Structure of a fin field effect transistor (finfet) comprising epitaxial structures

Abstract

A fin field effect transistor (FinFET) includes a fin extending from a substrate, where the fin includes a lower region, a mid region, and an upper region, the upper region having sidewalls that extend laterally beyond sidewalls of the mid region. The FinFET also includes a gate stack disposed over a channel region of the fin, the gate stack including a gate dielectric, a gate electrode, and a gate spacer on either side of the gate stack. A dielectric material is included that surrounds the lower region and the first interface. A fin spacer is included which is disposed on the sidewalls of the mid region, the fin spacer tapering from a top surface of the dielectric material to the second interface, where the fin spacer is a distinct layer from the gate spacers. The upper region may include epitaxial source/drain material.