Abstract
The integration of photodetectors for optical com- munication into standard nanoscale CMOS process technologies can enable low cost for emerging high volume short-reach parallel optical communication. Whereas past work has highlighted the challenges that face integrated photodetectors in highly sca led CMOS technologies, this work e xamines the opportunities af- forded by these new technologies. First, scaling promises improved extrinsic photodetector bandwidth thanks to improved TIA p er- formance. Second, modern advanced process features enable new photodetector structures with improved performance. A phototransistor employing deep n-wells is charact erized in 65-nm CMOS and exhibits a more than ten-fold increase in responsivity over a similar structure without t he buried n-well. Third, equal- ization techniques bene fit from technology scali ng and are only just beginning to be applied to CMOS integrated photodetectors. In particular, decision feedback equalization appears to offer potential for 10+ Gbps operation.