Development of InGaAs/GaAsSb type-II QW SWIR focal plane array with cutoff-wavelength of 2.5 µm (Conference Presentation)

Abstract

Short wavelength infrared (SWIR) focal plane array (FPA), has an attractive application such as night vision, chemical sensing, remote monitoring of infrastructure and so on. In spite of the many trials on alternative material, FPA with HgCdTe (MCT) keep predominant position in SWIR region, especially over wavelength of 1.7μm. However, MCT is not suitable for commercial application due to its containing environmentally hazardous substances. For a commercial use, so far, Sumitomo Electric has developed FPA with InGaAs/GaAsSb type-II quantum well structures, which are based on maturity of III-V compound semiconductor epitaxial and device fabrication technology. Recently, we have successfully extended cutoff-wavelength up to 2.5μm, which showed comparable spectral range to MCT. By adopting asymmetrically the thicker layer of InGaAs in quantum wells, we modified spectral response related to the type-II transition in the quantum well. The 250-pair InGaAs/GaAsSb quantum wells structure lattice-matched InP substrates were grown by metal organic vaper phase epitaxy. The p-n junction of each pixel was formed by selective zinc diffusion. Dark current density was less than 1μA/cm2 at 213K, which means comparably to low dark current of MCT. Temperature dependence of dark current density showed diffusion current limited mode. These results means InGaAs/GaAsSb type-II FPA is a promising candidate for commercial applications. In the presentation, we will report the characteristics of InGaAs/GaAsSb type-II quantum well and the operational results of SWIR FPA.