基于表面微结构与深沟道隔离协同的近红外响应增强CMOS图像传感器设计

Design of Near Infrared Response Enhancement CMOS Image Sensor Based on Surface Microstructure and Deep Channel Isolation

阐述普通单晶硅在近红外区域消光系数偏低,需要设计不同表面微纳结构提升光程,以增加对近红外光的吸收,提高信噪比。然而,表面微纳结构将恶化传感器的暗电流和光学串扰,降低清晰度和分辨率。因此,在设计端需要将微纳结构与深沟道隔离协同处理,已达到提升红外吸收与降低光学串扰,同时平衡外延硅层结构破坏带来的噪声。探讨光学仿真和实验倒金字塔型与几何沟槽型表面微结构的红外增强水平,对比测试了其光学性能、暗电流与白点水平,得到电学与光学性能的平衡设计方案。

This paper describes that the extinction coefficient of ordinary monocrystalline silicon is low in the near-infrared region,and it is necessary to design different surface micro/nano structures to improve the optical path,so as to increase the absorption of near-infrared light and improve the signalto-noise ratio.However,the surface micro/nano structure will deteriorate the dark current and optical crosstalk of the sensor,and reduce the definition and resolution.Therefore,the micro/nano structure and deep channel isolation need to be processed together at the design end to improve infrared absorption and reduce optical crosstalk,while balancing the noise caused by the structural damage of the epitaxial silicon layer.It discusses the infrared enhancement level of optical simulation and experiment inverted pyramid and geometric groove surface microstructures,compares their optical performance,dark current and white point level,and obtains a balanced design scheme of electrical and optical performance.