A 0.5-V P-Well/Deep N-Well Photodetector in 65-nm CMOS for Monolithic 850-nm Optical Receivers

This letter presents the design, measurement results, and modeling formula of a P-well/deep N-well photodetector (PD) realized in a standard 65-nm complementary metal-oxide-semiconductor without process modification. With 0.5-V reverse bias (VPD), the measured dc responsivity to an 850-nm light source is 51 mA/W and the -3-dB bandwidth is 500 MHz. Besides, a seamless cosimulation of the PD and the following receiver circuits are presented. Optical measurement results show that under 0.5-V VPD, the optical receiver achieves a new record data rate of 9 Gb/s for 2¹⁵-1 pseudorandom binary sequence with 10^-12 bit error rate and -4.2-dBm optical input sensitivity.