An InGaAs/AlAsSb Avalanche Photodiode With a Small Temperature Coefficient of Breakdown

Dark current and avalanche gain M on AlAs_0.56Sb_0.44 (hereafter referred to as AlAsSb) separate absorption multiplication (SAM) avalanche photodiodes (APDs) were measured at temperatures ranging from 77 K to 300 K. To avoid possible ambiguity in breakdown voltage due to edge breakdown and tunneling current, a phase-sensitive detection method with a tightly focused light spot in the center of the device was employed to measure M accurately. An extrapolation of 1/M to zero was used to deduce the breakdown voltage, from which the temperature coefficient of breakdown voltage Cbd was derived. The value of C_bd 1/4 8 mV/K, obtained for AlAsSb SAM APDs, is much smaller than that for commercial Si and InGaAs/InP APDs, as well as other SAM APDs in the literature, demonstrating the potential of AlAsSb avalanche regions in improving the thermal stability of APDs.