Reliable InP-based Geiger-mode Avalanche Photodiode Arrays

Arrays as large as 256 x 64 of single-photon counting avalanche photodiodes have been developed for defense applications in free-space communication and laser radar. Focal plane arrays (FPAs) sensitive to both 1.06 and 1.55 µm wavelength have been fabricated for these applications. At 240 K and 4 V overbias, the dark count rate (DCR) of 15 µm diameter devices is typically 250 Hz for 1.06 µm sensitive APDs and 1 kHz for 1.55 µm APDs. Photon detection efficiencies (PDE) at 4 V overbias are about 45% for both types of APDs. Accounting for microlens losses, the full FPA has a PDE of 30%. The reset time needed for a pixel to avoid afterpulsing at 240 K is about 3-4 µsec. These devices have been used by system groups at Lincoln Laboratory and other defense contractors for building operational systems. For these fielded systems the device reliability is a strong concern. Individual APDs as well as full arrays have been run for over 1000 hrs of accelerated testing to verify their stability. The reliability of these GM-APDs is shown to be under 10 FITs at operating temperatures of 250 K, which also corresponds to an MTTF of 17,100 yrs.U.S. Defense Advanced Research Project Agency (Air Force contract number FA8721-05-C-0002