Liquid crystal display and fabricating method thereof

• US 7,342,616 B2
• Filed: 12/28/2001
• Issued: 03/11/2008
• Est. Priority Date: 06/05/2001
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Chae, Gee Sung
• Primary Examiner(s): Nguyen; Dung T.
• Application Number:
  US10/028,687
• Publication Number:
  US 20020180897A1
• Time in Patent Office: 2,265 Days
• Field of Search: 349 38- 42
• US Class Current: 349/39
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio

Abstract

A liquid crystal display increases the capacitance of a storage capacitor while increasing aperture ratio. The liquid crystal display includes a gate insulating film entirely covering a gate electrode, and an active layer on the gate insulating film overlaps the gate electrode. An ohmic contact layer is formed on the active layer, and source electrode and drain electrodes are on the ohmic contact layer such that a channel forms between them. A protective layer covers the source and the drain electrodes, and a data line crosses the gate line and connects to the source electrode by piercing the protective layer. A storage electrode is at a pixel cell area of the same layer as the gate electrode and the gate line, and a pixel electrode opposes the storage electrode having the gate insulating film in between them.

Claims

1. A liquid crystal display, comprising:

a gate electrode over a substrate;

a gate insulating film entirely deposited over the substrate to cover said gate electrode;

an active layer formed on said gate insulating film which overlaps with said gate electrode;

an ohmic contact layer formed on said active layer;

a source electrode formed on said ohmic contact layer;

a drain electrode formed on said ohmic contact layer, the drain electrode being opposed to said source electrode to form a channel;

a buffer layer formed over said source and drain electrodes;

a storage electrode formed of a transparent conductive material located in a same layer as said gate electrode and a gate line;

an auxiliary storage electrode connected to said storage electrode;

a pixel electrode formed to oppose to said storage electrode having said gate insulating film in between said pixel electrode and said storage electrode, and said pixel electrode being electrically connected with said drain electrode without using a contact hole; and

a protective layer covering said source electrode, said drain electrode and some portions of the pixel electrode, wherein a storage capacitor formed by the pixel electrode and the storage electrode that is located in the same layer as the gate electrode and the gate line are substantially the same size to stabilize a pixel voltage.

2. The liquid crystal display according to claim 1, wherein a contact hole connects said source electrode with a data line on the protective layer.

3. The liquid crystal display according to claim 2, wherein said buffer metal layer is formed from at least one material selected from the group consisting of molybdenum, titanium and tantalum.

4. The liquid crystal display according to claim 1, further comprising a data line crossed with said gate line and connected to said source electrode by piercing said protective layer.

5. The liquid crystal display according to claim 1, further comprising the gate line in the same layer as said gate electrode and said storage electrode.

6. The liquid crystal display according to claim 1, wherein said buffer metal layer reduces contact resistance.

7. The liquid crystal display according to claim 1, wherein said transparent conductive material comprises indium tin oxide.

8. The liquid crystal display according to claim 1, wherein said protective layer comprises an organic insulating material.

9. The liquid crystal display according to claim 1, wherein the pixel electrode is electrically in contact with the buffer metal layer over the drain electrode.

10. The liquid crystal display according to claim 1, wherein the pixel electrode is formed from ITO, IZO or ITZO.

11. The liquid crystal display according to claim 1, wherein the buffer layer entirely covers each of the source electrode and the drain electrode.

12. A method of fabricating a liquid crystal display, comprising:

forming a gate electrode and a gate line over a substrate and at the same time forming a storage electrode in a same layer where said gate electrode and said gate line are formed, said storage electrode being formed of a transparent conductive material located in a same layer as said gate electrode and said gate line;

forming an auxiliary storage electrode connecting to said storage electrode;

forming a gate insulating film to cover said gate electrode, said gate line and said storage electrode;

forming an active layer over said gate insulating film to overlap with said gate electrode;

forming an ohmic contact layer over said active layer;

forming a source electrode and a drain electrode by patterning to expose said active layer;

forming a buffer metal layer over said source electrode and said drain electrode;

forming a pixel electrode opposed to said storage electrode having said gate insulating film in between said pixel electrode and said storage electrode, and said pixel electrode being contacted with said drain electrode without using a contact hole;

forming a protective layer over said source electrode and said drain electrode;

forming a contact hole that pierces said protective layer; and

forming a data line crossed with said gate line and connected with said source electrode through said contact hole, wherein a storage capacitor formed by the pixel electrode and the storage electrode that is located in the same layer as the gate electrode and the gate line are substantially the same size to stabilize a pixel voltage.

13. The method according to claim 12, wherein the buffer metal layer reduces contact resistance.

14. The method of according to claim 12, wherein said buffer metal layer is formed from at least one material selected from the group consisting of molybdenum, titanium and tantalum.

15. The method of according to claim 12, wherein the transparent conductive material comprises indium tin oxide.

16. The method of according to claim 12, wherein said protective layer comprises an organic insulating material.

17. The method of according to claim 16, wherein said organic insulating material is at least one material selected from the group consisting of acrylics, polytetrafluoroethylene, benzocyclobutene, perfluoropolymer resin and perfluorocyclobutane.

18. The method according to claim 12, wherein the pixel electrode is electrically in contact with the buffer metal layer over the drain electrode.

19. The method according to claim 12, wherein the pixel electrode is formed from ITO, IZO or ITZO.

20. The method according to claim 12, wherein the buffer layer entirely covers each of the source electrode and the drain electrode.

21. A liquid crystal display, comprising:

a gate electrode over a substrate;

a gate insulating film entirely deposited over the substrate to cover said gate electrode;

an active layer formed on said gate insulating film which overlaps with said gate electrode;

an ohmic contact layer formed over said active layer;

a source electrode formed over said ohmic contact layer;

a drain electrode formed over said ohmic contact layer, the drain electrode being opposed to said source electrode to form a channel;

a buffer metal layer over said source and drain electrode;

a protective layer covering said source and said drain electrodes;

a storage electrode formed of a transparent conductive material located in a same layer as said gate electrode and a gate line; and

a pixel electrode formed to oppose to said storage electrode having said gate insulating film in between said pixel electrode and said storage electrode, and said pixel electrode being electrically connected with said drain electrode without using a contact hole, wherein a storage capacitor formed by the pixel electrode and the storage electrode that is located in the same layer as the gate electrode and a gate line are substantially the same size to stabilize a pixel voltage.

22. The liquid crystal display according to claim 21, wherein the pixel electrode is electrically in contact with the buffer metal layer over the drain electrode.

23. The liquid crystal display according to claim 21, wherein the pixel electrode is formed from ITO, IZO or ITZO.

24. The liquid crystal display according to claim 21, wherein the buffer layer entirely covers each of the source electrode and the drain electrode.