Thin-film transistor and method for preparing the same, display substrate and display device

Patent metadata

Field	Value
Publication number	US-11664460-B2
Application number	US-201916608549-A
Country	US
Kind code	B2
Filing date	Apr 25, 2019
Priority date	May 11, 2018
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

The present disclosure relates to a thin-film transistor, a method for preparing the same, and a display substrate. The method for preparing the thin-film transistor includes the steps of forming a source electrode, a drain electrode, and an active layer, in which the step of forming the source electrode, the drain electrode, and the active layer includes: forming a first thin film from a first metal oxide material in an atmosphere of a first oxygen content; and forming a second thin film from a second metal oxide material in an atmosphere of a second oxygen content, in which the first thin film is configured to form the active layer, the second thin film is configured to form a source electrode and a drain electrode, and the second oxygen content is less than the first oxygen content.

First claim

What is claimed is:

1. A method for preparing a thin-film transistor, comprising a step of forming a source electrode, a drain electrode, and an active layer; and a step of forming a passivation layer covering the source electrode, the drain electrode and the active layer, wherein the step of forming the source electrode, the drain electrode, and the active layer comprises:
forming a first thin film from a first metal oxide material in an atmosphere with a first oxygen gas content of a volume percentage;
forming a second thin film from a second metal oxide material in an atmosphere with a second oxygen gas content of a volume percentage; and
performing an annealing process on the first thin film at a first temperature and performing an annealing process on the second thin film at a second temperature,
wherein the first thin film is configured to form the active layer, the second thin film is configured to form the source electrode and the drain electrode, the first oxygen gas content and the second oxygen gas content are measured under the same condition with respect to a total volume of a reaction chamber for forming the first thin film and the second thin film, and the second oxygen gas content is less than the first oxygen gas content,
wherein the passivation layer is directly in physical contact with the source electrode, the drain electrode and the active layer,
wherein the first temperature ranges from 300° C. to 420° C. and the second temperature ranges from 240° C. to 260° C., and
wherein said forming the source electrode, the drain electrode and the active layer comprises:
forming the second thin film on the first thin film; and
subjecting the first thin film and the second thin film to a single patterning process to form the source electrode, the drain electrode, and the active layer.

2. The method of claim 1 , wherein the second oxygen gas content is 30%, and the second thin film has a thickness greater than or equal to 700 Å.

3. The method of claim 1 , wherein the step of forming the second thin film from the second metal oxide material in the atmosphere with the second oxygen gas content comprises: introducing an H atom-containing gas to form the second thin film from the second metal oxide material in an atmosphere having the second oxygen gas content greater than 0.

4. The method of claim 3 , wherein the H atom-containing gas is one or more selected from the group consisting of water vapor and ammonia.

5. The method of claim 4 , wherein the H atom-containing gas is water vapor, and the water vapor has an input rate greater than or equal to 1 sccm.

6. The method of claim 1 , wherein the first thin film and the second thin film are formed in the reaction chamber and using a same target by a sputtering process.

7. The method of claim 6 , wherein both the first metal oxide material and the second metal oxide material comprise an indium gallium tin oxide, and a molar content of indium in the first metal oxide material and the second metal oxide material are greater than or equal to 50 mol %.

8. The method of claim 1 , wherein said subjecting the first thin film and the second thin film to perform the single patterning process to form the source electrode, the drain electrode and the active layer comprises:
coating a photoresist on the second thin film, and exposing and developing the photoresist to form a photoresist completely reserved region, a photoresist partially reserved region, and a photoresist non-reserved region, wherein the photoresist completely reserved region corresponds to a region where the source electrode and the drain electrode are located, the photoresist partially reserved region corresponds to a part of a region where the active layer is located, and the photoresist non-reserved region corresponds to other regions;
removing the first thin film and the second thin film of the photoresist non-reserved region;
removing the photoresist on the photoresist partially reserved region by an ashing process, and then removing the second thin film on the photoresist partially reserved region; and
stripping a remaining photoresist to form the active layer, the source electrode, and the drain electrode.

Assignees

• Boe Technology Group Co Ltd

Inventors

• Zhang Wenlin
• Sun Jianming
• Hu hehe

Classifications

• H10D86/0229

  characterised by control of the annealing or irradiation parameters · CPC title

• H10D30/6713 Primary

  characterised by the properties of the source or drain regions, e.g. compositions or sectional shapes · CPC title

• H10D99/00

  Subject matter not provided for in other groups of this subclass · CPC title

• H10D86/0231

  using masks, e.g. half-tone masks · CPC title

• H10D86/423

  comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO · CPC title