US Patent 11316016 Composite oxide semiconductor and transistor

A novel material is provided. A composite oxide semiconductor includes a first region and a second region. The first region contains indium. The second region contains an element M (the element M is one or more of Ga, Al, Hf, Y, and Sn). The first region and the second region are arranged in a mosaic pattern. The composite oxide semiconductor further includes a third region. The element M is gallium. The first region contains indium oxide or indium zinc oxide. The second region contains gallium oxide or gallium zinc oxide. The third region contains zinc oxide.