多晶硅部分剥离技术对抗辐照VDMOS动态特性的影响

在考虑VDMOS器件的抗辐照特性时,为了总剂量辐照加固的需求,需要减薄氧化层的厚度,然而,从VDMOS器件的开关特性考虑,希望栅氧化层厚度略大些。本文论证了在保证抗辐照特性的需求的薄氧化层条件下,采用漂移区多晶硅部分剥离技术以器件动态特性的可行性,研究了该结构对器件开启电压、击穿电压、导通电阻、寄生电容、栅电荷等参数的影响,重点研究了漂移区多晶硅窗口尺寸对于VDMOS动态特性的影响。模拟结果显示,选取合理的多晶硅尺寸,可以降低栅电荷Qg,减小了栅-漏电容Cgd,减小器件的开关损耗、提高器件的动态性能。

The Affect of Polysilicon Lift-off Technic on Dynamic Performance of Anti-radiation VDMOS

Considering anti-radiation performance of VDMOS device, thinning oxidation should be used to meet radiation hardened demand.But thick oxidation is essential because of demand for good devices switch features.This paper demonstrated the feasibility of improving VDMOS dynamic performance by using polysilicon lift-off technique.Each of the devices parameters, such as threshold voltage, breakdown voltage, on-resistance and gate electric charge, was studied and the improvement of dynamic performance at distinct polysilicon lift-offwindow condition was mainly studied.Simulation result showed that gate electric charge （Qg） , gate-source capacitance （Cgd） , switching loss and dynamic performance of VDMOS device would be improved significantly if the size of lift-off window is designed properly.