多Tap时间分辨型光传感像元电荷调制机理研究

To realize the charge modulation of the photoelectric signal in the pixel is a key problem to break through the acquisition of the depth information from the light intensity response of the traditional image sensor. When the integral APS pixel is used for TOF distance measurement, There are many problems such as low quantum efficiency of near infrared spectrum, small response bandwidth of PPD structure, slow charge transfer caused by barrier of transmission node, and occupying capacity by background light, which limits the measurement range and accuracy. This project is based on the high precision of TOF sensor resolution when the pixel charge modulation method for the target, quantum theory to analyze the CIS process conditions, material properties and other parameters based on the established system constraint model, the device to carry out the near infrared wavelengths of high bandwidth and quantum efficiency of structure research; through the analysis of the potential distribution of the transmission gate channel, build the three-dimensional potential model, mechanism of double channel using two-dimensional electron gas, to carry out research on high potential distribution mechanism of vertical drift field formed by the noise transfer function; research on the key technology of multi channel charge modulation in pixel to carry out background light suppression, high accuracy and resolution when solving the basic and key location the problem. Finally, the rationality of the research conclusions is demonstrated by model parameter extraction and testability design. The research results will provide a theoretical foundation for the development of TOF ranging measure, 3D imaging chip and system based on APS pixel.

实现光电信号在像元内的电荷调制是突破传统图像传感器由光强度响应向深度信息获取的关键性问题。传统积分型APS像元开展TOF应用存在硅基材料近红外频谱量子效率低、PPD结构响应带宽小、传输栅势垒引发电荷转移慢、背景光占据阱容等问题，限制了测量范围和精度。本项目以研究TOF传感器的高精度辨时像元电荷调制方法为目标，基于量子阱理论对CIS工艺条件、材料特性等参数进行分析，建立完备的系统约束模型，开展近红外波段高带宽与量子效率的器件结构研究；通过对传输栅沟道电势分布的分析，利用二维电子气机理建立体、表双沟道电势模型，开展形成垂直电势分布的高漂移场机理研究；通过噪声传函反推法，开展像元内背景光抑制的多通路电荷调制关键技术研究，解决高精度辨时测距的基础性和关键性问题。最终通过模型参数提取及可测性设计论证研究结论的合理性，研究成果将为基于APS像元的TOF测距、3D成像芯片和系统的研制奠定理论基础。

本项目以研究TOF传感器的高精度辨时像元电荷调制方法为目标，基于量子阱理论对CIS工艺条件、材料特性等参数进行分析，建立了完备的系统约束模型，开展了近红外波段高带宽与量子效率的器件结构研究；通过对传输栅沟道电势分布的分析，利用二维电子气机理建立体、表双沟道电势模型，形成垂直电势分布的高漂移场机理研究；通过噪声传函反推法，实现了像元内背景光抑制的多通路电荷调制关键技术研究，解决了高精度辨时测距的基础性和关键性问题。最终通过试制与测试完成对上述研究成果的验证。该项目成果包括：实现了一款像素数>7万；Cmod>50%@80MHz；QE>15%@940nm；ADC有效位>11bit的iTOF近红外传感器研制；基于该研制器件开发了一款flash型激光雷达原型机，其雷达指标为：320×240分辨率；80m量程，精度1%（10%反射率），动态范围90dB。该项目的研究成果将为基于APS像元的TOF测距、3D成像芯片和新探测机理的激光雷达系统研制奠定理论基础。