基于标准CMOS工艺的有源像素单元结构的研究

Research of Active Pixel Structure Based on Standard CMOS Technology

基于标准N阱互补金属氧化物半导体集成电路(CM O S)工艺,设计了P+/N-w e ll/P-sub光电管结构和传统的N+/P-sub光电管结构的有源像素单元。像素单元面积为100μm×100μm,感光面积百分比分别为77.6%和89%,采用了上华0.6μm两层金属两层多晶硅CM O S工艺研制。测试分析结果表明P+/N-w e ll/P-sub结构在暗电流大小,光照响应信号大小,感光灵敏度和感光动态范围上均优于传统的N+/P-sub结构。通过改变复位信号频率,将P+/N-w e ll/P-sub结构像素的感光动态范围提高到139.8 dB,改善了有源像素的感光性能。

In this paper, the research of active pixel sensors with different photodiodes structures is carried out. The photodiodes structures include P^＋/N-well/P-sub and traditional N^＋/P-sub. The size of each pixel is 100 μm × 100 μm, and the fill factor of the two structures are 77.6% and 89% separately. The chip is fabricated in CSMC with 0.6μm double metal double poly CMOS process. Measurement results show that P^＋/N-well/P-sub structure has low dark current, large photo-response, high sensitivity and large dynamic range. When the reset signal frequency is adjusted according to illumination intensity, the total dynamic range of the P^＋/N-well/P-sub sensor can be increased to 139.8 dB. With P^＋/N-well/P-sub structure photodiodes, performance of pixel is improved.