Patent attributes
A semiconductor device with high design flexibility is provided. A first transistor and a second transistor having electrical characteristics different from those of the first transistor are provided over the same layer without significantly increasing the number of manufacturing steps. For example, semiconductor materials with different electron affinities are used for a semiconductor layer in which a channel of the first transistor is formed and a semiconductor layer in which a channel of the second transistor is formed. This allows the threshold voltages of the first transistor and the second transistor to differ from each other. Forming a gate electrode using a damascene process enables miniaturization and high density of the transistors. Furthermore, a highly-integrated semiconductor device is provided.
