Monolithic Integration of Photo-Diode and Transimpedance Amplifier in CMOS 90 nm Technology

Herein, we designed and simulated the monolithic integration of photo-diode (PD) and transimpedance amplifier (TIA) in CMOS 90 nm technology. In the standard process, a PN-junction structure with an illuminated area of 39.48 $\mu$m × 39.48 $\mu$m was designed as the PD. The breakdown voltage of the PD is -10.5V. At a reverse bias voltage of 3V, the PD has a dark current of 2.6 pA and a capacitance of 1.03 pF. The TIA is composed of a regulated gate cascode circuit, a differential amplifier paralleling with an edge peak generator. The PD and the TIA are monolithically integrated, the overall transimpedance gain is 40.3 dB$\Omega$, and the bandwidth is 4.1 GHz. The integrated design of PD and TIA could be applied in 5 Gb/s optical receivers.