SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20100117079A1
• Filed: 11/10/2009
• Published: 05/13/2010
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: OSADA, Takeshi, AKIMOTO, Kengo, YAMAZAKI, Shunpei, MIYAIRI, Hidekazu
• Granted Patent: US 8,518,739 B2
• Time in Patent Office: Days
• 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: H01L 29/78648 arranged on opposing sides of the channel
• 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

As a display device has a higher definition, the number of pixels, gate lines, and signal lines are increased. When the number of the gate lines and the signal lines are increased, there occurs a problem that it is difficult to mount an IC chip including a driver circuit for driving the gate and signal lines by bonding or the like, whereby manufacturing cost is increased. A pixel portion and a driver circuit for driving the pixel portion are provided over the same substrate, and at least part of the driver circuit includes a thin film transistor using an oxide semiconductor interposed between gate electrodes provided above and below the oxide semiconductor. Therefore, when the pixel portion and the driver circuit are provided over the same substrate, manufacturing cost can be reduced.

Claims

1. A display device comprising:

a first gate electrode over an insulating surface;

a first insulating layer over the first gate electrode;

a first source region or a first drain region over the first insulating layer;

a source electrode or a drain electrode over the first source region or the first drain region;

a second source region or a second drain region over the source electrode or the drain electrode;

an oxide semiconductor layer over the second source region or the second drain region;

a second insulating layer covering the oxide semiconductor layer;

a second gate electrode over the second insulating layer,

wherein the oxide semiconductor layer is formed over the first insulating layer and is overlapped with the first gate electrode,

wherein at least a part of the oxide semiconductor layer is disposed between the source electrode and the drain electrode, and

wherein the second gate electrode overlaps with the oxide semiconductor layer and the first gate electrode.

2. A display device according to claim 1,

wherein at least parts of side surfaces of the first source region and the first drain region are in contact with the oxide semiconductor layer, and at least parts of an upper surface and a side surface of the second source region and the second drain region are in contact with the oxide semiconductor layer.

3. A display device according to claim 1, wherein a width of the first gate electrode is larger than a width of the second gate electrode.

4. A display device according to claim 1, wherein a width of the first gate electrode is smaller than a width of the second gate electrode.

5. A display device according to claim 1, wherein a width of the second gate electrode is smaller than a distance between the source electrode and the drain electrode.

6. A display device according to claim 1, wherein the display device is incorporated into one selected from the group consisting of an electronic paper, a portable information terminal device, a camera, a computer, a television set, a digital photo frame, and a mobile phone.

7. A display device according to claim 1, wherein the first gate electrode and the second gate electrode have a same potential.

8. A display device according to claim 1, wherein the first gate electrode and the second gate electrode have different potentials.

9. A semiconductor device comprising:

a pixel portion and a driver circuit,

wherein the pixel portion includes at least a first thin film transistor having a first oxide semiconductor layer,

wherein the driver circuit includes an EDMOS circuit in which at least a second thin film transistor having a second oxide semiconductor layer and a third thin film transistor having a third oxide semiconductor layer are included,

wherein the third thin film transistor includes a first gate electrode below the third oxide semiconductor layer and a second gate electrode above the third oxide semiconductor layer, and

wherein at least a part of the third oxide semiconductor layer is disposed between a source electrode and a drain electrode, source regions are provided over and under the source electrode, and drain regions are provided over and under the drain electrode; and

the second gate electrode overlaps with the third oxide semiconductor layer and the first gate electrode.

10. A semiconductor device according to claim 9, wherein the first thin film transistor is electrically connected to a pixel electrode, and the pixel electrode is formed using a same material as the second gate electrode.

11. A semiconductor device according to claim 9, wherein the first thin film transistor is electrically connected to a pixel electrode, and the pixel electrode is formed using a different material from the second gate electrode.

12. A semiconductor device according to claim 9, wherein the first oxide semiconductor layer, the second oxide semiconductor layer, the third oxide semiconductor layer, the source regions, and the drain regions include at least one of indium, gallium, and zinc.

13. A semiconductor device according to claim 9, wherein the first gate electrode and the second gate electrode have a same potential.

14. A semiconductor device according to claim 9, wherein the first gate electrode and the second gate electrode have different potentials.

15. A semiconductor device according to claim 9, wherein the semiconductor device is incorporated into one selected from the group consisting of an electronic paper, a portable information terminal device, a camera, a computer, a television set, a digital photo frame, and a mobile phone.

16. A method for manufacturing a semiconductor device, comprising:

forming a first gate electrode over an insulating surface;

forming a first insulating layer over the first gate electrode;

forming a first source region or a first drain region over the first insulating layer;

forming a source electrode or a drain electrode over the first source region or the first drain region;

forming a second source region or a second drain region over the source electrode or the drain electrode;

forming an oxide semiconductor layer over the second source region and the second drain region after plasma treatment is performed on the first insulating layer, the second source region, and the second drain region;

forming a second insulating layer covering the oxide semiconductor layer; and

forming a second gate electrode over the second insulating layer.

17. A method for manufacturing a semiconductor device according to claim 16, wherein the semiconductor device is incorporated into one selected from the group consisting of an electronic paper, a portable information terminal device, a camera, a computer, a television set, a digital photo frame, and a mobile phone.

18. A method for manufacturing a semiconductor device according to claim 16, wherein reverse sputtering in which an argon gas is introduced and plasma is generated with an RF power is performed, so that the first insulating layer is subjected to the plasma treatment.

19. A method for manufacturing a semiconductor device according to claim 16, further comprising performing heat treatment after the formation of the oxide semiconductor layer.

20. A method for manufacturing a semiconductor device according to claim 19, wherein the heat treatment is performed in a nitrogen atmosphere at 200 to 600°

C.