Sputtering target, method for manufacturing sputtering target, and method for forming thin film

摘要

There have been cases where transistors formed using oxide semiconductors are inferior in reliability to transistors formed using amorphous silicon. Thus, in the present invention, a semiconductor device including a highly reliable transistor formed using an oxide semiconductor is manufactured. An oxide semiconductor film is deposited by a sputtering method, using a sputtering target including an oxide semiconductor having crystallinity, and in which the direction of the c-axis of a crystal is parallel to a normal vector of the top surface of the oxide semiconductor. The target is formed by mixing raw materials so that its composition ratio can obtain a crystal structure.

主权项

1. A method for manufacturing a sputtering target comprising the steps of:
obtaining a mixed material by mixing an InOX raw material, a MOY raw material, and a ZnOZ raw material, M being one of Ga, Sn, Hf, Al, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; forming an In-M-Zn—O compound powder by performing a first baking to the mixed material and then grinding the mixed material; spreading part of the In-M-Zn—O compound powder in a mold; forming a compound film by performing a second baking and a first pressure treatment on the part of the In-M-Zn—O compound powder spread in the mold; spreading another part of the In-M-Zn—O compound powder over the compound film in the mold; and performing a third baking and a second pressure treatment on the another part of the In-M-Zn—O compound powder and the compound film in the mold, wherein the first baking is performed in a first atmosphere and then in a second atmosphere, wherein the first atmosphere is an inert atmosphere or a reduced-pressure atmosphere, and wherein the second atmosphere is an oxidation atmosphere.