IGBT集电结局域寿命控制的比较与分析

Comparison and Analysis of Local Lifetime Control near IGBT's Collector Junction

新型的电场终止型绝缘栅双极晶体管(FS-IGBT)改善了传统穿通型(PT)IGBT性能上的不足,但对于1 200 V以下器件需要超薄片加工。为打破加工技术的限制,用简易的厚片工艺实现薄片性能,可以在集电结附近设置载流子局域寿命控制层(LCLC)来改善器件性能。目前有两种方案:将LCLC区置于集电区内形成内透明集电极IGBT(ITC-IGBT);或置于缓冲层内,形成缓冲层局域寿命控制IGBT。对这两种结构的600 V器件结合具体参数进行了仿真和比较。仿真结果表明,两种结构的器件可实现几近相同的折中特性,但当LCLC区位于缓冲层内时,需要更低的局域寿命,且更易发生通态特性的回跳现象,影响器件性能。因此将LCLC区置于集电区,即形成ITC-IGBT结构是一个更好的选择,为探索用厚片工艺制造高性能IGBT提供了必要的参考。

The novel field stop insulated gate bipolar translator （FS-IGBT） improves the deficiency of conventional punch through IGBT （PT-IGBT）, but it is difficult to fabricate the devices below 1 200 V because of ultrathin wafer process. To break the confine of process technology and reach the performance of thin wafer with thick wafer, the local carrier lifetime control layer （LCLC） can be set near the collector junction. There are two ways： putting the LCLC in the collector region to form ITC- IGBT, and putting it in the buffer region to form buffer local lifetime control IGBT. The 600 V devices of these two structures with specific parameters were simulated and compared. Simulation results show that the tradeoff curves of these two IGBT structures are very close. However, when the LCLC is located in the buffer layer, a lower local lifetime is needed. What＇s more,a snap-back which will affect the device performance is observed. Therefore, the structure with LCLC in the collector region which forms ITC- IGBT structure is a better choice and a necessary reference to explore the fabrication of high performance IGBT with thick wafer is provided.