US Patent 9508829 Nanosheet MOSFET with full-height air-gap spacer

A semiconductor device includes a gate positioned on a substrate; a nanosheet that extends through the gate, protrudes from a sidewall of the gate, and forms a recess between the substrate and the nanosheet; a dielectric spacer disposed in the recess; a source/drain contact positioned on a source/drain disposed on the substrate adjacent to the gate; an air gap spacer positioned along the sidewall of the gate and in contact with a dielectric material disposed on the nanosheet, the air gap spacer being in contact with the source/drain contact; and an interlayer dielectric (ILD) disposed on the air gap spacer.