One of Sofradir’s overriding strengths is its deep knowledge of and high-level technological expertise in IR, in which it makes significant investments to insure its future competitiveness.
MCT technology: History at a glance
The military first used Mercury Cadmium Telluride (MCT or HgCdTe) technology jointly developed by Sofradir and CEA-Leti, a leading international technology research center, in the 1980s in what was called second-generation IRFPAs (Infrared Focal Planar Arrays). These included a readout integrated circuit (ROIC) for signal pre-processing and multiplexing on the focal plane. This technology first entered the market in the early 1990s.
This move to second-generation IR detectors paved the way for new levels of performance, such as high-resolution scanned arrays featuring time delay integration. Cooled “staring” two-dimensional arrays operating in the medium and long wavelength infrared bands were also developed, known to the industry as “2.5-generation” infrared detectors. These imagers became available commercially in the late 1990s. 2.5-generation IR detectors are recognized by the number of pixels they have, which is typically 320 x 256 and 640 x 512, with a pixel pitch between 15 and 30µm. They are suitable for applications such as FLIR (Forward-Looking Infrared), IR payloads and missiles.
As a result of the major technological improvements made with this generation of MCT cooled staring arrays, it inspired further developments by Sofradir to bring the performance of MCT IR detectors to even higher levels and improve the industrial process. In particular, Sofradir increased the size of the MCT wafer and its uniformity. The size of pixel pitches has been decreased, which has brought about reductions in the size of IR systems and increases in optical resolution.
More work is being done at Sofradir to enhance electro-optical performances, compactness and reliability of its MCT IR detectors, as well as the ability of its IR detectors to operate in all-weather conditions. Researchers at Sofradir, in collaboration with the CEA-Leti, are also working on new technologies to improve performance in ”true” third generation IR detectors, as well as reduce the overall production cost. This is one of the main challenges of cooled IR detectors. These new developments are mainly based on the new MCT material developed from molecular beam epitaxy (MBE) growth.
Big Benefits from Using One Production Line to make Standard and Customized Products
Due to the versatility of its MCT technology, Sofradir is fully equipped to carry out large-scale customization, up to 10,000 units per year, and can produce custom IR detectors with any wavelength using a single production line.