US 2013/0256802 A1 · Replacement Gate With Reduced Gate Leakage Current

Abstract

Replacement gate work function material stacks are provided, which provides a work function about the energy level of the conduction band of silicon. After removal of a disposable gate stack, a gate dielectric layer is formed in a gate cavity. A metallic compound layer including a metal and a non-metal element is deposited directly on the gate dielectric layer. At least one barrier layer and a conductive material layer is deposited and planarized to fill the gate cavity. The metallic compound layer includes a material, which provides, in combination with other layer, a work function about 4.4 eV or less, and can include a material selected from tantalum carbide, metallic nitrides, and a hafnium-silicon alloy. Thus, the metallic compound layer can provide a work function that enhances the performance of an n-type field effect transistor employing a silicon channel. Optionally, carbon doping can be introduced in the channel.

Claims18

Dependent claims

A semiconductor structure comprising:

a first field effect transistor having a first gate dielectric, said first gate dielectric comprising a first interfacial dielectric layer contacting a channel of said first field effect transistor, a planar metal-doped gate dielectric layer contacting a top surface of said first interfacial dielectric layer, and a first U-shaped gate dielectric layer having a horizontal portion in contact with said planar metal-doped gate dielectric layer and a vertical portion that extends to a topmost portion of a first dielectric gate spacer laterally surrounding said first U-shaped gate dielectric layer;
and
a second field effect transistor having a second gate dielectric, said second gate dielectric comprising a second interfacial dielectric layer contacting a channel of said second field effect transistor, and a second U-shaped gate dielectric layer having a horizontal portion in contact with said second interfacial dielectric layer and a vertical portion that extends to a topmost portion of a second dielectric gate spacer laterally surrounding said second U-shaped gate dielectric layer.

Dependencies are inferred from the claim text.

Replacement Gate With Reduced Gate Leakage Current

Life of this patent

Replacement Gate With Reduced Gate Leakage Current

Life of this patent

Abstract

Claims18