Projection TV

• US 6,876,038 B2
• Filed: 08/22/2003
• Issued: 04/05/2005
• Est. Priority Date: 02/25/1998
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohtani, Hisashi, Hayakawa, Masahiko, Yamazaki, Shunpei
• Primary Examiner(s): Ngo, Ngan V.
• Application Number:
  US10/645,611
• Publication Number:
  US 20040041190A1
• Time in Patent Office: 592 Days
• Field of Search: 257/350, 257/59, 257/72, 257/296
• US Class Current: 257/350
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78678 with inverted-type structure, e.g. with bottom gate

Abstract

Thin-film transistors constituting a liquid crystal module have a channel forming region that is a crystal structural body in which a plurality of rod-like or flat-rod-like crystals are arranged in a particular direction. In the thin-film transistors, deteriorations in device characteristics due to hot carrier injection or the like can be prevented effectively when the temperature is in a range of 80° C.-250° C. (preferably 100° C.-200° C.). Therefore, a projection TV that is very high in reliability can be realized.

Claims

1. An active matrix display device having a pixel matrix circuit, said pixel matrix circuit comprising:

at least one active layer comprising crystalline semiconductor film over an insulating surface of a substrate, said active layer having at least channel, source, and drain regions of a thin-film transistor;

a gate electrode formed over the channel region with a gate insulating film therebetween;

a pair of side walls formed adjacent to side surfaces of the gate electrode;

a pair of low impurity concentration regions formed in the active layer below the side walls; and

an auxiliary capacitor comprising a first electrode connected to one of the source and drain regions, and a second electrode,

wherein the channel region has a plurality of crystals extending approximately in parallel with a carrier flow direction of the channel region.

2. The device according to claim 1, wherein said active matrix display device is a liquid crystal device.

3. The device according to claim 1 further comprising a pixel electrode over the auxiliary capacitor wherein said pixel electrode is connected to said first electrode.

16. The device according to claim 1, wherein said thin-film transistor has an operation temperature of 80°

C.-250°

C.

4. An active matrix display device having a pixel matrix circuit, said pixel matrix circuit comprising:

at least one active layer comprising crystalline semiconductor film over an insulating surface of a substrate, said active layer having at least channel, source, and drain regions of a thin-film transistor;

a gate electrode formed over the channel region with a gate insulating film therebetween;

a pair of side walls formed adjacent to side surfaces of the gate electrode, wherein said active layer is provided with a pair of metal silicide regions formed on the source and drain regions;

a pair of low impurity concentration regions formed in the active layer below the side walls; and

an auxiliary capacitor comprising a first electrode connected to one of the source and drain regions, and a second electrode,

wherein the channel region has a plurality of crystals extending approximately in parallel with a carrier flow direction of the channel region.

5. The device according to claim 4, wherein said active matrix display device is a liquid crystal device.

6. The device according to claim 4 further comprising a pixel electrode over the auxiliary capacitor wherein said pixel electrode is connected to said first electrode.

17. The device according to claim 4, wherein said thin-film transistor has an operation temperature of 80°

C.-250°

C.

7. An active matrix display device having a pixel matrix circuit, said pixel matrix circuit comprising:

at least one active layer comprising crystalline semiconductor film over an insulating surface of a substrate, said active layer having at least channel, source, and drain regions of a thin-film transistor;

a gate electrode comprising crystalline silicon formed over the channel region with a gate insulating film therebetween;

a pair of side walls formed adjacent to side surfaces of the gate electrode, wherein said active layer is provided with a pair of metal silicide regions formed on the source and drain regions;

a pair of low impurity concentration regions formed in the active layer below the side walls; and

an auxiliary capacitor comprising a first electrode connected to one of the source and drain regions, and a second electrode,

wherein an upper surface of said gate electrode comprises a metal silicide, and

wherein the channel region has a plurality of crystals extending approximately in parallel with a carrier flow direction of the channel region.

8. The device according to claim 7, wherein said active matrix display device is a liquid crystal device.

9. The device according to claim 7 further comprising a pixel electrode over the auxiliary capacitor wherein said pixel electrode is connected to said first electrode.

18. The device according to claim 7, wherein said thin-film transistor has an operation temperature of 80°

C.-250°

C.

10. A projection device having an active matrix display device including a pixel matrix circuit, said pixel matrix circuit comprising:

at least one active layer comprising crystalline semiconductor film over an insulating surface of a substrate, said active layer having at least channel, source, and drain regions of a thin-film transistor;

a gate electrode formed over the channel region with a gate insulating film therebetween;

a pair of side walls formed adjacent to side surfaces of the gate electrode;

a pair of low impurity concentration regions formed in the active layer below the side walls; and

an auxiliary capacitor comprising a first electrode connected to one of the source and drain regions, and a second electrode,

wherein the channel region has a plurality of crystals extending approximately in parallel with a carrier flow direction of the channel region.

11. The device according to claim 10, wherein said active matrix display device is a liquid crystal device.

12. The device according to claim 10 further comprising a pixel electrode over the auxiliary capacitor wherein said pixel electrode is connected to said first electrode.

19. The device according to claim 10, wherein said thin-film transistor has an operation temperature of 80°

C.-250°

C.

13. A projection device having an active matrix display device including a pixel matrix circuit, said pixel matrix circuit comprising:

at least one active layer comprising crystalline semiconductor film over an insulating surface of a substrate, said active layer having at least channel, source, and drain regions of a thin-film transistor;

a gate electrode formed over the channel region with a gate insulating film therebetween;

a pair of side walls formed adjacent to side surfaces of the gate electrode, wherein said active layer is provided with a pair of metal silicide regions formed on the source and drain regions;

a pair of low impurity concentration regions formed in the active layer below the side walls; and

an auxiliary capacitor comprising a first electrode connected to one of the source and drain regions, and a second electrode,

wherein the channel region has a plurality of crystals extending approximately in parallel with a carrier flow direction of the channel region.

14. The device according to claim 13, wherein said active matrix display device is a liquid crystal device.

15. The device according to claim 13 further comprising a pixel electrode over the auxiliary capacitor wherein said pixel electrode is connected to said first electrode.

20. The device according to claim 13, wherein said thin-film transistor has an operation temperature of 80°

C.-250°

C.