A microelectronic transistor may be fabricated having an airgap spacer formed as a gate sidewall spacer, such that the airgap spacer is positioned between a gate electrode and a source contact and/or a drain contact of the microelectronic transistor. As the dielectric constant of gaseous substances is significantly lower than that of a solid or a semi-solid dielectric material, the airgap spacer may result in minimal capacitive coupling between the gate electrode and the source contact and/or the drain contact, which may reduce circuit delay of the microelectronic transistor.