Patent ID: 8148245

Claim:
A method for producing an amorphous In—Ga—Zn—O based oxide thin film, comprising: providing a sintered oxide material consisting essentially of indium (In), gallium (Ga), zinc (Zn), and oxygen (O) as constituent elements, wherein a ratio [In]/([In]+[Ga]) of the number of indium atoms to a total number of indium and gallium atoms is from 20% to 80%, a ratio [Zn]/([In]+[Ga]+[Zn]) of the number of zinc atoms to a total number of indium, gallium and zinc atoms is from 10% to 50%, and the sintered oxide material has a specific resistance of 5.0×10 −3 Ωcm or less; and producing a film on a substrate by direct current sputtering at a substrate temperature of 25 to 50° C. and a sputtering power density of 2.7 to 6.6 W/cm 2 using the sintered oxide material as a sputtering target.