Thin-Film Transistor and Display Device using Oxide Semiconductor

• US 20090072232A1
• Filed: 02/23/2007
• Published: 03/19/2009
• Est. Priority Date: 03/17/2006
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sano, Masafumi, Abe, Katsumi, Hayashi, Ryo
• Granted Patent: US 7,923,723 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

The thin-film transistor of the present invention has at least a semiconductor layer including: on a substrate, a source electrode, a drain electrode, and a channel region; a gate insulating film; and a gate electrode, wherein the semiconductor layer is an oxide semiconductor layer, and wherein the gate insulating film is amorphous silicon including at least O and N, and the gate insulating film has a distribution of an oxygen concentration in a thickness direction so that the oxygen concentration is high in the side of an interface with an oxide semiconductor layer and the oxygen concentration decreases toward the side of the gate electrode.

Claims

1. A thin-film transistor comprising:

on a substrate, a semiconductor layer including a source electrode, a drain electrode, and a channel region;

a gate insulating film; and

a gate electrode,

wherein the semiconductor layer is an oxide semiconductor layer, and

wherein the gate insulating film is amorphous silicon containing at least O and N, and the gate insulating film has a distribution of an oxygen concentration in a thickness direction so that the oxygen concentration is high in a side of an interface with the oxide semiconductor layer, and the oxygen concentration decreases toward a side of the gate electrode.

2. :

The thin-film transistor according to claim 1, wherein the semiconductor layer is an oxide semiconductor layer containing In, Zn, and O.

3. :

The thin-film transistor according to claim 2, wherein the semiconductor layer further contains at least one kind selected from the group consisting of Ga, Al, Fe, Sn, Mg, Ca, Si, and Ge, and the semiconductor layer is an amorphous oxide having a resistance value less than 10¹⁰ Ω

·

cm.

4. :

A display device comprising, on a substrate, a display element, and a thin-film transistor according to claim 1, wherein a source or drain electrode of the thin-film transistor is connected to an electrode of the display element.

5. :

The display device according to claim 4, wherein the display element is an electroluminescence element.

6. :

The display device according to claim 4, wherein the display element is a liquid crystal cell.

7. :

The display device according to claim 4, wherein a plurality of the display elements and a plurality of the thin-film transistors are two-dimensionally arranged on the substrate.

8. :

A display device comprising, on a substrate, a display element, and a thin-film transistor according to claim 2, wherein a source or drain electrode of the thin-film transistor is connected to an electrode of the display element.

9. :

A display device comprising, on a substrate, a display element, and a thin-film transistor according to claim 3, wherein a source or drain electrode of the thin-film transistor is connected to an electrode of the display element.

10. :

The display device according to claim 8, wherein the display element is an electroluminescence element.

11. :

The display device according to claim 9, wherein the display element is an electroluminescence element.

12. :

The display device according to claim 8, wherein the display element is a liquid crystal cell.

13. :

The display device according to claim 9, wherein the display element is a liquid crystal cell.

14. :

The display device according to claim 5, wherein a plurality of the display elements and a plurality of the thin-film transistors are two-dimensionally arranged on the substrate.

15. :

The display device according to claim 6, wherein a plurality of the display elements and a plurality of the thin-film transistors are two-dimensionally arranged on the substrate.