基于poly-Si键合层的SACM型Ge/Si APD的优化设计研究  

Optimal Design of SACM Ge/Si APD Based on Poly-Si Bonding Layer

作　　者：张娟 苏小萍 李嘉辉 王战仁 柯少颖 Zhang Juan;Su Xiaoping;Li Jiahui;Wang Zhanren;Ke Shaoying(Key Laboratory of Light Field Manipulation and System Integration Applications in Fujian Province,College of Physics and Information Engineering,Minnan Normal University,Zhangzhou 363000,Fujian,China)

机构地区：[1]闽南师范大学物理与信息工程学院光场调控及其系统集成应用福建省高校重点实验室,福建漳州363000

出　　处：《中国激光》2024年第8期46-59,共14页Chinese Journal of Lasers

基　　金：国家自然科学基金(62004087)。

摘　　要：Ge/Si雪崩光电二极管(APD)被广泛应用于近红外探测领域,但由于Ge和Si之间存在4.2%的晶格失配,故难以获得高性能的Ge/Si APD。提出在Ge/Si键合界面处引入多晶硅(poly-Si)键合中间层,弱化Ge/Si失配晶格对APD器件性能的影响。poly-Si引入后键合界面电场发生变化,导致APD内部的电场重新分布,极大地影响了器件性能。因此,重点对Ge吸收层和Si倍增层的掺杂浓度进行调控,探究了掺杂浓度对Ge/Si APD电场、复合率、载流子浓度、碰撞电离等性能的影响,最终设计出高性能键合Ge/Si APD。本工作将为低噪声、高增益Ge/Si APD的研究提供理论指导。Objective Ge/Si avalanche photodiodes(APDs)are widely used in near-infrared detection;however,obtaining high-performance Ge/Si APD is challenging due to the 4.2%lattice mismatch between Ge and Si.Therefore,this study proposes introducing a polycrystalline silicon(poly-Si)bonding intermediate layer at the Ge/Si bonding interface to mitigate the effects of the Ge/Si lattice mismatch on APD device performance.With the introduction of poly-Si,the electric field at the bonding interface changes,causing a redistribution of the electric field inside the APD,which significantly impacts device performance.Consequently,this study focuses on regulating the doping concentrations of the Ge absorption layer and Si multiplication layer.It explores the effects of doping concentration on the electric field,recombination rate,carrier concentration,impact ionization,and other properties of Ge/Si APD.Ultimately,the aim is to design high-performance bonded Ge/Si APD.This study offers theoretical guidance for future research on Ge/Si APD with low noise and high gain.Methods In this study,a 2-nm thick layer of poly-Si material is introduced at the Ge/Si bonding interface,and the influence of the doping concentrations of the Ge and Si layers on the APD properties is investigated.Initially,changes in the APD optical and dark currents with doping concentration are simulated.The changes in the recombination rate and carrier concentration are then simulated to explore the reasons for the changes in the optical current.Next,to further understand the reasons for the change in electron concentration,changes in the energy band of the APD are simulated.Following this,changes in the charge concentration,impact ionization rate,electric field,and other parameters with the doping concentration are simulated.Finally,the gain,bandwidth,and gain-bandwidth product of the APD are simulated and compared with previous studies.The optimal doping concentration for APD devices is identified to improve device performance.Results and Discussions After introduci

关 键 词：材料 Ge/Si雪崩光电二极管 晶格失配 poly-Si键合层 掺杂浓度 

分 类 号：TN315[电子电信—物理电子学]