一维0.18μm CMOS光电二极管量子效率的研究与模拟

Quantum Efficiency Analysis and Simulation of One-Dimensional 0.18 μm CMOS Photodiode

为了建立更精确的CMOS光电二极管SPICE模型,使之在像素电路模拟中能够更好地反映实际的光电转换物理现象。使用连续性方程和不同的边界条件对CMOS光电二极管建立了一维物理模型,然后代入普通CMOS0.18工艺参数在温度为300K、反偏电压为2.2V时,对N-diff/P-epi,N-well/P-epi两种结构的二极管量子效率进行了模拟。其中考虑了表面复合速率、外延层厚度、P+衬底与P外延同质结等因素对模拟结果的影响。在此基础上,还对CMOS光栅二极管的量子效率进行了计算。模拟结果符合这些器件已知的特性。

For settling accurate CMOS photodiode SPICE model, this paper utilizes the continuity equation and various boundary conditions to build a CMOS photodiode model. The analytical solution was verified with numerical simulations based on generic 0. 18 μm CMOS process when reverse bias voltage is 2.2 V and T= 300 K. An improved analysis of quantum efficiency including surface recombination velocity, epitaxial doping concentration and depth, P-substrate and P-epitaxial high-low j unction has been derived. With regarding high-low junction effect, we also analysed quantum efficiency of CMOS photogate. The simulation result accords with characteristic of these device.