T2SL manufacturing capability at L3 Space & Sensors Technology Center

L3 Space & Sensors Technology Center (L3 SSTC) has a nearly 60-year history developing and manufacturing infrared (IR) detectors. Starting with crystal growth of indium arsenide antimonide (InAs,,Sbi and lead tin telluride (PbSnTe) crystals for single detectors in the 1960s, we moved into producing linear arrays of InAs and InSb in the 1970s and 1980s, and in the 1990s consolidated production on two dimensional focal plane arrays (FPAs) using commercially available InSb wafers. The tri-service Vital Infrared Sensor Technology Acceleration (VISTA) program rapidly matured III-V semiconductor epitaxy to produce tactically viable detectors using Type II Superlattice (T2SL) structures. Our participation in this program allowed us to develop a manufacturing capability for T2SL higher operating temperature (HOT) mid-wave infrared (MWIR) detectors on 125 mm substrates. Our work started by defining the characteristics of the gallium antimonide (GaSb) substrates. We leveraged the literature from silicon maturation to define the thickness and edge bevel. Next, we worked with the epitaxial suppliers developed under the VISTA program to establish the multi-wafer growth capability. Through a program funded by the Office of the Secretary of Defense (OSD) and managed by the Army Night Vision and Electronic Sensor Directorate (NVESD), we were able to improve FPA yield to match InSb manufacturing levels.