Oxide semiconductor film and semiconductor device

A transistor comprising:

• a gate electrode having an island shape;
• a gate insulating film over the gate electrode;
• an oxide semiconductor film comprising a channel region overlapping with the gate electrode with the gate insulating film therebetween;
• and
• a source electrode and a drain electrode electrically connected to the oxide semiconductor film,
• wherein the gate electrode comprises copper,
• wherein the gate insulating film comprises silicon oxide,
• wherein the oxide semiconductor film comprises In, Ga and Zn,
• wherein the oxide semiconductor film comprises a first region which does not overlap with the gate electrode,
• wherein the first region has a surface parallel or substantially parallel to a side surface of the gate electrode,
• wherein the first region comprises a plurality of crystals in which c-axes are aligned in a first direction perpendicular or substantially perpendicular to the surface of the first region,
• wherein a crystal in the plurality of crystals has a YbFe2O4 structure, a Yb2Fe3O7 structure, a modified structure of the YbFe2O4 structure, or a modified structure of the Yb2Fe3O7 structure, and
• wherein the first region comprises an amorphous region surrounding the plurality of crystals.

A transistor comprising:

• a gate electrode having an island shape;
• and
• an oxide semiconductor film comprising a channel region over the gate electrode,
• wherein the gate electrode comprises copper,
• wherein the oxide semiconductor film comprises In, Ga and Zn,
• wherein the oxide semiconductor film comprises a first region which does not overlap with the gate electrode,
• wherein the first region has a surface parallel or substantially parallel to a side surface of the gate electrode,
• wherein the first region comprises a plurality of crystals in which c-axes are aligned in a first direction perpendicular or substantially perpendicular to the surface of the first region,
• wherein a crystal in the plurality of crystals has a YbFe2O4 structure, a Yb2Fe3O7 structure, a modified structure of the YbFe2O4 structure, or a modified structure of the Yb2Fe3O7 structure, and
• wherein the first region comprises an amorphous region surrounding the plurality of crystals.