Oxide semiconductor film and formation method thereof

Patent metadata

Field	Value
Publication number	US-9824888-B2
Application number	US-201414278530-A
Country	US
Kind code	B2
Filing date	May 15, 2014
Priority date	May 21, 2013
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

To provide a crystalline oxide semiconductor film. By collision of ions with a target including a crystalline In—Ga—Zn oxide, a flat-plate-like In—Ga—Zn oxide is separated. In the flat-plate-like In—Ga—Zn oxide, a first layer including a gallium atom, a zinc atom, and an oxygen atom, a second layer including a zinc atom and an oxygen atom, a third layer including an indium atom and an oxygen atom, and a fourth layer including a gallium atom, a zinc atom, and an oxygen atom are stacked in this order. After the flat-plate-like In—Ga—Zn oxide is deposited over a substrate while maintaining the crystallinity, the second layer is gasified and exhausted.

First claim

The invention claimed is:

1. An oxide semiconductor film over a substrate, comprising a plurality of flat-plate-like crystalline In—Ga—Zn oxides,
wherein flat planes of the plurality of flat-plate-like crystalline In—Ga—Zn oxides face an upper surface of the substrate,
wherein a grain boundary between the plurality of flat-plate-like crystalline In—Ga—Zn oxides is not observed with a transmission electron microscope,
wherein metal atoms of the flat-plate-like crystalline In—Ga—Zn oxides are shown to be arranged in a hexagonal configuration in an image,
wherein the oxide semiconductor film has a continuous structure in which different crystal regions are connected while maintaining c-axis alignment, and
wherein a gap among the plurality of flat-plate-like crystalline In—Ga—Zn oxides is filled with zinc oxide.

2. The oxide semiconductor film according to claim 1 , wherein the plurality of flat-plate-like crystalline In—Ga—Zn oxides are stacked.

3. The oxide semiconductor film according to claim 1 , wherein an equivalent circle diameter of the flat plane of one of the flat-plate-like crystalline In—Ga—Zn oxides is 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 a thickness of one of the flat-plate-like crystalline In—Ga—Zn oxides is greater than or equal to 0.5 nm and less than or equal to 0.9 nm.

5. The oxide semiconductor film according to claim 1 , wherein the zinc oxide has an amorphous structure.

6. The oxide semiconductor film according to claim 1 , wherein the image is obtained by image processing where a high resolution plane-view TEM image is transferred by a Fourier transform, filtered, and transferred by an inverse Fourier transform.

7. An oxide semiconductor film over a substrate, comprising a plurality of flat-plate-like crystalline In—Ga—Zn oxides,
wherein flat planes of the plurality of flat-plate-like crystalline In—Ga—Zn oxides face an upper surface of the substrate,
wherein a grain boundary between the plurality of flat-plate-like crystalline In—Ga—Zn oxides is not observed with a transmission electron microscope,
wherein metal atoms of the flat-plate-like crystalline In—Ga—Zn oxides are shown to be arranged in a hexagonal configuration in an image,
wherein end portions of the plurality of flat-plate-like crystalline In—Ga—Zn oxides are terminated with oxygen,
wherein the oxygen is negatively charged, and
wherein a gap among the plurality of flat-plate-like crystalline In—Ga—Zn oxides is filled with zinc oxide.

8. The oxide semiconductor film according to claim 7 , wherein the plurality of flat-plate-like crystalline In—Ga—Zn oxides are stacked.

9. The oxide semiconductor film according to claim 7 , wherein an equivalent circle diameter of the flat plane of one of the flat-plate-like crystalline In—Ga—Zn oxides is greater than or equal to 1 nm and less than or equal to 3 nm.

10. The oxide semiconductor film according to claim 7 , wherein a thickness of one of the flat-plate-like crystalline In—Ga—Zn oxides is greater than or equal to 0.5 nm and less than or equal to 0.9 nm.

11. The oxide semiconductor film according to claim 7 , wherein the zinc oxide has an amorphous structure.

12. The oxide semiconductor film according to claim 7 , wherein the image is obtained by image processing where a high resolution plane-view TEM image is transferred by a Fourier transform, filtered, and transferred by an inverse Fourier transform.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10P14/3816

  Pulsed laser beam · CPC title

• H10P14/3456

  Polycrystalline · CPC title

• H10P14/3426

  Oxides · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• H10P14/3434 Primary

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title