P型掺杂区工艺对Si基Pinned型光电二极管量子效率的影响  

Influence of P-type doping process conditions on the quantum efficiency in silicon-based pinned photodiode

作　　者：曹琛[1] 张冰[1] 王俊峰[1] 吴龙胜[1] 

机构地区：[1]西安微电子技术研究所,陕西西安710071

出　　处：《光电子．激光》2015年第1期54-62,共9页Journal of Optoelectronics·Laser

基　　金：国防预先研究项目基金(51311050301095)资助项目

摘　　要：为了更全面、系统地分析Si基Pinned型光电二极管（PPD,pinned photodiode）量子效率的工艺敏感特性,基于考虑表面（SRH,shockley-read-hall）复合率模型的时域有限差分数值模拟方法,对不同P＋型表面层和P型外延（EPI,epitaxial）层工艺条件下PPD可见光谱量子效率的变化特征及物理机制进行了研究。结果表明,P＋型表面层离子束注入剂量和注入能量的增加分别引起非平衡载流子SRH复合率升高和PPD势垒区顶部下移,均可导致低于500nm波段量子效率的衰减,而后者进一步引起的势垒区纵向宽度缩减使该影响可持续至650nm波段;P型EPI掺杂浓度增加引起PPD势垒区底部上移,导致500~750nm波段量子效率的衰减;P型EPI厚度增加引起衬底强SRH复合区光电荷比重降低,导致高于700nm波段量子效率得到提升并趋向饱和。通过分析发现,Si基材料中光子吸收深度对波长的强依赖关系是导致两种P型掺杂区工艺条件对量子效率存在波段差异性影响的根本原因。In order to analyze the process sensitivity of the quantum efficiency in silicon-based pinned photodiode （PPD） more comprehensively and systematically,based on the finite difference time domain numerical simulation by taking account of surface Shockley-Read-Hall （SRH） recombination rate model, the variation characteristics of the visible spectral quantum efficiency and the corresponding physical mechanisms are both studied under different process conditions of P^＋-type surface layer and P-type epitaxial （EPI） layer. Results show that the quantum efficiency of the wavelength under 500 nm decreases with both the SRH recombination rate increases and the top position of PPD barrier region moves down, which can be induced by the increases ion implant dose and energy of P^＋-type surface layer respectively, and the reduction of the barrier region width further induced by the latter one can make the quantum ef- ficiency attenuation extend to the wavelength of 650 nm. The quantum efficiency of the wavelength be tween 500 nm and 750 nm decreases with the bottom position of PPD barrier region moves up,which can be induced by the increase doping concentration in P-type EPI layer. The quantum efficiency of the wavelength above 700 nrn promotes and tends to be saturation due to the reduction of photo charges in the strong SRH recombination region in substrate,which can be induced by the increase EPI thickness. The significant wavelength differences presented in the influence of P-type process conditions on the quantum efficiency can be fundamentally attributed to the intense dependence of photon absorption depth on the incident wavelength in silicon-based material.

关 键 词：Pinned型光电二极管(PPD) 量子效率 工艺条件 数值模拟 

分 类 号：TN364[电子电信—物理电子学]