Transistor, semiconductor device including the transistor, and manufacturing method of the transistor and the semiconductor device

摘要

An object is to suppress deterioration in electric characteristics in a transistor including an oxide semiconductor layer or a semiconductor device including the transistor. In a transistor in which a channel layer is formed using an oxide semiconductor, a silicon layer is provided in contact with a surface of the oxide semiconductor layer, an impurity semiconductor layer is provided over the silicon layer, and a source electrode layer and a drain electrode layer are provided to be electrically connected to the impurity semiconductor layer.