LIGHT-EMITTING DEVICE AND MANUFACTURING METHOD THEREOF

• US 20110062434A1
• Filed: 09/13/2010
• Published: 03/17/2011
• Est. Priority Date: 09/16/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: EGUCHI, Shingo, OIKAWA, Yoshiaki, MARUYAMA, Hotaka, OKAZAKI, Kenichi
• Granted Patent: US 8,377,762 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• 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 29/78678 with inverted-type structure, e.g. with bottom gate
• 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 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/126 Shielding, e.g. light-blocking means over the TFTs
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 77/111 Flexible substrates
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

An object of the invention is to improve the reliability of a light-emitting device. Another object of the invention is to provide flexibility to a light-emitting device having a thin film transistor using an oxide semiconductor film. A light-emitting device has, over one flexible substrate, a driving circuit portion including a thin film transistor for a driving circuit and a pixel portion including a thin film transistor for a pixel. The thin film transistor for a driving circuit and the thin film transistor for a pixel are inverted staggered thin film transistors including an oxide semiconductor layer which is in contact with a part of an oxide insulating layer.

Claims

1. A semiconductor device comprising:

a flexible substrate;

a driving circuit portion over the flexible substrate, comprising;

a first transistor comprising;

a first gate electrode layer over the flexible substrate;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer over the gate insulating layer;

a first source electrode layer over the first oxide semiconductor layer;

a first drain electrode layer over the first oxide semiconductor layer; and

an oxide insulating layer over the first oxide semiconductor layer, the first source electrode layer, and the first drain electrode layer, the oxide insulating layer being in contact with at least a part of the first oxide semiconductor layer between the first source electrode layer and the first drain electrode layer;

a pixel portion over the flexible substrate, comprising;

a second transistor comprising;

a second gate electrode layer over the flexible substrate;

the gate insulating layer over the second gate electrode layer;

a second oxide semiconductor layer over the gate insulating layer;

a second source electrode layer over the second oxide semiconductor layer;

a second drain electrode layer over the second oxide semiconductor layer; and

the oxide insulating layer over the second oxide semiconductor layer, the second source electrode layer, and the second drain electrode layer, the oxide insulating layer being in contact with at least a part of the second oxide semiconductor layer between the second source electrode layer and the second drain electrode layer,

a color filter over the oxide insulating layer;

a first electrode layer over the color filter and electrically connected to the second transistor;

an EL layer over the first electrode layer; and

a second electrode layer over the EL layer,

wherein the first transistor comprises a conductive layer over the oxide insulating layer, the conductive layer overlapping with the first gate electrode layer and the first oxide semiconductor layer.

2. The semiconductor device according to claim 1,

wherein the conductive layer is a light-transmitting conductive film formed in the same process as the first electrode layer, and

wherein the conductive layer is electrically connected to the first transistor.

3. The semiconductor device according to claim 1 further comprising:

a first oxide conductive layer provided between the first oxide semiconductor layer and the first source electrode layer;

a second oxide conductive layer provided between the first oxide semiconductor layer and the first drain electrode layer;

a third oxide conductive layer provided between the second oxide semiconductor layer and the second source electrode layer; and

a fourth oxide conductive layer provided between the second oxide semiconductor layer and the second drain electrode layer.

4. A semiconductor device comprising:

a flexible substrate;

a driving circuit portion over the flexible substrate, comprising;

a first transistor comprising;

a first gate electrode layer over the flexible substrate;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer over the gate insulating layer;

a first source electrode layer over the first oxide semiconductor layer;

a first drain electrode layer over the first oxide semiconductor layer; and

an oxide insulating layer over the first oxide semiconductor layer, the first source electrode layer, and the first drain electrode layer, the oxide insulating layer being in contact with at least a part of the first oxide semiconductor layer between the first source electrode layer and the first drain electrode layer,

a pixel portion over the flexible substrate, comprising;

a second transistor comprising;

a second gate electrode layer over the flexible substrate;

the gate insulating layer over the second gate electrode layer;

a second oxide semiconductor layer over the gate insulating layer;

a second source electrode layer over the second oxide semiconductor layer;

a second drain electrode layer over the second oxide semiconductor layer; and

the oxide insulating layer over the second oxide semiconductor layer, the second source electrode layer, and the second drain electrode layer, the oxide insulating layer being in contact with at least a part of the second oxide semiconductor layer between the second source electrode layer and the second drain electrode layer;

a color filter over the oxide insulating layer;

a first electrode layer over the color filter and electrically connected to the second transistor through a connection electrode layer;

an EL layer over the first electrode layer; and

a second electrode layer over the EL layer,

wherein the first transistor comprises a conductive layer over the oxide insulating layer, the conductive layer overlapping with the first gate electrode layer and the first oxide semiconductor layer.

5. The semiconductor device according to claim 4,

wherein the conductive layer is a light-transmitting conductive film formed in the same process as the first electrode layer, and

wherein the conductive layer is electrically connected to the first transistor.

6. The semiconductor device according to claim 4 further comprising:

a first oxide conductive layer provided between the first oxide semiconductor layer and the first source electrode layer;

a second oxide conductive layer provided between the first oxide semiconductor layer and the first drain electrode layer;

a third oxide conductive layer provided between the second oxide semiconductor layer and the second source electrode layer; and

a fourth oxide conductive layer provided between the second oxide semiconductor layer and the second drain electrode layer.

7. A method for manufacturing a semiconductor device, comprising the steps of:

forming a separation layer over a first substrate;

forming a first transistor for a driving circuit portion and a second transistor for a pixel portion over the separation layer;

forming a first electrode layer electrically connected to the second transistor;

transferring the first transistor, the second transistor, and the first electrode layer from the first substrate to a second substrate using the separation layer;

transferring to a flexible substrate the first transistor, the second transistor, and the first electrode which have been transferred to the second substrate;

forming an EL layer over the first electrode layer transferred to the flexible substrate; and

forming a second electrode layer over the EL layer,

wherein the first transistor includes a first oxide semiconductor layer and the second transistor includes a second oxide semiconductor layer, and

wherein the first oxide semiconductor layer and the second oxide semiconductor layer are formed at the same time.

8. The method for manufacturing a semiconductor device according to claim 7, wherein the oxide semiconductor layer is subjected to heat treatment for dehydration or dehydrogenation.

9. The method for manufacturing a semiconductor device according to claim 7, wherein a silicon oxide film or an aluminum oxide film is formed in contact with the oxide semiconductor layer by a sputtering method.

10. The method for manufacturing a semiconductor device according to claim 7, further comprising the step of forming a color filter, wherein the first electrode layer is over the color filter.

11. The method for manufacturing a semiconductor device according to claim 7, further comprising the step of forming a conductive layer over the first oxide semiconductor layer, wherein the conductive layer is formed at the same process as the first electrode layer.

12. A method for manufacturing a semiconductor device, comprising the steps of:

forming a separation layer over a first substrate;

forming a first transistor for a driving circuit portion and a second transistor for a pixel portion over the separation layer;

forming a first electrode layer electrically connected to the second transistor;

transferring the first transistor, the second transistor, and the first electrode layer from the first substrate to a second substrate using the separation layer;

transferring to a flexible substrate the first transistor, the second transistor, and the first electrode which have been transferred to the second substrate;

forming an EL layer over the first electrode layer transferred to the flexible substrate;

forming a second electrode layer over the EL layer; and

forming a flexible metal substrate over the second electrode layer so that the driving circuit portion and the pixel portion are sealed with the flexible metal substrate,

wherein the first transistor includes a first oxide semiconductor layer and the second transistor includes a second oxide semiconductor layer, and

wherein the first oxide semiconductor layer and the second oxide semiconductor layer are formed at the same time.

13. The method for manufacturing a semiconductor device according to claim 12, wherein the oxide semiconductor layer is subjected to heat treatment for dehydration or dehydrogenation.

14. The method for manufacturing a semiconductor device according to claim 12, wherein a silicon oxide film or an aluminum oxide film is formed in contact with the oxide semiconductor layer by a sputtering method.

15. The method for manufacturing a semiconductor device according to claim 12, further comprising the step of forming a color filter, wherein the first electrode layer is over the color filter.

16. The method for manufacturing a semiconductor device according to claim 12, further comprising the step of forming a conductive layer over the first oxide semiconductor layer, wherein the conductive layer is formed at the same process as the first electrode layer.