# US 11,908,909 B2 · Fluorine-free interface for semiconductor device performance gain

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- Number: US 11,908,909 B2
- Document ID: US11908909B2
- Status: Granted
- Kind: B2
- Application number: 17/816,062
- Filed: 2022-07-29
- Published: 2022-12-01
- Granted: 2024-02-20
- Earliest claimed: 2021-04-08
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Yu-Ting Tsai; Chung-Liang Cheng; Hong-Ming Lo; Chun-Chih Lin; Chyi-Tsong Ni
- Web page: https://patentgrep.com/patent/US11908909B2

## CPC

- H10D 64/258: {characterised by the relative positions of the source or drain electrodes with respect to the gate electrode}
- H10B 10/00: Static random access memory [SRAM] devices
- H10D 30/6713: {characterised by the properties of the source or drain regions, e.g. compositions or sectional shapes}
- H10D 30/6729: {characterised by the electrodes}
- H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes}
- H10D 30/6737: {characterised by the electrode materials}
- H10D 30/6739: {Conductor-insulator-semiconductor electrodes}
- H10D 30/6743: {Silicon}
- H10D 64/01: Manufacture or treatment
- H10D 64/513: {within recesses in the substrate, e.g. trench gates, groove gates or buried gates}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A semiconductor may include an active region, an epitaxial source/drain formed in and extending above the active region, and a first dielectric layer formed over a portion of the active region. The semiconductor may include a first metal gate and a second metal gate formed in the first dielectric layer, a second dielectric layer formed over the first dielectric layer and the second metal gate, and a titanium layer, without an intervening fluorine residual layer, formed on the metal gate and the epitaxial source/drain. The semiconductor may include a first metal layer formed on top of the titanium on the first metal gate, a second metal layer formed on top of the titanium layer on the epitaxial source/drain, and a third dielectric layer formed on the second dielectric layer. The semiconductor may include first and second vias formed in the third dielectric layer.

## Claims

### Claim 1

A semiconductor device comprising:
an active region;
an epitaxial source/drain in and extending above the active region;
a first dielectric layer over a portion of the active region;
a first metal gate and a second metal gate in the first dielectric layer;
a second dielectric layer over the first dielectric layer and the second metal gate;
a titanium layer on the first metal gate and on the epitaxial source/drain,
wherein the titanium layer is on the first metal gate without an intervening fluorine residual layer,
wherein the titanium layer is on the epitaxial source/drain with an intervening silicide layer;
a first metal layer on top of the titanium layer on the first metal gate;
a second metal layer on top of the titanium layer on the epitaxial source/drain;
a third dielectric layer on the second dielectric layer;
a first via, in the third dielectric layer, filled with a material;
a second via, in the third dielectric layer, filled with the material;
a metal layer on the third dielectric layer, the first via, and the second via; and
a fourth dielectric layer on portions of the metal layer.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the titanium layer on the first metal gate and on the epitaxial source/drain each includes:
a width in a range from approximately twenty-two nanometers to approximately twenty-four nanometers, and
an aspect ratio in a range from approximately two to approximately four.

### Claim 3 (depends on 2)

The semiconductor device of claim 2, wherein the first via and the second via each includes:
a width in a range from approximately fourteen nanometers to approximately twenty-two nanometers, and
an aspect ratio in a range from approximately one to approximately two.

### Claim 4 (depends on 1)

The semiconductor device of claim 1, wherein the titanium layer includes a thickness in a range from approximately eighty angstroms to approximately two-hundred angstroms.

### Claim 5 (depends on 1)

The semiconductor device of claim 1, further comprising:
an insulation layer substantially planar with the active region,
wherein the first dielectric layer resides above the insulation layer.

### Claim 6 (depends on 1)

The semiconductor device of claim 1, wherein the first metal gate and the second metal gate are on opposite sides of the epitaxial source/drain.

### Claim 7

A semiconductor device, comprising:
an active region;
an epitaxial source/drain within and extending above the active region;
an insulation layer adjacent to the active region;
a plurality of dielectric layers that each reside above the insulation layer;
a first layer stack residing above the active region and in one or more of the plurality of dielectric layers; and
a second layer stack residing above the epitaxial source/drain and in the one or more of the plurality of dielectric layers,
wherein each of the first layer stack and the second layer stack comprises:
a first titanium layer residing on a bottom of each of the first layer stack and the second layer stack and on a portion of sides of each of the first layer stack and the second layer stack,
a second titanium layer and a first metal layer that each reside on the first titanium layer,
a second metal layer residing on the second titanium layer and the first metal layer, and
a tungsten layer residing on the second metal layer.

### Claim 8 (depends on 7)

The semiconductor device of claim 7, further comprising:
silicon nitride sidewalls along sidewalls of the first layer stack and along sidewalls of the second layer stack.

### Claim 9 (depends on 7)

The semiconductor device of claim 7, further comprising:
a metal gate residing between the active region and the first layer stack.

### Claim 10 (depends on 7)

The semiconductor device of claim 7, wherein the first layer stack is in a first dielectric layer of the plurality of dielectric layers, and
wherein the second layer stack is in the first dielectric layer and a second dielectric layer of the plurality of dielectric layers.

### Claim 11 (depends on 7)

The semiconductor device of claim 7, wherein the first titanium layer is a titanium silicide layer.

### Claim 12 (depends on 7)

The semiconductor device of claim 7, wherein the second metal layer is substantially planar with the plurality of dielectric layers.

### Claim 13 (depends on 7)

The semiconductor device of claim 7, wherein the second metal layer comprises at least one of a cobalt material, a ruthenium material, an iridium material, or a molybdenum material.

### Claim 14 (depends on 7)

The semiconductor device of claim 7, further comprising:
a third metal layer residing above at least one dielectric layer of the plurality of dielectric layers and the tungsten layer of each of the first layer stack and the second layer stack.

### Claim 15

A semiconductor device, comprising:
an active region;
an epitaxial source/drain within and extending above the active region;
a first metal gate residing on at least a portion of the active region;
an insulation layer adjacent to the active region;
a plurality of dielectric layers that each reside above the insulation layer;
a first layer stack residing on the first metal gate and in the plurality of dielectric layers; and
a second layer stack, residing directly above and intersecting with the epitaxial source/drain, and residing in the plurality of dielectric layers,
wherein each of the first layer stack and the second layer stack comprises:
a material layer residing on a bottom of each of first layer stack and the second layer stack and on a portion of sides of each of the first layer stack and the second layer stack,
a titanium layer and a metal layer residing on the material layer, and
a metal layer residing on the titanium layer and the metal layer.

### Claim 16 (depends on 15)

The semiconductor device of claim 15 wherein:
the plurality of dielectric layers includes a first dielectric layer and a second dielectric layer,
the first dielectric layer residing above the insulation layer, the second dielectric layer residing above the first dielectric layer, and
the second dielectric layer is substantially planar with the metal layer of the first layer stack and the second layer stack.

### Claim 17 (depends on 15)

The semiconductor device of claim 15, further comprising a second metal gate residing above the active region,
wherein the first metal gate and the second metal gate reside on opposite sides of the epitaxial source/drain.

### Claim 18 (depends on 15)

The semiconductor device of claim 15, wherein a height of the first layer stack is less than a height of the second layer stack.

### Claim 19 (depends on 15)

The semiconductor device of claim 15, wherein the material layer comprises a titanium silicide layer, a nickel silicide layer, a cobalt silicide layer, or a platinum silicide layer.

### Claim 20 (depends on 15)

The semiconductor device of claim 15, further comprising:
a first via residing in a remaining portion of the first layer stack; and
a second via residing in a remaining portion of the second layer stack.