基于HV-CMOS工艺集成PIN光敏元的CMOS传感器设计

PIN光电二极管相对于pn结型光电二极管具有结电容小、量子效率高等优点,但采用标准低压CMOS(LV-CMOS)工艺研制的CMOS传感器只能实现基于n阱/p衬底的pn结光敏元与片上电路的集成,高压CMOS(HV-CMOS)工艺的发展为CMOS电路与PIN光敏元列阵的单片集成提供了可能。基于HV-CMOS工艺设计了一种集成PIN光敏元列阵的CMOS传感器,并对器件的光电响应进行了测试评估。结果表明,集成PIN光敏元的CMOS传感器具有更高的像素增益和量子效率,而暗电流、输出摆幅、线性度等特性保持良好。在500~900nm宽波段范围内,器件的量子效率均达到80%以上,在950nm附近的量子效率达到25%,优于采用其他工艺制作的CMOS传感器。

Design of CMOS Sensor Integrated with PIN Photodiodes by HV-CMOS Process

Compared with pn photodiodes, PIN photodiodes present the advantages of small junction capacitance and high quantum efficiency. However, the CMOS sensors fabricated with standard low-voltage CMOS (LV-CMOS) process can only realize the integration of pn photosensitive elements formed by n-well/p substrates and on-chip circuits. The development of high voltage CMOS (HV-CMOS) process makes it possible to integrate CMOS circuits with PIN photosensitive elements on a single chip. In this paper, based on HV-CMOS process, the CMOS sensor integrated with PIN photosensitive array was designed, and the photoelectric response of the device was tested and evaluated. The results show that CMOS sensor integrated with PIN photosensitive elements has higher pixel gain and quantum efficiency, while its dark current, output swing, linearity and other properties remain good. The quantum efficiency of the devices is higher than 80% in the broad band range of 500~900nm, and reaches 25% near 950nm, which is better than that of CMOS sensors fabricated with other processes.