Optimized silicon CMOS reach-through avalanche photodiode with 2.3-GHz bandwidth

Optimizing avalanche photodiodes (APDs) in standard complementary metal–oxide–semiconductor (CMOS) processes is challenging due to fixed doping concentrations of the available wells. A speed-improved APD in pin photodiode CMOS technology for high-sensitivity and high-speed applications using a lateral well modulation-doping technique is presented. The increased operating voltage of the presented device leads to a −3-dB bandwidth of 2.30 GHz with a multiplication factor of 20 for 1-μW optical power. This corresponds to a responsivity of 7.40 A/W. A multiplication factor of 44,500 was measured at 10-nW optical power. The thick absorption zone leads to an unamplified quantum efficiency of 72.2% at 635-nm wavelength.