US Patent 8188467 Amorphous oxide and field effect transistor

In a field effect transistor, a channel layer of the field effect transistor is composed of an amorphous oxide including In, Zn, N and O, an atomic composition ratio of N to N and O (N/(N+O)) in the amorphous oxide is equal to or larger than 0.01 atomic percent and equal to or smaller than 3 atomic percent, and the amorphous oxide does not include Ga, or, in a case where the amorphous oxide includes Ga, the number of Ga atoms contained in the amorphous oxide is smaller than the number of N atoms.