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US 9,871,114 B2Granted
Metal gate scheme for device and methods of forming
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChung-Chiang Wu, Chia-Ching Lee, Da-Yuan Lee, Hsueh Wen Tsau
Life of this patent
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Abstract
Gate structures and methods of forming the gate structures are described. In some embodiments, a method includes forming source/drain regions in a substrate, and forming a gate structure between the source/drain regions. The gate structure includes a gate dielectric layer over the substrate, a work function tuning layer over the gate dielectric layer, a metal-containing compound over the work function tuning layer, and a metal over the metal-containing compound, wherein the metal-containing compound comprises the metal as an element of the compound.
Claims20
A method comprising:
- forming a first epitaxial source/drain region and a second epitaxial source/drain region in a substrate;
- forming a gate structure between the first epitaxial source/drain region and the second epitaxial source/drain region and over the substrate, wherein forming the gate structure comprises:
- forming an interfacial dielectric layer over the substrate;
- forming a gate dielectric layer over the interfacial dielectric layer;
- forming a titanium nitride (TiN) layer over the gate dielectric layer;
- forming a tantalum nitride (TaN) layer over the TiN layer;
- forming a work function tuning layer over the TaN layer, the work function tuning layer comprising TiN;
- forming a metal-containing compound over the work function tuning layer, the metal-containing compound comprising tungsten (W), the metal-containing compound further comprising C, N, O, or a combination thereof;
- forming a tungsten layer over the metal-containing compound;
- and
- forming a dielectric cap over topmost surfaces of the interfacial dielectric layer, the gate dielectric layer, the TiN layer, the TaN layer, the work function tuning layer, the metal-containing compound, and the tungsten layer;
- forming a first spacer on a first sidewall of the gate structure, the first spacer being in physical contact with the dielectric cap, the first spacer extending along a first sidewall of the dielectric cap, at least a portion of the first epitaxial source/drain region being disposed below the first spacer;
- and
- forming an etch stop layer along a sidewall of the first spacer and over the first epitaxial source/drain region and the second epitaxial source/drain region.
11 more elements
A method comprising:
- forming a dummy gate structure over a substrate;
- forming spacers on opposing sidewalls of the dummy gate structure;
- forming a first epitaxial source/drain region and a second epitaxial source/drain region in the substrate, the dummy gate structure being interposed between the first epitaxial source/drain region and the second epitaxial source/drain region;
- forming an etch stop layer over the dummy gate structure, the first epitaxial source/drain region and the second epitaxial source/drain region;
- forming an inter-layer dielectric over the spacers, the dummy gate structure and the substrate, the etch stop layer being interposed between the spacers and the inter-layer dielectric;
- removing the dummy gate structure to form an opening through the inter-layer dielectric;
- forming a gate dielectric layer in the opening and over the substrate;
- forming a titanium nitride (TiN) layer over the gate dielectric layer;
- forming a tantalum nitride (TaN) layer over the TiN layer;
- forming a work function tuning layer in the opening and over the TaN layer, the work function tuning layer comprising TiN;
- forming a metal-containing compound in the opening and over the work function tuning layer, the metal-containing compound comprising tungsten (W);
- forming a tungsten layer in the opening and over the metal-containing compound, wherein the tungsten layer overfills the opening, and wherein the metal-containing compound has a greater work function than tungsten;
- recessing the gate dielectric layer, the TiN layer, the TaN layer, the work function tuning layer, the metal-containing compound, and the tungsten layer below a topmost surface of the inter-layer dielectric to form a recess in the inter-layer dielectric, the recess exposing sidewalls of the spacers;
- and
- forming a dielectric cap in the recess, a topmost surface of the dielectric cap being co-planar with the topmost surface of the inter-layer dielectric, the dielectric cap being in physical contact with the sidewalls of the spacers.
12 more elements
A structure comprising:
- a first epitaxial source/drain region and a second epitaxial source/drain region in a substrate;
- a gate structure on the substrate and between the first epitaxial source/drain region and the second epitaxial source/drain region, the gate structure comprising:
- a gate dielectric layer over the substrate;
- a titanium nitride (TiN) layer over the gate dielectric layer;
- a tantalum nitride (TaN) layer over the TiN layer;
- a work function tuning layer over the TaN layer, the work function tuning layer comprising TiN;
- a tungsten-containing compound over the work function tuning layer;
- a tungsten layer over the tungsten-containing compound, wherein the tungsten-containing compound has a greater work function than tungsten;
- and
- a dielectric cap over the tungsten layer, the dielectric cap being in physical contact with the gate dielectric layer, the TiN layer, the TaN layer, the work function tuning layer, the tungsten-containing compound, and the tungsten layer;
- a spacer on a sidewall of the gate structure, the spacer being in physical contact with the dielectric cap, the spacer extending along a sidewall of the dielectric cap;
- an inter-layer dielectric over the substrate and around the gate structure, a topmost surface of the inter-layer dielectric being co-planar with a topmost surface of the dielectric cap;
- and
- an etch stop layer separating the spacer, the first epitaxial source/drain region and the second epitaxial source/drain region from the inter-layer dielectric.
11 more elements
Dependencies are inferred from the claim text.