Thin film transistor and flat display device

• US 9,082,859 B2
• Filed: 06/14/2011
• Issued: 07/14/2015
• Est. Priority Date: 12/24/2010
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Hwang, Won-Mi, Jung, Young-Bae
• Primary Examiner(s): Tran, Tran
• Application Number:
  US13/067,610
• Publication Number:
  US 20120161134A1
• Time in Patent Office: 1,491 Days
• Field of Search: 257/43, 257/57, 257/59
• US Class Current: 1/1
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

A thin film transistor (TFT) includes a scan line on a substrate, the scan line including a straight portion extending along a first direction, an active layer including an oxide semiconductor and overlapping the straight portion of the scan line, the active layer having a first region, a second region, and a third region that are linearly and sequentially aligned along the first direction, a first insulating layer between the active layer and the scan line, a first electrode connected to the first region of the active layer, and a second electrode connected to the third region of the active layer.

Claims

1. A thin film transistor (TFT), comprising:

a scan line on a substrate, the scan line including a straight portion extending along a first direction;

an active layer including an oxide semiconductor and overlapping the straight portion of the scan line, the active layer having a first region, a second region, and a third region that are linearly and sequentially aligned along the first direction;

a first insulating layer between the active layer and the scan line;

a first electrode connected to the first region of the active layer; and

a second electrode connected to the third region of the active layer,

wherein a width of the active layer in a second direction is larger than a width of the straight portion of the scan line in the second direction, the second direction being substantially perpendicular to the first direction, and

wherein the straight portion of the scan line extends along and overlaps an entire length of the active layer along the first direction, and the first and second electrodes are separate electrodes.

2. The TFT of claim 1, wherein the scan line, the first insulating layer, and the active layer are sequentially stacked on the substrate, the first insulating layer covering the scan line.

3. The TFT of claim 2, wherein the active layer is between the insulating layer and each of the first and second electrodes.

4. The TFT of claim 1, wherein a width of the active layer in a second direction is almost the same as a width of the first or second electrode in the second direction, the second direction being substantially perpendicular to the first direction.

5. The TFT of claim 1, wherein a width of the active layer in a second direction is substantially the same as a width of the straight portion of the scan line in the second direction, the second direction being substantially perpendicular to the first direction.

6. The TFT of claim 1, wherein the active layer includes indium tin oxide (ITO) or indium zinc oxide (IZO).

18. The TFT of claim 1, wherein the first electrode is connected only to the first region of the active layer, and the second electrode is connected only to the third region of the active layer, the first and third regions of the active layer being at opposite sides of the active layer along the first direction and being completely separated from each other by a channel region.

7. A flat display device, comprising:

a thin film transistor (TFT), the TFT including;

a scan line on a substrate, the scan line including a straight portion extending along a first direction,

an active layer including an oxide semiconductor and overlapping the straight portion of the scan line, the active layer having a first region, a second region, and a third region that are linearly and sequentially aligned along the first direction,

a first insulating layer between the active layer and the scan line,

a first electrode connected to the first region of the active layer, and

a second electrode connected to the third region of the active layer;

a first capacitor electrode on the substrate;

a second capacitor electrode connected to the second electrode of the TFT, the second capacitor electrode being insulated from the first capacitor electrode; and

a pixel electrode connected to the second electrode of the TFT and to the second capacitor electrode.

8. The flat display device of claim 7, wherein the second capacitor electrode is integral with the pixel electrode, the second capacitor electrode and pixel electrode including a same material.

9. The flat display device of claim 7, wherein the first capacitor electrode and the scan line are at a same height with respect to the substrate and include a same material.

10. The flat display device of claim 7, wherein the scan line, the first insulating layer, and the active layer are sequentially stacked on the substrate, the first insulating layer covering the scan line.

11. The flat display device of claim 10, wherein the active layer is between the insulating layer and each of the first and second electrodes.

12. The flat display device of claim 7, wherein a width of the active layer in a second direction is almost the same as a width of the first or second electrode, the second direction being substantially perpendicular to the first direction.

13. The flat display device of claim 7, wherein a width of the active layer in a second direction is larger than a width of the straight portion of the scan line, the second direction being substantially perpendicular to the first direction.

14. The flat display device of claim 12, wherein a width of the active layer in a second direction is substantially the same as a width of the straight portion of the scan line, the second direction being substantially perpendicular to the first direction.

15. The flat display device of claim 7, wherein the active layer includes indium tin oxide (ITO) or indium zinc oxide (IZO).

16. The flat display device of claim 7, wherein the first capacitor electrode is a single layer.

17. The flat display device of claim 7, wherein the second capacitor electrode and the pixel electrode contact each other to define a single layer, the second electrode of the TFT extending along the first insulating layer to directly contact an upper surface of the second capacitor electrode.