| 摘要 |
It is an object to provide a thin film transistor with high speed operation, in which a large amount of current can flow when the thin film transistor is on and off-state current is extremely reduced when the thin film transistor is off. The thin film transistor is a vertical thin film transistor in which a channel formation region is formed using an oxide semiconductor film in which hydrogen is contained in an oxide semiconductor at a concentration of lower than or equal to 5×1019/cm3, preferably lower than or equal to 5×1018/cm3, more preferably lower than or equal to 5×1017/cm3, hydrogen or an OH group contained in the oxide semiconductor is/are removed, and carrier concentration is lower than or equal to 5×1014/cm3, preferably lower than or equal to 5×1012/cm3. |
