Characterization and Modeling of Integrated Photosensors in Standard CMOS Technology

This paper describes the electrical and spectral characteristics of different layers to construct photosensitive elements in standard 1,2 ¿m CMOS technology. The use of commercial CMOS processes guarantees good reproduceability of the integrated sensors and optimized cointegration with sensor signal conditioning circuits. Deep and shallow photosensitive PN diodes and a vertical PNP phototransistor are investigated. Electrical on wafer measurements with optical stimulation are performed and parameter extraction algorithms are established to create SPICE models. These models are suitable for the development of opto-ASICS. The validity of the model is tested using a 0,3 mm² photodiode together with a two-stage transimpedance amplifier with a transimpedance of 5 M¿ at a 3 dB bandwidth of 90 kHz. The whole circuit is packaged using an optically transparent window in a plastic package.