Patent ID: 8203143
Filing Date: 2012-06-19
Classification: H01L

Abstract:
1. A thin film field effect transistor comprising: at least a gate electrode, a gate insulating layer, an active layer, a source electrode and a drain electrode on a substrate, wherein the active layer comprises an amorphous oxide semiconductor containing at least In and Zn; a plurality of the active layers are provided, and an intermediate interface layer is disposed between active layers which are adjacent to each other, the intermediate interface layer comprising an amorphous oxide semiconductor containing Ga or Al, and a content of Ga or Al in the amorphous oxide semiconductor of the intermediate layer being higher than the content of Ga or Al in the amorphous oxide semiconductor of the plurality of active layers; a first interface layer comprising an amorphous oxide semiconductor containing Ga or Al is disposed between the gate insulating layer and the active layer such that the first interface layer is adjacent to at least the active layer, a content of Ga or Al in the amorphous oxide semiconductor of the first interface layer being higher than a content of Ga or Al in the amorphous oxide semiconductor of the active layer; and a second interface layer comprising an amorphous oxide semiconductor containing Ga or Al is disposed on the opposite side of the active layer with respect to the first interface layer such that the second interface layer is adjacent to the active layer, a content of Ga or Al in the amorphous oxide semiconductor of the second interface layer being higher than the content of Ga or Al in the amorphous oxide semiconductor of the active layer.