Finmeccanica (formerly Selex ES) introduced high performance mercury cadmium telluride (MCT) infrared detectors on an 8μm pitch in 2015 with their SuperHawk device which builds on standard production processes already used for the manufacture of 24μm, 20μm, 16μm and 12μm pitch devices. The flexibility of the proprietary Finmeccanica designed diode structure, used in conjunction with the mature production Metal Organic Vapour Phase Epitaxy (MOVPE) MCT growth process at Finmeccanica, enables fine control of diode electrical and optical structure including free choice of cut-off wavelength. The mesa pixel design inherently provides major system performance benefits by reducing blurring mechanisms, including optical scattering, inter-pixel cross-talk and carrier diffusion, to negligible levels. The SuperHawk detector has demonstrated unrivalled MTF and NETD performance, even when operating at temperatures in excess of 120K. The SuperHawk Integrated Detector Cooler Assembly (IDCA) benefits from recent dewar developments at Finmeccanica, which have improved thermal efficiencies while maintaining mechanical integrity over a wide range of applications, enabling use of smaller cryo-coolers to reduce system SWAP-C. Performance and qualification results are presented together with example imagery. SuperHawk provides an easy high resolution upgrade for systems currently based on standard definition 16μm and 15μm infrared detector formats. The paper also addresses further work to increase the operating temperature of the established 8μm process, exploiting High Operating Temperature (HOT) MCT at Finmeccanica, as well as options for LWIR variants of the SuperHawk device.
The fabrication of high performance infrared detectors using mercury cadmium telluride (MCT) grown on GaAs substrates by Metal Organic Vapour Phase Epitaxy (MOVPE) is now an established mature production process at Selex ES. Recent years have seen a substantial reduction in MCT pixel sizes, driven by system requirements for increased resolutions, lower power consumption and reduced costs. From initial devices with 30μm pixels, previous developments have produced MOVPE grown MCT arrays of 24μm, 20μm and 16μm pixels with response in short, long, mid and dual wavebands (SWIR, LWIR, MWIR and DWIR). High definition (HD) format and multi-megapixel arrays of 12μm MWIR pixels have also been produced using MOVPE grown MCT. The mesa structure of MOVPE grown MCT pixels inherently controls optical scattering, inter-pixel cross-talk, carrier diffusion and other blurring defects to negligible levels. This allows the goal for pixel size reduction to ultimately be determined by optical diffraction and Nyquist- Shannon sampling criteria alone.
This paper discusses the development of a new MCT detector at Selex ES, introducing the next generation of small pixels on an 8μm pitch. Transition to smaller silicon design rules has enabled the pixel size reduction in the read-out integrated circuit (ROIC) to be achieved with minimum sacrifice of storage capacity. The ROIC has a completely digital control with on-chip digital generation of photodiode bias voltage. Low power proximity electronics providing a fully digitised output have been developed to ease interface with the detector. Characteristics of the pixel design together with measured performance of the detector and its application to infrared sensor development, including updates of standard definition (SD) products to HD and better performance, will be addressed.
A highly ruggedized infra-red sensor module has been developed which is suitable for a variety of fast framing
applications in hostile fire detection and in scientific or industrial metrology. The sensor offers <1000fps in the full
384x384 format and useful images up to 6500fps in smaller formats. High operability for either mid-wave or long-wave
IR applications is assured with high performance MOVPE fabrication technology. The paper reports design concepts
and performance data for the MW variant.