Composite oxide semiconductor, semiconductor device using the composite oxide semiconductor, and display device having the semiconductor device

Provided is a novel composite oxide semiconductor that can be used for a transistor including an oxide semiconductor film. A complex oxide semiconductor in which a first region and a second region are mixed, wherein the first region has a plurality of first clusters containing In and oxygen as main components, The second region has a plurality of second clusters mainly composed of Zn and oxygen, the plurality of first clusters have portions connected to each other, and the plurality of second clusters are , Each having a portion connected to each other.