Metal Oxide Film and Semiconductor Device

Patent metadata

Field	Value
Publication number	US-2021343843-A1
Application number	US-202117370221-A
Country	US
Kind code	A1
Filing date	Jul 8, 2021
Priority date	Dec 29, 2015
Publication date	Nov 4, 2021
Grant date	—

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%.

First claim

1 . A semiconductor device comprising:
a first conductive film over a substrate; a first insulating film over the first conductive film; an oxide semiconductor layer over the first insulating film; a second insulating film over the oxide semiconductor layer; a second conductive film over the second insulating film; a third conductive film over the second conductive film; and a third insulating film over the third conductive film, wherein the oxide semiconductor layer comprises indium, an element M, and zinc, wherein the element M is Al, Ga, Y, or Sn, wherein a plurality of crystal parts is observed in a transmission electron microscope image in a direction perpendicular to a surface of the oxide semiconductor layer, 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%, and wherein the third insulating film has a region in contact with a top surface of the oxide semiconductor layer and a top surface of the first insulating film.

2 . The semiconductor device 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 of the oxide semiconductor layer than crystal parts aligned in other directions.

3 . The semiconductor device according to claim 1 ,
wherein a first image is an image obtained by subjecting a cross-sectional TEM image to fast Fourier transform, wherein a second image is obtained by subjecting the first image to inverse fast Fourier transform after mask treatment by which a periodic region remains, wherein in the second image, the proportion of the remaining area subtracted from an original image is more than or equal to 20% and less than 60%.

4 . The semiconductor device according to claim 1 , wherein the proportion of the region other than the plurality of crystal parts is higher than or equal to 30% and lower than or equal to 50%.

5 . The semiconductor device according to claim 1 ,
wherein when electron diffraction with a probe diameter of 50 nm or more is performed on a slice of the oxide semiconductor layer 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 diffraction pattern that includes the two first spots and a plurality of second spots distributed in a circumferential direction is observed.

6 . The semiconductor device according to claim 5 ,
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 oxide semiconductor layer 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 a luminance of the two first spots is the highest.

7 . The semiconductor device according to claim 6 ,
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 diffraction pattern and a second straight line that intersects with the first straight line.

8 . The semiconductor device according to claim 7 ,
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.

9 . A semiconductor device comprising:
a first conductive film over a substrate; a first insulating film over the first conductive film; an oxide semiconductor layer over the first insulating film; a second insulating film over the oxide semiconductor layer; a second conductive film over the second insulating film; a third conductive film over the second conductive film; and a third insulating film over the third conductive film, wherein the oxide semiconductor layer comprises indium, an element M, and zinc, wherein the element M is Al, Ga, Y, or Sn, wherein a plurality of crystal parts is observed in a transmission electron microscope image in a direction perpendicular to a surface of the oxide semiconductor layer, 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%, wherein the third insulating film has a region in contact with a top surface of the oxide semiconductor layer and a top surface of the first insulating film, and wherein a length of the second insulating film is longer than a length of the second conductive film in a cross sectional view of the semiconductor device.

10 . The semiconductor device according to claim 9 ,
wherein the plurality of crystal parts has a higher proportion of crystal parts in which c-axes are aligned in a thickness direction of the oxide semiconductor layer than crystal parts aligned in other directions.

11 . The semiconductor device according to claim 9 ,
wherein a first image is an image obtained by subjecting a cross-sectional TEM image to fast Fourier transform, wherein a second image is obtained by subjecting the first image to inverse fast Fourier transform after mask treatment by which a periodic region remains, wherein in the second image, the proportion of the remaining area subtracted from an original image is more than or equal to 20% and less than 60%.

12 . The semiconductor device according to claim 9 , wherein the proportion of the region other than the plurality of crystal parts is higher than or equal to 30% and lower than or equal to 50%.

13 . The semiconductor device according to claim 9 ,
wherein when electron diffraction with a probe diameter of 50 nm or more is performed on a slice of the oxide semiconductor layer 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 diffraction pattern that includes the two first spots and a plurality of second spots distributed in a circumferential direction is observed.

14 . The semiconductor device according to claim 13 ,
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 oxide semiconductor layer 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 a luminance of the two first spots is the highest.

15 . The semiconductor device according to claim 14 ,
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 diffraction pattern and a second straight line that intersects with the first straight line.

16 . The semiconductor device acc

Assignees

• Semiconductor Energy Lab

Inventors

• Hosaka Yasuharu
• Obonai Toshimitsu
• Shima Yukinori
• Jintyou Masami
• Kurosaki Daisuke
• Hamochi Takashi
• Koezuka Junichi
• Okazaki Kenichi
• Yamazaki Shunpei

Classifications

• H10D86/411

  characterised by materials, geometry or structure of the substrates · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · CPC title

• C23C14/34

  Sputtering · CPC title

• H10D62/875

  being semiconductor metal oxide, e.g. InGaZnO (Group II-VI materials H10D62/86; Group I-VI materials H10D62/871; Pb compounds or alloys H10D62/874) · CPC title

• H10D64/691

  comprising metallic compounds, e.g. metal oxides or metal silicates  (insulators comprising nitrogen H10D64/693) · CPC title