Texas Instruments Corporation

Raytheon Company

Advanced Technology Materials, Inc.

Howard R Beratan

Scott Robert Summerfelt

Charles M Hanson

James F Belcher

Bruce E Gnade

Chih-Chen Cho

Robert A Owen

Bernard M Kulwicki

Edward G Meissner

Monte A Douglas

Peter S Kirlin

Steven N Frank

William K Walker

Paul O Johnson

Robert J Kyle

Gail D Shelton

James E Robinson

Kevin N Sweetser

Thomas R Schimert

Robert Yung-Hsi Tsu

John H Tregilgas

K R Udayakumar

Kevin Soch

Tony A Owens

Steven E Frank

Ida M Gist

Ferroelectric materials useful in monolithic uncooled infrared imaging use Ca and Sn substitutions in PbTiO3 and also have alternatives with dopants such as Dy, Ho, Bi, Ce, and Fe. The ferroelectrics may also be used in non-volatile integrated circuit memories.

Integrated circuit ferroelectric infrared detector and method

An infrared detector ( ) includes a substrate ( ) having thereon an array of detector elements ( ). Each detector element has a membrane ( ), which includes an amorphous silicon layer ( ) in contact with at least two electrodes ( ) that are made of a titanium/aluminum alloy which absorbs infrared radiation. In order to obtain a desired temperature coefficient of resistance (TCR), the amorphous silicon layer may optionally be doped. The effective resistance between the electrodes is set to a desired value by appropriate configuration of the electrodes and the amorphous silicon layer. The membrane includes two outer layers ( ) made of an insulating material. Openings ( ) may optionally be provided through the membrane.

Infrared detector with amorphous silicon detector elements, and a method of making it

A preferred embodiment of this invention comprises a conductive lightly donor doped perovskite layer (e.g. lightly La doped BST ), and a high-dielectric-constant material layer (e.g. undoped BST ) overlaying the conductive lightly donor doped perovskite layer. The conductive lightly donor doped perovskite layer provides a substantially chemically and structurally stable electrical connection to the high-dielectric-constant material layer. A lightly donor doped perovskite generally has much less resistance than undoped, acceptor doped, or heavily donor doped HDC materials. The amount of donor doping to make the material conductive (or resistive) is normally dependent on the process conditions (e.g. temperature, atmosphere, grain size, film thickness and composition). This resistivity may be further decreased if the perovskite is exposed to reducing conditions. The lightly donor doped perovskite can be deposited and etched by effectively the same techniques that are developed for the high-dielectric-constant material. The same equipment may used to deposit and etch both the perovskite electrode and the dielectric. These structures may also be used for multilayer capacitors and other thin-film ferroelectric devices such as pyroelectric materials, non-volatile memories, thin-film piezoelectric and thin-film electro-optic oxides.

Lightly donor doped electrodes for high-dielectric-constant materials

The invention described is a method of forming an improved dielectric material by adding lead to an original perovskite material having an original critical grain size to form a lead enhanced perovskite material, then forming a layer of the lead enhanced perovskite material having an average grain size less than the original critical grain size whereby the dielectric constant of the layer is substantially greater than the dielectric constant of the original perovskite material with an average grain size similar to the average grain size of the layer. The critical grain size, as used herein, means the largest grain size such that the dielectric constant starts to rapidly decrease with decreasing grain sizes. Preferably, the lead enhanced perovskite material is further doped with one or more acceptor dopants whereby the resistivity is substantially increased and/or the loss tangent is substantially decreased. Preferably, the original perovskite material has a chemical composition ABO , where A is one or more monovalent, divalent or trivalent elements, and B is one or more pentavalent, tetravalent, trivalent or divalent elements.

PB substituted perovskites for thin films dielectrics

A capacitor dielectric with multiple layers of differing high dielectric constant materials such as SrTiO3 and BaSrTiO3 in which an inner layer has a higher dielectric constant but also higher leakage current than outer layers on each side of the inner layer which have lower leakage currents but also lower dielectric constants.

Electrode interface for high-dielectric-constant materials

Micro-bolometer cell structure

A preferred embodiment of this invention comprises a conductive lightly donor doped perovskite layer (e.g. lightly La doped BST,), and a high-dielectric-constant material layer (e.g. undoped BST,) overlaying the conductive lightly donor doped perovskite layer. The conductive lightly donor doped perovskite layer provides a substantially chemically and structurally stable electrical connection to the high-dielectric-constant material layer. A lightly donor doped perovskite generally has much less resistance than undoped, acceptor doped, or heavily donor doped HDC materials. The amount of donor doping to make the material conductive (or resistive) is normally dependent on the process conditions (e.g. temperature, atmosphere, grain size, film thickness and composition). This resistivity may be further decreased if the perovskite is exposed to reducing conditions. The lightly donor doped perovskite can be deposited and etched by effectively the same techniques that are developed for the high-dielectric-constant material. The same equipment may used to deposit and etch both the perovskite electrode and the dielectric. These structures may also be used for multilayer capacitors and other thin-film ferroelectric devices such as pyroelectric materials, non-volatile memories, thin-film piezoelectric and thin-film electro-optic oxides.

Ceramic powder (,) may be disposed within a flexible mold (,and,) to form a dense ceramic wafer (,) by hydrostatic pressing. The ceramic powder (,) may include various types of pyroelectric material or bolometric material. One or more substrates (,and,) may be disposed within the flexible mold (,and,) to form the desired dense ceramic wafer (,). The flexible mold (,and,) may be placed in one or more vacuum sealed bags (,) prior to hydrostatic pressing. Also, a vibration table (,) may be used to minimize any void spaces in the ceramic powder (,) prior to hydrostatic pressing.

Methods of fabrication of ceramic wafers

A method of polishing ferroelectric materials and specifically perovskite materials and still more specifically barium strontium titanate (,) wherein the surface (,) to be polished is initially partially smoothened or planarized by mechanical abrading with final smoothening or planarization provided by a chemical polishing with a polishing wheel using an acidic solution containing essentially the acid, hydrogen peroxide and water. Preferred acids are perchloric acid, acetic acid, nitric acid and combinations thereof.

Chemical polishing of barium strontium titanate

An optical coating for an uncooled focal plane array detector where the optical coating comprises a porous film. The porous film preferably comprises a xerogel.

High MTF optical coating for hybrid UFPA's

A method and structure for etching a thin film perovskite layer (e.g., barium strontium titanate 836) overlying a second material without substantially etching the second material. The method comprises forming a substantially-silicon-free dielectric etchstop layer (e.g., aluminum nitride 858) on a second dielectric layer comprising silicon (e.g., silicon dioxide 818), depositing the perovskite layer over the etchstop layer, forming a mask layer (e.g., photoresist 842) over the perovsklte layer, patterning and removing portions of the mask layer to form a desired pattern, and etching portions of the perovskite layer not covered by the mask layer, whereby the etching stops on the etchstop layer. The structure comprises a substantially-silicon-free dielectric etchstop layer overlying a second dielectric layer comprising silicon, and a perovskite layer having a desired pattern and comprising an etched side overlying a substantially unetched portion of the etchstop layer.

Method and structure for etching a thin film perovskite layer

Thermal sensor (36) may include a thermally sensitive element (50), a first thin film electrode (52) and a second thin film electrode (54). The thermally sensitive element (50) may include a plurality of preferentially-ordered crystals. The first thin film electrode (52) may include a plurality of digits (53) in communication with the thermally sensitive element (50). The digits (53) of the first thin film electrode (52) may be in spaced relation with one another. The second thin film electrode (54) may include a plurality of digits (55) in communication with the thermally sensitive element (50) opposite the first thin film electrode (52). The digits (55) of the second thin film electrode (54) may be in spaced relation with one another and in spaced interposed relation with the digits (53) of the first thin film electrode (52).

Thermal detector with inter-digitated thin film electrodes and method

A thermal sensor (36, 84, 114) comprising a thermal assembly (44, 88, 118) and a signal flowpath (46, 90, 120). The thermal assembly (44, 88, 118) may comprise a thermally sensitive element (50) and a pair of electrodes (52, 54). The thermally sensitive element (50) may generate a signal representative of an amount of thermal radiation incident to the thermally sensitive element (50). The electrodes (52, 54) may collect the signal generated by the thermally sensitive element (50). The signal flowpath (46, 90, 120) may transmit the signal collected by the electrodes (52, 54) to the substrate (34, 82, 112). The signal flowpath (46, 90, 120) may comprise a pair of arms (56, 58, 92, 122) each extending from an electrode (52, 54) and be connected to the substrate (34, 82, 112). The arms (56, 58, 92, 122) may support the thermal assembly (44, 88, 118) in spaced relation with the substrate (34, 82, 112). The arms (56, 58, 92, 122) may be formed of a thermally insulating material.

Thermal isolation of monolithic thermal detector

Method of stress-aligning a thermally sensitive element may comprise the step of forming a thin film layer of thermally sensitive material (80). The thin film layer of thermally sensitive material (80) may be crystallized. A stress alignment layer (82) may be formed in communication with the thin film layer of thermally sensitive material (80). The thin film layer of thermally sensitive material (80) may be heated above a transition temperature of the thermally sensitive material. The stress alignment layer (82) may be expanded relative to the thin film layer of thermally sensitive material (80). The thin film layer of thermally sensitive material (80) may be cooled below the transition temperature of the thermally sensitive material. The stress alignment layer (82) may be compressed relative to the thin film layer of thermally sensitive material (80) as the thin film layer of thermally sensitive material (80) cools below the transition temperature to preferentially-order crystals of the thermally sensitive material.

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Richardson, TX, United States of America

Howard R Beratan