CMOS图像传感器光电二极管模型

Modeling of Photodiode for CMOS Image Sensor

为了更好的对CMOS图像传感器中光电二极管的光电转换物理现象进行研究,需要建立正确合适的光电二极管数学物理模型。通过少数载流子稳态连续方程建立光电二极管的一维物理模型,求解方程后,代入参数在MATLAB中对两层结构的n+/p-sub型和n-well/p-sub型,以及三层结构的p+/n-well/p-sub型二极管进行了计算模拟,得到了3种二极管响应率与波长的关系曲线。最后将结果与实际值进行了对比分析,确认了模型能够在一定程度上反映实际的物理情况。

In order to research on the photoelectric conversion phenomena of photodiode for CMOS image sensor,we construct an accurate and reasonable mathematical-physical model. We utilize the minority carrier equilibrium continuity equations to establish an one-dimensional physical model of photodiode. By means of MATLAB,the relationship between responsivity and wavelength of photodiode（ including three types： two-layer structure of n^＋/ p^-sub type and n^-well / p^-sub type,and three-layer structure of p^＋/ n^-well / p^-sub type） is found out. Finally,the simulation results are analyzed and compared with practical data. We confirmed the model can basically reflect the actual physical situation.