Scaling of dark count rate with active area in 1.06μm photon-counting InGaAsP∕InP avalanche photodiodes

Reducing the active area of InGaAsP∕InP avalanche photodiodes operated in Geiger mode is investigated for reducing the dark count rate. The dark count rate in Geiger mode is found to scale linearly with the detector’s active area for mesa diameters of 10, 15, and 20μm. Scaling the mesa size from 20to10μm results in a reduction of the room-temperature dark count rate from 290to44kHz at ∼4.5V of overbias, while the photon detection efficiency is ∼45% for all device diameters. The trade-offs associated with shrinking the active area, including reduced optical coupling and higher on-state resistance, are discussed briefly.