Metal oxide film and semiconductor device

• US 10,096,684 B2
• Filed: 12/27/2016
• Issued: 10/09/2018
• Est. Priority Date: 12/29/2015
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hosaka, Yasuharu, Obonai, Toshimitsu, Shima, Yukinori, Jintyou, Masami, Kurosaki, Daisuke, Hamochi, Takashi, Koezuka, Junichi, Okazaki, Kenichi, Yamazaki, Shunpei
• Primary Examiner(s): Nguyen, Cuong Q
• Assistant Examiner(s): Kim, Tong-Ho
• Application Number:
  US15/391,186
• Publication Number:
  US 20170186843A1
• Time in Patent Office: 651 Days
• Field of Search: 257 43, 438104
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: C03C 2218/151 by vacuum evaporation
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3293 Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
• CPC Class Codes: C04B 2235/787 Oriented grains
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/01 based on oxide ceramics
• CPC Class Codes: C04B 35/453 based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
• CPC Class Codes: C04B 35/62218 obtaining ceramic films, e.g. by using temporary supports
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/5853 Oxidation
• 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 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/7782 with confinement of carriers by at least two heterojunctions, e.g. DHHEMT, quantum well HEMT, DHMODFET
• CPC Class Codes: H01L 29/7786 with direct single heterostructure, i.e. with wide bandgap layer formed on top of active layer, e.g. direct single heterostructure MIS-like HEMT
• CPC Class Codes: H01L 29/78648 arranged on opposing sides of the channel
• 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 29/78696 : 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 metal oxide film includes indium, M, (M is Al, Ga, Y, or Sn), and zinc and includes a region where a peak having a diffraction intensity derived from a crystal structure is observed by X-ray diffraction in the direction perpendicular to the film surface. Moreover, a plurality of crystal parts is observed in a transmission electron microscope image in the direction perpendicular to the film surface. The proportion of a region other than the crystal parts is higher than or equal to 20% and lower than or equal to 60%.

Claims

1. A metal oxide film comprising:

indium;

M which is Al, Ga, Y, or Sn; and

zinc,

wherein a peak having a diffraction intensity derived from a crystal structure is observed by X-ray diffraction in a direction perpendicular to a surface of the metal oxide film,

wherein a plurality of crystal parts is observed in a transmission electron microscope image in the direction perpendicular to the surface of the metal oxide film, and

wherein a proportion of a region other than the plurality of crystal parts is higher than or equal to 20% and lower than or equal to 60%.

2. The metal oxide film according to claim 1, wherein the plurality of crystal parts has a higher proportion of crystal parts in which c-axes are aligned in a thickness direction than crystal parts aligned in other directions.

3. The metal oxide film according claim 1,

wherein in a second image obtained in such a manner that a first image that is an image obtained by subjecting a cross-sectional TEM image to fast Fourier transform is subjected to inverse fast Fourier transform after mask treatment by which a periodic region remains, the proportion of the remaining area subtracted from an original image is more than or equal to 20% and less than 60%.

4. The metal oxide film according to claim 1,

wherein when electron diffraction with a probe diameter of 50 nm or more is performed on a slice of the metal oxide film having a thickness of greater than or equal to 10 nm and less than or equal to 50 nm in the direction perpendicular to its cross section, a first electron diffraction pattern that includes a ring-like diffraction pattern and two first spots overlapping with the ring-like diffraction pattern is observed, and

wherein when electron diffraction with a probe diameter of greater than or equal to 0.3 nm and less than or equal to 5 nm is performed thereon, a second electron diffiaction pattern that includes the two first spots and a plurality of second spots distributed in a circumferential direction is observed.

5. The metal oxide film according to claim 4,

wherein the two first spots are symmetric with respect to a center,

wherein an angle between a first straight line and the direction of a normal vector of the surface of the metal oxide film is more than or equal to 0°

and less than or equal to 10°

, and

wherein the first straight line passes through the center and a point at which the luminance of the two first spots is the highest.

6. The metal oxide film according to claim 5,

wherein in the first electron diffraction pattern, the luminance of the ring-like diffraction pattern is lower than that of the two first spots at a point of intersection of the ring-like diffiaction pattern and a second straight line that intersects with the first straight line.

7. The metal oxide film according to claim 6,

wherein the luminance of the two first spots is greater than 1 time and less than or equal to 9 times the luminance of the ring-like diffraction pattern at the point of intersection of the ring-like diffraction pattern and the second straight line.

8. A semiconductor device comprising:

a semiconductor layer;

a gate insulating layer; and

a gate,

wherein the semiconductor layer includes the metal oxide film according to claim 1.