International Business Machines Corporation

David K Lord

Chung H Lam

Judith A Wright

Steven J Holmes

James Spiros Nakos

Jerome Brett Lasky

Stephen Frank Geissler

Craig M Hill

A semiconductor trench capacitor structure having a first level aligned insulation structure and buried strap that extends from within the trench into the semiconductor substrate. The semiconductor trench capacitor structure may be fabricated by forming a shallow trench extending into both the trench capacitor and the semiconductor substrate, depositing and densifying an insulating material within the shallow trench and using a resist layer to define and etch a strap trench aligned with the wall of the shallow trench, depositing a layer of conductive material within the strap trench and followed by depositing an insulating material therein.

Semiconductor trench capacitor cell having a buried strap

Method of making semiconductor trench capacitor cell having a buried

The invention provides a method for electrically connecting a polysilicon-filled trench to a diffusion region in a semiconductor device, wherein the trench and diffusion region are separated by a dielectric. The method provides for formation of a strap or bridge contact by utilizing a diffusion barrier layer which prevents diffusion into an overlying polysilicon layer when a subsequent boron out-diffusion step is performed. Selective etching is then utilized to remove the polysilicon layer where no boron has diffused, leaving a polysilicon strap connecting the trench and diffusion region.

Boron out-diffused surface strap process

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Colchester, VT, United States of America

David K Lord