# US 10,483,401 B2 · Thin-film transistor having oxide semiconductor channel layer vertically exending along lateral sides of source electrode, separation layer, and drain electrode and array substrate including same

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- Number: US 10,483,401 B2
- Document ID: US10483401B2
- Status: Granted
- Kind: B2
- Application number: 15/569,388
- Filed: 2017-09-15
- Published: 2019-03-21
- Granted: 2019-11-19
- Earliest claimed: 2017-08-28
- Assignees: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Applicants: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd.
- Inventors: Chenghao Bu
- Web page: https://patentgrep.com/patent/US10483401B2

## CPC

- H10D 30/6728: {Vertical TFTs}
- H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)}
- H10D 30/6758: {characterised by the insulating substrates}
- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10D 99/00: Subject matter not provided for in other groups of this subclass
- H10D 64/011: {of electrodes ohmically coupled to a semiconductor}
- H10D 86/411: {characterised by materials, geometry or structure of the substrates}
- H10D 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10D 86/60: wherein the TFTs are in active matrices
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

The present invention provides a thin-film transistor and a fabrication method thereof, and an array substrate. The thin-film transistor includes a separation layer (5) arranged between the source electrode (4) and the drain electrode (6). An oxide semiconductor channel layer (7) is arranged on one side of the separation layer (5) and the drain electrode (6) to contact a portion of an upper surface of the drain electrode (6), a side surface of the drain electrode (6) and the organic separation layer (5), and a portion of an upper surface of the source electrode (4) to serve as a vertical channel, of which a channel length corresponds to a thickness of the separation layer (5). Varying the thickness of the separation layer to reduce the length of the vertical channel to a sub-micrometer order would greatly reduce the size of the thin-film transistor and reduce the area of a pixel. The vertical channel does not cause a short channel effect so as to improve electrical performance of the thin-film transistor. Using a multiple-layered hexagonal boron nitride film to make a moisture/oxygen barrier layer (2) and using a double-layered graphene film to make the source electrode (4) and the drain electrode (6) help significantly improve bending durability of the thin-film transistor.

## Claims

### Claim 1

A thin-film transistor, comprising:
a flexible backing;
a moisture/oxygen barrier layer arranged on the flexible backing;
a buffer layer arranged on the moisture/oxygen barrier layer;
a source electrode arranged on the buffer layer;
a separation layer arranged on the source electrode and exposing at least one side portion of the source electrode;
a drain electrode arranged on the separation layer;
an oxide semiconductor channel layer arranged at one side of the separation layer and the drain electrode to sequentially contact a portion of an upper surface of the drain electrode, a side surface of the drain electrode and the separation layer, and a portion of an upper surface of the source electrode;
a gate insulation layer arranged on the oxide semiconductor channel layer; and
a gate electrode arranged on the gate insulation layer,
wherein the separation layer is arranged to expose two side portions of the source electrode; a source contact electrode is arranged on one of the side portions of the source electrode that is distant from the oxide semiconductor channel layer; and a drain contact electrode is arranged on one side portion of the drain electrode that is distant from the oxide semiconductor channel layer, the source contact electrode and the drain contact electrode being spaced from each other in a vertical direction in which the source electrode and the drain electrode is separated from each other by the separation layer.

### Claim 2 (depends on 1)

The thin-film transistor as claimed in claim 1, wherein the moisture/oxygen barrier layer comprises a multiple-layered hexagonal boron nitride film; the source electrode and the drain electrode each comprises a double-layered graphene film; the oxide semiconductor channel layer is formed of a material comprising indium oxide, indium gallium zinc oxide, or zinc oxide.

### Claim 3 (depends on 2)

The thin-film transistor as claimed in claim 2, wherein the separation layer is formed of a material that comprises polyimide and has a thickness of 400 nm-800 nm.

### Claim 4 (depends on 1)

The thin-film transistor as claimed in claim 1 further comprising a planarization layer covering the buffer layer, the source electrode, the source contact electrode, the drain electrode, the drain contact electrode, and the gate electrode.

### Claim 5 (depends on 1)

The thin-film transistor as claimed in claim 1, wherein the source contact electrode and the drain contact electrode are each formed of a material comprising gold; and the gate electrode is formed of a material comprising aluminum-doped zinc oxide.

### Claim 6 (depends on 1)

An array substrate, comprising a number of the thin-film transistors as claimed in claim 1, which are arranged in an array.