摘要
由于InGaAs与Si之间存在7.7%的晶格失配,因此难以获得制备方式简单、性能良好的InGaAs/Si雪崩光电二极管(APD)。从理论上提出了一种从源头弱化InGaAs/Si晶格失配对APD性能影响的办法,即在InGaAs/Si键合界面引入一层a-Ge或poly-Ge键合层,模拟比较了InGaAs/Si APD性能随键合层厚度的变化情况。研究指出,a-Ge和poly-Ge材料作为键合层对载流子有阻挡或俘获作用,因此器件能够获得超低暗电流,且由于键合层导带势垒对载流子的阻挡作用,APD雪崩之后出现了光暗电流间隙,可以在较小暗电流情况下获得大的光电流。当a-Ge厚度为0.5 nm时,APD雪崩击穿前增益可达最大值451.3,而当poly-Ge厚度为0.5 nm时,雪崩击穿前增益仅为7.9。这种差异是由于poly-Ge键合层处价带出现了势阱,载流子浓度下降。该工作为超低噪声和高增益InGaAs/Si APD的研制提供了理论指导。
Objective InGaAs materials as absorption layers and Si materials as multiplication layers are potential alternatives for achieving high-performance avalanche photodiodes(APDs).However,simple and well-performing InGaAs/Si APDs are difficult to fabricate owing to the 7.7% lattice mismatch between InGaAs and Si.Investigators have recently reported that a-Si was introduced at the InGaAs/Si APD bonding interface to inhibit the nucleation of mismatch dislocations and realize an ultra-low dark current.However,owing to the large bandgap of a-Si,the bonding interface has a large conduction band and valence band offset.This causes the gain of the device to decrease.Ge and Si are both indirect band gap semiconductors,and Ge materials have the advantages of a small gap width and a long absorption cutoff wavelength in the infrared region.Hence,in this study,a method to mitigate the effect of the InGaAs/Si lattice mismatch on APD performance from the source side is theoretically proposed.Here,a-Ge or poly-Ge bond layers are introduced into the InGaAs/Si bond interface,and the variation in the InGaAs/Si APD performance with the bond layer thickness is simulated and compared.In this work,theoretical guidance for the development of ultralow-noise and high-gain InGaAs/Si APDs will emerge.Methods An a-Ge or poly-Ge bond layer is introduced into the InGaAs/Si bond interface,and variations in APD performance with bond layer thickness are simulated and compared.Initially,the optical and dark currents of the APD are simulated and compared considering the thickness of the bonding layer.Subsequently,the recombination rate and carrier concentration of the APD under light conditions are simulated to understand the cause of the change in the APD optical current.To further understand the cause of the change in the electron concentration of the APD,the changes in the APD energy band under light conditions are simulated.Then,the changes in charge concentration,impact ionization rate,electric field,and other parameters with the bond layer thick
作者
鲍诗仪
母浩龙
周锦荣
黄志伟
柯少颖
Bao Shiyi;Mu Haolong;Zhou Jinrong;Huang Zhiwei;Ke Shaoying(College of Physics and Information Engineering,Minnan Normal University,Zhangzhou 363000,Fujian,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2023年第14期50-62,共13页
Chinese Journal of Lasers
基金
国家自然科学基金(62004087)
福建省自然科学基金(2020J01815)
漳州市自然科学基金(ZZ2020J32)。
