Liquid crystal display device

• US 8,896,778 B2
• Filed: 04/26/2011
• Issued: 11/25/2014
• Est. Priority Date: 07/20/2007
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Kianni, K. Cyrus
• Application Number:
  US13/093,897
• Publication Number:
  US 20110198595A1
• Time in Patent Office: 1,309 Days
• Field of Search: 349/42, 349/43, 257/E51.005, 257/E29.151, 345/92, 438/149, 438/142
• US Class Current: 349/43
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• 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 29/786 Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785
• 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 liquid crystal display device including a thin film transistor with high electric characteristics and high reliability. As for a liquid crystal display 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, and a channel protective layer which is formed over the buffer layer so as to overlap with the channel formation region of the microcrystalline semiconductor film.

Claims

1. A semiconductor device comprising:

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 channel protective layer over the channel formation region of the microcrystalline semiconductor film;

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

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

an insulating film over the channel protective layer, the source electrode, and the drain electrode;

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate electrode;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region, and

wherein an entire portion of the microcrystalline semiconductor film is overlapped with the gate electrode.

3. The semiconductor device according to claim 1, wherein the semiconductor film is a microcrystalline semiconductor film.

2. A semiconductor device comprising:

a substrate capable of transmitting light;

a gate wiring over the substrate;

a gate insulating film over the gate wiring;

a semiconductor film comprising silicon, the semiconductor film including a channel formation region over the gate wiring with the gate insulating film therebetween;

a source electrode and a drain electrode over the semiconductor film;

an insulating film over the semiconductor film, the source electrode, and the drain electrode; and

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate wiring;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region, and

wherein an entire portion of the semiconductor film is overlapped with the gate wiring.

4. The semiconductor device according to claim 2, wherein the gate insulating film comprises a first film and a second film on the first film, the first film comprising silicon nitride or silicon nitride oxide, and the second film comprising silicon oxide or silicon oxynitride.

5. The semiconductor device according to claim 2, wherein the insulating film comprises a silicon oxynitride.

6. The semiconductor device according to claim 2, further comprising:

a source region and a drain region over the semiconductor film.

7. The semiconductor device according to claim 2, further comprising:

a first semiconductor film on the semiconductor film,

wherein each of the source electrode and the drain electrode is in contact with an upper surface of the first semiconductor film.

8. The semiconductor device according to claim 7, wherein the first semiconductor film has a larger band gap than the semiconductor film.

9. A semiconductor device comprising:

a substrate capable of transmitting light;

a gate wiring over the substrate;

a gate insulating film over the gate wiring;

a semiconductor film, the semiconductor film including a channel formation region over the gate wiring with the gate insulating film therebetween;

a source electrode and a drain electrode over the semiconductor film;

an insulating film over the semiconductor film, the source electrode, and the drain electrode; and

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate wiring;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region, and

wherein an entire portion of the semiconductor film is overlapped with the gate wiring.

10. The semiconductor device according to claim 9, wherein the semiconductor film is a microcrystalline semiconductor film.

11. The semiconductor device according to claim 9, wherein the gate insulating film comprises a first film and a second film on the first film, the first film comprising silicon nitride or silicon nitride oxide, and the second film comprising silicon oxide or silicon oxynitride.

12. The semiconductor device according to claim 9, wherein the insulating film comprises a silicon oxynitride.

13. The semiconductor device according to claim 9, further comprising:

a source region and a drain region over the semiconductor film.

14. The semiconductor device according to claim 9, further comprising:

a first semiconductor film on the semiconductor film,

wherein each of the source electrode and the drain electrode is in contact with an upper surface of the first semiconductor film.

15. The semiconductor device according to claim 14, wherein the first semiconductor film has a larger band gap than the semiconductor film.

16. A semiconductor device comprising:

a substrate capable of transmitting light;

a gate wiring over the substrate;

a gate insulating film over the gate wiring;

a semiconductor film, the semiconductor film including a channel formation region over the gate wiring with the gate insulating film therebetween;

a source electrode and a drain electrode over the semiconductor film;

an insulating film over the semiconductor film, the source electrode, and the drain electrode; and

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate wiring;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region,

wherein an entire portion of the semiconductor film is overlapped with the gate wiring, and

wherein the semiconductor film comprises amorphous portion and crystalline portion.

17. The semiconductor device according to claim 16, wherein the semiconductor film is a microcrystalline semiconductor film.

18. The semiconductor device according to claim 16, wherein the gate insulating film comprises a first film and a second film on the first film, the first film comprising silicon nitride or silicon nitride oxide, and the second film comprising silicon oxide or silicon oxynitride.

19. The semiconductor device according to claim 16, wherein the insulating film comprises a silicon oxynitride.

20. The semiconductor device according to claim 16, further comprising:

a source region and a drain region over the semiconductor film.

21. The semiconductor device according to claim 16, further comprising:

a first semiconductor film on the semiconductor film,

wherein each of the source electrode and the drain electrode is in contact with an upper surface of the first semiconductor film.

22. The semiconductor device according to claim 21, wherein the first semiconductor film has a larger band gap than the semiconductor film.

23. A semiconductor device comprising:

a substrate capable of transmitting light;

a gate wiring over the substrate;

a gate insulating film over the gate wiring;

a semiconductor film, the semiconductor film including a channel formation region over the gate wiring with the gate insulating film therebetween;

a channel protective layer over the channel formation region;

a source electrode and a drain electrode over the semiconductor film;

an insulating film over the channel protective layer, the source electrode, and the drain electrode; and

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate wiring;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region, and

wherein an entire portion of the semiconductor film is overlapped with the gate wiring.

24. The semiconductor device according to claim 23, wherein the semiconductor film is a microcrystalline semiconductor film.

25. The semiconductor device according to claim 23, wherein the gate insulating film comprises a first film and a second film on the first film, the first film comprising silicon nitride or silicon nitride oxide, and the second film comprising silicon oxide or silicon oxynitride.

26. The semiconductor device according to claim 23, wherein the insulating film comprises a silicon oxynitride.

27. The semiconductor device according to claim 23, further comprising:

a source region and a drain region over the semiconductor film.

28. The semiconductor device according to claim 23, further comprising:

a first semiconductor film on the semiconductor film,

wherein each of the source electrode and the drain electrode is in contact with an upper surface of the first semiconductor film.

29. The semiconductor device according to claim 28, wherein the first semiconductor film has a larger band gap than the semiconductor film.

30. A semiconductor device comprising:

a substrate capable of transmitting light;

a gate wiring over the substrate;

a gate insulating film over the gate wiring;

a semiconductor film, the semiconductor film including a channel formation region over the gate wiring with the gate insulating film therebetween;

a channel protective layer over the channel formation region;

a source electrode and a drain electrode over the semiconductor film;

an insulating film over the channel protective layer, the source electrode, and the drain electrode; and

a pixel electrode over the insulating film, the pixel electrode being electrically connected to the source electrode or the drain electrode;

a spacer over the pixel electrode, the spacer overlapping with the gate wiring;

a counter electrode over the spacer; and

a light blocking film, a first color filter film, and a second color filter film over the counter electrode,

wherein the light blocking film includes a region overlapping with the spacer,

wherein each of the first color filter film and the second color filter film overlaps with the region,

wherein an entire portion of the semiconductor film is overlapped with the gate wiring, and

wherein the semiconductor film comprises amorphous portion and crystalline portion.

31. The semiconductor device according to claim 30, wherein the semiconductor film is a microcrystalline semiconductor film.

32. The semiconductor device according to claim 30, wherein the gate insulating film comprises a first film and a second film on the first film, the first film comprising silicon nitride or silicon nitride oxide, and the second film comprising silicon oxide or silicon oxynitride.

33. The semiconductor device according to claim 30, wherein the insulating film comprises a silicon oxynitride.

34. The semiconductor device according to claim 30, further comprising:

a source region and a drain region over the semiconductor film.

35. The semiconductor device according to claim 30, further comprising:

a first semiconductor film on the semiconductor film,

wherein each of the source electrode and the drain electrode is in contact with an upper surface of the first semiconductor film.

36. The semiconductor device according to claim 35, wherein the first semiconductor film has a larger band gap than the semiconductor film.