SEMICONDUCTOR DEVICE HAVING LASER-ANNEALED SEMICONDUCTOR DEVICE, DISPLAY DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

• US 20010040541A1
• Filed: 09/04/1998
• Published: 11/15/2001
• Est. Priority Date: 09/08/1997
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: YONEDA, KIYOSHI, KIHARA, KATSUYA
• Application Number:
  US09/148,606
• Publication Number:
  US 20010040541A1
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1274 using crystallisation of amorphous semiconductor or recrystallisation of crystalline semiconductor

Abstract

In a driver built-in type p-Si TFT LCD, a channel width direction of a sampling TFT (6) constituting a part of a driver and having a large channel width is formed in a direction non-parallel with sides of a substrate or sides of pulse laser beams radiated for poly-crystallization of a-Si. For example, the channel width direction of the sampling TFT (6) is formed to have an angle of 45° relative to the substrate sides. Therefore, even when a dispersion in energy intensity is generated in an irradiated plane of pulse laser beams radiated to a-Si in a poly-crystallization process and a defective crystallized region [R] is formed on a p-Si film (13) in a direction corresponding to the dispersion, the defective crystallized region [R] extends across a part of each TFT (6). Formation of only a specified TFT (6) in the defective crystallized region [R] and occurrence of a difference in characteristics between the specified TFT and another TFT (6) are prevented. Consequently, generation of a low display-quality portion on a specified column on LCD and deterioration of display quality of the entire LCD are prevented.

Claims

1. A semiconductor device in which a plurality of semiconductor elements are formed on a substrate, wherein

in some or all of said semiconductor elements, a channel width of a channel region formed in a semiconductor layer to which laser annealing is applied is larger than a channel length thereof, and a channel width direction is formed in a direction different from a side direction of said substrate.

2. The semiconductor device according to

claim 1

wherein

said laser annealing is performed to poly-crystallize an amorphous semiconductor layer and obtain a polycrystalline semiconductor layer.

3. A semiconductor device in which a plurality of semiconductor elements are formed on a substrate, wherein

in some or all of said semiconductor elements, a channel width of a channel region formed in a semiconductor layer to which laser annealing is applied is larger than a channel length thereof, and a channel width direction is formed in a direction different from a major-axis direction and/or a minor-axis direction of a laser-beam irradiated region at the time of application of said laser annealing.

4. The semiconductor device according to

claim 3

wherein

said laser annealing is performed to poly-crystallize an amorphous semiconductor layer and obtain a polycrystalline semiconductor layer.

5. A display device comprising,

a plurality of pixel electrodes arranged on a substrate;

a plurality of first thin-film transistors connected to corresponding pixel electrodes among said plurality of pixel electrodes for supplying signals for operating pixels to the connected pixel electrodes; and

a plurality of second thin-film transistors constituting a scanning drive circuit for scanning said plurality of first thin-film transistors and/or a display drive circuit for supplying display signals to said plurality of first thin-film transistors, wherein

in some or all of said plurality of second thin-film transistors, a channel width of a channel region formed in a semiconductor film to which laser annealing is applied is larger than a channel length thereof, and a channel width direction is formed in a direction different from a side direction of said substrate.

6. The display device according to

claim 5

wherein

among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width is larger than the channel length and the channel width direction is formed in a direction different from the side direction of said substrate

are used, in said display drive circuit, as sampling transistors for sampling video signals at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors.

7. The display device according to

claim 5

wherein

said display drive circuit comprises:

a video signal line to which the video signals are supplied from outside, sampling transistors for sampling the video signals from said video signal line at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors, and a shift register for controlling switching operation of said sampling transistors,

and wherein, among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width is larger than the channel length and the channel width direction is formed in a direction different from a side direction of said substrate are used in said sampling transistors and the shift register.

8. The display device according to

claim 5

wherein

said laser annealing is performed to poly-crystallize an amorphous semiconductor film and obtain a polycrystalline semiconductor film.

9. The display device according to

claim 5

wherein

said channel width direction of said some or all of second thin-film transistors is set to a direction of about 45°

relative to any one or all of a plurality of side directions of said substrate.

10. A display device comprising,

a plurality of pixel electrodes arranged on a substrate;

a plurality of first thin-film transistors connected to corresponding pixel electrodes among said plurality of pixel electrodes for supplying signals for operating pixels to the connected pixel electrodes; and

a plurality of second thin-film transistors constituting a scanning drive circuit for scanning said plurality of first thin-film transistors and/or a display drive circuit for supplying display signals to said plurality of first thin-film transistors, wherein

in some or all of said plurality of second thin-film transistors, a channel width of a channel region formed in a semiconductor film to which laser annealing is applied is larger than a channel length thereof, and a channel width direction is formed in a direction different from a major-axis direction and/or a minor-axis direction of a laser-beam irradiated region at the time of application of said laser annealing.

11. The display device according to

claim 10

wherein

among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width is larger than the channel length and the channel width direction is formed in a direction different from the major-axis direction and/or the minor-axis direction of said laser-beam irradiated region

are used, in said display drive circuit, as sampling transistors for sampling video signals at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors.

12. The display device according to

claim 10

wherein

said display drive circuit comprises:

a video signal line to which the video signals are supplied from outside, sampling transistors for sampling the video signals from said video signal line at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors, and a shift register for controlling switching operation of said sampling transistors,

and wherein, among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width is larger than the channel length and the channel width direction is formed in a direction different from the major-axis direction and/or the minor-axis direction of said laser-beam irradiated region are used in said sampling transistors and the shift register.

13. The display device according to

claim 10

wherein

said laser annealing is performed to poly-crystallize an amorphous semiconductor film and obtain a polycrystalline semiconductor film.

14. The display device according to

claim 10

wherein

said channel width direction of said some or all of second thin-film transistors is set to a direction of about 45°

relative to the major-axis direction and/or the minor-axis direction of said laser-beam irradiated region.

15. A liquid crystal display device comprising,

a plurality of pixel electrodes arranged on one of a pair of substrates holding a liquid crystal therebetween;

a plurality of first thin-film transistors connected to corresponding pixel electrodes among said plurality of pixel electrodes for supplying signals for operating the liquid crystal to the connected pixel electrodes; and

a plurality of second thin-film transistors constituting a scanning drive circuit for scanning said plurality of first thin-film transistors and/or a display drive circuit for supplying display signals to said plurality of first thin-film transistors,

channel regions of said plurality of first and second thin-film transistors being formed in a semiconductor film to which laser annealing is applied, and

in some or all of said plurality of second thin-film transistors, a channel width being larger than a channel length, and a channel width direction of some or all of second thin-film transistors being formed non-parallel with and non-orthogonal to a channel width direction of said first thin-film transistors.

16. The liquid crystal display device according to

claim 15

wherein

among said plurality of second thin-film transistors, in said some or all of second thin-film transistors in which the channel width direction is formed non-parallel with and non-orthogonal to the channel width direction of said first thin-film transistors,

the channel width direction is further formed in a direction different from a side direction of said substrate or in a direction different from a major-axis direction and/or a minor-axis direction of a laser-beam irradiated region at the time of application of said laser annealing.

17. The liquid crystal display device according to

claim 15

wherein

among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width direction is formed non-parallel with and non-orthogonal to the channel width direction of said first thin-film transistors

are used, in said display drive circuit, as sampling transistors for sampling video signals at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors.

18. The liquid crystal display device according to

claim 15

wherein

said display drive circuit comprises:

a video signal line to which the video signals are supplied from outside, sampling transistors for sampling the video signals from said video signal line at a predetermined timing and supplying said display signals to the corresponding plurality of first thin-film transistors, and a shift register for controlling switching operation of said sampling transistors,

and wherein, among said plurality of second thin-film transistors, said some or all of second thin-film transistors in which the channel width direction is formed non-parallel with and non-orthogonal to the channel width direction of said first thin-film transistors

are used in said sampling transistors and the shift register.

19. The liquid crystal display device according to

claim 15

wherein

said laser annealing is performed to poly-crystallize an amorphous semiconductor film and obtain a polycrystalline semiconductor film.

20. The liquid crystal display device according to

claim 15

wherein

said channel width direction of the channel region of said some or all of second thin-film transistors is set to a direction of about 45°

relative to the channel width direction of said first thin-film transistors.