Producing phototransistors in a standard digital CMOS technology

Development of a standard CMOS fingerprint identification system has necessitated the search for a photodetector with the optimum performance of responsivity, crosstalk, dynamic range, and matching parameters. Pixel resolution is also important in order that fingerprint features on the order of 80 /spl mu/m may be detected. This paper discusses six phototransistor configurations easily produced in CMOS technology and compares their experimental performance.