Optimization of InGaAs/InAlAs APDs for SWIR detection with demand for high gain and low breakdown voltage

Abstract

ABSTRACT We report on the development and optimization of mesa-processed InGaAs/InAlAs avalanche photodiodes (APD)for short-wave infrared applications with demand for gain and low breakdown voltage. The APDs weregrown by molecular beam epitaxy. Dark and photo current measurements of fully processed APDs reveal highdynamic range of 10 4 and gain larger than 40 for 25 V reverse bias voltage and cooled operation at 140 K. Amaximum gain larger than 300 is demonstrated for room temperature as well as 140 K. Two di erent approachesto determine the gain of the APD structures are discussed.Keywords: InGaAs, short-wave infrared, SWIR, avalanche photodiode, detector, APD, imaging 1. INTRODUCTION High-performance short-wave infrared (SWIR) detectors attain more and more interest, particularly for surveil-lance and reconnaissance applications. The rather high bandgap, compared to mid- and long-wave infrared(MWIR/LWIR) detectors, of the absorber material indium gallium arsenide (InGaAs) enables operation withmoderate or even without any cooling. The signi cantly reduced Rayleigh-scattering, in contrast to wavelengthsof the visible range, enables an improved vision through fog, dust or smoke. A natural light source, i.e. nightglow, with a peak emission at around 1 :6  m,