Barrett E. Cole

High-temperature superconducting microbolometer

A superconducting microbolometer employing a DyBaCuO film deposited upon a silicon microstructure was found to have a responsivity of 800 V/W at 89 K and a response time of 1 ms.

Micromachined pixel arrays integrated with CMOS for infrared applications

Large arrays of small micromachined structures with low thermal mass and low thermal-conductance above silicon CMOS substrates and operate as (1) sensitive uncooled IR cameras or (2) high-temperature IR projectors. Arrays of small thin micromachined structures with high thermal masses, are suspended above the underlying silicon substrate by supports that are extremely well thermally isolated from the substrate with a high thermal conductance. This high thermal isolation allows for efficient heating of the microstructure with small currents (the case for microemitters), or small amounts of infrared (IR) incident flux (for microbolometers). The low mass ensures that despite the low conductance, the thermal time constants are in the millisecond range. We show the basic microstructure design common to both microbolometers and microemitters.

512×512 Infrared cryogenic scene projector arrays

Abstract A mosaic array of resistively heated microbridges offers much flexibility for infrared scene simulations. Dynamic scene simulations are important for the testing of the real-time performance capability of IR camera and seeker systems. The excellent thermal properties of the emitter pixels achieved with thin films and unique thermal isolation structures make it possible to achieve high temperatures at power levels ≈ 1 μW per pixel per degree temperature rise. High radiance and high dynamic range are achieved by having pixels with high emissivity and high fill factors, which operate with the substrate and drive electronics at cryogenic temperatures to achieve low background radiance. The thermal time constants of the pixels are defined by material properties and pixel design and are in the millisecond range, making it possible to achieve dynamic frame rates in excess of 100 Hz. Two types of cryogenic resistor arrays have been fabricated and are described, 512×512 arrays with pixels on a 3.5 mil pitch, and 128×128 arrays with pixels on a 2 mil pitch.

High performance infrared detector arrays using thin film microstructures

Honeywell has developed a unique uncooled thermal detector technology based on fabricating thin film structures with temperature sensitive detector materials. High TCR resistive materials such as VOx and YBaCuO, and pyroelectric PbTiO/sub 3/ have been used. Two dimensional imaging arrays of sizes up to 240/spl times/336 have been integrated with Si substrate electronics to achieve temperature sensitivities of less than .04 C operating at room temperature. The thin film detector materials are deposited on microstructure thin film pixels of 2 mil sizes which are subsequently thermally isolated from the substrate by etching away the underlying substrate. The thermal isolation of the microstructure pixel provides the temperature rise and the detector material provides the conversion to an electrical signal.