Method for manufacturing semiconductor device comprising forming oxide semiconductor by sputtering

摘要

It is an object to provide a thin film transistor having favorable electric characteristics and high reliability and a semiconductor device which includes the thin film transistor as a switching element. An In—Ga—Zn—O-based film having an incubation state that shows an electron diffraction pattern, which is different from a conventionally known amorphous state where a halo shape pattern appears and from a conventionally known crystal state where a spot appears clearly, is formed. The In—Ga—Zn—O-based film having an incubation state is used for a channel formation region of a channel etched thin film transistor.

主权项

1. A method for manufacturing a semiconductor device comprising the steps of:
introducing a substrate into a chamber, wherein the chamber is provided with a magnet system and a target comprising In, Ga and Zn, and wherein a relative density of the target is greater than or equal to 80%; forming an oxide semiconductor layer by magnetron sputtering using the magnet system and the target over the substrate after reverse sputtering is performed, wherein the substrate is heated during the magnetron sputtering; patterning the oxide semiconductor layer into an island-shaped region including a channel formation region; and performing dehydration or dehydrogenation by heat treatment in a heat treatment apparatus after the oxide semiconductor layer is patterned, wherein the oxide semiconductor layer comprises In, Ga and Zn, and wherein a purity of an inert gas which is introduced into the heat treatment apparatus during the heat treatment is set greater than or equal to 99.9999%.