Field-effect transistor including transparent oxide and light-shielding member, and display utilizing the transistor

• US 20070090365A1
• Filed: 10/19/2006
• Published: 04/26/2007
• Est. Priority Date: 10/20/2005
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sano, Masafumi, Abe, Katsumi, Hayashi, Ryo, Kumomi, Hideya, Nishi, Kojiro
• Application Number:
  US11/583,022
• Publication Number:
  US 20070090365A1
• Time in Patent Office: Days
• US Class Current: 257/72
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/78633 with a light shield
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/126 Shielding, e.g. light-blocking means over the TFTs

Abstract

A field-effect transistor includes a substrate, a source electrode, a drain electrode, a gate electrode, a gate-insulating film, and an active layer. The active layer contains an oxide having a transmittance of 70% or more in the wavelength range of 400 to 800 nm. A light-shielding member is provided as a light-shielding structure for the active layer, for example, on the bottom face of the substrate.

Claims

1. A field-effect transistor comprising a substrate, a source electrode, a drain electrode, a gate electrode, a gate-insulating film, and an active layer, wherein

the active layer contains an oxide having a transmittance of 70% or more in the wavelength range of 400 to 800 nm;

and

a light-shielding structure is provided between the substrate and the active layer or is provided on the surface of the substrate on the side opposite the active layer.

2. The field-effect transistor according to claim 1, wherein the light-shielding structure has a light-shielding property that prevents entry of light from the substrate side toward the active layer.

3. The field-effect transistor according to claim 1, wherein the light-shielding structure has a light-shielding property that prevents entry of light having a wavelength range of 400 to 800 nm.

4. The field-effect transistor according to claim 1, wherein the light-shielding structure has a light-shielding property that prevents entry of at least light or an electromagnetic wave having a wavelength range of 300 to 500 nm.

5. The field-effect transistor according to claim 1, wherein the oxide is an amorphous oxide.

6. The field-effect transistor according to claim 1, wherein the oxide contains at least one of In, Zn, and Sn.

7. The field-effect transistor according to claim 1, wherein the oxide is an amorphous oxide containing at least one of In, Zn, and Ga.

8. A display comprising a plurality of pixel parts each provided with a field-effect transistor according to claim 1 and a liquid-crystal layer or a light-emitting layer.

9. A field-effect transistor comprising a substrate, a source electrode, a drain electrode, a gate electrode, a gate-insulating film, and an active layer, wherein

the active layer contains an oxide having a transmittance of 70% or more in the wavelength range of 400 to 800 nm;

and

the substrate has a light-shielding property.

10. The field-effect transistor according to claim 9, wherein the substrate has a light-shielding property that prevents entry of light from the substrate side toward the active layer.

11. The field-effect transistor according to claim 9, wherein the substrate has a light-shielding property that prevents entry of light having a wavelength range of 400 to 800 nm.

12. The field-effect transistor according to claim 9, wherein the substrate has a light-shielding property that prevents entry of at least light or an electromagnetic wave having a wavelength range of 300 to 500 nm.

13. The field-effect transistor according to claim 9, wherein the oxide is an amorphous oxide.

14. The field-effect transistor according to claim 9, wherein the oxide contains at least one of In, Zn, and Ga.

15. The field-effect transistor according to claim 9, wherein the oxide is an amorphous oxide containing at least one of In, Zn, and Ga.

16. A display comprising a plurality of pixel parts each provided with a field-effect transistor according to claim 9 and a liquid-crystal layer or a light-emitting layer.

17. A field-effect transistor comprising a substrate, a source electrode, a drain electrode, a gate electrode, a gate-insulating film, an active layer, and a light-shielding structure, wherein

the active layer contains an oxide having a transmittance of 70% or more in the wavelength range of 400 to 800 nm;

and

the light-shielding structure is provided over the active layer.

18. The field-effect transistor according to claim 17, wherein the light-shielding structure has a light-shielding property that prevents entry of light from the active layer side toward the substrate.

19. The field-effect transistor according to claim 17, wherein the light-shielding structure has a light-shielding property that prevents entry of light at angles of less than 90 degrees to the surface of the substrate toward the active layer.

20. The field-effect transistor according to claim 17, wherein the light-shielding structure overlaps the source electrode and the drain electrode.