The magnetoresistive random access memory process makes a great contribution to threshold voltage deterioration of metal-oxide-silicon field-effect transistors,especially on p-type devices.Herein,a method was proposed...The magnetoresistive random access memory process makes a great contribution to threshold voltage deterioration of metal-oxide-silicon field-effect transistors,especially on p-type devices.Herein,a method was proposed to reduce the threshold voltage degradation by utilizing back-side stress.Through the deposition of tensile material on the back side,positive charges generated by silicon-hydrogen bond breakage were inhibited,resulting in a potential reduction in threshold voltage shift by up to 20%.In addition,it was found that the method could only relieve silicon-hydrogen bond breakage physically,thus failing to provide a complete cure.However,it holds significant potential for applications where additional thermal budget is undesired.Furthermore,it was also concluded that the method used in this work is irreversible,with its effect sustained to the chip package phase,and it ensures competitive reliability of the resulting magnetic tunnel junction devices.展开更多
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 mechani...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.展开更多
Under the back-side windy condition,the convection and radiation heat transfer characteristics in an iso-flux upward-facing cylindrical cavity were studied by three-dimensional numerical simulation.The impacts of cavi...Under the back-side windy condition,the convection and radiation heat transfer characteristics in an iso-flux upward-facing cylindrical cavity were studied by three-dimensional numerical simulation.The impacts of cavity tilt angle,wind incident angle and wind speed on convection and radiation heat transfer Nusselt number Nuc and Nur were analyzed,and the possible explanations for their impacts were presented.Results show that due to the disturbance of wind,the influence of cavity tilt angle becomes more complicated and is related to wind incident angle and wind speed.The variation of Nuc or Nur with wind incident angle is different for different cavity tilt angles.Despite of the changes of cavity tilt angle or wind incident angle,the Nuc increases with the wind speed while the Nur presents a declination with the increasing of wind speed.Hence,compared with cavity tilt angle and wind incident angle,wind speed may be the dominant factor affecting or controlling the convective and radiation heat transfer of cavity.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51672246)the National Key Research and Development Program of China(Grant Nos.2017YFA0304302 and 2020AAA0109003)the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C01002)。
文摘The magnetoresistive random access memory process makes a great contribution to threshold voltage deterioration of metal-oxide-silicon field-effect transistors,especially on p-type devices.Herein,a method was proposed to reduce the threshold voltage degradation by utilizing back-side stress.Through the deposition of tensile material on the back side,positive charges generated by silicon-hydrogen bond breakage were inhibited,resulting in a potential reduction in threshold voltage shift by up to 20%.In addition,it was found that the method could only relieve silicon-hydrogen bond breakage physically,thus failing to provide a complete cure.However,it holds significant potential for applications where additional thermal budget is undesired.Furthermore,it was also concluded that the method used in this work is irreversible,with its effect sustained to the chip package phase,and it ensures competitive reliability of the resulting magnetic tunnel junction devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61176069 and 61376079)
文摘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funded by National Key Research and Development Program of China(Grant No.2017YFB0602002,and Grant No.2016YFC0203700)。
文摘Under the back-side windy condition,the convection and radiation heat transfer characteristics in an iso-flux upward-facing cylindrical cavity were studied by three-dimensional numerical simulation.The impacts of cavity tilt angle,wind incident angle and wind speed on convection and radiation heat transfer Nusselt number Nuc and Nur were analyzed,and the possible explanations for their impacts were presented.Results show that due to the disturbance of wind,the influence of cavity tilt angle becomes more complicated and is related to wind incident angle and wind speed.The variation of Nuc or Nur with wind incident angle is different for different cavity tilt angles.Despite of the changes of cavity tilt angle or wind incident angle,the Nuc increases with the wind speed while the Nur presents a declination with the increasing of wind speed.Hence,compared with cavity tilt angle and wind incident angle,wind speed may be the dominant factor affecting or controlling the convective and radiation heat transfer of cavity.
