Thin-film transistor display devices

• US 6,878,966 B2
• Filed: 04/03/2003
• Issued: 04/12/2005
• Est. Priority Date: 02/29/1996
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Dong-gyu
• Primary Examiner(s): Abraham, Fetsum
• Application Number:
  US10/406,668
• Publication Number:
  US 20030201436A1
• Time in Patent Office: 740 Days
• Field of Search: 257/59, 257347-350
• US Class Current: 257/59
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/13629 Multilayer wirings
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate

Abstract

Thin-film transistor display devices include composite electrodes which provide low resistance contacts and paths for electrical signals and are less susceptible to parasitic metal migration which can limit display quality and lifetime. In particular, a thin-film transistor (TFT) display device is provided having an insulated gate electrode on a face of a substrate (e.g., transparent substrate) and a semiconductor layer on the insulated gate electrode, opposite the face of the substrate. Spaced apart source and drain electrodes are also provided on the semiconductor layer. These source and drain electrodes each preferably comprise a composite of at least two layers containing respective metals therein of different element type. Preferably, one of the layers comprises a metal which is capable of forming a low resistance contact with electrodes such as a pixel electrode (e.g., transparent indium-tin-oxide electrode) and the other of the layers comprises a relatively low resistance metal so that the overall effective resistance of each composite electrode is maintained at a low level.

Claims

1. A thin film transistor display device, comprising:

a substrate;

a gate line on a face of said substrate;

a first insulating layer having a first contact hole therein that exposes at least a part of side surfaces of said gate line;

a second insulating layer having a first contact hole therein that exposes at least a part of side surfaces of said gate line;

a second insulating layer having a second contact hole therein coinciding with said first contact hole of said first insulating layer, so that at least said part of side surfaces of said gate line is exposed; and

a gate pad on said second insulating layer, said gate pad extending into said first and second contact holes and contacting said part of side surfaces of said gate line.

2. The display device of claim 1, wherein said gate line comprises at least a refractory metal layer.

3. The display device of claim 2, wherein said gate line comprises an underlying refractory metal layer on said substrate and an additional metal layer on said underlying refractory metal layer different from said refractory metal layer.

4. The display device of claim 1, further comprising a data line on said first insulating layer and a data pad on said second insulating layer, said data pad extending into said contact hole and contacting said part of side surfaces of said data lines, wherein said second insulating layer having a third contact hole therein that exposes at least a part of side surfaces of said data line.

5. The display device of claim 1, wherein said gate electrode is getting narrower from the bottom to the top thereof.

9. The display device of claim 1, wherein said first insulating layer comprises another contact hole therein substantially coinciding with said contact hole of said second insulating layer, so that said data pad extends into said another contact hole and contacting said part of side surfaces of said data line.

10. The display device of claim 1, further comprises a gate electrode on said substrate, wherein said gate electrode is getting narrower from the bottom to the top thereof.

6. A thin film transistor display device, comprising:

a substrate;

a first insulating layer on said substrate;

a data line on said first insulating layer;

a second insulating layer having a contact hole therein that exposes at least a part of side surfaces of said data line; and

a data pad on said second insulating layer, said data pad extending into said contact hole and contacting said part of side surfaces of said data line.

7. The display device of claim 6, wherein said data line comprises at least a refractory metal layer.

8. The display device of claim 7, wherein said data line comprises an underlying refractory metal layer on said substrate and an additional metal layer on said underlying refractory metal layer different from said refractory metal layer.