In advanced field plate trench power MOSFETs (FP-MOSFETs), narrow and deep trench causes lots of challenges for process integration. Especially, process optimization for silicon in trench is the most crucial. Sequential phosphorus doping process is expected to form decent silicon electrodes in narrow and deep trenches. Therefore, we studied new process optimization of FP-MOSFETs with sequential phosphorus-doped silicon method, compared with “conventional” phosphorus diffusion method. We succeeded in reducing processing variations in field plates and decreasing wafer warpage by processing phosphorus-doped silicon without activation annealing. Inserting 800° C annealing before 1000° C annealing contributed no voids in silicon field plates and gates. In addition, good electrical characteristics was demonstrated with the optimized process.

中文翻译：

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用于沟槽场板功率 MOSFET 的顺序掺磷硅新工艺集成


在先进的场板沟槽功率 MOSFET (FP-MOSFET) 中，窄而深的沟槽给工艺集成带来了许多挑战。尤其是沟槽硅的工艺优化最为关键。顺序磷掺杂工艺有望在窄而深的沟槽中形成良好的硅电极。因此，我们研究了采用顺序磷掺杂硅法的 FP-MOSFET 新工艺优化，与“传统”磷扩散法进行比较。我们通过在不进行活化退火的情况下加工磷掺杂硅，成功地减少了场板的加工偏差并减少了晶圆翘曲。在 1000°C 退火之前插入 800°C 退火不会导致硅场板和栅极中出现空洞。此外，优化的工艺还展示了良好的电气特性。