High-performance back-illuminated InGaAs/InAlAs MSM photodetector with a record responsivity of 0.96 A/W

A high-performance back-illuminated In/sub 0.53/Ga/sub 0.47/As/In/sub 0.52/Al/sub 0.48/As/InP metal-semiconductor-metal (MSM) detector is reported. A record responsivity of 0.96 A/W at 1.3- mu m wavelength, corresponding to a quantum efficiency of 92%, was measured at 5 V and showed virtually no internal gain at 20 V. Packaged devices with 150- mu m-diameter large detection area showed a 3-dB bandwidth of 4 GHz at 5 V with fiber pigtail butt-coupled package and 3.5 GHz with fiber pigtail silicon V-grooved package. Switching to front-illumination improves the bandwidth by 30-40% with 45-50% reduction of responsivity. Planar and mesa devices both show a low capacitance per unit area of 3.0 nF/cm/sup 2/ and dark current density of 5.6*10/sup -5/ A/cm/sup 2/ at 5 V. Preliminary reliability test results show that the detector biased at 5 V survived temperature cycling of -35 degrees C to 200 degrees C, high-temperature burn-in at 125 degrees C for 168 h and subsequent short-term accelerated aging at 200 degrees C for 120 h without degradation.<
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