State-of-the-art HgCdTe infrared devices

Mercury Cadmium Telluride (HgCdTe) material growth, detector array fabrication and Read Out Integrated Circuit (ROIC) design and fabrication technologies have continued to advance and have led to the demonstration of high resolution. low noise and large format reliable hybrid Infrared Focal Plane Arrays (IRFPAs). MBE HgCdTe-based p-on-n planar heterostructure device technology has matured to a point that high performance IREPAs are being fabricated routinely for applications in the 1-16 mu m spectral region. Control and flexibility have proven to be distinct advantages of MBE. Rapid advances in the commercial submicron SI-CMOS process continue to allow increasing functionality on ROICs. Hybrid focal plane arrays, formed by cold welding of indium columns deposited on the detector and the ROIC, are being fabricated to suit a broad range of military, civilian and scientific applications. High performance HgCdTe/CdZnTe 256 x 256, 640 x 480 and 1024 x 1024 focal plane arrays operating over a broad range of wavelengths, temperatures, and background radiation flux, have been produced. To mitigate issues associated with the thermal expansion coefficient mismatch between Si ROIC and CdZnTe substrate, growth of HgCdTe on alternate substrates, such as Si and sapphire. has been developed for large, 1024 x 1024 and 2048 x 2048 HgCdTe FPAs operating in the Short Wavelength infrared (SWIR) 0.9-2.5 mu m and Mid Wavelength Infrared (MWIR) 2.5-5.5 mu m spectral bands. Simultaneous two-color IR imaging has been proven feasible, using MBE in situ grown multilayer structures. Hybrid Visible Silicon Imager (HyViSiI), when detectors are processed on silicon and hybridized to the same ROIC fabricated originally for HgCdTe devices, is emerging as a competitive technology for imaging in the 0.3 - 1.05 mu m spectral region. This paper provides an overview of the status of HgCdTe materials, detectors and FPA technologies at Rockwell Science Center.