Electrically erasable and programmable read only memory with non-uniform dielectric thickness

US5606521A · kind A · utility

Assignee

• Philips Electronics North America Corporation · US

Inventors

• Di-Son Kuo · Hsinchu, TW
• Len Yuan Tsou · New City, US
• Satyendranath Mukherjee · Yorktown Heights, US
• Mark Simpson · Houston, US

Key dates

• Filing date: Jun 28, 1995
• Grant date: Feb 25, 1997
• Expiry date: Jun 28, 2015

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D30/6894

Abstract

An electrically erasable and programmable read only memory (EEPROM) is provided with an insulated control gate and an insulating floating gate in a trench in a semiconductor body. A dielectric layer is disposed along the sidewalls of the trench to separate the floating gate and the semiconductor body. The thickness of the dielectric layer along at least one sidewall of the trench is greater than the thickness of the dielectric layer along the other sidewalls of the trench in order to increase the programming speed due to a higher electric field in the gate oxide along the remaining sidewalls.