The Anti-Reflection Coating Design for the Very-Long-Wave Infrared Si-Based Blocked Impurity Band Detectors

Abstract

An anti-reflection coating on a back-illuminated 128 × 128 array Si-based blocked impurity band (BIB) detector in a very-long-wave infrared range was designed in this work. The reflectance and transmittance spectra of ZnS films with different thicknesses on intrinsic Si substrates were studied with a FDTD simulation and experiment. Compared to bare Si substrate, the reflectance of Si coated with 1.5, 2.0, 2.5, and 3.0 μm thick ZnS significantly decreased, while the transmittance increased in the range of 10.0~25.0 μm band. The transmittance enhancement ratio reached approximately 32%, 32%, 28%, and 29%, respectively. It was evidenced that the enhanced transmission at a specific wavelength was caused by the effective interference cancellation effect. Then, a 2.0 μm thick ZnS thin film was deposited on the backside of the 128 × 128 array Si-based BIB detector. The spectral responsivity of the detector increased significantly. Additionally, the blackbody responsivity increased by approximately 36%, suggesting that the ZnS film is an ideal anti-reflection material for VLWIR detectors in the range of 10.0~25.0 μm band.

The effect of antireflection coating on the characteristics of wideband silicon avalanche photodetectors

“…For UV antireflective coatings [5][6][7] , the quantum efficiency can reach over 60% by using single or multi-layer antireflective coatings; adopt δ doped CCD can achieve high quantum efficiency in the ultraviolet and visible light bands [8] , and nearinfrared designed antireflection coatings can be applied to aerospace silicon imagers [9] . ZnS thin coatings are ideal antireflection materials for long wave infrared detectors [10][11] . Various research institutions have designed and developed wideband detectors and their antireflection coatings [12][13][14][15][16][17] .…”

Comparative Study of Polarization‐Dependent Conversion Efficiency of GaAs and Si Solar Cells at Oblique Incident Angles Using Surface DLAR Coating of MgF2/ZnSe

“…Thus, anti‐reflection measures are required. [ 7 ] Anti‐reflection coatings (ARCs) have grown in significance and use as a means of enhancing light transmission from windows and screens to eyeglass lenses and cell phone cameras while decreasing light reflection. [ 8 ] A wide range of industries and applications have shown interest in anti‐reflection coatings because of their great stability, high surface hardness, and good attachability.…”