Patent ID: 7015092

Claim:
A method for forming a vertical gate contact structure, comprising: forming a trench in a semiconductor substrate; forming a gate oxide on sidewalls of the trench; depositing a conformal layer of conductive material to cover the substrate and underfill the trench with the conductive material, wherein the conformal layer of conductive material forms a first aperture in a central region of the trench, the first aperture extending from a top surface of the conformal layer of conductive material into the trench; forming a nitride plug in the first aperture; etching the conformal layer of conductive material to recess the conductive material underfill in the trench to a depth below a surface of the semiconductor substrate to form a divot; filling the divot with an oxide material to form an oxide spacer; removing the nitride plug to form a second aperture in the central region of the trench, the second aperture extending from a top surface of the oxide spacer into the trench; and forming a gate contact plug in the second aperture, wherein the gate contact plug contacts the conductive material underfill in the trench.