gate structure and the carrier storage layer, superior short-circuit characteristics is obtained. Finally, this thesis designed the process and layout for the CSTS-LIGBT to adapt intelligent power module application.At last, for the improved device, test results demonstrate that the short-circuit withstand time is 27.4?s in 25? and 7.6?s in 200? @ Vge=5V, Vce=300V with no degradation of any other static and dynamic parameters compared with the conventional device, which meets the application requirements of intelligent power module.