Large Fill Factor, High Aspect Ratio Dual Band Superlattice Detectors and Focal Plane Arrays

We propose the development of an improved fabrication process for the mid-wave and long-wave infrared (MWIR, LWIR) focal plane arrays (FPA) based on nBn, InAs/InAsSb, Type II Superlattice (T2SL) structures. The Phase I effort will demonstrate an etch process to achieve a trench with large depth (at least 10 µm), high aspect ratio (trench widths below 4 µm), and V-shaped sidewalls. This etch process and the resultant detectors are critical steps towards an FPA using T2SL structures and achieving small pixels, large array formats (> 512×512), and high optical fill factors. Performance metrics for Phase I focus on the mesa geometry and surface characteristics, but ultimate goal of the effort is to develop a manufacturable, dual-band, IR FPA that meets the needs of Army applications such as night vision and missile defense.