Thermoelectrically Cooled MWIR Avalanche Photodiodes on Silicon Substrates

Modern Air Force weapon systems need to detect, recognize and track a variety of targets under a wide spectrum of atmospheric conditions. Recent technology developments are paving the way toward imaging optical radars with wavelengths in MWIR range for these applications. The best suited detectors for optical radars are the avalanche photodiodes (APDs) due to their high gain-bandwidth characteristics. Robust silicon-APDs are limited to visible and near infrared region, while InGaAs works well up to wavelengths of about 1.5 microns. Longer wavelength source-detector systems are required to overcome the practical and seasonal conditions of the atmosphere. The semiconductor alloy HgCdTe, with its wavelength tunability over a broad spectral range, high quantum efficiency, low dielectric constant permitting high speed operation, and low noise performance in APDs (due to the resonant enhancement of the ionization coefficient), is an attractive material for MWIR APDs. We propose to use our extensive experience in HgCdTe growth by molecular beam epitaxy (MBE) and device processing to fabricate thermoelectrically cooled MWIR avalanche photodiodes on silicon substrates as single elements and focal plane arrays. The proposing team EPIR Technology- University of Illinois at Chicago integrates the technical strength and extensive knowledge of reputed and accomplished scientists in MBE HgCdTe growth, devices and APD technology.