InGaAs/Si avalanche photodiodes fabricated by wafer bonding

摘要

We report here on wafer-bonded InGaAs/Si avalanche photodiodes (APDs) demonstrating very low excess noise factors that were fabricated using a high-yield, wafer-scale bonding process. The bonding interface quality was evaluated using high-resolution x-ray diffraction and dark current measurements. Measured dark currents on 20 μm diameter mesas are 25 nA and 170 nA at gains of 10 and 50, respectively. Low excess noise factors, which are predicted due to the superior noise properties of Si as a multiplication layer, were measured to be more than 3 times lower than commercial InGaAs/InP APDs at a gain of 10, and more than 9 times lower at a gain of 50. The corresponding electron/hole ionization coefficient ratio k in these devices is as low as 0.02.