| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an invention for a logic circuit, a light-emitting device, a semiconductor device, and an electronic device, wherein an object is to obtain a desired threshold voltage for a thin-film transistor with oxide semiconductors, and another object is to suppress a change of the threshold voltage over time, and a further object is to specifically apply the thin-film transistor to a logic circuit to be formed by a transistor with a desired threshold voltage. <P>SOLUTION: In order to achieve each object, a thin-film transistor in which oxide semiconductor layers with respectively different thicknesses are included is formed on the same substrate, and a logic circuit is formed by using the thin-film transistor whose threshold voltage is controlled by the thicknesses of the oxide semiconductor layers. In addition, a change in a threshold voltage over time is suppressed and the reliability of a logic circuit can be improved by using an oxide semiconductor film which is formed when an oxide insulating film is in contact thereto after dehydration or dehydrogenation treatment. <P>COPYRIGHT: (C)2011,JPO&INPIT |
