High-K metal gate
AssigneeTexas Instruments Incorporated
InventorsHiroaki Niimi, James Joseph Chambers
Life of this patent
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Abstract
An integrated circuit containing metal replacement gates may be formed by forming a nitrogen-rich titanium-based barrier between a high-k gate dielectric layer and a metal work function layer of a PMOS transistor. The nitrogen-rich titanium-based barrier is less than 1 nanometer thick and has an atomic ratio of titanium to nitrogen of less than 43:57. The nitrogen-rich titanium-based barrier may be formed by forming a titanium based layer over the gate dielectric layer and subsequently adding nitrogen to the titanium based layer. The metal work function layer is formed over the nitrogen-rich titanium-based barrier.
Claims20
An integrated circuit, comprising:
- a substrate comprising semiconductor material;
- and
- a p-channel metal oxide semiconductor (PMOS) transistor, comprising:
- a high-k gate dielectric layer over said substrate;
- a nitrogen-rich titanium-based barrier over said high-k gate dielectric layer, said nitrogen-rich titanium-based barrier having a thickness of 0.3 nanometers to 1.0 nanometers, and having a ratio of titanium to nitrogen of less than 43:57;
- and
- a PMOS metal work function layer over said nitrogen-rich titanium-based barrier, wherein said PMOS metal work function layer is part of a metal gate of said PMOS transistor, wherein the metal gate includes a fill metal layer over the PMOS metal work function layer.
A method of forming an integrated circuit, comprising the steps:
- providing a substrate comprising semiconductor material;
- removing a PMOS sacrificial gate from a PMOS transistor of said integrated circuit;
- forming a titanium-based layer over a high-k gate dielectric layer in said PMOS transistor, said high-k gate dielectric layer being disposed over said substrate, said titanium-based layer being 0.3 nanometers to 1.0 nanometers thick;
- adding nitrogen to said titanium-based layer to form a nitrogen-rich titanium-based barrier having a ratio of titanium to nitrogen of less than 43:57;
- forming a PMOS metal work function layer over said nitrogen-rich titanium-based barrier;
- forming a layer of fill metal over said PMOS metal work function layer without exposing said nitrogen-rich titanium-based barrier to ambient air or an oxidizing ambient;
- and
- removing said layer of fill metal and said PMOS metal work function layer from areas outside a gate of said PMOS transistor.
Dependencies are inferred from the claim text.