Texas Instruments Corporation

Monica A Beals

Kalipatnam V Rao

Joel T Tomlin

A method for forming LOCOS isolation regions which includes the steps of forming a polysilicon buffer layer between the pad oxide layer and the nitride layer and forming a sidewall seal around the perimeter of the active moat regions prior to the field oxidation step. The resulting field oxide isolation region has reduced oxide encroachment into the active moat region.

Sidewall-sealed poly-buffered LOCOS isolation

This is a semiconductor device, comprising: a semiconductor body having an isolation region separating at least two active device regions; pad oxide layers disposed on said active regions; polysilicon layers disposed on said pad oxide layers; silicon nitride layers disposed on said polysilicon layers; and a sidewall seal disposed all along the perimeter of the active device regions to seal said active device regions against oxygen diffusion. The resulting field oxide isolation region has reduced oxide encroachment into the active moat region.

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Dallas, TX, United States of America

Monica A Beals