DISPLAY DEVICE

• US 20100084653A1
• Filed: 10/01/2009
• Published: 04/08/2010
• Est. Priority Date: 10/03/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: AKIMOTO, Kengo, YAMAZAKI, Shunpei, UOCHI, Hideki, KOMORI, Shigeki, FUTAMURA, Tomoya, KASAHARA, Takahiro
• Granted Patent: US 7,989,815 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/0266 using field effect transistors as protective elements
• 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

The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first wiring layer and a second wiring layer which are over the gate insulating film and whose end portions overlap with the gate electrode; and an oxide semiconductor layer which is over the gate electrode and in contact with the gate insulating film and the end portions of the first wiring layer and the second wiring layer. The gate electrode of the non-linear element and a scan line or a signal line is included in a wiring, the first or second wiring layer of the non-linear element is directly connected to the wiring so as to apply the potential of the gate electrode.

Claims

1. A display device comprising:

a scan line;

a common wiring;

a pixel portion comprising a pixel electrode and a thin film transistor, the thin film transistor including a first oxide semiconductor film; and

a first non-linear element comprising;

a first gate electrode connected to the scan line;

a first gate insulating film over the first gate electrode;

a first wiring layer over the first gate insulating film;

a second wiring layer over the first gate insulating film; and

a second oxide semiconductor film above and in contact with the first gate insulating film, the first wiring layer, and the second wiring layer,

wherein the first gate electrode is electrically connected to the scan line,

wherein the first gate electrode and the scan line are formed of the same material,

wherein the first wiring layer is electrically connected to the common wiring,

wherein the first wiring layer and the common wiring are formed of the same material, and

wherein the second wiring layer is directly connected to the scan line.

2. The display device according to claim 1, wherein each of the first oxide semiconductor film and the second oxide semiconductor film includes indium, gallium, and zinc.

3. The display device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film are formed of the same material.

4. The display device according to claim 1, further comprising a second non-linear element, the second non-linear element comprising:

a second gate electrode;

a second gate insulating film over the second gate electrode;

a third wiring layer over the second gate insulating film;

a fourth wiring layer over the second gate insulating film; and

a third oxide semiconductor film above and in contact with the second gate insulating film, the third wiring layer, and the fourth wiring layer,

wherein the third wiring layer is electrically connected to the scan line,

wherein the second gate electrode is electrically connected to the fourth wiring layer and the common wiring,

wherein the fourth wiring and the common wiring are formed of the same material, and

wherein the second oxide semiconductor film and the third oxide semiconductor film are formed of the same material.

5. The display device according to claim 4, wherein the first gate insulating film and the second gate insulating film are formed of the same material.

6. The display device according to claim 1, wherein the thin film transistor further comprising a source electrode and a drain electrode,

wherein one of the source electrode and the drain electrode is electrically connected to the pixel electrode.

7. The display device according to claim 1, wherein the display device is included in any one of a poster, an advertisement, an electronic book reader, a television device, a digital photo frame, a portable game console, a slot machine and a cellular phone.

8. A display device comprising:

a signal line;

a common wiring;

a pixel portion comprising a pixel electrode and a thin film transistor, the thin film transistor including a first oxide semiconductor film; and

a first non-linear element comprising;

a first gate electrode connected to the signal line;

a first gate insulating film over the first gate electrode;

a first wiring layer over the first gate insulating film;

a second wiring layer over the first gate insulating film; and

a second oxide semiconductor film above and in contact with the first gate insulating film, the first wiring layer, and the second wiring layer,

wherein the first gate electrode is electrically connected to the signal line,

wherein the first gate electrode and the signal line are formed of the same material,

wherein the first wiring layer is electrically connected to the common wiring,

wherein the first wiring layer and the common wiring are formed of the same material, and

wherein the second wiring layer is directly connected to the signal line.

9. The display device according to claim 8, wherein each of the first oxide semiconductor film and the second oxide semiconductor film includes indium, gallium, and zinc.

10. The display device according to claim 8, wherein the first oxide semiconductor film and the second oxide semiconductor film are formed of the same material.

11. The display device according to claim 8, further comprising a second non-linear element, the second non-linear element comprising:

a second gate electrode;

a second gate insulating film over the second gate electrode;

a third wiring layer over the second gate insulating film;

a fourth wiring layer over the second gate insulating film; and

a third oxide semiconductor film above and in contact with the second gate insulating film, the third wiring layer, and the fourth wiring layer,

wherein the third wiring layer is electrically connected to the signal line,

wherein the second gate electrode is electrically connected to the fourth wiring layer and the common wiring,

wherein the fourth wiring and the common wiring are formed of the same material, and

wherein the second oxide semiconductor film and the third oxide semiconductor film are formed of the same material.

12. The display device according to claim 11, wherein the first gate insulating film and the second gate insulating film are formed of the same material.

13. The display device according to claim 8, wherein the thin film transistor further comprising a source electrode and a drain electrode,

wherein one of the source electrode and the drain electrode is electrically connected to the pixel electrode.

14. The display device according to claim 8, wherein the display device is included in any one of a poster, an advertisement, an electronic book reader, a television device, a digital photo frame, a portable game console, a slot machine and a cellular phone.

15. A display device comprising:

a substrate;

a scan line over the substrate;

a signal line intersecting with the scan line over the substrate;

a pixel portion including pixel electrodes, the pixel electrodes being arranged in matrix in the pixel portion; and

a first non-linear element provided over the substrate in a region outside the pixel portion,

wherein the pixel portion comprises a thin film transistor in which a channel formation region is formed in a first oxide semiconductor film,

wherein the thin film transistor comprises;

a first gate electrode connected to the scan line;

a first wiring layer connected to the signal line and the first oxide semiconductor film; and

a second wiring layer connected to one of the pixel electrodes and the first oxide semiconductor film,

wherein the first non-linear element comprises;

a second gate electrode;

a gate insulating film over the second gate electrode;

a first wiring layer and a second wiring layer over the gate insulating film, wherein end portions of the first wiring layer and the second wiring layer are overlapped with the second gate electrode; and

a second oxide semiconductor film overlapping with the second gate electrode, wherein the second oxide semiconductor film is over and in contact with the gate insulating film and the end portions of the first wiring layer and the second wiring layer,

wherein the second gate electrode is connected to one of the scan line and the signal line, and

wherein the first wiring layer of the first non-linear element is directly connected to a gate electrode layer including the second gate electrode and the one of the scan line and the signal line.

16. The display device according to claim 15,

wherein each of the first oxide semiconductor film and the second oxide semiconductor film includes indium, gallium, and zinc.

17. The display device according to claim 15,

wherein the first oxide semiconductor film and the second oxide semiconductor film are formed of the same material.

18. The display device according to claim 15, wherein the same potential of the second gate electrode is applied to the first wiring layer of the first non-linear element.

19. The display device according to claim 15 further comprising a common wiring, and a second non-linear element comprising:

a third gate electrode;

the gate insulating film over the third gate electrode;

a first wiring layer and a second wiring layer over the third gate electrode; and

a third oxide semiconductor film above and in contact with the gate insulating film, the first wiring layer, and the second wiring layer,

wherein the third gate electrode is connected to the common wiring.

20. The display device according to claim 19, wherein the second oxide semiconductor film and the third oxide semiconductor film are formed of the same material.

21. The display device according to claim 15, wherein the display device is included in any one of a poster, an advertisement, an electronic book reader, a television device, a digital photo frame, a portable game console, a slot machine and a cellular phone.

22. A display device comprising:

a substrate;

a scan line over the substrate;

a signal line intersecting with the scan line over the substrate;

a pixel portion including pixel electrodes, the pixel electrodes being arranged in matrix in the pixel portion; and

a first non-linear element provided over the substrate in a region outside the pixel portion,

wherein the pixel portion comprises a thin film transistor, the thin film transistor comprising;

a first gate electrode connected to the scan line;

a first gate insulating film over the first gate electrode;

a first wiring layer over the first gate insulating film, the first wiring layer being connected to the signal line;

a second wiring layer over the first gate insulating film, the second wiring layer being connected to one of the pixel electrodes; and

a first oxide semiconductor film above and in contact with the first gate insulating film, the first wiring layer, and the second wiring layer,

wherein the first non-linear element comprises;

a second gate electrode;

a second gate insulating film over the second gate electrode;

a first wiring layer and a second wiring layer over the second gate insulating film, wherein end portions of the first wiring layer and the second wiring layer are overlapped with the second gate electrode; and

a second oxide semiconductor film overlapping with the second gate electrode, wherein the second oxide semiconductor film is over and in contact with the second gate insulating film and the end portions of the first wiring layer and the second wiring layer,

wherein the second gate electrode is connected to one of the scan line and the signal line, and

wherein the first wiring layer of the first non-linear element is directly connected to a gate electrode layer including the second gate electrode and the one of the scan line and the signal line.

23. The display device according to claim 22,

wherein each of the first oxide semiconductor film and the second oxide semiconductor film includes indium, gallium, and zinc.

24. The display device according to claim 22,

wherein the first oxide semiconductor film and the second oxide semiconductor film are formed of the same material.

25. The display device according to claim 22, wherein the same potential of the second gate electrode is applied to the first wiring layer of the first non-linear element.

26. The display device according to claim 22 further comprising a common wiring, and a second non-linear element comprising:

a third gate electrode;

a third gate insulating film over the third gate electrode;

a first wiring layer and a second wiring layer over the third gate electrode; and

a third oxide semiconductor film above and in contact with the third gate insulating film, the first wiring layer, and the second wiring layer,

wherein the third gate electrode is connected to the common wiring.

27. The display device according to claim 26, wherein the second oxide semiconductor film and the third oxide semiconductor film are formed of the same material.

28. The display device according to claim 22, wherein the display device is included in any one of a poster, an advertisement, an electronic book reader, a television device, a digital photo frame, a portable game console, a slot machine and a cellular phone.