A method for providing a FinFET device with an air gap spacer includes providing a substrate a plurality of fins and a dummy gate arranged transverse to the plurality of fins; depositing a sacrificial spacer around the dummy gate; depositing a first interlayer dielectric (ILD) layer around the sacrificial spacer; selectively etching the dummy polysilicon gate relative to the first ILD layer and the sacrificial spacer; depositing a replacement metal gate (RMG); etching a portion of the RMG to create a recess surrounded by the sacrificial spacer; and depositing a gate capping layer in the recess. The gate capping layer is at least partially surrounded by the sacrificial spacer and is made of silicon oxycarbide (SiOC).