CMOS图像传感器钳位光敏二极管夹断电压模型研究

A novel analytical model of pinch-off voltage for CMOS image pixels with a pinned photodiode structure is proposed. The derived model takes account of the gradient doping distributions in the N buried layer due to the impurity compensation formed by manufacturing processes; the impurity distribution characteristics of two boundary PN junctions located in the region for particular spectrum response of a pinned photodiode are quantitative analyzed. By solving Poisson＇s equation in vertical barrier regions, the relationships between the pinch-off voltage and the corresponding process parameters such as peak doping concentration, N type width and doping concentration gradient of the N buried layer are established. Test results have shown that the derived model features the variations of the pinch-off voltage versus the process implant conditions more accurately than the traditional model. The research conclusions in this paper provide theoretical evidence for evaluating the pinch-off voltage design.     

一种新型开关电容共模反馈电路

本文设计了一种应用于CMOS全差分折叠共源共栅结构运放中的开关电容共模反馈(SC-CMFB)电路。同传统结构的SC-CMFB电路相比,该结构能够使输出共模电平具有零延迟建立的特性,同时,共模反馈电路所需的电容减少了一半,控制时序也相对简单。基于HspiceD对电路进行了仿真验证,结果表明,该结构的共模电平建立时间相对于传统结构缩短了至少六个周期。     

基于BP神经网络的手部尺寸预测模型构建

针对手部尺寸测量项目多、繁杂的问题,文章提出构建基于数据驱动的数学模型来预测手部尺寸的方法。通过三维扫描仪采集232名在校女大学生手部三维点云数据,构建辅助点、线、面标准化测量方法,获取人33项特征部位尺寸,运用主成分分析得到影响手部形态的5个因子,采用相关指数最大值法获取手长、手宽、中指长、食指近位指关节围、无名指到腕中心距离5个典型指标,分别构建了BP神经网络、多元线性回归手部尺寸预测模型。结果表明：BP神经网络预测模型的MAE较低,相关性系数R²接近于1.000,25项手部尺寸的Sig.值大于0.050,预测效果良好,稳定性较高。研究结果可为通过少量易测量的手部尺寸预测其他手部尺寸提供参考。     

一种串扰抑制型倒U掩埋式掺杂钳位光敏二极管光电特性研究

A design of an inverse U-shape buried doping in a pinned photodiode(PPD) of CMOS image sensors is proposed for electrical crosstalk suppression between adjacent pixels.The architecture achieves no extra fill factor consumption,and proper built-in electric fields can be established according to the doping gradient created by the injections of the extremely low P-type doping buried regions in the epitaxial layer,causing the excess electrons to easily drift back to the photosensitive area rarely with a diffusion probability; the overall junction capacitance and photosensitive area extensions for a full well capacity(FWC) and internal quantum efficiency(IQE) improving are achieved by the injection of a buried N-type doping.By considering the image lag issue,the process parameters of all the injections have been precisely optimized.Optical simulation results based on the finite difference time domain method show that compared to the conventional PPD,the electrical crosstalk rate of the proposed architecture can be decreased by 60%–80% at an incident wavelength beyond 450 nm,IQE can be clearly improved at an incident wavelength between 400 and 600 nm,and the FWC can be enhanced by 107.5%.Furthermore,the image lag performance is sustained to a perfect low level.The present study provides important guidance on the design of ultra high resolution image sensors.     

CMOS图像传感器4T像素本底噪声分析

为了抑制本底噪声,提高图像动态范围,首先给出CMOS图像传感器的4T像素结构,分析该结构下的基本噪声源.然后,分别讨论了各本底噪声分量的形成及对信号的影响,并以噪声电子数的形式对各噪声分量进行了定量分析,提出了相应的噪声抑制措施,且进行了仿真验证.     

一种提升4T-APS像元量子效率的方法

通过调整钳位光电二极管P+层掺杂浓度与阈值注入浓度,抑制了4T-APS像元传输管亚阈值漏电,提升了像元的满阱能力与量子效率,并应用TCAD工具进行了仿真验证.结果表明,像元满阱容量可由3500e-提升至7900e-,550nm入射光条件下量子效率可提升27.8%.     

激波诱导非晶合金Fe78B13Si9的晶化

用ＸＲＤ和ＤＴＡ研究了波对Ｆｅ７８Ｂ１３Ｓｉ９非晶合金的影响。结果表明，一定强度的激波能使非晶态转变为晶态，且其晶粒尺寸在纳米范围内。