DISPLAY DEVICE

• US 20110133183A1
• Filed: 02/03/2011
• Published: 06/09/2011
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: CHIBA, Yoko, KOMORI, Shigeki, WADA, Rihito, AKIMOTO, Kengo, YAMAZAKI, Shunpei, UOCHI, Hideki
• Granted Patent: US 9,343,517 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: G02F 1/13392 spacers dispersed on the cell substrate, e.g. spherical particles, microfibres
• CPC Class Codes: G02F 1/13398 Spacer materials; Spacer properties
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G09G 2300/0804 Sub-multiplexed active matrix panel, i.e. wherein one active driving circuit is used at pixel level for multiple image producing 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 27/1244 for preventing breakage, peeling or short circuiting
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• 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: H10K 50/82 Cathodes
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 59/8052 Cathodes

Abstract

A display device includes a pixel portion in which a pixel electrode layer is arranged in a matrix, and an inverted staggered thin film transistor having a combination of at least two kinds of oxide semiconductor layers with different amounts of oxygen is provided corresponding to the pixel electrode layer. In the periphery of the pixel portion in this display device, a pad portion is provided to be electrically connected to a common electrode layer formed on a counter substrate through a conductive layer made of the same material as the pixel electrode layer. One objection of our invention to prevent a defect due to separation of a thin film in various kinds of display devices is realized, by providing a structure suitable for a pad portion provided in a display panel.

Claims

1. A semiconductor device comprising:

a gate electrode;

a gate insulating layer over the gate electrode;

a semiconductor layer comprising an oxide semiconductor including indium over the gate insulating layer; and

a source electrode and a drain electrode over the semiconductor layer,

wherein the semiconductor layer has a recessed portion between the source electrode and the drain electrode, and

wherein an entirety of the semiconductor layer overlaps with the gate electrode.

2. The semiconductor device according to claim 1, wherein a side surface of the recessed portion aligns with a side surface of one of the source electrode and the drain electrode.

3. The semiconductor device according to claim 1, wherein the oxide semiconductor is an In—

Ga—

Zn—

O based oxide semiconductor.

4. The semiconductor device according to claim 1, further comprising:

an insulating layer over the semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the semiconductor layer in the recessed portion.

5. The semiconductor device according to claim 1, further comprising:

an insulating layer over the semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the semiconductor layer in the recessed portion, and

wherein the insulating layer comprises aluminum oxide.

6. The semiconductor device according to claim 1, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the pixel electrode comprises a transparent conductive material.

7. The semiconductor device according to claim 1, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode, and

a second gate electrode adjacent to the gate electrode,

wherein the second gate electrode extends to form a gate wiring, and

wherein the pixel electrode overlaps with the gate wiring.

8. The semiconductor device according to claim 1,

wherein the source electrode is in contact with a side surface of the semiconductor layer, and

wherein the drain electrode is in contact with a side surface of the semiconductor layer.

9. A semiconductor device comprising:

a gate electrode;

a gate insulating layer over the gate electrode;

a first semiconductor layer comprising a first oxide semiconductor including indium over the gate insulating layer; and

a second semiconductor layer comprising a second oxide semiconductor over and in contact with the first semiconductor layer;

a third semiconductor layer comprising the second oxide semiconductor over and in contact with the first semiconductor layer;

a source electrode over the second semiconductor layer; and

a drain electrode over the third semiconductor layer,

wherein the first semiconductor layer has a recessed portion between the source electrode and the drain electrode, and

wherein an entirety of the semiconductor layer overlaps with the gate electrode.

10. The semiconductor device according to claim 9, wherein a side surface of the recessed portion, a side surface of one of the second semiconductor layer and the third semiconductor layer, and a side surface of one of the source electrode and the drain electrode align with one another.

11. The semiconductor device according to claim 9, wherein the first oxide semiconductor is an In—

Ga—

Zn—

O based oxide semiconductor.

12. The semiconductor device according to claim 9, further comprising:

an insulating layer over the first semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the first semiconductor layer in the recessed portion.

13. The semiconductor device according to claim 9, further comprising:

an insulating layer over the first semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the first semiconductor layer in the recessed portion, and

wherein the insulating layer comprises aluminum oxide.

14. The semiconductor device according to claim 9, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the pixel electrode comprises a transparent conductive material.

15. The semiconductor device according to claim 9, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode, and

a second gate electrode adjacent to the gate electrode,

wherein the second gate electrode extends to form a gate wiring, and

wherein the pixel electrode overlaps with the gate wiring.

16. The semiconductor device according to claim 9,

wherein the source electrode is in contact with a side surface of the first semiconductor layer, and

wherein the drain electrode is in contact with a side surface of the first semiconductor layer.

17. A semiconductor device comprising:

a gate electrode;

a gate insulating layer over the gate electrode;

a first semiconductor layer comprising a first oxide semiconductor including indium over the gate insulating layer; and

a second semiconductor layer comprising a second oxide semiconductor over and in contact with the first semiconductor layer;

a third semiconductor layer comprising the second oxide semiconductor over and in contact with the first semiconductor layer;

a source electrode over the second semiconductor layer; and

a drain electrode over the third semiconductor layer,

wherein the first semiconductor layer has a recessed portion between the source electrode and the drain electrode,

wherein an entirety of the semiconductor layer overlaps with the gate electrode, and

wherein the second semiconductor layer and the third semiconductor layer each has a higher electric conductivity than the first semiconductor layer.

18. The semiconductor device according to claim 17, wherein a side surface of the recessed portion, a side surface of one of the second semiconductor layer and the third semiconductor layer, and a side surface of one of the source electrode and the drain electrode align with one another.

19. The semiconductor device according to claim 17, wherein the first oxide semiconductor is an In—

Ga—

Zn—

O based oxide semiconductor.

20. The semiconductor device according to claim 17, further comprising:

an insulating layer over the first semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the first semiconductor layer in the recessed portion.

21. The semiconductor device according to claim 17, further comprising:

an insulating layer over the first semiconductor layer, the source electrode, and the drain electrode,

wherein the insulating layer is in contact with the first semiconductor layer in the recessed portion, and

wherein the insulating layer comprises aluminum oxide.

22. The semiconductor device according to claim 17, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the pixel electrode comprises a transparent conductive material.

23. The semiconductor device according to claim 17, further comprising:

a pixel electrode electrically connected to one of the source electrode and the drain electrode, and

a second gate electrode adjacent to the gate electrode,

wherein the second gate electrode extends to form a gate wiring, and

wherein the pixel electrode overlaps with the gate wiring.

24. The semiconductor device according to claim 17,

wherein the source electrode is in contact with a side surface of the first semiconductor layer, and

wherein the drain electrode is in contact with a side surface of the first semiconductor layer.