# US 10,373,835 B2 · Method of lateral oxidation of nFET and pFET high-K gate stacks

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- Number: US 10,373,835 B2
- Document ID: US10373835B2
- Status: Granted
- Kind: B2
- Application number: 15/892,884
- Filed: 2018-02-09
- Published: 2018-06-21
- Granted: 2019-08-06
- Earliest claimed: 2014-05-02
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Takashi Ando; Robert H. Dennard; Martin M. Frank
- Web page: https://patentgrep.com/patent/US10373835B2

## CPC

- H10D 64/01338: {with a treatment, e.g. annealing, after the formation of the conductor}
- H10D 64/00: Electrodes of devices having potential barriers
- H10D 64/01: Manufacture or treatment
- H10D 64/011: {of electrodes ohmically coupled to a semiconductor}
- H10D 64/01354: {passivation or protection of the electrode, e.g. using re-oxidation}
- H10D 64/015: {removing at least parts of gate spacers, e.g. disposable spacers}
- H10D 64/021: {using multiple gate spacer layers, e.g. bilayered sidewall spacers}
- H10D 64/671: {the conductor having lateral variation in doping or structure}
- H10D 64/68: characterised by the insulator, e.g. by the gate insulator
- H10D 64/683: {being parallel to the channel plane}
- H10D 84/0144: {Manufacturing their gate insulating layers}
- H10D 84/0181: {Manufacturing their gate insulating layers}
- H10D 84/0184: {Manufacturing their gate sidewall spacers}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/85: Complementary IGFETs, e.g. CMOS
- H10P 14/6304: {Formation by oxidation, e.g. oxidation of the substrate}
- H10P 14/6314: {of a metallic layer}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for fabricating a semiconductor circuit includes obtaining a semiconductor structure having a gate stack of material layers including a high-k dielectric layer; oxidizing in a lateral manner the high-k dielectric layer, such that oxygen content of the high-k dielectric layer is increased first at the sidewalls of the high-k dielectric layer; and completing fabrication of a n-type field effect transistor from the gate stack after laterally oxidizing the high-k dielectric layer of the gate stack.

## Claims

### Claim 1

A method for fabricating a semiconductor circuit, the method comprising:
obtaining a semiconductor structure having a first gate stack and a second gate stack, each containing material layers that include a high-k dielectric layer and a work-function conductor layer;
oxidizing in a lateral manner (i) the high-k dielectric layer of the first gate stack, such that an oxygen content of the high-k dielectric layer of the first gate stack increases first at the sidewalls of the high-k dielectric layer of the first gate stack, (ii) the high-k dielectric layer of the second gate stack, such that the oxygen content of the high-k dielectric layer of the second gate stack increases first at the sidewalls of the high-k dielectric layer of the second gate stack, and (iii) the work-function conductor layer of the first gate stack, such that oxygen content increases first near the sidewalls of the work-function conductor layer of the first gate stack; and
fabricating (i) a n-type field effect transistor from the first gate stack after laterally oxidizing at least the high-k dielectric layer of the first gate stack, and (ii) a p-type field effect transistor from the second gate stack after laterally oxidizing at least the high-k dielectric layer of the second gate stack.

### Claim 2 (depends on 1)

The method of claim 1, wherein the high-k dielectric layer of the first gate stack and the high-k dielectric layer of the second gate stack are comprised of the same selection of dielectric material.

### Claim 3 (depends on 1)

The method of claim 1, wherein the high-k dielectric layer of the first gate stack and the high-k dielectric layer of the second gate stack are not comprised of the same selection of dielectric material.

### Claim 4 (depends on 1)

The method of claim 1, wherein the oxidizing further comprises achieving complete lateral oxidation of the high-k dielectric layer of the first gate stack, such that oxygen diffuses to the center of the high-k dielectric layer of the first gate stack.

### Claim 5 (depends on 4)

The method of claim 4, wherein oxidizing further comprises achieving complete lateral oxidation of the high-k dielectric layer of the second gate stack, such that oxygen diffuses to the center of the high-k dielectric layer of the second gate stack.

### Claim 6 (depends on 1)

The method of claim 1, wherein the oxidizing further comprises achieving partial lateral oxidation of the high-k dielectric layer of the first gate stack, such that oxygen does not diffuse to the center of the high-k dielectric layer of the first gate stack.

### Claim 7 (depends on 6)

The method of claim 6, wherein oxidizing further comprises achieving complete lateral oxidation of the high-k dielectric layer of the second gate stack, such that oxygen diffuses to the center of the high-k dielectric layer of the second gate stack.

### Claim 8 (depends on 1)

The method of claim 1, wherein the oxidizing further comprises achieving complete lateral oxidation of the high-k dielectric layer of the first gate stack.

### Claim 9 (depends on 8)

The method of claim 8, wherein oxidizing further comprises achieving partial lateral oxidation of the high-k dielectric layer of the second gate stack, such that oxygen does not diffuse to the center of the high-k dielectric layer of the second gate stack.

### Claim 10 (depends on 1)

The method of claim 1, wherein the oxidizing further comprises achieving partial lateral oxidation of the high-k dielectric layer of the first gate stack, such that oxygen does not diffuse to the center of the high-k dielectric layer of the first gate stack.

### Claim 11 (depends on 10)

The method of claim 10, wherein oxidizing further comprises achieving partial lateral oxidation of the high-k dielectric layer of the second gate stack, such that oxygen does not diffuse to the center of the high-k dielectric layer of the second gate stack.

### Claim 12 (depends on 1)

The method of claim 1, wherein oxidizing further comprises oxidizing in a lateral manner the work-function conductor layer of the second gate stack, such that oxygen content increases first near the sidewalls of the work-function conductor layer of the second gate stack.

### Claim 13 (depends on 1)

The method of claim 1, wherein the work-function conductor layer of the first gate stack and the work-function conductor layer of the second gate stack are of the same work-function conductor material.

### Claim 14 (depends on 13)

The method of claim 13, wherein the high-k dielectric layer of the first gate stack and the high-k dielectric layer of the second gate stack are of the same selection of dielectric material.

### Claim 15 (depends on 14)

The method of claim 14, wherein the work-function conductor layer of the first gate stack and the work-function conductor layer of the second gate stack are of the same work-function conductor material, and the high-k dielectric layer of the first gate stack and the high-k dielectric layer of the second gate stack are not of the same selection of dielectric material.

### Claim 16 (depends on 1)

The method of claim 1, wherein the work-function conductor layer of the first gate stack and the work-function conductor layer of the second gate stack are not of the same work-function conductor material, and the high-k dielectric layer of the first gate stack and the high-k dielectric layer of the second gate stack are not of the same selection of dielectric material.