We designed, fabricated and tested a new planar InGaAs/InP Single-Photon Avalanche Diode (SPAD). By optimizing
design and fabrication processes, we obtained low afterpulsing and very good timing jitter, with very fast tail. The
detector has a separate absorption, charge and multiplication structure, with double p-type Zn diffusion into n-type InP
for defining the p-n high-field avalanching junction. The SPAD can be operated at temperatures achievable with thermoelectric
coolers mounted in compact packages (like TO-8). When operated in gated mode with 5 V excess bias, the 25
μm active area diameter InGaAs/InP SPAD reaches good performance at 225 K: i) photon detection efficiency of 40% at
1 μm and 25% at 1.55 μm; ii) dark count rate below 100 kcps (counts per second); iii) low afterpulsing allowing to set a
hold-off time as short as 1 μs, corresponding to 1 Mcps; iv) timing jitter less than 90 ps (full width at half maximum) and
time constant of decaying tail of just 30 ps.
Overall this new planar InGaAs/InP SPAD can be exploited in many near-infrared (up to 1.7 μm) applications where low
light, wide dynamic range waveforms have to be acquired, e.g. in Time-Correlated Single-Photon Counting (TCSPC)
measurements or Time-of-Flight LIDAR applications for eye-safe 3D ranging.