肖特基结多数载流子积累新型绝缘栅双极晶体管

Novel majority carrier accumulation insulated gate bipolartransistor with Schottky junction

绝缘栅双极晶体管(insulated gate bipolar transistor,IGBT)是现代功率半导体器件的核心,因其良好的电学特性得到了广泛的应用.本文提出了一种具有肖特基结接触的栅半导体层新型多数载流子积累模式IGBT,并对其进行特性研究和仿真分析.当新型IGBT处于导通状态,栅极施加正向偏压,由于肖特基势垒二极管极低的正向导通压降,使得栅半导体层的电压几乎等于栅极电压,从而能够在漂移区中积累大量的多数载流子电子.除了现有的电子外,这些积累的电子增大了漂移区的电导率,从而显著降低了正向导通压降.因此,打破了传统IGBT正向导通压降受漂移区掺杂浓度的限制.轻掺杂的漂移区可以使新型IGBT具有较高的击穿电压,同时减小了关断过程中器件内部耗尽层电容,因此整体米勒电容减小,提升了关断速度,减小了关断时间和关断损耗.分析结果表明,600 V级别的击穿电压时,新型IGBT的正向导通压降,关断损耗和关断时间相比常规IGBT分别降低了46.2%,52.5%,30%,打破了IGBT中正向导通压降和关断损耗之间的矛盾.此外,新型IGBT具有更高的抗闩锁能力和更大的正偏安全工作区.新型结构的提出满足了未来IGBT器件性能的发展要求,对于功率半导体器件领域具有重大指导意义.

Insulated gate bipolar transistor(IGBT)is the core of modern power semiconductor device,and has been widely used due to its excellent electrical characteristics.A novel majority carrier accumulation mode IGBT with Schottky junction contact gate semiconductor layer(AC-SCG IGBT)is proposed and investigated by TCAD simulation in this article.When the AC-SCG IGBT is in the on-state,a forward bias is applied to the gate.Due to the very low forward voltage drop(VF)of the Schottky barrier diode,the potential of the gate semiconductor layer is almost equal to the gate potential,which can accumulate a large number of majority carrier electrons in the drift region.In addition to the electrons existing,these accumulated electrons increase the conductivity of the drift region,thus significantly reducing VF.Therefore,the doping concentration of the drift region is not limited by VF.The lightly doped drift region can make AC-SCG IGBT have a higher breakdown voltage(BV).Moreover,it also reduces the barrier capacitance in the turn-off process,thus the overall Miller capacitance is small,which can quickly turn off and reduce the turn-off time(Toff)and turn-off loss(Eoff).The simulation results indicate that at the BV of 600 V,the VF of 0.84 V for the proposed AC-SCG IGBT is reduced by 46.2%compared with that for the conventional IGBT(VF of 1.56 V).The Eoff of the ACSCG IGBT(0.77 mJ/cm2)is reduced by 52.5%compared with that for the conventional IGBT(1.62 mJ/cm2),and the Toff(155.8–222.7 ns)is reduced by 30%.The contradiction between VF and Eoff is eliminated.In addition,the proposed AC-SCG IGBT has a better anti-latch-up capability and is coupled with its higher BV,so it has a larger forward biased safe operating area(FBSOA).The proposed novel structure meets the development requirements for future IGBT device performance,and has great significance for guiding the development of the power semiconductor device field.