US Patent 8232551 Channel layers and semiconductor devices including the same

Channel layers and semiconductor devices including the channel layers are disclosed. A channel layer may include a multi-layered structure. Layers forming the channel layer may have different carrier mobilities and/or carrier densities. The channel layer may have a double layered structure including a first layer and a second layer which may be formed of different oxides. Characteristics of the transistor may vary according to materials used to form the channel layers and/or thicknesses thereof.