Electrical isolation structures for ultra-thin semiconductor-on-insulator devices

摘要

After formation of raised source and drain regions, a conformal dielectric material liner is deposited within recessed regions formed by removal of shallow trench isolation structures and underlying portions of a buried insulator layer in a semiconductor-on-insulator (SOI) substrate. A dielectric material that is different from the material of the conformal dielectric material liner is subsequently deposited and planarized to form a planarized dielectric material layer. The planarized dielectric material layer is recessed selective to the conformal dielectric material liner to form dielectric fill portions that fill the recessed regions. Horizontal portions of the conformal dielectric material liner are removed by an anisotropic etch, while remaining portions of the conformal dielectric material liner form an outer gate spacer. At least one contact-level dielectric layer is deposited. Contact via structures electrically isolated from a handle substrate can be formed within the contact via holes.

主权项

1. A semiconductor structure comprising:
a semiconductor material portion located within a top semiconductor layer in a semiconductor-on-insulator (SOI) substrate; a dielectric material liner laterally contacting a sidewall of said semiconductor material portion and a sidewall of at least an upper portion of a buried insulator layer within said SOI substrate; at least one dielectric fill portion filling a volume inside said dielectric material liner and comprising a first dielectric material; a contact-level dielectric layer in contact with said at least one dielectric fill portion and comprising a second dielectric material that is different from said first dielectric material; and a contact via structure in contact with a component of a device on said top semiconductor layer, said dielectric material liner, said at least one dielectric fill portion, and said contact-level dielectric layer, wherein an interface between said contact via structure and said at least one dielectric fill portion is coplanar with an interface between said at least one dielectric fill portion and said contact-level dielectric layer.