High-Speed High-Efficiency Photon-Trapping Broadband Silicon PIN Photodiodes for Short-Reach Optical Interconnects in Data Centers

Monolithic integration of high-speed, high-efficiency photodiodes with receiver electronics on a single silicon chip is a key to reduce cost and improve the performance of data centers’ short reach optical interconnects. We report a CMOS-compatible surface illuminated silicon PIN photodiode with integrated micro- and nano-scale holes that trap photons for longer interaction with semiconductors resulting in higher absorption efficiencies. The fabricated photodiode demonstrates more than 55% external quantum efficiency (EQE) at 850 nm, and a measured Full-Width at Half Maximum (FWHM) impulse response of 29 ps, 31 ps, and 34 ps at 15 V, 10 V, and 3 V reverse biases, respectively. Simulation results indicate the possibility of operation up to 12.5 Gb/s (NRZ) with no equalization.