Integrated circuit capacitors and process for making the same

US5614018A · kind A · utility

Assignees

• Symetrix, Inc. · US
• Matsushita Electronics Corporation · JP

Inventors

• Masamichi Azuma · Colorado Springs, US
• Carlos A. Paz de Araujo · Colorado Springs, US
• Michael C. Scott · Colorado Springs, US
• Joseph D. Cuchiaro · Colorado Springs, US

Key dates

• Filing date: Jul 11, 1994
• Grant date: Mar 25, 1997
• Expiry date: Jul 11, 2014

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/682
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A xylene exchange is performed on a stock solution of BST of greater then 99.999% purity dissolved in methoxyethanol, and a carboxylate of a dopant metal, such as magnesium 2-ethylhexanoate is added to form a precursor. The precursor is spun on a first electrode, dried at 400.degree. C. for 2 minutes, then annealed at 750.degree. C. to 800.degree. C. for about an hour to form a layer of accurately doped BST. A second electrode is deposited, patterned, and annealed at between 750.degree. C. to 800.degree. C. for about 30 minutes. Excellent leakage current results if the dopant is magnesium of about 5% molarity. For other dopants, such as Mg, Nb, Y, Bi, and Sn the preferred dopant range is 0.2% to 0.3% molarity. The magnesium-doped material is used as a buffer layer between the electrodes and BST dielectric of an undoped BST capacitor.