Display device

• US 8,242,505 B2
• Filed: 12/26/2007
• Issued: 08/14/2012
• Est. Priority Date: 01/16/2007
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Hitachi I Displays Limited, Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: Kawamura, Tetsufumi, Sato, Takeshi, Hatano, Mutsuko, Toyota, Yoshiaki
• Primary Examiner(s): NGUYEN, CUONG QUANG
• Application Number:
  US12/003,462
• Publication Number:
  US 20080169469A1
• Time in Patent Office: 1,693 Days
• Field of Search: 257 59- 63, 257/72, 257/E29.273
• US Class Current: 257/72
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• 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 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A display device for improving an aperture ratio of the pixel is provided. In the display device, a transparent oxide layer, an insulating film, and a conductive layer are sequentially stacked on a pixel region on a substrate, the conductive layer has a gate electrode of a thin film transistor connected to a gate signal line, and a region of the transparent oxide layer other than at least a channel region portion directly below the gate electrode is converted into an electrically conductive region, and a source signal line, a source region portion of the thin film transistor connected to the source signal line, a pixel electrode, and a drain region portion of the thin film transistor connected to the pixel electrode are formed from the conductive region.

Claims

1. A display device, wherein a transparent oxide layer and a semiconductor layer, either of which is taken as an upper layer, are formed on a pixel region on a substrate, and an insulating film and a conductive layer are sequentially stacked thereon, the conductive layer has a gate electrode of a thin film transistor connected to a gate signal line, an opening portion or a notched portion is formed in a region of the transparent oxide layer corresponding to at least a channel region portion directly below the gate electrode and the transparent oxide layer is converted into an electrically conductive layer, and a source signal line, a source region portion of the thin film transistor connected to the source signal line, a pixel electrode, and a drain region portion of the thin film transistor connected to the pixel electrode are formed from the conductive layer, and the semiconductor layer is formed in the opening portion or the notched portion of the transparent oxide layer and is connected to the source region portion and the drain region portion.

2. The display device according to claim 1, wherein the transparent oxide layer is formed on an entire region of the pixel region, and the source signal line, the source region portion of the thin film transistor connected to the source signal line, the pixel electrode, and the drain region portion of the thin film transistor connected to the pixel electrode are formed by selectively converting regions of the transparent oxide layer into electrically conductive layer regions.

3. The display device according to claim 1, wherein the conductive layer has a counter electrode including a plurality of electrodes overlapped on the pixel electrode and disposed in parallel on the insulating film and a common signal line supplying a signal to each electrode of the counter electrode.

4. The display device according to claim 1, wherein the insulating film is formed on an entire region of the pixel region.

5. The display device according to claim 1, wherein the conductive layer is constituted of a metal layer.

6. The display device according to claim 1, wherein the conductive layer is constituted of an ITO film.

7. The display device according to claim 1, wherein the conductive layer is formed by selectively converting the transparent oxide layer formed on an entire region of the pixel region into an electrically conductive layer.

8. The display device according to claim 1, wherein LDD region portions with a carrier concentration lower than those of a source region and a drain region are formed in the transparent oxide layer between a portion directly below the gate electrode and the source region and between the portion and the drain region, respectively.

9. The display device according to claim 1, wherein a metal layer is formed on or below a portion of the transparent oxide layer constituting the source signal line.