United States of America As Represented by the Secretary of the Air Force

Jonathan M Mooney

Michael N Alexander

James E Murguia

Freeman D Shepherd

Prabha K Tedrow

Jerry Silverman

Steven DiSalvo

Darin J Leahy

Maxwell M Chi

A new kind of thermal detector and thermal imager for infrared radiation. A thermal detector/imager is a device for detecting/imaging in the infrared portion of the electromagnetic spectrum. This produces a video image, where the video brightness is a function of the incident power. The new thermal imager consists of a thermionic thermal detector having: a substrate having a thermal insulating gap; and a reverse biased CoSi.sub.2 diode suspended over the thermal insulating gap of the substrate and which senses temperature of thermionic emission by producing an output signal with a current that changes exponentially with temperature changes. The substrate is a silicon on insulator (SOI) wafer which has said thermal insulating gap on its top surface; an oxide insulator layer that covers the top surface of the thick silicon support layer, including the thermal insulating gap; and support legs placed on the top surface of the oxide insulator layer. The support legs support the reverse biased CoSi.sub.2 diode in place.

Thermionic thermal detector and detector array

The invention provides method and apparatus for fast, accurate, and nondestructive imaging of defects and determining defect densities in solid materials including a semiconductor wafer. A wafer is illuminated on one side by an infrared (IR) source and a camera is placed on the other side of the wafer, to detect IR radiation that is transmitted through such wafer. The inventive method employs an imaging camera, e.g. a focal plane array camera, to image the so illuminated wafer. The wafer material must be substantially transparent in the camera bandwidth but can contain defects that absorb or scatter radiation in such bandwidth. Camera filters are used, for example, to select specific wavelengths or bands of wavelengths, to detect and image precipitates, subsurface defects, residual damage from polishing and other defects.

Locating defects in solid material

Plateau Equalization (PE), automatically optimizes, tracks changes in luminance, and adjusts in real time the display of wide dynamic range imagery from infrared cameras. The PE approach includes an automated contrast control system which uses an infrared camera, a microprocessor, and an 8 bit monitor to display the IR scenes with automatic control of the contrast of the IR data. This system allows 8 bit monitors to be used with 12 bit cameras. The camera acquires IR data which is digitized for the microprocessor. The microprocessor processes the IR data with a plateau equalization program to output digital IR data for the monitor with controlled contrast. The monitor displays the output of the microprocessor. Plateau Equalization occurs as peaks in infrared data are cut off into an assigned plateau value so that the display allocation emphasizes smaller features of interest in the scene and remains immune to flicker noise.

Noise immune automated contrast control for infrared cameras

An improvement of the design of Schottky barrier infrared detector (SBIR) arrays, as taught by Roosild, et al. We describe modifications of the detector unit cell design which maximize the fraction of detector electrode area exhibiting full spectral emission response. In particular we recommend changes in the impurity density profile, or 'doping', under the Schottky electrode. The new detector cell design can result in a two-fold increase in the photoemission of SBIR arrays, which have small detector cell dimensions.

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Winchester, MA, United States of America

Jonathan M Mooney