Measurement of the mobile ion concentration in the oxide layer of a semiconductor wafer

US5773989A · kind A · utility

Assignees

• University of South Florida · US
• Semiconductor Diagnostics, Inc. · US

Inventors

• Piotr Edelman · Tampa, US
• Andrew M. Hoff · State College, US
• Lubek Jastrzebski · Tampa, US
• Jacek Lagowski · Woburn, US

Key dates

• Filing date: Jul 14, 1995
• Grant date: Jun 30, 1998
• Expiry date: Jul 14, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/4914
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus for measuring the concentration of mobile ions in the oxide layer of a semiconductor wafer from the contact potential shift caused by ion drift across the oxide that includes depositing charge (e.g., using a corona discharge device) on the surface of the oxide and heating the wafer to allow mobile ions in the oxide (especially Na.sup.+) to drift. The difference in the contact potential measured before and after heating provides an indication of the mobile ion concentration in the oxide layer.