【作者】 黄东；

【导师】 孔谋夫；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2020， 硕士

【摘要】 作为应用于电力领域的新兴的电力电子技术,功率半导体器件的研究和发展对促进电力电子技术的发展起着至关重要的作用。由于横向功率半导体器件的各个电极都位于芯片的表面,易于集成,因而在功率集成电路领域获得了广泛的应用。在横向功率半导体器件中,横向双扩散金属-氧化物-半导体场效应晶体管(lateral double-diffused metal-oxide-semiconductor field effect,LDMOS)和横向绝缘栅双极晶体管(lateral insulated gate bipolar transistor,LIGBT),因其自身的许多优点成为两种被广泛应用的主流器件。本文的主要工作是在简要阐述横向耐压区优化技术后,基于传统的LDMOS和LIGBT,提出了两种具有多晶硅耐压层的新型LDMOS和LIGBT功率器件,并对器件结构、原理和性能进行了详细分析:1)LDMOS虽然具有易驱动、开关速度快等诸多优点,但也存在着突出的问题,例如,其比导通电阻会随着耐压的提高而显著增加。结终端技术以及RESURF(Reduced SURface Field)技术通过优化器件漂移区表面的电场从而在不增加比导通电阻的情况下提高了器件的耐压。同时,积累层技术通过引入额外的电子积累层,在不影响器件耐压的条件下实现了器件比导通电阻的降低。在此基础上,本文提出一种新型具有多晶硅耐压层的LDMOS(AG LDMOS)器件,并对其特性进行了详细的分析,AG(accumulation-mode extended gate)结构不仅在器件导通时增加了漂移区表面的电荷密度,而且在器件耐压时优化了漂移区表面的电场分布。仿真结果表明,与具有相同尺寸的RESURF LDMOS相比,在相同的500 V耐压下,本文提出的AG LDMOS器件的比导通电阻降低了近80%。2)LIGBT具有输入阻抗高、导通压降低等优点,已逐渐成为自动控制和功率变换的核心部件。RC-LIGBT(reverse-conducting LIGBT)是具有反向导通功能的LIGBT。通过在结构上引入一个由N~+集电区,漂移区以及P基区构成的反并联的续流二极管来实现反向导电的能力,由于集成续流二极管的影响,器件在正向导通时先工作于体电阻较大的MOS模式,再工作于体电阻较小的IGBT模式,由此引发了电压折回的现象。本文提出一种基于SOI技术的具有多晶硅耐压层的RC-LIGBT,通过将续流二极管做在多晶硅耐压层上来实现LIGBT与续流二极管的隔离,器件在正向导通时只工作在IGBT模式,从而消除了电压折回的现象。同时,多晶硅耐压层还具有调制漂移区表面电场的作用。仿真结果表明,与具有相同器件参数的传统RC-LIGBT相比,在相同的500 V耐压下,本文提出的RC-LIGBT器件的导通压降在关断损耗为2.17 mJ/cm~2时降低了33.5%,关断损耗在导通压降为1.98 V时降低了87.5%,同时,反向恢复时间也减少了85.5%。更多还原

【Abstract】 As a noval power electronics technology applied to the field of power,the research and development of power semiconductor devices play a key role in promoting the development of power electronics technology.Because the electrodes of the lateral power device are located on the surface of the chip and are easy to be integrated,they have been widely used in power integrated circuits.Among lateral power semiconductor devices,lateral double-diffused field effect transistors（LDMOS）and lateral insulated gate bipolar transistors（LIGBT）have become two widely used mainstream devices because of their many advantages.In this thesis,after briefly explain the optimization technology of lateral voltage sustaining region,and based on the convention LDMOS and LIGBT,two noval LDMOS and LIGBT power devices with polysilicon voltage sustaining layers are proposed,and the device structures,opetrating principles and performances are analyzed in detail:1)Although LDMOS has many advantages such as easy driving and fast switching speed,it also has outstanding problems:its specific on-resistance increases significantly with the increase of breakdown voltage.Junction termination technology and RESURF（Reduced RURface Field）technology improve the breakdown voltage of the device without increasing the specific on-resistance by optimizing the electric field on the surface drift region of the device.And the accumulation layer technology reduces the specific on-resistance of the device without affecting the breakdown voltage of the device by introducing an additional electron accumulation layer.Based on these technologies,this thesis analyzes the characteristics of a noval LDMOS（AG LDMOS）device with a polysilicon voltage-sustaining layer.The AG（accumulated-extension modeed gate）structure not only increases the charge density on the surface of the drift region when the device is turned on,but also optimizes the electric field distribution on the surface of the drift region when the device is turned off.The simulation results show that,compared with RESURF LDMOS with the same size,the AG LDMOS device’s specific on-resistance is reduced by nearly 80%at the same 500 V breakdown voltage.2)LIGBT has gradually become the core component of automatic control and power transformation because of its advantages such as high input impedance and low on-state voltage drop.RC-LIGBT is a LIGBT with reverse conduction function.By introducing an inverse parallel freewheeling diode consisting of N⁺collector region,drift region and P base in the structure to realize the reverse conduction ability.Due to the influence of the freewheeling diode,the device operates in MOS mode with large body resistance during forward conduction state,and then in IGBT mode with small body resistance,which causes the phenomenon of voltage snap-back.This thesis proposes a new reverse-conducting lateral insulated gate bipolar transistor（RC-LIGBT）device with a polysilicon voltage-sustaining layer,which eliminates the phenomenon of voltage snap-back by isolating LIGBT and freewheeling diode,and the device only operates in IGBT mode during forward conduction state.At the same time,the polysilicon voltage-sustaining layer can be used to optimize the surface electric field in the drift region.The simulation results show that,compared with the convention RC-LIGBT with the same device parameters,the on-state voltage drop of the RC-LIGBT device proposed in this thesis is reduced by 33.5%(@E_off=2.17 mJ/cm²)and the E_off is reduced by 87.5%(@V_on=1.98V)at the same 500 V breakdown voltage,and the reverse recovery time has been reduced by 85.5%.更多还原