North American Philips Corporation

Philips Electronics North America Corporation

Len-Yuan Tsou

Satyendranath Mukherjee

Di-Son Kuo

Mark Simpson

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.

Electrically erasable and programmable read only memory with non-uniform

The present invention is directed to a technique for selectively oxidizing trench side walls in a silicon substrate. Each of the side walls can be oxidized individually and to different thicknesses according to the requirements of the trench IC.

Selective oxidation of silicon trench sidewall

An Erasable and Programmable Read Only Memory (EEPROM) cell is provided with an insulated control gate and an insulating floating gate formed in a trench in a semiconductor body. A surface-adjoining drain region is provided alongside an upper portion of a sidewall of the trench, while a source region is provided alongside a lower portion of the trench sidewall, with a channel region extending along the sidewall of the trench between the source and drain regions. The EEPROM cell is programmed by hot electron injection through the sidewall of the trench alongside the channel region, and is erased by Fowler Nordhiem tunneling through a corner region in the bottom of the trench by creating a localized high electric field density in the corner region. In this manner, a highly compact, efficient and durable EEPROM cell is obtained.

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New City, NY, United States of America

Len-Yuan Tsou