OXIDE SEMICONDUCTOR, THIN FILM TRANSISTOR, AND DISPLAY DEVICE

• US 20100102311A1
• Filed: 10/19/2009
• Published: 04/29/2010
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: HOSOBA, Miyuki, SASAKI, Toshinari, SAKATA, Junichiro, ITO, Shunichi
• Granted Patent: US 8,878,172 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/247 Amorphous materials
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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

An object is to control composition and a defect of an oxide semiconductor, another object is to increase a field effect mobility of a thin film transistor and to obtain a sufficient on-off ratio with a reduced off current. A solution is to employ an oxide semiconductor whose composition is represented by InMO₃(ZnO)_m, where M is one or a plurality of elements selected from Ga, Fe, Ni, Mn, Co, and Al, and m is preferably a non-integer number of greater than or equal to 1 and less than 50. The concentration of Zn is lower than the concentrations of In and M. The oxide semiconductor has an amorphous structure. Oxide and nitride layers can be provided to prevent pollution and degradation of the oxide semiconductor.

Claims

1. An oxide semiconductor comprising oxygen (O), indium (In), gallium (Ga), and zinc (Zn),

wherein a concentration of Zn is comprised between 5 atomic % and 10 atomic %, and

wherein concentrations of In and Ga are each comprised between 15 atomic % and 20 atomic %.

3. The oxide semiconductor according to claim 1, wherein the oxide semiconductor has an amorphous structure.

2. An oxide semiconductor represented by a formula:

InMO₃(ZnO)_m,

wherein M is one or a plurality of elements selected from gallium (Ga), iron (Fe), nickel (Ni), manganese (Mn), cobalt (Co), and aluminum (Al) and m is a non-integer number of greater than or equal to 1 and less than 50, and

wherein a concentration of Zn is lower than concentrations of In and M.

4. The oxide semiconductor according to claim 2, wherein the oxide semiconductor has an amorphous structure.

5. A thin film transistor comprising an oxide semiconductor layer as a channel formation region,

wherein the oxide semiconductor layer comprises O, In, Ga, and Zn, and

wherein a concentration of Zn is comprised between 5 atomic % and 10 atomic %, and

wherein concentrations of In and Ga are each comprised between 15 atomic % and 20 atomic %.

7. The thin film transistor according to claim 5, wherein the oxide semiconductor layer has an amorphous structure.

9. The thin film transistor according to claim 5, further comprising an oxide insulating layer in contact with the oxide semiconductor layer.

11. The thin film transistor according to claim 5, further comprising an oxide insulating layer in contact with an upper side of the oxide semiconductor layer.

12. The thin film transistor according to claim 5, further comprising an oxide insulating layer in contact with a lower side of the oxide semiconductor layer.

15. The thin film transistor according to claim 11, further comprising a nitride insulating layer over the oxide semiconductor layer.

16. The thin film transistor according to claim 12, further comprising a nitride insulating layer under the oxide semiconductor layer.

19. A display device comprising the thin film transistor according to claim 5 in at least one pixel.

21. A display device comprising:

the thin film transistor according to claim 5 in at least one pixel; and

the thin film transistor according to claim 5 in a driver circuit for controlling a signal to be transmitted to the thin film transistor provided in the pixel.

23. A display device comprising:

the thin film transistor according to claim 5 in at least one pixel; and

the thin film transistor according to claim 5 in a selector circuit for controlling a signal to be transmitted to the thin film transistor provided in the pixel.

6. A thin film transistor comprising an oxide semiconductor layer as a channel formation region,

wherein the oxide semiconductor layer is represented by a formula:

InMO₃(ZnO)_m,

wherein M is one or a plurality of elements selected from Ga, Fe, Ni, Mn, Co, and Al and m is a non-integer number of greater than or equal to 1 and less than 50, and

wherein a concentration of Zn is lower than concentrations of In and M.

8. The thin film transistor according to claim 6, wherein the oxide semiconductor layer has an amorphous structure.

10. The thin film transistor according to claim 6, further comprising an oxide insulating layer in contact with the oxide semiconductor layer.

13. The thin film transistor according to claim 6, further comprising an oxide insulating layer in contact with an upper side of the oxide semiconductor layer.

14. The thin film transistor according to claim 6, further comprising an oxide insulating layer in contact with a lower side of the oxide semiconductor layer.

17. The thin film transistor according to claim 13, further comprising a nitride insulating layer over the oxide semiconductor layer.

18. The thin film transistor according to claim 14, further comprising a nitride insulating layer under the oxide semiconductor layer.

20. A display device comprising the thin film transistor according to claim 6 in at least one pixel.

22. A display device comprising:

the thin film transistor according to claim 6 in at least one pixel; and

the thin film transistor according to claim 6 in a driver circuit for controlling a signal to be transmitted to the thin film transistor provided in the pixel.

24. A display device comprising:

the thin film transistor according to claim 6 in at least one pixel; and

the thin film transistor according to claim 6 in a selector circuit for controlling a signal to be transmitted to the thin film transistor provided in the pixel.