# US 10,770,589 B2 · Fin field effect transistor including a single diffusion break with a multi-layer dummy gate

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- Number: US 10,770,589 B2
- Document ID: US10770589B2
- Status: Granted
- Kind: B2
- Application number: 16/106,429
- Filed: 2018-08-21
- Published: 2020-02-27
- Granted: 2020-09-08
- Earliest claimed: 2018-08-21
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Kangguo Cheng
- Web page: https://patentgrep.com/patent/US10770589B2

## CPC

- H10D 30/62: Fin field-effect transistors [FinFET]
- H10D 30/024: {of 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 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/834: {comprising FinFETs}
- H10D 30/6219: {characterised by the source or drain electrodes}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

In one example, a fin field effect transistor including a single diffusion break with a multi-layer dummy gate is disclosed. One example of field effect transistor includes a first transistor array comprising a first active gate, a second transistor array comprising a second active gate, and a single diffusion break formed between the first transistor array and the second transistor array, wherein the single diffusion break comprises a dummy gate comprising multiple layers of different materials.

## Claims

### Claim 1

A field effect transistor, comprising:
a first transistor array comprising a first active gate;
a second transistor array comprising a second active gate; and
a single diffusion break formed between the first transistor array and the second transistor array, wherein the single diffusion break comprises a dummy gate comprising a layer of dielectric material, and an inactive gate structure formed over the layer of dielectric material, wherein a lateral width of the layer of dielectric material is substantially equal to a lateral width of the inactive gate structure,
wherein a sidewall spacer directly contacts and separates the layer of dielectric material from an adjacent epitaxial source drain region.

### Claim 2 (depends on 1)

The field effect transistor of claim 1,
wherein the first transistor array further comprises:
a first channel formed as a first fin, where the first active gate wraps around the first fin, and
wherein the second transistor array further comprises:
a second channel formed as a second fin, where the second active gate wraps around the second fin.

### Claim 3 (depends on 2)

The field effect transistor of claim 2, wherein a top surface of the layer of the dielectric material sits higher than top surfaces of the first fin and the second fin.

### Claim 4 (depends on 1)

The field effect transistor of claim 1, wherein upper most surfaces of both the layer of dielectric material and the adjacent epitaxial source drain region are above a lower most surface of the sidewall spacer.

### Claim 5 (depends on 4)

The field effect transistor of claim 4, further comprising:
a semiconductor substrate on which the first transistor array, the second transistor array, and the single diffusion break are formed,
wherein the layer of the dielectric material fills a recess formed in a portion of the semiconductor substrate, the recess corresponding with a size and a location of a first fin and a second fin.

### Claim 6 (depends on 5)

The field effect transistor of claim 5, wherein a depth of the recess is lower than a depth to which bottom surfaces of the first transistor array and the second transistor array reach.

### Claim 7 (depends on 1)

The field effect transistor of claim 1, wherein the inactive gate, the first active gate, and the second active gate are formed from identical materials.

### Claim 8 (depends on 7)

The field effect transistor of claim 7, wherein the identical materials comprise:
a gate dielectric layer;
a gate conductor layer formed over the gate dielectric layer; and
a gate cap layer formed over the gate conductor layer.

### Claim 9 (depends on 1)

The semiconductor structure of claim 1, wherein sidewalls of the single dielectric material are coplanar with sidewalls of the one gate structure.

### Claim 10

A field effect transistor, comprising:
a substrate;
a first transistor array formed on the substrate, comprising:
a first channel formed as a first fin;
a first active gate wrapping around the first fin;
a second transistor array formed on the substrate, comprising:
a second channel formed as a second fin;
a second active gate wrapping around the second fin; and
a single diffusion break formed between the first transistor array and the second transistor array, the single diffusion break comprising:
a layer of dielectric material, wherein a top surface of the layer of the dielectric material sits higher than top surfaces of the first fin and the second fin; and
an inactive gate formed over the layer of dielectric material, wherein the inactive gate, the first active gate, and the second active gate are formed from identical materials,
wherein a lateral width of the layer of dielectric material is substantially equal to a lateral width of the inactive gate,
wherein upper most surfaces of both the layer of dielectric material and adjacent epitaxial source drain regions are above a lower most surface of a sidewall spacer separating the layer of dielectric material from the adjacent epitaxial source drain regions.

### Claim 11 (depends on 10)

The field effect transistor of claim 10, wherein the layer of dielectric material fills a recess in a portion of the substrate, and the recess sits at a depth that is lower than a depth to which bottom surfaces of the first fin and the second fin reach.

### Claim 12 (depends on 10)

The field effect transistor of claim 10, wherein the identical materials comprise:
a gate dielectric layer;
a gate conductor layer formed over the gate dielectric layer; and
a gate cap layer formed over the gate conductor layer,
wherein upper most surfaces of the gate cap layer above each of the inactive gate, the first active gate, and the second active gate are substantially flush with one another.

### Claim 13

A semiconductor structure comprising:
a first array of fins and a second array of fins on a substrate;
an array of gate structures perpendicular to and wrapping portions of both the first array of fins and the second array of fins; and
a single dielectric material directly below one gate structure, the single dielectric material isolates the first array of fins from the second array of fins, wherein sidewalls of the single dielectric material are coplanar with sidewalls of the one gate structure.

### Claim 14 (depends on 13)

The semiconductor structure of claim 13, wherein a portion of the single dielectric material extends downward into the substrate below the first array of fins and below the second array of fins, wherein the portion of the single dielectric material corresponds with a size and a location of opposing fins from the first array of fins and below the second array of fins.

### Claim 15 (depends on 13)

The semiconductor structure of claim 13, wherein upper most surfaces of a gate cap, a gate dielectric, and a sidewall spacer are substantially flush with one another.

### Claim 16 (depends on 13)

The semiconductor structure of claim 13, wherein upper most surfaces of both the single dielectric material and adjacent epitaxial source drain regions are above a lower most surface of a sidewall spacer separating the single dielectric material from the adjacent epitaxial source drain regions.

### Claim 17 (depends on 13)

The semiconductor structure of claim 13, wherein a vertical sidewall of a gate dielectric layer of the one gate structure is in direct contact with a sidewall spacer, the sidewall spacer is in direct contact with a vertical sidewall of an adjacent epitaxial source drain region, and a bottom most surface of the sidewall spacer is below an upper most surface of the adjacent epitaxial source drain regions.

### Claim 18 (depends on 13)

The semiconductor structure of claim 13, wherein a width of the single dielectric material is substantially equal to a width of the one gate structure.

### Claim 19 (depends on 13)

The semiconductor structure of claim 13, wherein each gate of the array of gate structures comprises:
a gate dielectric layer;
a gate conductor layer formed over the gate dielectric layer; and
a gate cap layer formed over the gate conductor layer.