In order to study the effect of different passivation films on the detector performance, the front-illuminated planar-type 256×1 element InGaAs/InP detectors were fabricated with SiN<sub>x</sub> film and SiO<sub>2</sub> film. The SiN<sub>x</sub> film was deposited by plasma enhanced chemical vapor deposition (PECVD) and SiO<sub>2</sub> film was deposited by magnetron sputtering technology. The electrical properties and photoresponse characteristics were investigated after the detector mounted on dewar. The photoresponse maps from laser beam induced current (LBIC) method show that the isolation of adjacent elements of the detector with SiN<sub>x</sub> film is better than the detector with SiO<sub>2</sub> film. Furthermore, at room temperature the average density of dark current and the average peak detectivity of the two kinds of detector is 26.8 nA/cm<sup>2</sup> and 41.2 nA/cm<sup>2</sup> at 100 mV reverse bias, 1.21×10<sup>12</sup> cm·Hz<sup>1/2</sup>/W and 1.08×10<sup>12</sup> cm·Hz<sup>1/2</sup>/W respectively. Therefore, the detector with SiN<sub>x</sub> film deposited by PECVD could availably passivate the surface in comparison with the detector with SiO<sub>2</sub> film by magnetron sputtering technology.
The spectral irradiance of moonlight and air glow is mainly in the wavelength region from visible to short-wave infrared (SWIR) band. The imaging over the wavelength range of visible to SWIR is of great significance for applications such as civil safety, night vision, and agricultural sorting. In this paper, 640×512 visible-SWIR InGaAs focal plane arrays (FPAs) were studied for night vision and SWIR imaging. A special epitaxial wafer structure with etch-stop layer was designed and developed. Planar-type 640×512 InGaAs detector arrays were fabricated. The photosensitive arrays were bonded with readout circuit through Indium bumps by flip-chip process. Then, the InP substrate was removed by mechanical thinning and chemical wet etching. The visible irradiance can reach InGaAs absorption layer and then to be detected. As a result, the detection spectrum of the InGaAs FPAs has been extended toward visible spectrum from 0.5μm to 1.7μm. The quantum efficiency is approximately 15% at 0.5μm, 30% at 0.7μm, 50% at 0.8μm, 90% at 1.55μm. The average peak detectivity is higher than 2×1012 cm·Hz<sup>1/2</sup>/W at room temperature with an integrated time of 10 ms. The Visible-SWIR InGaAs FPAs were applied to an imaging system for SWIR and visible light imaging.