Light-emitting device

• US 8,022,405 B2
• Filed: 07/15/2008
• Issued: 09/20/2011
• Est. Priority Date: 07/20/2007
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Lebentritt; Michael S
• Assistant Examiner(s): WHALEN, DANIEL B
• Application Number:
  US12/219,025
• Publication Number:
  US 20090020759A1
• Time in Patent Office: 1,162 Days
• Field of Search: 257/57, 257/59, 257/66, 257/82, 257/257, 257/E21.411, 438/30, 438149-152, 438/155, 438/158, 438/164, 349/42, 349/43, 349/47
• US Class Current: 257/59
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

It is an object to provide a light-emitting device including a thin film transistor with high electric characteristics and high reliability, and a method for manufacturing the light-emitting device with high productivity. As for a light-emitting device including an inverted staggered thin film transistor of a channel stop type, the inverted staggered thin film transistor includes a gate electrode, a gate insulating film over the gate electrode, a microcrystalline semiconductor film including a channel formation region over the gate insulating film, a buffer layer over the microcrystalline semiconductor film, a channel protective layer which is provided over the buffer layer so as to overlap with the channel formation region of the microcrystalline semiconductor film, a source region and a drain region over the channel protective layer and the buffer layer, and a source electrode and a drain electrode over the source region and the drain region.

Claims

1. A light-emitting device comprising:

a gate electrode over a substrate;

a gate insulating film formed over the gate electrode;

a microcrystalline semiconductor film including a channel formation region formed over the gate insulating film;

a buffer layer formed over and being in contact with the microcrystalline semiconductor film;

a channel protective layer formed over and being in contact with the buffer layer wherein the channel protective layer overlaps the channel formation region;

a source region and a drain region formed over the channel protective layer and the buffer layer;

a source electrode and a drain electrode formed over the source region and the drain region; and

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

wherein end portions of the microcrystalline semiconductor film are positioned more inwardly than end portions of the gate electrode.

2. The light-emitting device according to claim 1, wherein the buffer layer is an amorphous semiconductor film.

3. The light-emitting device according to claim 2, wherein the amorphous semiconductor film contains nitrogen.

4. The light-emitting device according to claim 2, wherein the amorphous semiconductor film contains hydrogen.

5. The light-emitting device according to claim 2, wherein the amorphous semiconductor film contains fluorine, chlorine, bromine, or iodine.

6. The light-emitting device according to claim 2, wherein the amorphous semiconductor film contains nitrogen, carbon, and oxygen at a total concentration of greater than or equal to 1×

10²⁰ atoms/cm³ and less than or equal to 15×

10²⁰ atoms/cm³.

7. The light-emitting device according to claim 1, wherein an area of the source region and the drain region which overlaps with the pixel electrode is larger than that of the source electrode and the drain electrode which overlaps with the pixel electrode.

8. An electronic device having the light-emitting device according to claim 1, wherein the electronic device is one selected from the group consisting of a camera, a goggle-type display, a car navigation system, a projector, a car stereo, a personal computer, a portable information terminal, a television device, and a lamp.

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

wherein the gate electrode has an upper surface and a tapered-shape side surface,

wherein the microcrystalline semiconductor film is over the upper surface of the gate electrode, and

wherein the microcrystalline semiconductor film is not overlapped with the tapered-shape side surface.

10. The light-emitting device according to claim 1, wherein the channel protective layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, and silicon nitride oxide.

11. The light-emitting device according to claim 1, wherein the channel protective layer comprises a material selected from the group consisting of a photosensitive organic material and a non-photosensitive organic material.

12. A light-emitting device comprising:

a pixel portion and a driver circuit over a substrate, each of the pixel portion and the driver circuit comprising;

a gate electrode;

a first insulating film formed over the gate electrode;

a microcrystalline semiconductor film including a channel formation region formed over the first insulating film;

a buffer layer formed over and being in contact with the microcrystalline semiconductor film;

a channel protective layer formed over and being in contact with the buffer layer wherein the channel protective layer overlaps the channel formation region;

a source region and a drain region formed over the channel protective layer and the buffer layer;

a source electrode and a drain electrode formed over the source region and the drain region; and

a second insulating film formed over the channel protective layer, the source electrode, and the drain electrode;

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

a partition formed over the pixel electrode;

a light emitting layer formed over the pixel electrode and the partition; and

a common electrode formed over the light emitting layer,

wherein end portions of the microcrystalline semiconductor film of the pixel portion and the driver circuit are positioned more inwardly than end portions of the gate electrode of the pixel portion and the driver circuit.

13. The light-emitting device according to claim 12, wherein the buffer layer of the pixel portion and the driver circuit is an amorphous semiconductor film.

14. The light-emitting device according to claim 13, wherein the amorphous semiconductor film contains nitrogen.

15. The light-emitting device according to claim 13, wherein the amorphous semiconductor film contains hydrogen.

16. The light-emitting device according to claim 13, wherein the amorphous semiconductor film contains fluorine, chlorine, bromine, or iodine.

17. The light-emitting device according to claim 13, wherein the amorphous semiconductor film contains nitrogen, carbon, and oxygen at a total concentration of greater than or equal to 1×

10²⁰ atoms/cm³ and less than or equal to 15×

10²⁰ atoms/cm³.

18. The light-emitting device according to claim 12, wherein an area of the source region and the drain region of the pixel portion which overlaps with the pixel electrode is larger than that of the source electrode and the drain electrode of the pixel portion which overlaps with the pixel electrode.

19. An electronic device having the light-emitting device according to claim 12, wherein the electronic device is one selected from the group consisting of a camera, a goggle-type display, a car navigation system, a projector, a car stereo, a personal computer, a portable information terminal, a television device, and a lamp.

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

wherein the gate electrode has an upper surface and a tapered-shape side surface,

wherein the microcrystalline semiconductor film is over the upper surface of the gate electrode, and

wherein the microcrystalline semiconductor film is not overlapped with the tapered-shape side surface.

21. The light-emitting device according to claim 12, wherein the channel protective layer comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, and silicon nitride oxide.

22. The light-emitting device according to claim 12, wherein the channel protective layer comprises a material selected from the group consisting of a photosensitive organic material and a non-photosensitive organic material.