| abstract |
A semiconductor device having good electrical characteristics is provided. A semiconductor device with stable electrical characteristics is provided. A highly reliable display device is provided. A step of forming a semiconductor layer containing a metal oxide, a step of forming a first conductive layer and a second conductive layer spaced apart from the semiconductor layer on the semiconductor layer, and an oxidizing gas and a reducing gas in the region where the semiconductor layer is exposed performing a plasma treatment using a mixed gas of It is set as the manufacturing method of the semiconductor device which has the process of forming. The first insulating layer is formed by a plasma chemical vapor deposition method using a gas containing silicon, an oxidizing gas, and a mixed gas containing ammonia gas. Further, the first insulating layer is continuously formed without exposure to the atmosphere after the plasma treatment. |