Planar InAlAs/InGaAs avalanche photodiode with 360 GHz gain×bandwidth product

This paper describes a guardring-free planar InAlAs/InGaAs avalanche photodiode (APD) by computational simulations and experimental results. The APD adopts the structure of separate absorption, charge, and multiplication (SACM) with top-illuminated. Computational simulations demonstrate how edge breakdown effect is suppressed in the guardring-free structure. The fabricated APD experiment results show that it can obtain a very low dark current while achieving a high gain×bandwidth (GB) product. The dark current is 3 nA at 0.9V_br, and the unit responsivity is 0.4 A/W. The maximum 3 dB bandwidth of 24 GHz and a GB product of 360 GHz are achieved for the fabricated APD operating at 1.55 μm.