Process Optimization of Trench Field Plate Power MOSFETs with Sequential Phosphorus-Doped Silicon

Sequential phosphorus doping process is expected to form decent silicon electrodes in narrow and deep trenches. We performed process optimization of FP-MOSFETs with sequential phosphorus-doped silicon. We succeeded in reducing processing variations in field plates and decreasing wafer warpage by processing phosphorus-doped silicon without activation annealing. In addition, inserting 800°C annealing before 1000°C annealing contributes no voids in silicon field plates.