根据行为级模型方法对CMOS 图像传感器的BJPG 晶体管的分析

本文提出一种新的用于CMOS图像传感器像素的光电检测器－－双极结型光栅晶体管。由于引入p^ n注入结，光电荷的读出速率大大增加，改善了CMOS图像传感器的工作速率和响应灵敏度。尽管传统的光电集成电路的电路级模拟采用微电子集成电路的模拟方法，但是光电子集成电路不仅含有微电子器件和电信号还含有光电检测器和光信号，采用传统的集成电路模拟方法有其局限性。本文提出一种行为级模拟方法（光电子检测器设计的新方法，利用C、MATLAB和HSPICE等语言写出光电子器件的模拟器）来模拟分析双极结型光栅晶体管的特性。基于0.6μm CMOS工艺的分析结果表明双极结型光栅晶体管在不同栅氧化层厚度随栅压变化与传统光栅晶体管的特性一样，但光电流密度呈指数式增长且光电流密度增大，因此改善了CMOS图像传感器的工作速率和响应灵敏度。

Analysis of Bipolar Junction Photogate Transistor for CMOS Image Sensor Based on Behavioral Modeling Methodology

In this paper, a new photodetector, the bipolar junction photogate transistor, has been presented. Due to an injection p+n junction introduced, the photo-charges drift through the p+n junction by the applied electronic field and on the other hand the p+n junction inject the carriers into the channel to carry the photo-charges. Therefore the bipolar junction photogate transistor may increase the photo-charges′ readout rate and improve the operating speed of CMOS image sensor. Although it is possible for the study of the circuit-level simulation of the optoelectronic integrated circuit to adopt the methos of the microelectronic circuit-level simulation, the properties of the optoelectronic integrated circuit are differ from those of the microelectronic integrated circuit because there are not only microelectronic devices and electricity signal but also optoelectronic devices and optics signal in the optoelectronic integrated circuit. Therefore we propose the behavioral modeling methodology, which is a novel analytic method in the field of the analysis and simulation of the photoelectron device design, for the bipolar junction photogate transistor in this paper. The device designers can write customized simulators using C code, MATLAB code or HSPICE code to analysis and simulate the characteristics of optoelectronic device. We have simulated the bipolar junction photogate transistor with the technology parameter of the 0.6 μm CMOS process based on the behavioral modeling methodology. The simulated results have illustrated that the bipolar junction photogate has the similar characteristics of the traditional potogate like the relation of the grid voltage and the surface potential under the different oxide thickness. And that the photo current density increases exponentially with the incidence light power due to introducing the injection p+n junction, which means that its operating rate is quicker than the traditional photogate.