Polarization method for minimizing the effects of hydrogen damage on ferroelectric thin film capacitors

US6238933A · kind A · utility

Assignee

• RAMTRON INTERNATIONAL CORPORATION · US

Inventors

• Shan Sun · Wingdale, US
• Steven D. Traynor · Colorado Springs, US

Key dates

• Filing date: May 6, 1999
• Grant date: May 29, 2001
• Expiry date: May 6, 2019

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/682

Abstract

Ferroelectric switching properties are severely degraded in a hydrogen ambient atmosphere. By controlling the polarity of the capacitors in a ferroelectric memory during the manufacturing process, the amount of degradation can be significantly reduced. After metalization of a ferroelectric memory wafer, all of the ferroelectric capacitors are poled in the same direction. The polarization vector is in a direction that helps to counteract hydrogen damage. A hydrogen gas anneal is subsequently performed to control underlying CMOS structures while maintaining ferroelectric electrical properties. The wafer is then passivated and tested.