Semiconductor device and method for forming the same

Abstract

A semiconductor device includes: a substrate, a semiconductor layer including an oxide semiconductor disposed on the substrate, a barrier layer disposed on the semiconductor layer and an insulating layer disposed on the barrier layer. The semiconductor layer includes an oxide semiconductor, and the barrier layer includes a material having a lower standard electrode potential than a semiconductor material of the oxide semiconductor, a lower electron affinity than the semiconductor material of the oxide semiconductor, or a larger band gap than the semiconductor material of the oxide semiconductor. The insulating layer includes at least one of a silicon-based oxide or a silicon-based nitride, and the insulating layer includes a portion which contacts with an upper surface of the barrier layer.