Development of T2SLS LWIR focal plane arrays for the hyperspectral thermal imager (HyTI)

In this paper, we will report our recent efforts in achieving high performance in Antimonides type-II strained layer superlattice (T2SLS) based infrared photodetectors using the barrier infrared detector (BIRD) architecture. The high operating temperature (HOT) BIRD focal plane arrays (FPAs) offer the same high performance, uniformity, operability, manufacturability, and affordability advantages as InSb. However, mid-wavelength infrared (MWIR) HOT-BIRD FPAs can operate at significantly higher temperatures (>150K) than InSb FPAs (typically 80K). Moreover, while InSb has a fixed cutoff wavelength (~5.4 µm), the HOT-BIRD offers a continuous adjustable cutoff wavelength, ranging from ~4 µm to >15 µm, and is therefore also suitable for long wavelength infrared (LWIR) as well. The LWIR detectors based on the BIRD architecture has also demonstrated significant operating temperature advantages over those based on traditional p-n junction designs. Two 6U SmalSat mission HyTI (Hyperspectral Thermal Imager) are based on JPL’s T2SLS BIRD FPAs. Based on III-V compound semiconductors, the BIRD FPAs offer a breakthrough solution for the realization of low cost (high yield), high-performance FPAs with excellent uniformity and pixel-to-pixel operability.

本论文将报道我们在基于势垒型红外探测器（BIRD）架构、以锑化物第二类应变层超晶格（T2SLS）为材料的红外光电探测器上实现高性能的最新研究进展。高温工作（HOT）BIRD焦平面阵列（FPAs）具备与锑化铟（InSb）焦平面阵列一致的高性能、高均匀性、优良可操作性、可制造性及成本优势。然而，中波红外（MWIR）HOT-BIRD焦平面阵列的工作温度可显著高于锑化铟焦平面阵列（通常工作于80K），可达150K以上。此外，尽管锑化铟的截止波长固定（约5.4μm），HOT-BIRD架构的截止波长可连续调节，范围覆盖约4μm至15μm以上，因此同样适用于长波红外（LWIR）场景。基于BIRD架构的长波红外探测器，相较于传统pn结设计的同类器件，同样展现出显著的工作温度优势。两项搭载于6U小卫星的高光谱热成像仪（HyTI）任务，均采用了喷气推进实验室（JPL）的T2SLS BIRD焦平面阵列。作为III-V族化合物半导体基器件，BIRD焦平面阵列为实现低成本（高良率）、高性能且具备优异均匀性与像素间可操作性的焦平面阵列提供了突破性解决方案。