US Patent 9806201 Semiconductor device

A method for forming an oxide that can be used as a semiconductor of a transistor or the like is provided. In particular, a method for forming an oxide with fewer defects such as grain boundaries is provided. One embodiment of the present invention is a semiconductor device including an oxide semiconductor, an insulator, and a conductor. The oxide semiconductor includes a region overlapping with the conductor with the insulator therebetween. The oxide semiconductor includes a crystal grain with an equivalent circle diameter of 1 nm or more and a crystal grain with an equivalent circle diameter less than 1 nm.