InGaAsP/InP Geiger-Mode Avalanche Photodiode Towards Sub-kHz Dark Count Rate at 20% Photon Detection Efficiency

Geiger-mode InGaAsP/InP single photon avalanche photodiode (SPAD) with a low dark count rate (DCR) of 870 Hz at a photon detection efficiency (PDE) of 20% at 1064 nm is achieved for a 40 micron diameter device at −30 °C. Extensively optimized and accurately controlled shallow/deep two-step pn junction and doping profiles are identified to play decisive roles for the performance improvement. While a state-of-the-art specific detectivity of 1.4×10
¹⁴
cm·Hz
^1/2
/W is realized for the optimized SPAD, a temperature coefficient of the breakdown voltage (V
_br
) of 139 mV/K, a dark current of 200 pA at 90%V
_br
and a timing jitter of 280 ps at 20% PDE are also simultaneously attained. Thermal activation energies of approximate 0.5 eV are observed for both the dark current and the DCR at 253–293 K, indicates the dominant source of dark carriers is the mid-gap defect trapping states-related tunneling in the InGaAsP absorber.