P+/Nwell/Psub structure double-junction photodiode is proposed based on standard CMOS process. The photoelectric response model of double-junction photodiode sensor is established. MATLAB simulation is used to compare the photoelectric response sensitivity of single and double-junction photodiode. 3T and CTIA active pixel circuit are designed respectively for double-junction photodiode,and realized with 0. 5 μm CMOS process,the pixel size is 100μm×100μm. The photoelectric conversion characteristics of active pixel circuit is tested under different il-lumination intensity. The peak sensitivity of double-junction photodiode is 0. 59 A/W@440 nm,and the photoelectric conversion sensitivity of double-junction with 3T pixel is 42 V/(lux·S),while photoelectric conversion sensitivity of double-junction with CTIA pixel is 2 243 V/( lux·S ) . The results show that the photoelectric sensor has higher photoelectric conversion sensitivity to weak light with double-junction and CTIA structure. This photoelectric sensor can be used in environmental,biological and medical fluorescence detection.%基于标准CMOS工艺设计了P+/Nwell/Psub双结深光电二极管,建立了双结深光电二极管的光电响应模型,并用MATLAB仿真比较了单、双结光电二极管的光电响应灵敏度。针对双结深光电二极管分别设计了3T和CTIA有源像素电路,单个像素尺寸为100μm×100μm,采用0.5μm CMOS工艺实现。实验测试了在不同光强下有源像素电路的光电转换特性。双结深光电二极管的峰值灵敏度为0.59 A/W@440 nm,双结深的3T像素光电转换灵敏度为42 V/(lux·s),双结深的CTIA像素光电转换灵敏度为2243 V/( lux·s)。结果表明,采用双结深的CTIA光电传感电路对微弱的光具有更高的光电转换灵敏度,可以应用在环境、生物、医学荧光检测中。
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