Semiconductor device and method for manufacturing the same

• US 9,190,424 B2
• Filed: 03/16/2015
• Issued: 11/17/2015
• Est. Priority Date: 07/18/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Sakata, Junichiro, Miyake, Hiroyuki, Kuwabara, Hideaki
• Primary Examiner(s): ULLAH, ELIAS
• Application Number:
  US14/658,955
• Publication Number:
  US 20150194445A1
• Time in Patent Office: 246 Days
• Field of Search: 257/59, 257/71, 257/43
• US Class Current: 1/1
• 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 29/45 Ohmic electrodes

Abstract

A highly reliable display device which has high aperture ratio and includes a transistor with stable electrical characteristics is manufactured. The display device includes a driver circuit portion and a display portion over the same substrate. The driver circuit portion includes a driver circuit transistor and a driver circuit wiring. A source electrode and a drain electrode of the driver circuit transistor are formed using a metal. A channel layer of the driver circuit transistor is formed using an oxide semiconductor. The driver circuit wiring is formed using a metal. The display portion includes a pixel transistor and a display portion wiring. A source electrode and a drain electrode of the pixel transistor are formed using a transparent oxide conductor. A semiconductor layer of the pixel transistor is formed using the oxide semiconductor. The display portion wiring is formed using a transparent oxide conductor.

Claims

1. A display device comprising:

a pixel portion over a substrate; and

a driver circuit portion over the substrate,

wherein the driver circuit portion comprises;

a first gate electrode layer;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer being in contact with the gate insulating layer and including a channel formation region;

an oxide insulating layer over the first oxide semiconductor layer;

an insulating layer over the oxide insulating layer; and

a second gate electrode layer over the insulating layer, the second gate electrode layer overlapping the channel formation region.

2. The display device according to claim 1,

wherein the oxide insulating layer is in contact with the channel formation region.

3. The display device according to claim 1,

wherein a thickness of the channel formation region is smaller than a thickness of other parts of the first oxide semiconductor layer.

4. The display device according to claim 1,

wherein the oxide insulating layer is in contact with the gate insulating layer.

5. The display device according to claim 1,

wherein the oxide insulating layer is selected from a silicon oxide layer, a silicon nitride oxide layer, an aluminum oxide layer, and an aluminum oxynitride layer.

6. The display device according to claim 1,

wherein the pixel portion comprises:

a third gate electrode layer;

the gate insulating layer over the third gate electrode layer; and

a second oxide semiconductor layer over the gate insulating layer.

7. The display device according to claim 1,

wherein the insulating layer is a silicon nitride layer.

8. A mobile phone comprising:

a main body;

the display device according to claim 1; and

a band portion which enables the main body to be worn on a wrist.

9. A display device comprising:

a pixel portion over a substrate; and

a driver circuit portion over the substrate,

wherein the driver circuit portion comprises;

a first gate electrode layer;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer being in contact with the gate insulating layer and including a channel formation region;

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

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

a second gate electrode layer over the oxide insulating layer, the second gate electrode layer overlapping the channel formation region,

wherein the first gate electrode layer and the second gate electrode layer have a light-transmitting property.

10. The display device according to claim 9,

wherein the oxide insulating layer is in contact with the channel formation region.

11. The display device according to claim 9,

wherein a thickness of the channel formation region is smaller than a thickness of other parts of the first oxide semiconductor layer.

12. The display device according to claim 9,

wherein the oxide insulating layer is in contact with the gate insulating layer.

13. The display device according to claim 9,

wherein the oxide insulating layer is selected from a silicon oxide layer, a silicon nitride oxide layer, an aluminum oxide layer, and an aluminum oxynitride layer.

14. The display device according to claim 9,

wherein the pixel portion comprises:

a third gate electrode layer;

the gate insulating layer over the third gate electrode layer; and

a second oxide semiconductor layer over the gate insulating layer.

15. A display device comprising:

a pixel portion over a substrate; and

a driver circuit portion over the substrate,

wherein the driver circuit portion comprises;

a first gate electrode layer;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer being in contact with the gate insulating layer and including a channel formation region;

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

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

a second gate electrode layer over the oxide insulating layer, the second gate electrode layer overlapping the channel formation region,

wherein each of the source electrode layer and the drain electrode layer includes a metal.

16. The display device according to claim 15,

wherein the oxide insulating layer is in contact with the channel formation region.

17. The display device according to claim 15,

wherein a thickness of the channel formation region is smaller than a thickness of other parts of the first oxide semiconductor layer.

18. The display device according to claim 15,

wherein the oxide insulating layer is in contact with the gate insulating layer.

19. The display device according to claim 15,

wherein the oxide insulating layer is selected from a silicon oxide layer, a silicon nitride oxide layer, an aluminum oxide layer, and an aluminum oxynitride layer.

20. The display device according to claim 15,

wherein the pixel portion comprises:

a third gate electrode layer;

the gate insulating layer over the third gate electrode layer; and

a second oxide semiconductor layer over the gate insulating layer.