US Patent 9721897 Transistor with air spacer and self-aligned contact

A method of fabricating a semiconductor transistor and the semiconductor transistor include a source region and a drain region within a substrate. The method includes forming a gate above the substrate, forming a source contact above the source region and a drain contact above the drain region, and forming air spacers within a dielectric between the gate and each of the source contact and the drain contact. Metal caps are formed on the source contact and the drain contact, and a gate cap is formed between the dielectric and at least a portion of a bottom surface of higher-level contacts, which are contacts formed above the source contact and the drain contact.