# US 12,183,828 B2 · Thin film transistor and display apparatus comprising the same

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- Number: US 12,183,828 B2
- Document ID: US12183828B2
- Status: Granted
- Kind: B2
- Application number: 17/546,719
- Filed: 2021-12-09
- Published: 2022-06-23
- Granted: 2024-12-31
- Earliest claimed: 2020-12-23
- Assignees: LG Display Co., Ltd.
- Applicants: LG Display Co., Ltd.
- Inventors: Sunggu Kim; DaeHwan Kim
- Web page: https://patentgrep.com/patent/US12183828B2

## CPC

- 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 62/80: characterised by the materials
- 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
- H10K 59/123: Connection of the pixel electrodes to the thin film transistors [TFT]
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A thin film transistor and a display apparatus comprising the same are provided, in which the thin film transistor comprises an active layer, a barrier layer on the active layer; a gate insulating layer on the barrier layer; and a gate electrode on the gate insulating layer, wherein at least a portion of the gate electrode overlaps at least a portion of the active layer, and the barrier layer includes an oxide semiconductor material and has a resistivity greater than a resistivity of the active layer and has a thickness less than a thickness of the active layer.

## Claims

### Claim 1

A thin film transistor comprising:
an active layer including an oxide semiconductor material;
a barrier layer on the active layer;
a gate insulating layer on the barrier layer; and
a gate electrode on the gate insulating layer,
wherein at least a portion of the gate electrode overlaps at least a portion of the active layer, and
the barrier layer includes an oxide semiconductor material and has a resistivity that is greater than a resistivity of the active layer and has a thickness that is less than a thickness of the active layer,
wherein the barrier layer includes a first area overlapped with the gate electrode and a second area that is not overlapped with the gate electrode, and the first area has a thickness greater than a thickness of the second area.

### Claim 2 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer includes at least one of IGZO(InGaZnO)-based oxide semiconductor material, IGO(InGaO)-based oxide semiconductor material, IGZTO(InGaZnSnO)-based oxide semiconductor material, GZTO(GaZnSnO)-based oxide semiconductor material, GZO(GaZnO)-based oxide semiconductor material, or GO(GaO)-based oxide semiconductor material.

### Claim 3 (depends on 1)

The thin film transistor of claim 1, wherein the resistivity of the barrier layer is 1.0×106Ω·cm or more.

### Claim 4 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer has a carrier concentration less than a carrier concentration of the active layer.

### Claim 5 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer has a carrier concentration of 1.0×1017 ea/cm3 or less.

### Claim 6 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer has a mobility of 1 to 2 cm2/V·s.

### Claim 7 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer has an oxygen atom concentration greater than an oxygen atom concentration of the active layer.

### Claim 8 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer includes metal atoms and oxygen atoms, and
a number of oxygen atoms in the barrier layer is 1.2 to 2.5 times of a total number of metal atoms in the barrier layer.

### Claim 9 (depends on 1)

The thin film transistor of claim 1, wherein the thickness of the barrier layer is 0.5 nm to 5 nm.

### Claim 10 (depends on 1)

The thin film transistor of claim 1, wherein the thickness of the barrier layer is 1 nm to 3 nm.

### Claim 11 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer covers an upper surface and a lateral surface of the active layer.

### Claim 12 (depends on 11)

The thin film transistor of claim 11, wherein the barrier layer extends to outside of the active layer.

### Claim 13 (depends on 1)

The thin film transistor of claim 1, wherein a thickness ratio of a thickness of the first area and a thickness of the second area is 1:0.3 to 1:0.9.

### Claim 14 (depends on 1)

The thin film transistor of claim 1, wherein the barrier layer is disposed between the active layer and the gate insulating layer.

### Claim 15 (depends on 1)

The thin film transistor of claim 1, wherein the gate insulating layer is patterned.

### Claim 16 (depends on 1)

The thin film transistor of claim 1, wherein the active layer includes:
a first oxide semiconductor layer; and
a second oxide semiconductor layer on the first oxide semiconductor layer.

### Claim 17 (depends on 16)

The thin film transistor of claim 16, wherein the second oxide semiconductor layer includes FIZO(FeInZnO)-based oxide semiconductor material.

### Claim 18 (depends on 16)

The thin film transistor of claim 16, wherein the barrier layer is disposed between the second oxide semiconductor layer and the gate insulating layer.

### Claim 19 (depends on 18)

The thin film transistor of claim 18, wherein the gate insulating layer is patterned to correspond to the gate electrode.

### Claim 20 (depends on 19)

The thin film transistor of claim 19, wherein the barrier layer is not disposed in an area outside of the gate insulating layer.

### Claim 21 (depends on 16)

The thin film transistor of claim 16, wherein the barrier layer is disposed only on a channel portion.

### Claim 22

A thin film transistor comprising:
an active layer including an oxide semiconductor material;
a barrier layer on the active layer, wherein the barrier layer is a distinct layer from the active layer;
a gate insulating layer on the barrier layer; and
a gate electrode on the gate insulating layer,
wherein at least a portion of the gate electrode overlaps at least a portion of the active layer, and
the barrier layer includes an oxide semiconductor material having a carrier concentration that is less than a carrier concentration of the oxide semiconductor material included in the active layer,
wherein the barrier layer includes a first area overlapped with the gate electrode and a second area that is not overlapped with the gate electrode, and the first area has a thickness greater than a thickness of the second area.

### Claim 23 (depends on 22)

The thin film transistor of claim 22, wherein the carrier concentration of the oxide semiconductor material included in the barrier layer is 1.0×1017 ea/cm3 or less.

### Claim 24 (depends on 22)

The thin film transistor of claim 22, wherein an oxygen atom concentration of the oxide semiconductor material included in the barrier layer is greater than an oxygen atom concentration of the oxide semiconductor material included in the active layer.

### Claim 25 (depends on 22)

The thin film transistor of claim 22, wherein the barrier layer is thinner than the active layer.

### Claim 26 (depends on 22)

The thin film transistor of claim 22, wherein the active layer includes:
a first oxide semiconductor layer; and
a second oxide semiconductor layer on the first oxide semiconductor layer.

### Claim 27 (depends on 22)

The thin film transistor of claim 22, wherein the barrier layer covers an upper surface and side surfaces of the active layer.

### Claim 28

A thin film transistor comprising:
an active layer including an oxide semiconductor material;
a barrier layer on the active layer;
a gate insulating layer on the barrier layer; and
a gate electrode on the gate insulating layer,
wherein at least a portion of the gate electrode overlaps at least a portion of the active layer, and
the barrier layer includes an oxide semiconductor material and has a resistivity that is greater than a resistivity of the active layer and has a thickness that is less than a thickness of the active layer, and
wherein the barrier layer has an oxygen atom concentration greater than an oxygen atom concentration of the active layer.