Process for fabricating semiconductor memory device with high data retention including silicon nitride etch stop layer formed at high temperature with low hydrogen ion concentration

US6190966A · kind A · utility

Assignee

• Vantis Corporation · US

Inventors

• Minh Van Ngo · Fremont, US
• Sunil Mehta · Rumford, US

Key dates

• Filing date: Mar 25, 1997
• Grant date: Feb 20, 2001
• Expiry date: Mar 25, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/97

Abstract

A semiconductor memory device such as a flash Electrically Erasable Programmable Read-Only Memory (Flash EEPROM) includes a floating gate with high data retention. A tungsten damascene local interconnect structure includes a silicon nitride etch stop layer which is formed using Plasma Enhanced Chemical Vapor Deposition (PECVD) at a temperature of at least 480.degree. C. such that the etch stop layer has a very low concentration of hydrogen ions. The minimization of hydrogen ions, which constitute mobile positive charge carriers, in the etch stop layer, minimizes recombination of the hydrogen ions with electrons on the floating gate, and thereby maximizes data retention of the device.