Semiconductor structure for low parasitic gate capacitance

Abstract

A semiconductor structure provides lower parasitic capacitance between the gate electrode and contact vias while providing substantially the same level of stress applied by a nitride liner as conventional MOSFETs by reducing the height of the gate electrode and maintaining substantially the same height for the gate spacer. The nitride liner contacts only the outer sidewalls of the gate spacer, while not contacting inner sidewalls, or only a small area of the inner sidewalls of the gate spacer, therefore applying substantially the same level of stress to the channel of the MOSFET as conventional MOSFETs. The volume surrounded by the gate spacer and located above the gate electrode is either filled with a low-k dielectric material or occupied by a cavity having a dielectric constant of substantially 1.0. The reduced height of the gate electrode and the low-k dielectric gate filler or the cavity reduces the parasitic capacitance.