Field effect transistor

• US 20060113539A1
• Filed: 11/09/2005
• Published: 06/01/2006
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.), Japan Science And Technology Agency, Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.), Tokyo Institute of Technology (National University Corporation Tokyo Institute of Technology)
• Inventors: Sano, Masafumi, Kamiya, Toshio, Nomura, Kenji, Nakagawa, Katsumi, Hosono, Hideo
• Granted Patent: US 7,868,326 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• 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 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/51 Insulating materials associated therewith for MIS structures on thin film semiconductor H01L29/4908
• 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
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A novel field-effect transistor is provided which employs an amorphous oxide. In an embodiment of the present invention, the transistor comprises an amorphous oxide layer containing electron carrier at a concentration less than 1×10⁻¹⁸/cm³, and the gate-insulating layer is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer.

Claims

1. A field-effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of

an amorphous oxide in which an electron carrier concentration is lower than 10¹⁸/cm³, or

an amorphous oxide in which an electron mobility tends to increase with increase of the electron carrier concentration;

and

at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light.

2. The field effect transistor according to claim 1, which has a metal wiring connected to at least one the source electrode, the drain electrode and the gate electrode.

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

4. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide in which an electron carrier concentration is less than 10¹⁸/cm³, or an amorphous oxide in which an electron mobility tends to increase with increase of the electron carrier concentration;

and

having a lamination structure comprised of a first layer in which at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal, or

having a lamination structure comprised of a first layer in which a wiring connected at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light, and a second layer composed of a metal.

5. A field effect transistor-provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

wherein the active layer is comprised of an amorphous oxide transparent to visible light, and at least one of the source electrode, the drain electrode and the gate electrode is transparent to visible light.

6. The field-effect transistor according to claim 5, wherein the transistor is a normally-off type transistor.

7. The field-effect transistor according to claim 5, wherein a metal wiring is connected to an electrode transparent to light which belongs to the source electrode, the drain electrode or the gate electrode.

8. The field-effect transistor according to claim 5, wherein the amorphous oxide is any one selected from the group consisting of an oxide containing In, Zn and Sn;

an oxide containing In and Zn;

an oxide containing In and Sn; and

an oxide containing In.

9. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide in which an electron carrier concentration is lower than 10¹⁸/cm³, and the gate insulator is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer and is laminated on the first layer.

10. The field effect transistor according to claim 9, wherein the first layer is an insulation layer comprising HfO₂, Y₂O₃, or a mixed crystal compound containing HfO₂ or Y₂O₃.

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

12. The field effect transistor according to claim 9, wherein the first layer is an interface improvement layer for improving an interfacial property with the active layer, and the second layer is a current leakage prevention, layer for preventing leakage of electric, current.

13. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide, and the gate insulator is comprised of a first layer being in contact with the amorphous oxide and a second layer different from the first layer and is laminated on the first layer.

14. The field-effect transistor according to claim 13, wherein the amorphous oxide is any one selected from the group consisting of an oxide containing In, Zn and Sn;

an oxide containing In and Zn;

an oxide containing In and Sn; and

an oxide containing In.

15. The field-effect transistor according to claim 13, wherein the transistor is a normally-off type transistor.

16. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide in which an electron carrier concentration is less than 10¹⁸/cm³, or an amorphous oxide in which an electron mobility tends to increase with increase of the electron carrier concentration;

and

a passivation layer is provided between the active layer and the gate insulator.

17. The field effect transistor according to claim 16, wherein the amorphous oxide is an oxide containing at least one of In, Zn, and Sn, or an oxide containing In, Zn, and Ga.

18. The field effect transistor according to claim 16, wherein the passivation layer is a current leakage prevention layer for preventing leakage of electric current.

19. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide;

and

a passivation layer being provided between the active layer and the gate insulator.

20. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer on a substrate,

the active layer being comprised of an amorphous oxide in which an electron carrier concentration is less than 10¹⁸/cm³, or an amorphous oxide in which an electron mobility tends to increase with increase of the electron carrier concentration;

and

a surface-coating layer being provided between the active layer and the substrate.

21. The field effect transistor according to claim 20, wherein the amorphous oxide is an oxide containing at least one of In, Zn, and Sn, or an oxide containing In, Zn, and Ga.

22. The field effect transistor according to claim 20, wherein the surface-coating layer is an adhesion-improvement layer for improving the adhesiveness between the substrate and the active layer.

23. A field effect transistor provided with a source electrode, a drain electrode, a gate insulator, a gate electrode, and an active layer,

the active layer being comprised of an amorphous oxide;

and

a surface-coating layer being provided between the active layer and the substrate.