US Patent 11031485 Transistor with airgap spacer

A semiconductor device includes a gate having a gate spacer formed on a semiconductor substrate and a source or drain (S/D) formed on the substrate a distance away from the gate. A S/D contact including a contact spacer is formed on an upper surface of the S/D. A dielectric layer is interposed between the gate spacer and the contact spacer; and an airgap is in the dielectric layer.