Semiconductor film, transistor, semiconductor device, display device, and electronic appliance

An oxide semiconductor layer,

• wherein the oxide semiconductor layer has a plurality of electron diffraction patterns which are observed in such a manner that a surface where the oxide semiconductor layer is formed is irradiated with an electron beam having a probe diameter whose half-width is 1 nm while the position of the oxide semiconductor layer and the position of the electron beam are relatively moved,
• wherein the plurality of electron diffraction patterns include 50 or more electron diffraction patterns which are observed in different areas,
• wherein first electron diffraction patterns account for 100% of the 50 or more electron diffraction patterns,
• wherein the first electron diffraction patterns include observed points which indicates that a c-axis is oriented in a direction substantially perpendicular to the surface where the oxide semiconductor layer is formed, and
• wherein the plurality of electron diffraction patterns are oriented randomly.

A semiconductor device comprising:

• an oxide semiconductor layer comprising In, an element M, and Zn;
• and
• an insulating later that contains oxygen in excess of the stoichiometric compostion,
• wherein the insulating layer and the oxide semiconductor layer overlap each other,
• wherein the oxide semiconductor layer inculdes a plurality of crystals,
• wherein the element M is at least one of aluminum, gallium, yttrium, and tin,
• wherein an atomic ratio of In to the element M and Zn satisfies In:M:Zn=x:y:z, and
• wherein, in an equilibrium diagram with vertices of the three elements of In, the element M, and Zn, the atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (x:y:z=2:2:1), second coordinates (x:y:z=23:27:25), third coordinates (x:y:z=8:12:35), fourth coordinates (x:y:z=4:0:7), fifth coordinates (x:y:z=2:0:3), sixth coordinates (x:y:z=7:1:8), seventh coordinates (x:y:z=10:4:7), and the first coordinates, in this order.

A semiconductor device comprising:

• an oxide semiconductor layer comprising In, Ga, and Zn;
• and
• an insulating layer that contains oxygen in excess of the stoichiometric composition,
• wherein the insulating layer and the oxide semiconductor layer overlap each other,
• wherein the oxide semiconductor layer includes a pluraloty of crystals,
• wherein an atomic ratio of In to Ga and Zn satisfies In:Ga:Zn=x:y:z, and
• wherein, in an equilibrium diagram with vertices of the three elements of In, Ga, and Zn, the atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (x:y:z=2:2:1), second coordinates (x:y:z=23:27:25), third coordinates (x:y:z=8:12:35), fourth coordinates (x:y:z=4:0:7), fifth coordinates (x:y:z=2:0:3), sixth coordinates (x:y:z=7:1:8), seventh coordinates (x:y:z=10:4:7), and the first coordinates, in this order.

A semiconductor device comprising:

• a first oxide layer;
• a second oxide layer;
• and
• an insulating layer that contains oxygen in excess of the stoichiometric compostion,
• wherein the insulating layer and the second oxide layer overlap each other,
• wherein the second oxide layer includes a plurality of crystals,
• wherein the second oxide layer includes a region in contact with the first oxide layer,
• wherein the first oxide layer includes a first portion,
• wherein the second oxide layer includes a second portion,
• wherein the first portion includes In, an element M, and Zn,
• wherein an atomic ratio of In to the element M and Zn of the first portion satisfies In:M:Zn=xa:ya:za, and
• wherein xa, ya, za, and α satisfy one of the following conditions:
• xa:ya:za=(1−α):(1+α):1 and −0.33≦α≦+0.08;
• xa:ya:za=(1−α):(1+α):2 and −0.68≦α≦+0.32;
• xa:ya:za=(1−α):(1+α):3 and −1≦α≦+0.46;
• xa:ya:za=(1−α):(1+α):4 and −1≦α≦+0.54;
• and
• xa:ya:za=(1−α):(1+α):5 and −1≦α≦+0.72.

A semiconductor device comprising:

• a first oxide layer;
• and
• a second oxide layer;
• and
• an insulating layer that contains oxygen in excess of the stoichiometric composition,
• wherein the insulating layer and the second oxide layer overlap each other,
• wherein the second oxide layer includes a plurality of crystals,
• wherein the second oxide layer includes a region in contact with the first oxide layer,
• wherein the first oxide layer includes a first portion,
• wherein the second oxide layer includes a second portion,
• wherein the first portion includes In, an element M, and Zn,
• wherein a first atomic ratio of In to the element M and Zn of the first portion satisfies In:M:Zn=xa:ya:za,
• wherein the second oxide layer includes In, the element M, and Zn,
• wherein a second atomic ratio of In to the element M and Zn of the second oxide layer satisfies In:M:Zn=xb:yb:zb,
• wherein in an equilibrium diagram with vertices of the three elements of In, the element M, and Zn, the first atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (xa:ya:za=8:14:7), second coordinates (xa:ya:za=2:5:7), third coordinates (xa:ya:za=51:149:300), fourth coordinates (xa:ya:za=46:288:833), fifth coordinates (xa:ya:za=0:2:11), sixth coordinates (xa:ya:za=0:0:1), seventh coordinates (xa:ya:za=2:2:1), and the first coordinates, in this order, and
• wherein in an equilibrium diagram with vertices of the three elements of In, the element M, and Zn, the second atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (xb:yb:zb=2:2:1), second coordinates (xb:yb:zb=23:27:25), third coordinates (xb:yb:zb=8:12:35), fourth coordinates (xb:yb:zb=4:0:7), fifth coordinates (xb:yb:zb=2:0:3), sixth coordinates (xb:yb:zb=7:1:8), seventh coordinates (xb:yb:zb=10:4:7), and the first coordinates, in this order.

The semiconductor device comprising:

• an oxide semiconductor layer comprising In, an element M, and Zn;
• and
• an insulating layer that contains oxygen in excess of the stoichiometric composition,
• wherein the insulating layer and the oxide semiconductor layer overlap each other,
• wherein the oxide semiconductor layer includes a plurality of crystals,
• wherein the element M is at least one of aluminum, gallium, yttrium, and tin,
• wherein an atomic ratio of In to the element M and Zn satisfies In:M:Zn=x:y:z, and
• wherein, in an equilibrium diagram with vertices of the three elements of In, the element M, and Zn, the atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (x:y:z=2:2:1), second coordinates (x:y:z=23:27:25), third coordinates (x:y:z=8:12:35), fourth coordinates (x:y:z=4:0:7), fifth coordinates (x:y:z=2:0:3), sixth coordinates (x:y:z=7:1:8), seventh coordinates (x:y:z=15:5:8), and the first coordinates, in this order.

A semiconductor device comprising:

• an oxide semiconductor layer comprising In, an element M, and Zn;
• and
• an insulating layer that contains oxygen in excess of the stoichiometric composition,
• wherein the insulating layer and the oxide semiconductor layer overlap each other,
• wherein the oxide semiconductor layer includes a plurality of crystals,
• wherein the element M is at least one of aluminum, gallium, yttrium, and tin,
• wherein an atomic ratio of In to the element M and Zn satisfies In:M:Zn=x:y:z, and
• wherein, in an equilibrium diagram with vertices of the three elements of In, the element M, and Zn, the atomic ratio is within a range of an area surrounded by line segments that connect first coordinates (x:y:z=8:14:7), second coordinates (x:y:z=2:5:7), third coordinates (x:y:z=51:149:300), fourth coordinates (x:y:z=46:288:833), fifth coordinates (x:y:z=0:2:11), sixth coordinates (x:y:z=0:0:1), seventh coordinates (x:y:z=1:0:0), and the first coordinates, in this order.