SOI基横向SiGe HBT高频功率性能改善技术  

Improvement Technology of SOI-based Lateral SiGe HBT for High-frequency and High-power Performance

作　　者：金冬月 吴玲 张万荣 那伟聪 杨绍萌 贾晓雪 刘圆圆 杨滢齐 JIN Dongyue;WU Ling;ZHANG Wanrong;NA Weicong;YANG Shaomeng;JIA Xiaoxue;LIU Yuanyuan;YANG Yingqi(Faculty of Information Technology,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学信息学部,北京100124

出　　处：《北京工业大学学报》2022年第12期1280-1288,共9页Journal of Beijing University of Technology

基　　金：中国博士后科学基金资助项目(2015M580951);北京市教育委员会科研计划科技一般项目(KM201710005027)。

摘　　要：为了在高频下兼顾电流增益β和击穿电压V_(CBO)、V_(CEO)的同步改善,从而有效提升器件的高频功率性能,利用SILVACO TCAD建立了npn型绝缘层上硅(silicon-on-insulator,SOI)基横向硅锗(SiGe)异质结双极晶体管(heterojunction bipolar transistor,HBT)的器件模型.研究结果表明:通过基区Ge的摩尔分数的梯形分布设计,可在基区引入电子加速场,并减小有效基区宽度,一方面有利于缩短基区渡越时间,提高器件的特征频率f_(T);另一方面也有利于降低电子在基区的复合,提高基区输运系数,从而增大β.然而,在基区Ge的物质的量一定的情况下,随着Ge的摩尔分数的梯形拐点位置向集电结一侧不断靠近,集电结一侧对应的Ge的摩尔分数也将随之增加,此时,器件的集电极电流处理能力将显著下降,因此,需对摩尔分数值进行优化.同时,通过在衬底施加正偏压的衬底偏压结构设计,可在埋氧层上方形成电子积累层,提高发射结注入效率,从而增大β,但会退化击穿特性.进一步通过优化衬底偏压结构,设计出了兼具复合衬底偏压结构和基区Ge的摩尔分数的梯形分布设计的SOI基横向SiGe HBT.结果表明,与常规器件相比,新器件在保持峰值特征频率f_(Tm)=306.88 GHz的情况下,峰值电流增益βm提高了84.8,V_(CBO)和V_(CEO)分别改善了41.3%和21.2%.To improve the current gainβand breakdown voltages V_(CBO) and V_(CEO) under high frequency,as well as enhance the high-frequency and high power performance effectively,a model of npn silicon-on-insulator(SOI)-based lateral SiGe heterojunction bipolar transistor(HBT)was established by SILVACO TCAD.The research shows that an electron acceleration field is introduced in the trapezoidal profile design of Ge mole fraction in base and decreases the effective width of the base region,which shortens the base transit time and hence increases the cutoff frequency f_(T).At the same time,it is also conducive to decreasing the electrons recombination in the base region,which increases the transport cofficient of the base andβ.However,for a given amount of substance of Ge in base,the Ge mole fraction at the collector-base edge is increased as the kink point of the trapezoidal profile of Ge mole fraction shifts from emitter-base junction to collector-base juntion.The collector current handling capability of the device was degraded.Therefore,the value of Ge mole fraction needs to be optimized.Meanwhile,a positive substrate bias design forms an electron accumulation layer above the buried oxygen layer,which modulates the effective doping concentration and improves the injection efficiency of the emitter junction.As a result,theβis increased.However,the breakdown characteristics is degraded.Furthermore,a novel SOI-based lateral SiGe HBT with a composite substrate-voltage structure and a trapezoidal Ge profile in base was proposed.Compared with the conventional device,the peak of the current gainβm of the novel device was increased 84.8,the breakdown voltages including V_(CBO) and V_(CEO) of the device were improved by 41.3%and 21.2%,respectively,with a peak of the cutoff frequency f_(Tm) of 306.88 GHz,which effectively expand the high-frequency and high power performance of SOI-based lateral bipolar transistor.

关 键 词：SOI基横向SiGe HBT Ge的摩尔分数的梯形分布 衬底偏压结构 电流增益 特征频率 击穿电压 

分 类 号：TN385[电子电信—物理电子学]