硅基高灵敏度近红外单光子dTOF探测器  

Silicon-Based High-Sensitivity Near-Infrared Single-Photon dTOF Detector

作　　者：王帅康 刘丹璐 陈前宇 韩冬 王嘉源 徐跃[1,2] 曹平 Wang Shuaikang;Liu Danlu;Chen Qianyu;Han Dong;Wang Jiayuan;Xu Yue;Cao Ping(College of Integrated Circuit Science and Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,Jiangsu,China;National and Local Joint Engineering Laboratory of RF Integration&Micro-Assembly Technology,Nanjing 210023,Jiangsu,China;State Key Laboratory of Particle Detection and Electronics Technology,Hefei 244199,Anhui,China)

机构地区：[1]南京邮电大学集成电路科学与工程学院,江苏南京210023 [2]射频集成与微组装技术国家地方联合工程实验室,江苏南京210023 [3]核探测与核电子学国家重点实验室,安徽合肥244199

出　　处：《光学学报》2023年第20期20-29,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62171233);江苏省农业科技自主创新资金项目(CX(21)3062);核探测与核电子学国家重点实验室资助项目(SKLPDE-KF-202307);江苏省研究生创新计划(SJCX22_0261)。

摘　　要：基于0.18μm BCD工艺实现了一种高灵敏度、低暗计数噪声的近红外单光子直接飞行时间(dTOF)探测器。集成的单光子雪崩二极管(SPAD)探测器件采用新型的高压p阱/n+埋层作为深结雪崩倍增区的结构,显著提高了对近红外光子的探测概率;采用低掺杂的外延层作为虚拟保护环,有效减小了器件暗计数噪声。dTOF探测器读出电路采用三步式混合结构的时间数字转换器(TDC),获得了高时间分辨率和大动态范围。测试结果表明,SPAD器件在5 V过偏压下的光子探测概率(PDP)峰值达到45%,在905 nm近红外波长处的PDP大于7.6%,暗计数率(DCR)小于200 Hz。读出电路实现了130 ps的高时间分辨率和258 ns的动态范围,差分非线性度(DNL)和积分非线性度(INL)均小于±1 LSB(1 LSB=130 ps)。该dTOF探测器具有人眼安全阈值高、灵敏度高、噪声低和线性度好的优点,可应用于低成本、高精度的激光雷达测距系统。Objective Owing to outstanding advantages such as small size,low power consumption,and high time resolution,direct time of flight(dTOF)detectors have attracted great interest in numerous fields,including automotive driving,facial recognition,augmented and virtual reality(AR/VR),and 3D imaging.Such systems exploit a fast on-chip time-to-digital converter(TDC)in conjunction with single-photon avalanche diode(SPAD)to measure the TOF value,which can achieve high interference immunity and wide dynamic range.Currently,they are rapidly developing towards the direction of lowcost and high integration density compatible with the silicon-based process.However,some problems still exist in practical applications,such as the low safety threshold of human eyes and mutual restriction between resolution and dynamic range.To this end,we implement a near-infrared single-photon dTOF detector with high sensitivity,high time resolution,and wide dynamic range based on 0.18μm Bipolar-CMOS-DMOS(BCD)technology.Methods The detector is mainly composed of a TDC circuit,16 SPADs,and an analog front-end(AFE)circuit that is coupled with each SPAD(Fig.3).The integrated SPAD device(Fig.1)adopts a new structure with a deep high-voltage p well(HVPW)/buried n+junction as avalanche multiplication region to significantly improve the near-infrared photon detection probability(PDP).A certain distance is set aside between the high-voltage n well(HVNW)and HVPW,and is the guard ring width(dGRW).The virtual guard ring formed by the low doping p-type epitaxial layer helps lower the dark count noise.The proposed SPAD devices with dGRW is 0.5,1.5,2.5,and 3.5μm respectively are simulated by technology computer-aided design(TCAD)based on 0.18μm BCD technology to study the influence of dGRW on device performance(Fig.2).The simulation results show that the device can work normally at dGRW=2.5μm,and the high avalanche field can be obtained to ensure a higher detection probability for near-infrared photons.Meanwhile,the low field in the guard ring region can av

关 键 词：探测器 直接飞行时间 单光子雪崩二极管 光子探测概率 暗计数率 时间数字转换器 

分 类 号：TN491[电子电信—微电子学与固体电子学]