摘要
A uniform doping ultra-thin silicon-on-insulator（SOI） lateral-double-diffused metal-oxide-semiconductor（LDMOS）with low specific on-resistance（R_on,sp） and high breakdown voltage（BV） is proposed and its mechanism is investigated.The proposed LDMOS features an accumulation-mode extended gate（AG） and back-side etching（BE）. The extended gate consists of a P– region and two diodes in series. In the on-state with VGD〉 0, an electron accumulation layer is formed along the drift region surface under the AG. It provides an ultra-low resistance current path along the whole drift region surface and thus the novel device obtains a low temperature distribution. The R_on,sp is nearly independent of the doping concentration of the drift region. In the off-state, the AG not only modulates the surface electric field distribution and improves the BV, but also brings in a charge compensation effect to further reduce the R_on,sp. Moreover, the BE avoids vertical premature breakdown to obtain high BV and allows a uniform doping in the drift region, which avoids the variable lateral doping（VLD） and the ＂hot-spot＂ caused by the VLD. Compared with the VLD SOI LDMOS, the proposed device simultaneously reduces the R_on,sp by 70.2% and increases the BV from 776 V to 818 V.
A uniform doping ultra-thin silicon-on-insulator（SOI） lateral-double-diffused metal-oxide-semiconductor（LDMOS）with low specific on-resistance（R_on,sp） and high breakdown voltage（BV） is proposed and its mechanism is investigated.The proposed LDMOS features an accumulation-mode extended gate（AG） and back-side etching（BE）. The extended gate consists of a P– region and two diodes in series. In the on-state with VGD〉 0, an electron accumulation layer is formed along the drift region surface under the AG. It provides an ultra-low resistance current path along the whole drift region surface and thus the novel device obtains a low temperature distribution. The R_on,sp is nearly independent of the doping concentration of the drift region. In the off-state, the AG not only modulates the surface electric field distribution and improves the BV, but also brings in a charge compensation effect to further reduce the R_on,sp. Moreover, the BE avoids vertical premature breakdown to obtain high BV and allows a uniform doping in the drift region, which avoids the variable lateral doping（VLD） and the ＂hot-spot＂ caused by the VLD. Compared with the VLD SOI LDMOS, the proposed device simultaneously reduces the R_on,sp by 70.2% and increases the BV from 776 V to 818 V.
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.61176069 and 61376079)
