一种高效的任意梯度掺杂实现方法及其应用  

An Efficient Implementation Method of Arbitrary Gradient Doping and Its Application

作　　者：李全泽 黄尊恺 田犁[1] 祝永新 汪辉[1] 封松林[1] LI Quanze;HUANG Zunkai;TIAN Li;ZHU Yongxin;WANG Hui;FENG Songlin(Shanghai Advanced Research Institute Chinese Academy of Sciences,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海高等研究院,上海201210 [2]中国科学院大学,北京100049

出　　处：《光子学报》2022年第6期222-232,共11页Acta Photonica Sinica

基　　金：国家重点研发计划(No.2019YFC0117302);国家自然科学基金(No.62004201)。

摘　　要：基于菲克定律和电子漂移理论,对离子注入和扩散全过程进行深入理论分析,提出了一种高效的任意梯度掺杂分布的实现方法。以实现线性梯度掺杂分布为例,分别通过模拟计算和工艺仿真验证了该方法的正确性。通过该方法,可以精确地计算离子注入能量、注入剂量,以及热扩散需要的时间等工艺参数,进而针对目标掺杂分布设计特定结构的光刻掩模板,只通过一次离子注入,即可制造具有任意分布函数的掺杂区域。应用该方法设计了一个具有梯度掺杂Photodiode的5μm CMOS图像传感器像素,与同条件下传统工艺的像素进行对照实验,实验结果表明具有梯度掺杂Photodiode的像素内部光生电荷传输效率提升显著;在控制除了Photodiode以外的其他区域结构完全一致的条件下,应用本文方法设计的像素与传统工艺设计的像素相比,在复位阶段对相同栅极电压的响应速度提升了10倍,满阱容量与动态范围提升了20%。In the past twenty years,research heat and market demand for image sensor technologies have grown rapidly,and image technologies are undergoing the transition from Charge-Coupled Device(CCD)to Complementary Metal Oxide Semiconductor(CMOS).Since there are a large number of differences between the two technical difficulties,a lot of research directions have changed,but improving the transmission efficiency of charge in pixels has always been one of the most important research directions.The key point of CMOS Image Sensor(CIS)pixel design is the transfer of photo-generated charge in photo-diode.Especially in applications requiring large pixels,such as medical imaging and astronomical imaging,limited signals need to be detected at high speed,which requires high transmission efficiency of charges in photodiode.Charge transfer is a complex process affected by many factors.It is usually divided into drift,diffusion and self induced drift.In order to improve the charge transfer speed in CIS pixel,a large number of solutions have been proposed.Generally,it can be divided into two directions:increasing the bias electric field externally or generating the potential gradient internally.The method of adding an external bias electric field,has great scenic limitations.The methods of forming internal potential gradient in a photo-diode can be roughly divided into two directions:designing the special shape and manufacturing gradient doping.Designing specific diode shapes,are relatively complex,and the formation of a built-in electric field is actually the cost of reducing the filling factor,which reduces the space utilization and virtually increases the cost of actual production.Manufacturing gradient doping are lack complete theoretical analysis,which will take a lot of time to adjust parameters in practical operation,and there is no rigorous reference value.Therefore,there is a great need for a complete and relatively refined analysis method to provide theoretical support for the design and research of gradient doping.Based on

关 键 词：梯度掺杂 像素 CMOS图像传感器 热扩散 电荷转移 

分 类 号：TN201[电子电信—物理电子学]