一种集成近红外SPAD阵列的激光雷达测距系统  

LiDAR Ranging System with Integrated Near-Infrared SPAD Array

作　　者：陈前宇 许唐 刘志强[1] 马治强 袁丰[1] 徐跃[1] Chen Qianyu;Xu Tang;Liu Zhiqiang;Ma Zhiqiang;Yuan Feng;Xu Yue(College of Integrated Circuit Science and Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,Jiangsu,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

出　　处：《光学学报》2024年第12期299-308,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(CX(21)3062);核探测与核电子学国家重点实验室项目(SKLPDE-KF-202307);江苏省研究生创新计划(SJCX22_0261)。

摘　　要：基于0.18μm BCD(Bipolar-CMOS-DMOS)工艺实现了一种高探测效率、低暗计数噪声、低误码率、高分辨率、大动态范围的近红外激光雷达测距系统。该系统集成了一个4×4单光子雪崩二极管(SPAD)阵列和一个基于延迟锁相环(DLL)的两段式时间数字转换器(TDC)。SPAD阵列采用一种新型高压p阱/高压n+埋层的深雪崩区结构,显著提高了对近红外光子的探测概率(PDP)。TDC采用双链计数器以及相位插值法,降低了段间误码概率并获得了高分辨率和大动态范围。测试结果表明,SPAD器件在5 V过偏压下的暗计数率(DCR)低至162 s^(-1),在905 nm近红外波长处的PDP大于8.5%,可工作在人眼安全阈值较高的近红外波段。TDC实现了208 ps的高时间分辨率和1.28μs的动态范围,微分非线性度(DNL)和积分非线性度(INL)分别在±0.1L_(SB)(L_(SB)代表最低有效位)和±0.6L_(SB)范围内,在50~75 MHz输入时钟下的直接光子飞行时间(dTOF)测量误差为0.37 ns。Objective The laser ranging technology based on single-photon avalanche diode(SPAD)has been widely applied to unmanned driving,intelligent robots,and 3D imaging due to its long detection distance,high resolution,and strong antiinterference ability.The laser ranging methods mainly include direct time-of-flight(dTOF)and indirect time-of-flight(iTOF)measurement techniques.dTOF has higher anti-interference capability and a wider dynamic range than iTOF.Currently,the SPAD-based dTOF laser ranging technology is rapidly developing towards low cost and high integration with silicon-based processes.However,there are still problems such as low near-infrared light detection efficiency,poor ranging stability,and mutual constraints between time resolution and measurement error.To this end,we propose a nearinfrared laser ranging system based on a 0.18μm bipolar-CMOS-DMOS(BCD)process,which has high detection efficiency,low dark count noise,low bit error rate,high resolution,and large dynamic range.Methods The laser ranging system primarily consists of a pulse laser driver,an optical lens,a 4×4 SPAD array,quenching circuits,and a dTOF readout circuit(Fig.1).The integrated SPAD device employs a high-voltage p-well(HVPW)/high-voltage n+buried layer(HVBN)structure as the avalanche multiplication region(Fig.2).By utilizing the HVPW and HVBN,a thicker and deeply buried avalanche multiplication region is formed to enhance the absorption of near-infrared shortwave photons and improve quantum efficiency.Simultaneously,a low-voltage p-well is injected into the HVPW to increase the net doping concentration in the neutral photon collection region of the HVPW.This widens the effective photon collection region,and facilitates the transfer of optically generated electrons from the HVPW to the avalanche multiplication region,thereby triggering the avalanche effect and further improving the detection probability of near-infrared photons.Meanwhile,combined with an embedded deep-junction avalanche multiplication region,a lowdoped p-type epitaxi

关 键 词：传感器 直接飞行时间 单光子雪崩二极管 激光雷达 时间间隔测量 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]