光窗口对SiGe/Si异质结光电晶体管光响应的影响  

Effect of Optical Window on Optical Response Characteristics of SiGe/Si Heterojunction Phototransistor

作　　者：马佩 谢红云 沙印 向洋 陈亮[2] 郭敏 刘先程 张万荣 MA Pei;XIE Hong-yun;SHA Yin;XIANG Yang;CHEN Liang;GUO Min;LIU Xian-cheng;ZHANG Wan-rong(Faculty of Information Technology,Beijing University of Technology,Beijing 100124,China;College of Physics and Electronic Engineering,Taishan University,Taian,Shandong 271000,China)

机构地区：[1]北京工业大学信息学部,北京100124 [2]泰山学院物理与电子工程学院,山东泰安271000

出　　处：《光子学报》2020年第8期123-132,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.61604106,61774012,61901010);北京市未来芯片技术高精尖创新中心科研基金(No.KYJJ2016008);北京市自然科学基金项目(No.4192014);山东省自然科学基金(No.ZR2014FL025)。

摘　　要：分析了不同光窗口位置和不同光窗口面积对SiGe/Si异质结光电晶体管(HPT)光响应特性的影响.光窗口位于发射区时,HPTs吸收路径长,会产生较多的光生载流子,在发射结界面产生较大的发射结光生电压,有利于发射结的电子注入,因此获得较大的集电极输出电流和光增益.当入射光波长为650 nm,集电极电压为2.0 V,光窗口面积为10μm×10μm时,SiGe/SiHPT的光增益最大可以达到9.24.光窗口位于基区时,在较大的入射光功率下,HPTs吸收区的光生载流子密度大,光生空穴发生快速驰豫的可能性增加,一定程度上缓解了空穴迁移率低对器件工作速度的限制,提高了光特征频率.当入射光波长650 nm,集电极电压2.0 V,光窗口面积为10μm×10μm时,SiGe/SiHPT的光特征频率可达16.75 GHz.对于能够获得更高光增益光特征频率优值的发射区光窗口SiGe/SiHPTs,当光窗口面积从3μm×10μm到50μm×10μm逐渐增加时,电子在发射结界面的有效注入面积增加从而光增益逐渐增大;同时发射结和集电结的结电容也随之增大,RC延迟时间增长,光特征频率却逐渐减小.光增益·光特征频率优值随着光窗口面积的增加而逐渐提高,但随着面积的增加,光增益·光特征频率优值提高的速率变慢,并有逐渐趋于饱和的趋势.The effects of different optical window positions and different optical window areas on the optical response characteristics of SiGe/Si Heterojunction Phototransistor(HPT)are analyzed.HPTs with emitter optical window can generate more photo-generated carriers due to the longer absorption region,and then bring out a larger optical-generated voltage at emitter junction interface,which is beneficial for electronsto inject from the emitter into the base.Therefore,a larger collector current and optical gain are obtained.When the optical window area is 10μm×10μm,the maximum optical gain of SiGe/Si HPT can reach 9.24 with 650 nm incident light wavelength and 2.0 V collector voltage.HPTs with base optical window get larger photo-generated carrier density in the absorption region when incident power become larger,then the possibility of rapid relaxation for photo-generated holes increases,which relieves the limitation of the operating speed from hole’s low mobility to some extent,so the optical characteristic frequency is increased.When the optical window area is 10μm×10μm,the optical characteristics frequency of SiGe/Si HPT can reach 16.75 GHz with 650 nm incident light wavelength and 2.0 V collector voltage.For the SiGe/Si HPTs with emitter optical window that can achieve higher optical gain and optical characteristic frequency merit,when the optical window area gradually increases from 3μm×10μm to 50μm×10μm,the effective injection area of electrons at emitter junction interface gradually increases.However,at the same time the emitter junction capacitance and collector junction capacitance increase and results the RC delay time increasing,so the optical characteristic frequency gradually decreases.The optical gain and optical characteristic frequency merit increase gradually with the increase of the optical window area,but the rate of increase slows down and the optical gain and optical characteristic frequency merit tends to become saturated.

关 键 词：异质结光电晶体管 光窗口位置 光窗口面积 光增益 光特征频率 

分 类 号：TN2[电子电信—物理电子学]