Recovery of electronic properties in hydrogen-damaged ferroelectrics by low-temperature annealing in an inert gas

US6322849A · kind A · utility

Assignees

• Symetrix, Inc. · US
• Spemens AG · DE

Inventors

• Vikram Joshi · Los Gatos, US
• Narayan Solayappan · Colorado Springs, US
• Walter Hartner · Munich, DE
• Gunther Schindler · Hersbruck, DE

Key dates

• Filing date: Nov 13, 1998
• Grant date: Nov 27, 2001
• Expiry date: Nov 13, 2018

Classification

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

Abstract

An integrated circuit is formed containing a metal-oxide ferroelectric thin film. An inert-gas recovery anneal is conducted to reverse the degradation of ferroelectric properties caused by hydrogen. The inert-gas recovery anneal is conducted in an unreactive gas atmosphere at a temperature range from 300.degree. to 1000.degree. C. for a time period from one minute to two hours. Preferably, the metal-oxide thin film comprises layered superlattice material. Preferably, the layered superlattice material comprises strontium bismuth tantalate or strontium bismuth tantalum niobate. If the integrated circuit manufacture includes a forming-gas anneal, then the inert-gas recovery anneal is performed after the forming-gas anneal, preferably at or near the same temperature and for the same time duration as the forming-gas anneal. The inert-gas recovery anneal obviates oxygen-recovery annealing, and it allows continued use of conventional hydrogen-rich plasma processes and forming-gas anneals without the risk of permanent damage to the ferroelectric thin film. The unreactive gas atmosphere can contain a pure unreactive gas or a mixture of unreactive gases. The unreactive gas can be any relativ…