Chapter 1 - HgCdTe Infrared Detectors

Abstract

Significant advances in the areas of mercury cadmium telluride (HgCdTe)material growth, detector array fabrication, and readout integrated circuit (ROIC) design and fabrication have been accumulated over the past 20 years. These advances have led to the demonstration of reliable high-resolution, low-noise and large-format focal plane arrays (FPA). In the 1‑3 μm short wavelength infrared (SWIR) region, high-performance and reliable 1024 × 1024 FPAs for astronomy applications have been developed and 2048 × 2048 arrays are in development. In the 3–5 μm middle wavelength infrared (MWIR) spectral region, high-performance 640 × 480 and 1024 × 1024 FPA have been developed, while 256 × 256 FPA are in continuous production to support systems applications. In the 8–12 μm and beyond long wavelength infrared (LWIR) region, high-performance, 128 × 128 FPA have been developed on CdZnTe substrates. The molecular beam epitaxy (MBE) HgCdTe-based technique has emerged as a viable technology for manufacturing high-performance infrared FPA. Device-quality liquid phase epitaxy (LPE), metal-organic chemical vapor deposition (MOCVD), and MBE material are being grown routinely for applications in the 1.5–16.0 μm spectral region. Excellent control of composition, growth rate, layer thickness, doping concentration, dislocation density, and transport characteristics has been demonstrated. Excellent material quality has made possible high-performance very LWIR 128 × 128 FPAs operating between 40 and 60 K, low-background LWIR detectors operating at 40 K, and MWIR FPA for strategic surveillance applications. The future hopes to see further exploitation of the advances made to further fabricate multicolor FPA and smart FPA with increasing on-chip processing.