Electro-optical device and method of driving the same

• US 5,500,538 A
• Filed: 09/29/1994
• Issued: 03/19/1996
• Est. Priority Date: 12/20/1990
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Mase, Akira, Yamazaki, Shunpei
• Primary Examiner(s): MINTEL, WILLIAM A
• Application Number:
  US08/314,714
• Time in Patent Office: 537 Days
• Field of Search: 257/59, 257/72, 257/56, 257/102, 257/49, 359/59, 359/85, 359/57, 359/54
• US Class Current: 257/49
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/136245 having complementary transistors
• 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 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

An electro-optical device is disclosed. The electro-optical device comprises pixels arranged in rows and columns. Each pixel comprises at least one complementary TFT (thin film transistor) pair. Each complementary TFT pair consists of an n-channel TFT and a p-channel TFT. The gates of the complementary TFTs of each pixel are all connected to a signal line extending in the Y-direction. The input terminals of the TFTs of each pixel are connected to a pair of signal lines extending in the X-direction. Each pixel has at least one pixel electrode connected to the outputs of the TFTs thereof. In the operation of the electro-optical device, an electric signal is applied to the pair of signal lines extending in the X-direction and an electric signal is applied to the signal line extending in the Y-direction for the duration of the electric signal applied to the pair of signal lines extending in the X-direction.

Claims

1. An electro-optical device comprising:

a substrate having an insulating surface; and

at least two thin film transistors formed on said substrate,

wherein at least a channel of each of said thin film transistors contains oxygen at 4×

10¹⁹ to 4×

10²¹ atoms/cm³.

2. The device of claim 1 wherein said substrate comprises glass covered with a silicon oxide layer.

3. The device of claim 1 wherein each said thin film transistor has a gate insulating comprising silicon oxide doped with fluorine.

4. The device of claim 1 wherein said channel comprises silicon.

5. The device of claim 4 wherein said silicon is doped with hydrogen.

6. An electro-optical device comprising:

a substrate having an insulating surface; and

at least two thin film transistors formed on said substrate,

wherein a channel of each of said thin film transistors contains oxygen at 5×

10²⁰ to 5×

10²¹ atoms/cm³ and a source and a drain of each of said thin film transistors contains oxygen at 7×

10¹⁹ atoms/cm³ or less.

7. The device of claim 6 wherein said substrate comprises glass covered with a silicon oxide layer.

8. The device of claim 6 wherein each said thin film transistor has a gate insulating comprising silicon oxide doped with fluorine.

9. The device of claim 6 wherein said channel comprises silicon.

10. The device of claim 6 wherein said silicon is doped with hydrogen.

11. An electro-optical device comprising:

a substrate having an insulating surface; and

a plurality of pixel electrodes formed on said substrate in a matrix form, each of said pixel electrodes connected with at least one thin film transistor,

wherein a channel of said thin film transistors contains oxygen at 4×

10¹⁹ to 4×

10²¹ atoms/cm³.

12. The device of claim 11 wherein said substrate comprises glass covered with a silicon oxide layer.

13. The device of claim 11 wherein each said thin film transistor has a gate insulating comprising silicon oxide doped with fluorine.

14. The device of claim 11 wherein said channel comprises silicon.

15. The device of claim 14 wherein said silicon is doped with hydrogen.

16. An electro-optical device comprising:

a substrate having an insulating surface; and

a plurality of pixel electrodes formed on said substrate in a matrix form, each of said pixel electrodes connected with at least one thin film transistor,

wherein a channel of said thin film transistors contains oxygen at 5×

10²⁰ to 5×

10²¹ atoms/cm³ and a source and a drain thereof contains oxygen at 7×

10¹⁹ atoms/cm³ or less.

17. The device of claim 16 wherein said substrate comprises glass covered with a silicon oxide layer.

18. The device of claim 16 wherein each said thin film transistor has a gate insulating comprising silicon oxide doped with fluorine.

19. The device of claim 16 wherein said channel comprises silicon.

20. The device of claim 19 wherein said silicon is doped with hydrogen.

21. An active matrix display device comprising:

a glass substrate;

a plurality of pixel electrodes formed on said substrate;

a plurality of thin film semiconductor devices formed on said substrate and connected to said pixel electrodes;

a peripheral circuit comprising thin film transistors formed on said substrate,

wherein said thin film transistors of said peripheral circuit include channel semiconductor layers having at least one of an electron mobility of 15-300 cm² /V·

s and a hole mobility of 10-200 cm² /V·

s.

22. The device of claim 21 wherein said channel semiconductor layers comprise silicon in which oxygen is contained at a concentration not higher than 7×

10¹⁹ atoms/cm³.

23. An active matrix display device comprising:

a glass substrate;

a plurality of pixel electrodes formed on said substrate;

a plurality of thin film semiconductor devices formed on said substrate and connected to said pixel electrodes;

a peripheral circuit comprising thin film transistors formed on said substrate,

wherein said thin film transistors of said peripheral circuit have a channel semiconductor layer comprising silicon in which oxygen is contained at a concentration not higher than 7×

10¹⁹ atoms/cm³.