激光退火在硅基光电探测器中的应用  

Application of Laser Annealing in Silicon Photodetectors

作　　者：周弘毅[1] 李冲[1] 刘巧莉[1] 董建[1] 王文娟[1] 郭霞[1] 

机构地区：[1]北京工业大学光电子器件研究室,北京100124

出　　处：《半导体光电》2016年第1期36-40,49,共6页Semiconductor Optoelectronics

基　　金：国家自然科学基金项目(61222501;61335004);高等学校博士学科点专项科研基金项目(20111103110019)

摘　　要：分别对p-i-n和n-i-p两种结构的硅基光电探测器的背面离子注入层进行激光退火处理,辐照功率分别为0.5、1、1.25和1.5J/cm^2。根据激光退火激活载流子模式计算了载流子激活率,获得了载流子浓度和接触电阻的变化量。通过对比器件的电学和光学性能,发现采用1.5J/cm^2的激光,离子注入方式得到的硼离子和磷离子的激活率达到75.0%和92.6%,使得p-i-n和n-i-p结构器件的背接触电阻分别从未退火的22.3Ω和15.89Ω降低至7.32Ω和7.63Ω,显著改善了硅基光电探测器的正向特性。在100mV反向偏压下激光退火至少降低了10%的暗电流,并增强p-i-n结构峰值处约1%的光谱响应和n-i-p结构峰值处约5%的光谱响应。The backside ohmic contact of the p-i-n/n-i-p silicon photodetectors was fabricated by the laser annealing.The 532 nm laser was used with the irradiation power of 0.5J/cm^2,1J/cm^2,1.25J/cm^2 and 1.5J/cm^2.The effect of the laser annealing on the silicon photodetectors is in a comprehensive evaluation by comparing the device performance.According to the carriers activation model of the laser annealing,the carrier concentration and contact resistance of backside ion implantation were calculated.There exist strong correlations between fitting calculation and experiment results which show an effective carriers activation by the laser annealing.The laser with the 1.5J/cm^2 irradiation power can activate 92.6% implanted phosphorus ions and 75.0%implanted boron ions.The back contact resistance of p-i-n and n-i-p photodetectors is decreased from 22.3Ωand 15.89Ωto 7.32Ω and 7.63Ω after annealing,respectively.According to the ion implant damage fixed by the laser annealing and the active carriers enhancing the backside electric field,the dark current can be decreased at least 10% at100 mV,and the peak spectral response of p-i-n and n-i-p photodetectors can be increased by at least 1% and 5%,respectively.

关 键 词：激光退火 载流子激活 探测器 欧姆接触 

分 类 号：TN249[电子电信—物理电子学]