Raytheon Vision Systems (RVS) is producing large format, high definition HgCdTe-based MWIR and SWIR focal plane
arrays (FPAs) with pitches of 15 μm and smaller for various applications. Infrared sensors fabricated from HgCdTe
have several advantages when compared to those fabricated from other materials -- such as a highly tunable bandgap,
high quantum efficiencies, and R0A approaching theoretical limits. It is desirable to operate infrared sensors at elevated
operating temperatures in order to increase the cooler life and reduce the required system power. However, the
sensitivity of many infrared sensors, including those made from HgCdTe, declines significantly above a certain
temperature due to the noise resulting from increasing detector dark current.
In this paper we provide performance data on a MWIR and a SWIR focal plane array operating at temperatures up to
160K and 170K, respectively. The FPAs used in the study were grown by molecular beam epitaxy (MBE) on silicon
substrates, processed into a 1536x1024 format with a 15 μm pixel pitch, and hybridized to a silicon readout integrated
circuit (ROIC) via indium bumps to form a sensor chip assembly (SCA).
This data shows that the noise equivalent delta temperature (NEDT) is background limited at f/3.4 in the SWIR SCA
(cutoff wavelength of 3.7 μm at 130K) up to 140K and in the MWIR SCA (cutoff wavelength of 4.8 μm at 115K) up to