Metal oxide film and semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsTomonori NAKAYAMA, Hitoshi KUNITAKE, Shunpei YAMAZAKI
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Abstract
A metal oxide film having high carrier mobility is provided. In the metal oxide film, a sum of a content percentage of indium and a content percentage of zinc is greater than or equal to 95%. The metal oxide film includes a crystal. The crystal includes a layered crystal structure. In the crystal, the ratio of the number of zinc atoms to the number of indium atoms is greater than 0 and less than 1.5. The electron effective mass in the crystal is smaller than the electron effective mass in an indium oxide having a cubic crystal structure. The metal oxide film may include tin, and the content percentage of tin is higher than or equal to 0.1% and lower than or equal to 3%.
Claims20
A metal oxide film,
- wherein in the metal oxide film, a sum of a content percentage of indium and a content percentage of zinc is greater than or equal to 95%,
- wherein the metal oxide film comprises a crystal,
- wherein the crystal comprises a layered crystal structure,
- wherein in the crystal, a ratio of a number of zinc atoms to a number of indium atoms is greater than 0 and less than 1.5, and
- wherein an electron effective mass in the crystal is smaller than an electron effective mass in an indium oxide having a cubic crystal structure.
A metal oxide film,
- wherein in the metal oxide film, a sum of a content percentage of indium and a content percentage of zinc is greater than or equal to 95%,
- wherein the metal oxide film comprises a crystal,
- wherein the crystal comprises a first layer, a second layer, and a third layer positioned between the first layer and the second layer,
- wherein a ratio of a number of zinc atoms to a number of indium atoms in the third layer is higher than a ratio of a number of zinc atoms to a number of indium atoms in the first layer,
- wherein the ratio of the number of zinc atoms to the number of indium atoms in the third layer is higher than a ratio of a number of zinc atoms to a number of indium atoms in the second layer, and
- wherein the third layer comprises one, two, or three layers.
A metal oxide film,
- wherein in the metal oxide film, a sum of a content percentage of indium and a content percentage of zinc is greater than or equal to 95%,
- wherein the metal oxide film comprises a crystal,
- wherein the crystal comprises a first layer, a second layer, and a third layer positioned between the first layer and the second layer,
- wherein in a HAADF-STEM image, a luminance of an atom included in the third layer is lower than a luminance of an atom included in the first layer,
- wherein in the HAADF-STEM image, the luminance of the atom included in the third layer is lower than a luminance of an atom included in the second layer, and
- wherein the third layer comprises one, two, or three layers.
Dependencies are inferred from the claim text.