Patent ID: 7154154
Filing Date: 2006-12-26
Classification: H01L

Abstract:
1. A MOS transistor comprising: an inverted T-shaped gate electrode on a substrate, the inverted T-shaped gate electrode comprising a silicon base portion and a silicon column portion extending from the base portion, the silicon base portion and the silicon column portion doped with a same dopant material, the silicon base portion of the inverted T-shaped gate electrode including a first lateral protrusion extending laterally beyond a first sidewall of the silicon column portion of the inverted T-shaped gate electrode and a second lateral protrusion extending laterally beyond a second sidewall of the silicon column portion of the inverted T-shaped gate electrode; a drain region in the substrate comprising a first lightly-doped drain region under the first lateral protrusion, a second lightly-doped drain region that is deeper than the first lightly-doped drain region adjacent the first lightly-doped drain region, and a heavily-doped drain region adjacent to the second lightly-doped drain region; a source region in the substrate comprising a first lightly-doped source region under the second lateral protrusion, a second lightly-doped source region that is deeper than the first lightly-doped source region adjacent the first lightly-doped source region, and a heavily-doped source region adjacent to the second lightly-doped source region; a gate dielectric layer interposed between the inverted T-shaped gate electrode and the substrate; and a curing thermal oxide layer on the first and second sidewalls of the silicon column portion of the inverted T-shaped gate electrode, the first and second sidewalls of the gate dielectric, the second lightly-doped drain region and the second lightly-doped source region, wherein a first sidewall of the gate dielectric is aligned with a sidewall of the first lateral protrusion of the inverted T-shaped gate electrode and wherein a second sidewall of the gate dielectric is aligned with a sidewall of the second lateral protrusion of the inverted T-shaped gate electrode.