BORDERLESS CONTACT FOR ULTRA-THIN BODY DEVICES

摘要

After formation of a semiconductor device on a semiconductor-on-insulator (SOI) layer, a first dielectric layer is formed over a recessed top surface of a shallow trench isolation structure. A second dielectric layer that can be etched selective to the first dielectric layer is deposited over the first dielectric layer. A contact via hole for a device component located in or on a top semiconductor layer is formed by an etch. During the etch, the second dielectric layer is removed selective to the first dielectric layer, thereby limiting overetch into the first dielectric layer. Due to the etch selectivity, a sufficient amount of the first dielectric layer is present between the bottom of the contact via hole and a bottom semiconductor layer, thus providing electrical isolation for the ETSOI device from the bottom semiconductor layer.

主权项

1. A semiconductor structure comprising:
a semiconductor device located on a top semiconductor layer of a substrate; a shallow trench isolation structure having a top surface that is recessed below a top surface of said top semiconductor layer; a dielectric material portion including a first dielectric material, contacting said top surface of said shallow trench isolation structure, and having a first planar top surface; a contiguous dielectric layer including a second dielectric material that is different from said first dielectric material, contacting said dielectric material portion, and having a second planar top surface extending over said first planar top surface and said semiconductor device; a contact-level dielectric layer located over said contiguous dielectric layer; and at least one contact via structure extending through said contact-level dielectric layer and said contiguous dielectric layer and contacting a component of said semiconductor device located above said top surface of said top semiconductor layer.