Ramtron International Corporation

Inmos Limited

Ramtron Corporation

Lee Kammerdiner

Domokos Hadnagy

Tom Davenport

Robert E Jones, Jr

Michael R Reeder

Maria Huffman

Manoochehr Golabi-Khoozani

A lead zirconate titanate ferroelectric film used as the dielectric layer in a ferroelectric capacitor is doped with calcium and/or strontium, and the lead composition selected to improve data retention performance. The chemical formula for the ferroelectric film is: (Pb.sub.v Ca.sub.w Sr.sub.x La.sub.y)(Zr.sub.z Ti.sub.(1-z))O.sub.3 ; wherein v is ideally between 0.9 and 1.3; w is ideally between 0 and 0.1; x is ideally between 0 and 0.1; y is ideally between 0 and 0.1, and z is ideally between 0 and 0.9. In addition, the chemical composition of the ferroelectric film is further specified in that the measured opposite state charge at a specific time and temperature of the ferroelectric capacitor is greater than eight micro-Coulombs per square centimeter, and the rate of imprint degradation is less than fifteen percent per decade.

Use of calcium and strontium dopants to improve retention performance in

A lead zirconate titanate ferroelectric film used as the dielectric layer in a ferroelectric capacitor is doped with calcium and/or strontium, and the lead composition selected to improve data retention performance. The chemical formula for the ferroelectric film is: (Pb.sub.v Ca.sub.w Sr.sub.x La.sub.y)(Zr.sub.z Ti.sub.(1-z))O.sub.3 ; wherein v is ideally between 0.9 and 1.3; w is ideally between 0 and 0.1; x is ideally between 0 and 0.1; y is ideally between 0 and 0.1, and z is ideally between 0 and 0.9. In addition, the chemical composition of the ferroelectric film is further specified in that the measured opposite state charge at a specific time and temperature of the ferroelectric capacitor is greater than eight micro-Coulombs per square centimeter, and the rate of imprint degradation is less than fifteen percent per decade. The method for making the ferroelectric film as the dielectric layer in a ferroelectric capacitor includes sputtering onto a bottom electrode from a target comprising lead zirconate titanate doped with the combination of or subcombinations of calcium, strontium, and lanthanum to a film thickness between 750 Angstroms and 5000 Angstroms. A top electrode is subsequently formed, wherein the top and bottom electrodes are typically noble metals such as platinum. The resultant ferroelectric capacitor is coupled to an integrated MOS transistor to form a ferroelectric memory cell with improved retention performance.

A ferroelectric capacitor for an integrated circuit includes a stack formed by a layer of a noble metal, a layer of a conducting oxide, a layer of a ferroelectric material, another layer of a conducting oxide and another layer of a noble metal. The capacitor can also have another layer of conducting oxide located over the top layer of noble metal and below the first layer of the noble metal. A method of forming the same through establishing one layer over the other and annealing each layer is also disclosed.

Conducting electrode layers for ferroelectric capacitors in integrated

A process of manufacturing selectively restructurable conductive links between circuit elements and corresponding spare elements on a semiconductor. A continuous green light laser directed at a non-conductive amorphous region in the links causes the region to recrystallize. This makes the link electrically conductive thereby joining the circuit elements to a corresponding spare element on the semiconductor. The method permits for high density packing of circuit elements and creates a link without producing bulk material movement.

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Avondale, CO, United States of America

Lee Kammerdiner