HIGH-PERFORMANCE BACK-ILLUMINATED INGAAS INALAS MSM PHOTODETECTOR WITH A RECORD RESPONSIVITY OF 0.96 A/W

We report on a high-performance back-illuminated In0.53Ga0.47As/In0.52Al0.48As/InP metal-semiconductor-metal (MSM) detector. A record responsivity of 0.96 A/W at 1.3 mum 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/cm2 and dark current density of 5.6 x 10(-5) A/cm2 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. Therefore, the low capacitance, high-speed MSM photodetector with a large detection area would be very useful to potential new applications.