Amorphous oxide and field effect transistor

• US 20060108636A1
• Filed: 11/09/2005
• Published: 05/25/2006
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.), Japan Science & Technology Trading Co. Limited, 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: Kamiya, Toshio, Nomura, Kenji, Nakagawa, Katsumi, Hosono, Hideo, Sano, Masafumi
• Granted Patent: US 7,601,984 B2
• Time in Patent Office: Days
• US Class Current: 257/347
• 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 21/02592 amorphous
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/428 using electromagnetic radiation, e.g. laser radiation
• 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 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• 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
• 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

A novel amorphous oxide applicable, for example, to an active layer of a TFT is provided. The amorphous oxide comprises microcrystals.

Claims

1. An amorphous oxide comprising a microcrystal and having an electron carrier concentration of less than 10¹⁸/cm³.

2. The amorphous oxide according to claim 1, comprising at least one element selected from the group consisting of In, Zn and Sn.

3. The field-effect transistor according to claim 1, 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.

4. The amorphous oxide according to claim 1, comprising In, Ga, and Zn.

5. An amorphous oxide, wherein electron mobility increases as electron carrier concentration increases.

6. A field effect transistor comprising an active layer of an amorphous oxide containing a microcrystal, and a gate electrode formed so as to face the active layer through a gate insulator.

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

8. An amorphous oxide whose composition changes in a layer thickness direction and having an electron carrier concentration of less than 10¹⁸/cm³.

9. The amorphous oxide according to claim 8, wherein the amorphous oxide contains at least one element selected from the group consisting of In, Zn and Sn.

10. The field-effect transistor according to claim 8, 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.

11. The amorphous oxide according to claim 8, wherein the amorphous oxide contains In, Ga and Zn.

12. A field effect transistor comprising

an active layer of an amorphous oxide whose composition changes in a layer thickness direction, and

a gate electrode formed so as to face the active layer through a gate insulator,

wherein the active layer comprises a first region and a second region, which is closer to the gate insulator than the first region, and the oxygen concentration of the second region is higher than that of the first region.

13. A field effect transistor comprising

an active layer of an amorphous oxide having at least one element selected from the group consisting of In and Zn, and

a gate electrode formed so as to face the active layer through a gate insulator,

wherein the active layer comprises a first region and a second region, which is closer to the gate insulator than the first region, and the In concentration of the second region is higher than that of the first region, or the Zn concentration of the second region is higher than that of the first region.

14. An amorphous oxide whose composition changes in a layer thickness direction,

wherein electron mobility increases as electron carrier concentration increases.

15. A field effect transistor comprising

an active layer of an amorphous oxide having at least one element selected from the group consisting of In and Zn, and

a gate electrode formed so as to face the active layer through a gate insulator,

wherein the active layer comprises a first region and a second region, which is closer to the gate insulator than the first region, and the In concentration of the second region is higher than that of the first region, or the Zn concentration of the second region is higher than that of the first region.

16. An amorphous oxide comprising one type of element or a plurality of elements selected from the group consisting of Li, Na, Mn, Ni, Pd, Cu, Cd, C, N, P, Ti, Zr, V, Ru, Ge, Sn, and F and having an electron carrier concentration of less than 10¹⁸/cm³.

17. The amorphous oxide according to claim 16, comprising at least one element selected from the group consisting of In, Zn and Sn.

18. The field-effect transistor according to claim 16, 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.

19. The amorphous oxide according to claim 16, comprising In, Zn and Ga.

20. An amorphous oxide comprising at least one element selected from group consisting of Li, Na, Mn, Ni, Pd, Cu, Cd, C, N, P, Ti, Zr, V, Ru, Ge, Sn, and F, wherein electron mobility increases as electron carrier concentration increases.

21. A field effect transistor comprising

an active layer formed of an amorphous oxide containing at least one element selected from the group consisting of Li, Na, Mn, Ni, Pd, Cu, Cd, C, N, P, Ti, Zr, V, Ru, Ge, Sn, and F;

and

a gate electrode formed so as to face the active layer via a gate insulator.