Thin-film transistor, method for manufacturing the same and display device including the same

Patent metadata

Field	Value
Publication number	US-9240486-B2
Application number	US-201314095278-A
Country	US
Kind code	B2
Filing date	Dec 3, 2013
Priority date	Mar 29, 2013
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

A thin-film transistor, a method for manufacturing the same and a display device including the same are provided. The thin-film transistor may include a substrate, and an active layer formed on the substrate. The active layer may be made from an oxide semiconductor. A gate electrode may be formed above the active layer or below the active layer. A conductive layer may come in contact with the active layer, may be overlapped with at least a part of the gate electrode, and may be insulated from the gate electrode. A source electrode and a drain electrode may be electrically connected to the active layer. The conductive layer can reduce a channel length of the thin-film transistor and increase a capacitance between the source electrode and the gate electrode or between the drain electrode and the gate electrode.

First claim

What is claimed is:

1. A thin-film transistor comprising:
a gate electrode disposed on an insulating layer;
an active layer disposed on a substrate below the insulating layer, the active layer comprising a first region that laterally overlaps with the gate electrode, a first portion of the first region comprising a channel of the transistor;
a source electrode and a drain electrode each electrically connected to the active layer; and
one or more conductive layers, each conductive layer electrically connected to either the source or drain electrode, and disposed between the active layer and the substrate, wherein each conductive layer laterally overlapping and directly physically contacting a second portion of the first region of the active layer to reduce a length of the channel.

2. The thin-film transistor of claim 1 , wherein the active layer is formed with an oxide semiconductor material, and the one or more conductive layers are made of a conductive metal material.

3. The thin-film transistor of claim 1 , wherein the gate electrode and said one or more conductive layers are physically separated at least by the insulating layer, thereby creating capacitance between the gate electrode and the one or more conductive layers.

4. The thin-film transistor of claim 1 , wherein at least a portion of one of the conductive layers is interposed between the second portion of the first region of the active layer and the substrate.

5. The thin-film transistor of claim 1 , wherein the second portion of the first region of the active layer is interposed between one of the conductive layers and the gate electrode.

6. The thin-film transistor of claim 1 , wherein at least one of the source electrode and the drain electrode is in direct physical contact with a second region of the active layer, the second region laterally next to first region.

7. The thin-film transistor of claim 6 , wherein the second region of the active layer has higher electrical conductivity than the first region of the active layer.

8. The thin-film transistor of claim 6 , wherein one of either the source electrode or the drain electrode is electrically connected to the conductive layer, and the other is in direct physical contact with the second region of the active layer.

9. The thin-film transistor of claim 6 , wherein one of the conductive layers is in direct physical contact with the second region of the active layer.

10. The thin-film transistor of claim 1 , wherein said one or more conductive layers comprise:
a first conductive layer electrically connected to the source electrode; and
a second conductive layer electrically connected to the drain electrode.

11. The thin-film transistor of claim 10 , wherein both the first and second conductive layers have a portion in direct physical contact with the second portion of the first region of the active layer such that the length of the channel corresponds to a distance between a first end of the first conductive layer and a second end of the second conductive layer facing the first end.

12. The thin-film transistor of claim 10 , wherein both the first and second conductive layers are a light blocking layer interposed between the substrate and the active layer.

13. The thin-film transistor of claim 1 , further comprising a light scattering pattern, wherein the light scattering pattern and said one or more conductive layers are formed of a same material.

14. A thin-film transistor, comprising:
an active layer disposed on a substrate;
a gate electrode disposed below the active layer;
a source electrode and a drain electrode that are electrically connected to the active layer;
a gate insulating film disposed between the active layer and the gate electrode; and
a conductive layer in direct physical contact with the active layer, and disposed on the gate insulating film,
wherein the conductive layer is configured to laterally overlap with both at least a portion of the gate electrode and a portion of the gate insulating film.

15. The thin-film transistor of claim 14 , wherein the gate electrode is formed below the active layer, the transistor further comprising:
an etch stopper that is formed above the active layer,
wherein the conductive layer is completely overlapped by the etch stopper.

16. A thin-film transistor, comprising:
a gate electrode on a substrate;
a gate insulating film on the gate electrode;
an active layer above the gate electrode, the active layer comprising two channel regions that allow carriers to flow;
a conductive layer directly contacted to the active layer, overlapped with at least a part of the gate electrode and insulated from the gate electrode; and
a source electrode and a drain electrode electrically connected to the active layer,
wherein one of the two channel regions is a first area between a first portion of the active layer in contact with the source electrode and one end of the conductive layer, and the other of the two channel regions is second area between a second portion of the active layer in contact with the drain electrode and the other end of the conductive layer.

17. The thin-film transistor of claim 16 , further comprising:
an etch stopper made from an insulating material and on the active layer in a space between the source electrode and the drain electrode, the etch stopper being configured to prevent the active layer from being modified by etching.

18. The thin-film transistor of claim 17 , wherein a length of the channel region in the active layer is less than a length of the etch stopper.

19. The thin-film transistor of claim 17 , wherein the conductive layer is interposed between the active layer and the gate insulating film, and is overlapped with a part of the active layer defined by the etch stopper.

Assignees

• Lg Display Co Ltd

Inventors

• Cho Hyungnyuck

Classifications

• H10D30/6757

  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) · CPC title

• H10D86/481

  integrated with passive devices, e.g. auxiliary capacitors · CPC title

• H10D30/6755 Primary

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H10D99/00

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

• H10D30/6729

  characterised by the electrodes · CPC title