Transparent thin film transistor and image display unit

• US 7,872,261 B2
• Filed: 02/20/2009
• Issued: 01/18/2011
• Est. Priority Date: 02/22/2008
• Status: Expired due to Fees

• Current Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Original Assignee: Toppan Printing Co., Ltd. (TOPPAN Holdings, Inc.)
• Inventors: Ikeda, Noriaki
• Primary Examiner(s): Maldonado; Julio J
• Assistant Examiner(s): SCARLETT, SHAKA S
• Application Number:
  US12/390,224
• Publication Number:
  US 20090212291A1
• Time in Patent Office: 697 Days
• Field of Search: 438/149, 438/609, 438/22, 257/72, 257/59, 257/347, 257/258, 257/E33.064, 257/E31.126, 257/E51.005, 257/E51.006
• US Class Current: 257/59
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

An embodiment of the present invention is an transparent thin film transistor which has an substantially transparent substrate, a gate line made of a thin film of a substantially transparent conductive material, a substantially transparent gate insulating film, a substantially transparent semiconductor active layer, a source line made of a thin film of a metal material and a drain electrode made of a thin film of a substantially transparent conductive material. In addition, the source line and the drain electrode are formed apart from each other and sandwich the substantially transparent semiconductor active layer. Moreover, at least any one of the thin film of the gate line and the thin film of the source line is stacked with a thin film of a metal material.

Claims

1. A transparent thin film transistor comprising:

a substantially transparent substrate;

a gate line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked,

a substantially transparent gate insulating layer;

a substantially transparent semiconductor active layer; and

a source line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked, and

a drain electrode including a thin film of a substantially transparent conductive material, said source line and said drain electrode being formed apart from each other and sandwiching said substantially transparent semiconductor active layer,

wherein said thin film of said metal material of said source line is stacked on said substantially transparent conductive material of said source line, and said thin film of said substantially transparent conductive material of said gate line is stacked on said thin film of said metal material of said gate line, and

wherein a line width of said thin film of said metal material of said gate line and of said thin film of said metal material of said source line is narrower than a line width of said thin film of said substantially transparent conductive material of said gate line and of said thin film of said substantially transparent conductive material of said source line.

2. The transparent thin film transistor according to claim 1,

wherein a film thickness of any one or more of said thin film of said metal material of said gate line and of said thin film of said metal material of said source line is equal to or more than 5 nm and equal to or less than 150 nm.

3. The transparent thin film transistor according to claim 1,

wherein said substantially transparent semiconductor active layer has a metal oxide as a main component.

4. The transparent thin film transistor according to claim 1,

wherein a part where said source line and said substantially transparent semiconductor active layer meet is made of a substantially transparent oxide conductive material.

5. The transparent thin film transistor according to claim 1, further comprising a capacitor line including a thin film of a substantially transparent conductive material.

6. The transparent thin film transistor according to claim 1, further comprising a capacitor line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked,

wherein a line width of said thin film of said metal material of said capacitor line is narrower than a line width of said thin film of said substantially transparent conductive material of said capacitor line, and

wherein said thin film of said substantially transparent conductive material of said capacitor line is stacked on said thin film of said metal material of said capacitor line.

7. An image display unit comprising:

the transparent thin film transistor according to claim 1;

a substantially transparent interlayer insulating film and,

a substantially transparent pixel electrode which is electrically connected with said drain electrode, said substantially pixel electrode being formed on said interlayer insulating film.

8. The image display unit according to claim 7,

wherein a film thickness of any one or more of said thin film of said metal material of said gate line and of said thin film of said metal material of said source line is equal to or more than 5 nm and equal to or less than 150 nm.

9. The image display unit according to claim 7,

further comprising a capacitor line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked,

wherein a line width of said thin film of said metal material of said capacitor line is narrower than a line width of said thin film of said substantially transparent conductive material of said capacitor line, and

wherein said thin film of said substantially transparent conductive material of said capacitor line is stacked on said thin film of said metal material of said capacitor line.

10. The image display unit according to claim 7,

wherein said line width of said thin film of said metal material of said source line and of said thin film of said metal material of said gate line is equal to or more than 1 μ

m, and wherein

each area ratio of said line width to a display area of said image display unit is equal to or less than 10%.

11. The image display unit according to claim 7,

wherein said substantially transparent semiconductor active layer has metal oxide as a main component.

12. The image display unit according to claim 7,

wherein a part where said source line and said substantially transparent semiconductor active layer meet is made of a substantially transparent oxide conductive material.

13. The image display unit according to claim 7, wherein a color filter is formed between said substantially transparent substrate and a layer in which said gate line is formed.

14. The image display unit according to claim 7,

wherein said image display unit is any one of an electrophoresis reflective display unit, a transmission type liquid crystal display unit, a reflection type liquid crystal display unit, a semi-transmissive type liquid crystal display unit, an organic electroluminescence display unit or an inorganic electroluminescence display unit.

15. A transparent thin film transistor comprising:

a substantially transparent substrate;

a gate line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked,

a substantially transparent gate insulating layer;

a substantially transparent semiconductor active layer; and

a source line in which a thin film of a substantially transparent conductive material and a thin film of a metal material are stacked, and

a drain electrode including a thin film of a substantially transparent conductive material, said source line and said drain electrode being formed apart from each other and sandwiching said substantially transparent semiconductor active layer,

wherein said thin film of said metal material of said source line is stacked on said substantially transparent conductive material of said source line, and said thin film of said substantially transparent conductive material of said gate line is stacked on said thin film of said metal material of said gate line, and

wherein a line width of said thin film of said metal material of said gate line and of said thin film of said metal material of said source line is narrower than a line width of said thin film of said substantially transparent conductive material of said gate line and of said thin film of said substantially transparent conductive material of said source line, and

a film thickness of any one or more of said thin film of said metal material of said gate line and of said thin film of said metal material of said source line is equal to or more than 5 nm and equal to or less than 150 nm.

16. An image display unit comprising the transparent thin film transistor according to claim 15, wherein said line width of said thin film of said metal material of said source line and of said thin film of said metal material of said gate line is equal to or more than 1 μ

m, and wherein

each area ratio of said line width to a display area of said image display unit is equal to or less than 10%.