# US 2019/0172716 A1 · Hydrogenation and nitridization processes for modifying effective oxide thickness of a film

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- Number: US 2019/0172716 A1
- Document ID: US20190172716A1
- Status: Published application
- Kind: A1
- Application number: 16/244,051
- Filed: 2019-01-09
- Published: 2019-06-06
- Earliest claimed: 2016-06-20
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Houda Graoui; Johanes S. Swenberg; Wei Liu; Shashank Sharma
- Web page: https://patentgrep.com/patent/US20190172716A1

## CPC

- H10D 64/01356: {the insulator being formed after the semiconductor body, the semiconductor being a Group IV material and not being silicon, e.g. Ge, SiGe or SiGeC (H10D64/01364, H10D64/01366 take precedence)}
- H10D 62/85: being Group III-V materials, e.g. GaAs
- H10D 64/01: Manufacture or treatment
- H10D 64/0111: {to Group IV semiconductors}
- H10D 64/0116: {to Group III-V semiconductors}
- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10P 14/6532: {by exposure to a plasma}
- H10P 14/69394: {the material containing titanium, e.g. TiO2}
- H10P 52/403: {of conductive or resistive materials}
- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Embodiments described herein generally relate to enable the formation of a metal gate structure with a reduced effective oxide thickness over a similar structure formed via conventional methods. A plasma hydrogenation process followed by a plasma nitridization process, or a single-step plasma hydrogenation and nitridization process, is performed on a metal nitride layer in a film stack, thereby, according to some embodiments, removing oxygen atoms disposed within layers of the film stack and, in some embodiments, adding nitrogen atoms to the layers of the film stack. As a result, an effective oxide thickness of the metal gate structure is reduced with little or no accompanying flatband voltage shift.

## Claims

### Claim 1

A method of forming a structure in a semiconductor device, the method comprising:
depositing a metal nitride capping layer on a high-k dielectric layer formed over a surface of a substrate; and
exposing an exposed surface of the deposited metal nitride capping layer to a plasma that comprises a first gas that comprises a hydrogen containing species and a second gas that comprises a nitrogen containing species, wherein the hydrogen containing species in the first gas comprises nitrogen.

### Claim 2 (depends on 1)

The method of claim 1, wherein the metal nitride capping layer comprises a metal selected from a group consisting of titanium, tantalum and tungsten.

### Claim 3 (depends on 1)

The method of claim 1, wherein a substrate bias is applied to the semiconductor substrate while exposing the exposed surface to the plasma.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
forming a silicon dioxide containing interface layer on a surface of the semiconductor substrate,
wherein the high-k dielectric layer is formed on the silicon dioxide containing interface layer formed the semiconductor substrate.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
depositing a silicon-containing layer on the exposed surface of the deposited metal nitride capping layer after exposing the exposed surface to the plasma;
performing a thermal anneal process on the silicon-containing layer; and
removing the silicon-containing layer.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
depositing a sacrificial layer on the high-k dielectric layer;
depositing a silicon-containing layer on the sacrificial layer;
performing a thermal anneal process on the sacrificial layer and the silicon-containing layer; and
removing the sacrificial layer and the silicon-containing layer before deposition the metal nitride capping layer on the high-k dielectric layer.

### Claim 7 (depends on 1)

The method of claim 1, further comprising, prior to exposing the exposed surface to the plasma-excited hydrogen species and the plasma-excited nitrogen species, performing an oxygen-free plasma treatment process on at least one surface a process chamber in which the exposed surface is exposed to the plasma-excited hydrogen species when the semiconductor substrate is not disposed within the process chamber.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal nitride capping layer comprises titanium and nitrogen, and the plasma-excited hydrogen species comprises ammonia, and the plasma-excited nitrogen species comprises nitrogen gas (N2).

### Claim 9 (depends on 1)

The method of claim 1, wherein the plasma-excited hydrogen species comprises ammonia, and the plasma-excited nitrogen species comprises nitrogen gas (N2).

### Claim 10 (depends on 9)

The method of claim 9, wherein exposing the exposed surface to the plasma-excited hydrogen species and the plasma-excited nitrogen species further comprises exposing the exposed surface to argon (Ar).

### Claim 11

A method of forming a structure in a semiconductor device, the method comprising:
depositing a high-k dielectric layer on a semiconductor substrate;
depositing on the high-k dielectric layer a capping layer;
exposing an exposed surface of the capping layer to a plasma-excited hydrogen species and a plasma-excited nitrogen species;
exposing the exposed surface to air; and
performing a thermal anneal process on the high-k dielectric layer and the capping layer for a particular time and at a particular temperature.

### Claim 12 (depends on 11)

The method of claim 11, wherein the capping layer comprises nitrogen and a metal.

### Claim 13 (depends on 12)

The method of claim 12, wherein the capping layer comprises titanium (Ti).

### Claim 14 (depends on 11)

The method of claim 11, further comprising, prior to depositing the high-k dielectric layer, forming a silicon dioxide containing interface layer on which the high-k dielectric layer is subsequently formed.

### Claim 15 (depends on 11)

The method of claim 11, further comprising:
depositing a silicon-containing layer on the exposed surface;
performing a secondary thermal anneal process on the silicon-containing layer; and
removing the silicon-containing layer.

### Claim 16 (depends on 11)

The method of claim 11, further comprising:
depositing a sacrificial layer on the high-k dielectric layer;
depositing a silicon-containing layer on the sacrificial layer;
performing a tertiary thermal anneal process on the sacrificial layer and the silicon-containing layer; and
removing the sacrificial layer and the silicon-containing layer.

### Claim 17 (depends on 11)

The method of claim 11, further comprising, prior to exposing the exposed surface to the plasma-excited hydrogen species and the plasma-excited nitrogen species, performing an oxygen-free plasma treatment process on a process chamber in which the exposed surface is exposed to the plasma-excited hydrogen species.

### Claim 18 (depends on 11)

The method of claim 11, wherein a substrate bias is applied to the semiconductor substrate while exposing the exposed surface to the plasma-excited hydrogen species and the plasma-excited nitrogen species.

### Claim 19 (depends on 11)

The method of claim 11, wherein the plasma-excited hydrogen species comprises ammonia, and the plasma-excited nitrogen species comprises nitrogen gas (N2).

### Claim 20

A method of forming a structure in a semiconductor device, the method comprising:
depositing a high-k dielectric layer on a semiconductor substrate;
depositing a capping layer on the high-k dielectric layer to form a portion of the structure, wherein the portion includes the capping layer and the high-k dielectric layer, and wherein the deposited capping layer has an exposed surface; and
exposing the exposed surface to a plasma-excited hydrogen species and a plasma-excited nitrogen species, wherein the plasma-excited hydrogen species comprises ammonia, and the plasma-excited nitrogen species comprises nitrogen gas (N2).