Sputtering target, method for forming amorphous oxide thin film using the same, and method for manufacturing thin film transistor

A sputtering target composed of an oxide sintered body containing two or more homologous crystal structures, wherein the homologous crystal structures include a first crystal phase and a second crystal phase, wherein the first crystal phase and the second crystal phase are selected from the group consisting of a InMO3(ZnO)m crystal structure wherein M is a tervalent metal element and m is from 0.5 to 10, a (YbFeO3)2FeO type crystal structure and mixture thereof, and wherein a maximum peak strength of X-ray diffraction for the first crystal phase P(1) and a maximum peak strength of X-ray diffraction for the second crystal phase P(2) meet a peak strength ratio of P(1)/P(2)=0.05˜20.