Oxide for semiconductor layer of thin-film transistor, semiconductor layer of thin-film transistor having said oxide, and thin-film transistor

Abstract

The oxide of the present invention for thin-film transistors is an In—Zn—Sn-based oxide containing In, Zn, and Sn, wherein when the respective contents (atomic %) of metal elements contained in the In—Zn—Sn-based oxide are expressed by [Zn], [Sn], and [In], the In—Zn—Sn-based oxide fulfills the following expressions (2) and (4) when [In]/([In]+[Sn])≤0.5; or the following expressions (1), (3), and (4) when [In]/([In]+[Sn])>0.5. [In]/([In]+[Zn]+[Sn])≤0.3  (1), [In]/([In]+[Zn]+[Sn])≤1.4×{[Zn]/([Zn]+[Sn])}−0.5  (2), [Zn]/([In]+[Zn]+[Sn])≤0.83  (3), and 0.1≤[In]/([In]+[Zn]+[Sn])  (4). According to the present invention, oxide thin films for thin-film transistors can be obtained, which provide TFTs with excellent switching characteristics, and which have high sputtering rate in the sputtering and properly controlled etching rate in the wet etching.

Dependencies are inferred from the claim text.