Oxide semiconductor film, method for forming oxide semiconductor film, and semiconductor device

• US 9,583,632 B2
• Filed: 05/15/2014
• Issued: 02/28/2017
• Est. Priority Date: 07/19/2013
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): PRASAD, NEIL R
• Application Number:
  US14/278,157
• Publication Number:
  US 20150021593A1
• Time in Patent Office: 1,020 Days
• Field of Search: 257/43, 438/104
• US Class Current: 1/1
• 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

A crystalline oxide semiconductor film and a semiconductor device including the oxide semiconductor film are provided. One embodiment of the present invention is an oxide semiconductor film including a plurality of flat-plate particles each having a structure in which layers including a gallium atom, a zinc atom, and an oxygen atom are provided over and under a layer including an indium atom and an oxygen atom. In the semiconductor film, the plurality of flat-plate particles face in random directions, and a crystal boundary is not observed using a transmission electron microscope.

Claims

1. An oxide semiconductor film comprising:

a plurality of plate particles each having a structure in which layers including a gallium atom, a zinc atom, and an oxygen atom are provided over and under a layer including an indium atom and an oxygen atom,

wherein the plurality of plate particles is arranged irregularly.

2. The oxide semiconductor film according to claim 1, wherein a crystal boundary in the oxide semiconductor film is not observed by using a transmission electron microscope.

3. The oxide semiconductor film according to claim 1, wherein the plurality of plate particles each has a thickness of greater than or equal to 0.5 nm and less than or equal to 0.9 nm and an equivalent circle diameter of a plane of greater than or equal to 1 nm and less than or equal to 3 nm.

4. The oxide semiconductor film according to claim 1, wherein the plurality of plate particles each has regularity in atomic arrangement.

5. The oxide semiconductor film according to claim 1, wherein a plurality of circumferentially distributed spots is observed in a nanobeam electron diffraction pattern of the oxide semiconductor film.

6. The oxide semiconductor film according to claim 5, wherein a probe diameter of an electron beam is larger than or equal to 1 nm and smaller than or equal to 30 nm.

17. The oxide semiconductor film according to claim 1, wherein a halo pattern is observed in a selected-area electron diffraction pattern of the oxide semiconductor film.

7. An semiconductor device comprising:

a gate electrode;

an oxide semiconductor film;

a gate insulating layer between the gate electrode and the oxide semiconductor film; and

a source electrode and a drain electrode each electrically connected to the oxide semiconductor film,

wherein the oxide semiconductor film comprises a plurality of plate particles each having a structure in which layers including a gallium atom, a zinc atom, and an oxygen atom are provided over and under a layer including an indium atom and an oxygen atom, and

wherein the plurality of plate particles is arranged irregularly.

8. The semiconductor device according to claim 7, wherein a crystal boundary in the oxide semiconductor film is not observed by using a transmission electron microscope.

9. The semiconductor device according to claim 7, wherein the plurality of plate particles each has a thickness of greater than or equal to 0.5 nm and less than or equal to 0.9 nm and an equivalent circle diameter of a plane of greater than or equal to 1 nm and less than or equal to 3 nm.

10. The semiconductor device according to claim 7, wherein the plurality of plate particles each has regularity in atomic arrangement.

11. The semiconductor device according to claim 7, wherein a plurality of circumferentially distributed spots is observed in a nanobeam electron diffraction pattern of the oxide semiconductor film.

12. The semiconductor device according to claim 11, wherein a probe diameter of an electron beam is larger than or equal to 1 nm and smaller than or equal to 30 nm.

18. The semiconductor device according to claim 7, wherein a halo pattern is observed in a selected-area electron diffraction pattern of the oxide semiconductor film.

13. A method for forming an oxide semiconductor film, comprising steps of:

separating a plurality of plate particles from a target including indium, gallium, and zinc, wherein the plurality of plate particles each has a structure in which layers including a gallium atom, a zinc atom, and an oxygen atom are provided over and under a layer including an indium atom and an oxygen atom; and

depositing the plurality of plate particles over a substrate irregularly.

14. The method for forming an oxide semiconductor film according to claim 13, wherein a temperature of the substrate is higher than or equal to 15°

C. and lower than or equal to 35°

C.

15. The method for forming an oxide semiconductor film according to claim 13, wherein the target including indium, gallium, and zinc has a composition formula of InGaZnO₄.

16. The method for forming an oxide semiconductor film according to claim 13, wherein the separation of the plurality of plate particles occurs by collision of an ion with the target.

19. The method for forming an oxide semiconductor film according to claim 13, wherein a halo pattern is observed in a selected-area electron diffraction pattern of the oxide semiconductor film.