Field effect transistors containing electric field assist layers at gate corners and method of making the same

Abstract

A semiconductor structure includes a source region, a drain region, a channel region located between the source region and the drain region, a gate stack structure including a gate dielectric and a gate electrode that overlies the gate dielectric, such that a first gap region is present between an area of the source region and an area of the gate electrode in a plan view and a second gap region is present between an area of the drain region and the area of the gate electrode in the plan view, a contact-level dielectric layer overlying the source region and the drain region and laterally surrounding the gate stack structure, and at least one assist-field metallic plate located vertically above a top surface of the gate electrode and having an areal overlap with at least one of the first gap region and the second gap region in the plan view.