Semiconductor device and method for manufacturing the same

摘要

A semiconductor device in which a shift of the threshold voltage of a transistor is suppressed is provided. A semiconductor device in which a decrease in the on-state current of a transistor is suppressed is provided. The semiconductor device is manufactured as follows: forming a gate electrode layer over a substrate; forming a gate insulating film over the gate electrode layer; forming an oxide semiconductor film over the gate insulating film; forming a metal oxide film having a higher reducing property than the oxide semiconductor film over the oxide semiconductor film; performing heat treatment while the metal oxide film and the oxide semiconductor film are in contact with each other, thereby the metal oxide film is reduced so that a metal film is formed; and processing the metal film to form a source electrode layer and a drain electrode layer.

主权项

1. A semiconductor device comprising a transistor, the transistor comprising:
a gate electrode layer; an oxide semiconductor layer over the gate electrode layer; a gate insulating layer interposed between the gate electrode layer and the oxide semiconductor layer; a first conductive layer over and in contact with the oxide semiconductor layer; a second conductive layer over and in contact with the oxide semiconductor layer; an oxide insulating film over the oxide semiconductor layer, the first conductive layer and the second conductive layer, the oxide insulating film being capable of supplying oxygen; and an aluminum oxide film over the oxide insulating film, the aluminum oxide film having a film density of 3.2 g/cm3 or more, wherein the first conductive layer and the second conductive layer do not overlap each other, wherein the oxide semiconductor layer comprises indium, gallium and zinc, wherein each of the first conductive layer and the second conductive layer is formed using a first metal having a higher oxidation resistance than molybdenum, and wherein the first metal is ruthenium.