Field effect transistor with multi-layer metal oxide semiconductor and multi-layer metal oxide gate dielectric, and integrated circuit device including the same

Abstract

Provided is a field effect transistor including a gate electrode layer, an oxide semiconductor layer including gallium (Ga) and at least one metal element selected from indium (In) and zinc (Zn), and a dielectric layer between the gate electrode layer and the oxide semiconductor layer, wherein the oxide semiconductor layer includes a sub semiconductor layer in contact with the dielectric layer and a main semiconductor layer spaced apart from the dielectric layer with the sub semiconductor layer therebetween, the sub semiconductor layer has a first Ga content, and the first Ga content of the sub semiconductor layer is greater than contents of other metal elements included in the sub semiconductor layer and decreases as a distance from an interface of the sub semiconductor layer in contact with the dielectric layer increases.