# US 12,119,222 B2 · Method for preparing semiconductor structure and semiconductor structure

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- Number: US 12,119,222 B2
- Document ID: US12119222B2
- Status: Granted
- Kind: B2
- Application number: 17/393,465
- Filed: 2021-08-04
- Published: 2022-07-14
- Granted: 2024-10-15
- Earliest claimed: 2021-01-14
- Assignees: Changxin Memory Technologies, Inc.
- Applicants: Changxin Memory Technologies, Inc.
- Inventors: Mengmeng Yang; Jie Bai
- Web page: https://patentgrep.com/patent/US12119222B2

## CPC

- H10P 14/6309: {of silicon in uncombined form, i.e. pure silicon}
- H10P 14/6506: {Formation of intermediate materials}
- H10D 64/011: {of electrodes ohmically coupled to a semiconductor}
- H10D 64/01344: {in a nitrogen-containing ambient, e.g. N2O oxidation}
- H10D 64/01346: {in a gaseous ambient using an oxygen or a water vapour, e.g. oxidation through a layer (H10D64/01344 takes precedence)}
- H10D 64/01352: {with sacrificial oxide}
- H10D 64/27: Electrodes not carrying the current to be rectified, amplified, oscillated or switched, e.g. gates
- H10D 64/514: {characterised by the insulating layers}
- H10D 64/68: characterised by the insulator, e.g. by the gate insulator
- H10D 64/685: {being perpendicular to the channel plane}
- H10D 64/693: {the insulator comprising nitrogen, e.g. nitrides, oxynitrides or nitrogen-doped materials}
- H10P 14/6308: {of Group IV semiconductors}
- H10P 14/6322: {Formation by thermal treatments (formation by plasma treatment H10P14/6319)}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/6526: {introduced into an oxide material, e.g. changing SiO to SiON}
- H10P 14/6532: {by exposure to a plasma}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 14/6927: {the material being a silicon oxynitride, e.g. SiON or SiON:H}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10P 50/283: {by chemical means}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for preparing a semiconductor structure includes: providing a substrate which includes a device region and a shallow trench isolation region surrounding the device region, in which the device region is exposed from a surface of the substrate; depositing a barrier layer on the substrate, the barrier layer at least covering the device region; forming an initial oxide which is located in the device region and in contact with the barrier layer; and removing part of the initial oxide to form a device oxide.

## Claims

### Claim 1

A method for preparing a semiconductor structure, comprising: providing a substrate which comprises a device region and a shallow trench isolation region surrounding the device region, wherein the device region is exposed from a surface of the substrate; depositing a barrier layer on the substrate, wherein the barrier layer covers at least the device region, and a thickness of the barrier layer is 5 nm to 10 nm; thermally oxidizing part of the substrate in the device region by an in-situ steam generation process to form an initial oxide which is located between a remaining part of the substrate in the device region and the barrier layer, and in contact with the barrier layer; and removing the barrier layer by using an etching process; and removing part of the initial oxide and a remaining part of the initial oxide being formed as a device oxide, wherein a thickness of the initial oxide is less than or equal to 6 nm and a thickness of the device oxide is 1 nm to 3 nm.

### Claim 2 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein the device oxide is silicon oxide.

### Claim 3 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein a temperature of the in-situ steam generation process is 1000° C. to 1500° C.

### Claim 4 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein after the step of forming an initial oxide, and before the step of removing the barrier layer by using an etching process, the method further comprises:
nitriding the initial oxide.

### Claim 5 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein the step of removing part of the initial oxide comprises:
removing part of the initial oxide which is far away from the substrate by using a dilute hydrofluoric acid solution.

### Claim 6 (depends on 5)

The method for preparing a semiconductor structure of claim 5, wherein a mass ratio of hydrofluoric acid to deionized water in the dilute hydrofluoric acid solution ranges from 1:500 to 1:2000.

### Claim 7 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein the barrier layer is a silicon nitride layer or a silicon oxynitride layer.

### Claim 8 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein the step of depositing a barrier layer on the substrate comprises:
depositing the barrier layer on the substrate by an atomic layer deposition process.

### Claim 9 (depends on 1)

The method for preparing a semiconductor structure of claim 1, wherein a material of the shallow trench isolation region comprises silicon oxide.

### Claim 10 (depends on 1)

A semiconductor structure prepared with the method of claim 1, comprising:
the substrate which comprises the device region and the shallow trench isolation region surrounding the device region, wherein the device region is exposed from the surface of the substrate; and
the device oxide which is located in the device region.