PURPOSE: A method for changing a property of a thin film is provided to change the mobility of an oxide semiconductor thin film or a carrier of the oxide semiconductor thin film without high thermal energy by emitting hydrogen ions to the oxide semiconductor thin film or an oxide conductor thin film. CONSTITUTION: An oxide semiconductor thin film or oxide conductor thin film formed on a substrate is prepared(110). Energy of an ion accelerator and the density of hydrogen ions emitted to the oxide semiconductor thin film or oxide conductor thin film are determined(120). Hydrogen ions are emitted onto the oxide semiconductor thin film or oxide conductor thin film(130). The mobility of the oxide semiconductor thin film or a carrier of the oxide conductor thin film is confirmed(140). [Reference numerals] (110) Preparing an oxide semiconductor thin film or an oxide conductor thin film which is formed on a substrate; (120) Determining energy of an ion accelerator and the density of hydrogen ions emitted to an oxide semiconductor thin film or an oxide conductor thin film; (130) Emitting hydrogen ions to an oxide semiconductor thin film or an oxide conductor thin film; (140) Confirming the mobility of an oxide semiconductor thin film or a carrier of an oxide conductor thin film; (AA) Start; (BB) End
