Light-emitting device with plural kinds of thin film transistors and circuits over one substrate

• US 8,378,344 B2
• Filed: 08/26/2010
• Issued: 02/19/2013
• Est. Priority Date: 09/04/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Sakakura, Masayuki, Oikawa, Yoshiaki, Yamazaki, Shunpei, Sakata, Junichiro, Tsubuku, Masashi, Akimoto, Kengo, Hosoba, Miyuki
• Primary Examiner(s): Pizarro, Marcos D.
• Assistant Examiner(s): Montalvo, Eva Yan
• Application Number:
  US12/869,327
• Publication Number:
  US 20110210324A1
• Time in Patent Office: 908 Days
• Field of Search: 257/43, 257/61, 257/72, 257/E33.004, 349/43, 438/46
• US Class Current: 257/43
• 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: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

It is an object to provide a light-emitting device in which plural kinds of circuits are formed over one substrate and plural kinds of thin film transistors corresponding to characteristics of the plural kinds of circuits are provided. An inverted coplanar thin film transistor in which an oxide semiconductor layer overlaps with a source electrode layer and a drain electrode layer is used for a pixel, and a channel-etched thin film transistor is used for a driver circuit. A color filter layer is provided between the pixel thin film transistor and a light-emitting element which is electrically connected to the pixel thin film transistor so as to overlap with the light-emitting element.

Claims

1. A light-emitting device comprising:

a pixel portion including a first thin film transistor over a substrate; and

a driver circuit including a second thin film transistor over the substrate, wherein the first thin film transistor has a different structure from the second thin film transistor,

wherein the first thin film transistor comprises;

a first gate electrode layer over the substrate;

a gate insulating layer over the first gate electrode layer;

a first source electrode layer and a first drain electrode layer over the gate insulating layer;

a first oxide semiconductor layer over the gate insulating layer, the first source electrode layer, and the first drain electrode layer;

a first oxide insulating layer in contact with the first oxide semiconductor layer; and

a connection electrode layer over the gate insulating layer, wherein the connection electrode layer is electrically connected to one of the first source electrode layer and the first drain electrode layer,

wherein the pixel portion comprises;

a color filter layer over the first oxide insulating layer;

a pixel electrode over the color filter layer, wherein the pixel electrode is electrically connected to the connection electrode layer;

a light-emitting layer over the pixel electrode; and

an electrode over the light-emitting layer,

wherein the first gate electrode layer, the gate insulating layer, the first oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, and the first oxide insulating layer have a light-transmitting property, and

wherein the connection electrode layer is in contact with a top surface of the first oxide semiconductor layer, a side surface of the first oxide semiconductor layer, and a side surface of the one of the first source electrode layer and the first drain electrode layer.

2. The light-emitting device according to claim 1,

wherein the second thin film transistor comprises a second gate electrode layer, a second source electrode layer, and a second drain electrode layer which are formed using a material different from a material of the first gate electrode layer, the first source electrode layer, and the first drain electrode layer, and

wherein the second gate electrode layer, the second source electrode layer, and the second drain electrode layer are formed using a conductive material having lower resistance than a conductive material of the first source electrode layer, and the first drain electrode layer.

3. The light-emitting device according to claim 1,

wherein the connection electrode layer is formed using a film comprising an element selected from the group consisting of Al, Cr, Cu, Ta, Ti, Mo, and W as a main component, an alloy film comprising any of the elements, or a stacked film including the films in combination.

4. The light-emitting device according to claim 2,

wherein the second source electrode layer and the second drain electrode layer are formed using the same material as the connection electrode layer.

5. The light-emitting device according to claim 1,

wherein the first source electrode layer and the first drain electrode layer are formed using indium oxide, indium oxide-tin oxide alloy, indium oxide-zinc oxide alloy, or zinc oxide.

6. The light-emitting device according to claim 1,

wherein the second thin film transistor comprises:

a second oxide semiconductor layer; and

a second oxide insulating layer over the second oxide semiconductor layer, and

wherein a channel formation region of the second oxide semiconductor layer is in contact with the second oxide insulating layer.

7. The light-emitting device according to claim 6,

wherein the first oxide insulating layer and the second oxide insulating layer are formed using a silicon oxide film or an aluminum oxide film formed by a sputtering method.

8. The light-emitting device according to claim 1,

wherein the first oxide semiconductor layer comprises In—

Ga—

Zn—

O based oxide semiconductor.

9. The light-emitting device according to claim 1,

wherein the first oxide semiconductor layer is an i-type oxide semiconductor layer.

10. The light-emitting device according to claim 1,

wherein the first oxide semiconductor layer comprises indium, zinc, and oxygen.

11. A light-emitting device comprising:

a pixel portion including a first thin film transistor over a substrate; and

a driver circuit including a second thin film transistor over the substrate, wherein the first thin film transistor has a different structure from the second thin film transistor,

wherein the first thin film transistor comprises;

a first gate electrode layer over the substrate;

a gate insulating layer over the first gate electrode layer;

a first source electrode layer and a first drain electrode layer over the gate insulating layer;

a first oxide semiconductor layer over the gate insulating layer, the first source electrode layer, and the first drain electrode layer;

a first oxide insulating layer in contact with the first oxide semiconductor layer; and

a connection electrode layer over the gate insulating layer, wherein the connection electrode layer is electrically connected to one of the first source electrode layer and the first drain electrode layer,

wherein the pixel portion comprises;

a color filter layer over the first oxide insulating layer;

a pixel electrode over the color filter layer, wherein the pixel electrode is electrically connected to the connection electrode layer;

a light-emitting layer over the pixel electrode; and

an electrode over the light-emitting layer,

wherein the first gate electrode layer, the gate insulating layer, the first oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, and the first oxide insulating layer have a light-transmitting property,

wherein the first oxide insulating layer is in contact with a side surface of the first oxide semiconductor layer and a side surface of the other one of the first source electrode layer and the first drain electrode layer, and

wherein the connection electrode layer is in contact with a top surface of the first oxide semiconductor layer, a side surface of the first oxide semiconductor layer, and a side surface of the one of the first source electrode layer and the first drain electrode layer.

12. The light-emitting device according to claim 11,

wherein the second thin film transistor comprises a second gate electrode layer, a second source electrode layer, and a second drain electrode layer which are formed using a material different from a material of the first gate electrode layer, the first source electrode layer, and the first drain electrode layer, and

wherein the second gate electrode layer, the second source electrode layer, and the second drain electrode layer are formed using a conductive material having lower resistance than a conductive material of the first source electrode layer, and the first drain electrode layer.

13. The light-emitting device according to claim 11,

wherein the connection electrode layer is formed using a film comprising an element selected from the group consisting of Al, Cr, Cu, Ta, Ti, Mo, and W as a main component, an alloy film comprising any of the elements, or a stacked film including the films in combination.

14. The light-emitting device according to claim 13,

wherein the second source electrode layer and the second drain electrode layer are formed using the same material as the connection electrode layer.

15. The light-emitting device according to claim 11,

wherein the first source electrode layer and the first drain electrode layer are formed using indium oxide, indium oxide-tin oxide alloy, indium oxide-zinc oxide alloy, or zinc oxide.

16. The light-emitting device according to claim 11,

wherein the second thin film transistor comprises:

a second oxide semiconductor layer, and

a second oxide insulating layer over the second oxide semiconductor layer, and

wherein a channel formation region of the second oxide semiconductor layer is in contact with the second oxide insulating layer.

17. The light-emitting device according to claim 16,

wherein the first oxide insulating layer and the second oxide insulating layer are formed using a silicon oxide film or an aluminum oxide film formed by a sputtering method.

18. The light-emitting device according to claim 11,

wherein the first oxide semiconductor layer comprises In—

Ga—

Zn—

O based oxide semiconductor.

19. The light-emitting device according to claim 11,

wherein the first oxide semiconductor layer is an i-type oxide semiconductor layer.

20. The light-emitting device according to claim 11,

wherein the first oxide semiconductor layer comprises indium, zinc, and oxygen.