# US 10,770,299 B2 · Semiconductor device and method of forming the same

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- Number: US 10,770,299 B2
- Document ID: US10770299B2
- Status: Granted
- Kind: B2
- Application number: 16/726,012
- Filed: 2019-12-23
- Published: 2020-04-30
- Granted: 2020-09-08
- Earliest claimed: 2017-04-26
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Li-Jung Liu; Chun-Sheng Liang; Shu-Hui Wang
- Web page: https://patentgrep.com/patent/US10770299B2

## CPC

- H10P 14/43: Chemical deposition, e.g. chemical vapour deposition [CVD]
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10D 64/017: {using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes}
- H10D 64/518: {characterised by their lengths or sectional shapes}
- H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10D 64/669: {the conductor further comprising additional layers of alloy material, compound material or organic material, e.g. TaN/TiAlN}
- H10D 30/797: {being in source or drain regions, e.g. SiGe source or drain}
- H10D 62/822: comprising only Group IV materials heterojunctions, e.g. Si/Ge heterojunctions
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A semiconductor device includes a semiconductor fin and a gate structure. The semiconductor fin extends along a first direction above a substrate. The gate structure extends across the semiconductor fin along a second direction substantially perpendicular to the first direction. The gate structure includes a chlorine-containing N-work function metal layer wrapping around the semiconductor fin, and a filling metal over and in contact with the chlorine-containing N-work function metal layer.

## Claims

### Claim 1

A semiconductor device, comprising:
a semiconductor fin extending along a first direction above a substrate; and
a gate structure extending across the semiconductor fin along a second direction substantially perpendicular to the first direction, the gate structure comprising a chlorine-containing N-work function metal layer wrapping around the semiconductor fin, and a filling metal over and in contact with the chlorine-containing N-work function metal layer.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the gate structure further comprises a titanium nitride layer below and in contact with the chlorine-containing N-work function metal layer.

### Claim 3 (depends on 1)

The semiconductor device of claim 1, wherein the gate structure further comprises a gate dielectric layer below and spaced from the chlorine-containing N-work function metal layer.

### Claim 4 (depends on 1)

The semiconductor device of claim 1, wherein the filling metal is tungsten.

### Claim 5 (depends on 1)

The semiconductor device of claim 1, wherein the gate structure has a minimal width at a position between topmost and bottommost positions of the gate structure.

### Claim 6 (depends on 1)

The semiconductor device of claim 1, wherein the gate structure has a maximal width at a position between topmost and bottommost positions of the gate structure.

### Claim 7 (depends on 2)

The semiconductor device of claim 2, wherein the titanium nitride layer contains carbon.

### Claim 8 (depends on 2)

The semiconductor device of claim 2, wherein the gate structure further comprises a gate dielectric layer below and in contact with the titanium nitride layer.

### Claim 9 (depends on 8)

The semiconductor device of claim 8, wherein the titanium nitride layer has a thickness less than a thickness of the gate dielectric layer.

### Claim 10 (depends on 3)

The semiconductor device of claim 3, wherein the gate dielectric layer has a thickness greater than a thickness of the chlorine-containing N-work function metal layer.

### Claim 11

A semiconductor device, comprising:
a semiconductor fin protruding above a substrate;
an N-type source epitaxy structure and an N-type drain epitaxy structure on the semiconductor fin; and
a gate structure over the semiconductor fin, the gate structure comprising a high-k gate dielectric layer and a chlorine-containing N-work function metal layer spaced from the high-k gate dielectric layer and laterally between the N-type source epitaxy structure and the N-type drain epitaxy structure.

### Claim 12 (depends on 11)

The semiconductor device of claim 11, wherein the gate structure further comprises a titanium nitride layer over and in contact with the high-k gate dielectric layer, and laterally between the N-type source epitaxy structure and the N-type drain epitaxy structure.

### Claim 13 (depends on 11)

The semiconductor device of claim 11, wherein the gate structure further comprises a tungsten structure in contact with the chlorine-containing N-work function metal layer.

### Claim 14 (depends on 12)

The semiconductor device of claim 12, wherein the titanium nitride layer contains carbon.

### Claim 15

A method, comprising:
forming a fin extending from a semiconductor substrate;
forming a shallow trench isolation (STI) structure laterally surrounding a lower portion of the fin;
forming a dummy gate structure across an N-type field effect transistor (NFET) channel region in the fin;
forming an N-type source epitaxy structure and an N-type drain epitaxy structure respectively on opposite sides of the NFET channel region; and
replacing the dummy gate structure with a replacement gate structure, the replacing comprising forming a titanium nitride (TiN) layer of the replacement gate structure on the NFET channel region, and a chlorine-containing N-work function metal layer of the replacement gate structure over the TiN layer on the NFET channel region.

### Claim 16 (depends on 15)

The method of claim 15, wherein the replacing further comprises forming a tungsten layer of the replacement gate structure in contact with the chlorine-containing N-work function metal layer.

### Claim 17 (depends on 15)

The method of claim 15, wherein the replacing further comprises forming a gate dielectric layer of the replacement gate structure prior to forming the TiN layer.

### Claim 18 (depends on 15)

The method of claim 15, further comprising:
forming gate spacers on either side of the dummy gate structure prior to replacing the dummy gate structure with the replacement gate structure, wherein the gate spacers define a gate trench therebetween, and the gate trench has a minimal width at a position between topmost and bottommost positions of the gate trench.

### Claim 19 (depends on 15)

The method of claim 15, further comprising:
forming gate spacers on either side of the dummy gate structure prior to replacing the dummy gate structure with the replacement gate structure, wherein the gate spacers define a gate trench therebetween, and the gate trench has a maximal width at a position between topmost and bottommost positions of the gate trench.

### Claim 20 (depends on 16)

The method of claim 16, wherein the replacing further comprises performing a chemical mechanical polish (CMP) process on the tungsten layer.