Protection of semiconductor-oxide-containing gate dielectric during replacement gate formation

摘要

Semiconductor-oxide-containing gate dielectrics can be formed on surfaces of semiconductor fins prior to formation of a disposable gate structure. A high dielectric constant (high-k) dielectric spacer can be formed to protect each semiconductor-oxide-containing gate dielectric. Formation of the high-k dielectric spacers may be performed after formation of gate cavities by removal of disposable gate structures, or prior to formation of disposable gate structures. The high-k dielectric spacers can be used as protective layers during an anisotropic etch that vertically extends the gate cavity, and can be removed after vertical extension of the gate cavities. A subset of the semiconductor-oxide-containing gate dielectrics can be removed for formation of high-k gate dielectrics for first type devices, while another subset of the semiconductor-oxide-containing gate dielectrics can be employed as gate dielectrics for second type devices. The vertical extension of the gate cavities increases channel widths in the fin field effect transistors.

主权项

1. A semiconductor structure comprising:
a semiconductor fin located on a substrate; a shallow trench isolation layer in contact with sidewalls of a lower portion of said semiconductor fin; a semiconductor-oxide-containing gate dielectric in contact with sidewalls of an upper portion of said semiconductor fin; and a gate electrode straddling said semiconductor fin and overlying said semiconductor-oxide-containing gate dielectric, wherein a portion of said gate electrode protrudes downward into a recess within said shallow trench isolation layer, and is laterally spaced from said lower portion of said semiconductor fin by a vertical portion of said shallow trench isolation layer.