Study on Silicon Window Polarity of Partial-SOI LDMOS Power Devices

Yue Hu1,  Hao Wang1,  Cheng Wang1,  Jin He1,  Xiaoan Zhu1,  Sheng Chang2,  Qijun Huang2,  Dewen Wang3,  Qingxing He4,  Caixia Du4,  Shengju Zhong4
1Peking University, 2Wuhan University, 3Shenzhen SI Semiconductors, 4Shenzhen Huayue Terascale Chip


Abstract

The Effect of silicon window polarity on partial-SOI (partial silicon-on-insulator, PSOI) LDMOS power devices under high-voltage operation is studied. Different polarities of the silicon window in PSOI LDMOSFETs are analyzed to investigate their effects on electrical characteristics: breakdown voltage (BV) and on-resistance (Ron). In partial-SOI LDMOSFETs, the P-type silicon window is considered as a part of the substrate, while the N-type silicon window falls into the drift region, which affects the high-voltage operation of devices. The two-dimensional (2-D) simulation results show that the breakdown voltage of PSOI LDMOSFET with P-type window is higher than that of PSOI LDMOSFET with N-type window, while the on-resistance of PSOI LDMOSFET with P-type window is lower than that of PSOI LDMOSFET with N-type window.