高压CoolMOS的准饱和效应分析及优化设计

Study of Quasi-Saturation Effect in High Breakdown Voltage CoolMOS and Its Optimization Design

分析了利用多次外延/离子注入工艺方法制造的高压CoolMOS(>650 V)的准饱和现象,与普通的低压CoolMOS的准饱和现象进行了对比。结果发现,准饱和首先发生在N-Pillar的底部,分析了这种现象产生的原因。为了改善器件的准饱和效应,提出一种简单的优化结构,在几乎不改变器件的导通电阻和击穿电压的前提下,使器件的开态准饱和电流提高了约40%,并且利用仿真软件Sentaurus Device进行了模拟仿真。

Quasi-saturation effect of high breakdown voltage （ 〉 650 V） CoolMOS fabricated with multi-ion-implantation and multi-epitaxial method was investigated and compared with that of low breakdown voltage CoolMOS. It has been found that quasi-saturation began to occur at the bottom of N-Pillar of the high breakdown voltage CoolMOS. The cause for this unique phenomenon was studied. In order to improve quasi-saturation of the device, a simple optimized structure was proposed without changing on-resistance and breakdown voltage, which improved limited current by about 40%. Results were validated by TCAD tool Sentaurus Device.