Electronic device

• US 6,384,427 B1
• Filed: 10/26/2000
• Issued: 05/07/2002
• Est. Priority Date: 10/29/1999
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Konuma, Toshimitsu, Koyama, Jun, Yamazaki, Shunpei, Mizukami, Mayumi, Inukai, Kazutaka
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Tran, Thien F
• Application Number:
  US09/697,685
• Time in Patent Office: 558 Days
• Field of Search: 257/59, 257/72, 257/344, 257/347, 257/350-351
• US Class Current: 257/59
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• CPC Class Codes: H01L 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/8428 Vertical spacers, e.g. arranged between the sealing arrangement and the OLED
• CPC Class Codes: H10K 50/846 comprising getter material or desiccants
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

To provide an electronic device capable of bright image display. A pixel is structured such that a switching TFT and a current controlling TFT are formed on a substrate and an EL element is electrically connected to the current controlling TFT. A gate capacitor formed between a gate electrode of the current controlling TFT and an LDD region thereof holds a voltage applied to the gate electrode, and hence a capacitor (condenser) is not particularly necessary in the pixel, thereby making the effective light emission area of the pixel large.

Claims

1. An electronic device comprising:

a first thin film transistor;

a second thin film transistor having;

a gate electrode,

a gate insulating film,

at least an LDD region,

wherein the gate electrode of the second thin film transistor is electrically connected to a drain wiring of the first thin film transistor;

a self light emitting element,

wherein the self light emitting element is electrically connected to a drain wiring of the second thin film transistor,

wherein the second thin film transistor is a p-channel thin film transistor,

wherein at least a portion of the LDD region of the second thin film transistor is overlapped with the gate electrode with the gate insulating film interposed therebetween.

2. A device according to claim 1,

wherein the LDD region of the second thin film transistor includes a p-type impurity element at a concentration in a range of 1× 10¹⁵ to 5×

10¹⁷ atoms/cm³.

3. An electric apparatus using the electronic device of claim 1.

4. An electronic device comprising:

a first thin film transistor;

a second thin film transistor having;

a gate electrode,

a gate insulating film,

at least an LDD region,

wherein the gate electrode of the second thin film transistor is electrically connected to a drain wiring of the first thin film transistor;

a self light emitting element,

wherein the self light emitting element is electrically connected to a drain wiring of the second thin film transistor,

wherein the second thin film transistor is a p-channel thin film transistor,

wherein at least a portion of the LDD region of the second thin film transistor is overlapped with the gate electrode with the gate insulating film interposed therebetween,

wherein the first thin film transistor includes a plurality of thin film transistors being connected in series.

5. A device according to claim 4,

wherein the LDD region of the second thin film transistor includes a p-type impurity element at a concentration in a range of 1× 10¹⁵ to 5×

10¹⁷ atoms/cm³.

6. An electric apparatus using the electronic device of claim 4.

7. An electronic device comprising a pixel portion and a driver circuit portion, said electronic device comprising:

an n-channel thin film transistor being formed in the driver circuit portion, said n-channel thin film transistor having;

a first gate electrode,

a first gate insulating film,

at least a first LDD region,

wherein the first LDD region is overlapped with the first gate electrode with the first gate insulating film interposed therebetween,

a first thin film transistor being formed in the pixel portion;

a second thin film transistor being formed in the pixel portion, said second thin film transistor having;

a second gate electrode,

a second gate insulating film,

at least a second LDD region,

a self light emitting element being formed in the pixel portion,

wherein the self light emitting element is electrically connected to the second thin film transistor,

wherein the second thin film transistor is a p-channel thin film transistor,

wherein at least a portion of the second LDD region of the second thin film transistor is overlapped with the second gate electrode with the second gate insulating film interposed therebetween.

8. A device according to claim 7,

wherein the second LDD region of the second thin film transistor includes a p-type impurity element at a concentration in a range of 1× 10¹⁵ to 5×

10¹⁷ atoms/cm³.

9. An electric apparatus using the electronic device of claim 7.

10. An electronic device comprising a pixel portion and a driver circuit portion, said electronic device comprising:

an n-channel thin film transistor being formed in the driver circuit portion, said n-channel thin film transistor having;

a first gate electrode,

a first gate insulating film,

at least a first LDD region,

wherein the first LDD region is overlapped with the first gate electrode with the first gate insulating film interposed therebetween,

a first thin film transistor being formed in the pixel portion;

a second thin film transistor being formed in the pixel portion, said second thin film transistor having;

a second gate electrode,

a second gate insulating film,

at least a second LDD region,

a self light emitting element being formed in the pixel portion,

wherein the self light emitting element is electrically connected to the second thin film transistor,

wherein the second thin film transistor is a p-channel thin film transistor,

wherein at least a portion of the second LDD region of the second thin film transistor is overlapped with the second gate electrode with the second gate insulating film interposed therebetween,

wherein the thin film transistor includes a plurality of thin film transistors being connected in series.

11. A device according to claim 10,

wherein the second LDD region of the second thin film transistor includes a p-type impurity element at a concentration in a range of 1× 10¹⁵ to 5×

10¹⁷ atoms/cm³.

12. An electric apparatus using the electronic device of claim 10.