Tri-layer sti liner for nanosheet leakage control

Abstract

A semiconductor structure includes a plurality of fins on a semiconductor substrate, the plurality of fins including an alternating sequence of a first nanosheet made of epitaxially grown silicon and a second nanosheet made of epitaxially grown silicon germanium, and a shallow trench isolation region within the semiconductor substrate adjacent to the plurality of fins. The shallow trench isolation region including a recess within the substrate filled with a first liner, a second liner directly above the first liner, a third liner directly above the second liner, and a dielectric material directly above the third liner. The first liner is made of a first oxide material, the third liner is made of a nitride material, and the second liner is made of a second oxide material that creates a dipole effect for neutralizing positive charges within the third liner and positive charges between the third liner and the first liner.