Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode;
• forming an oxide semiconductor film overlapping with the gate electrode with the gate insulating film interposed therebetween;
• forming a source electrode and a drain electrode over the oxide semiconductor film;
• forming a metal oxide film over the source electrode and the drain electrode, the metal oxide film being in contact with the oxide semiconductor film;
• forming an insulating film over the metal oxide film;
• introducing oxygen to at least one of the oxide semiconductor film, the metal oxide film, and an interface between the oxide semiconductor film and the metal oxide film through the insulating film;
• and
• performing heat treatment after the step of introducing oxygen.

A method for manufacturing a semiconductor device, comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode;
• forming an oxide semiconductor film overlapping with the gate electrode with the gate insulating film interposed therebetween;
• performing first heat treatment on the oxide semiconductor film, the first heat treatment including heating in an inert atmosphere and cooling in an oxygen atmosphere;
• forming a source electrode and a drain electrode over the oxide semiconductor film;
• forming a metal oxide film over the source electrode and the drain electrode, the metal oxide film being in contact with the oxide semiconductor film;
• introducing oxygen to at least one of the oxide semiconductor film, the metal oxide film, and an interface between the oxide semiconductor film and the metal oxide film;
• forming an insulating film over the metal oxide film after the step of introducing oxygen;
• and
• performing second heat treatment after forming the insulating film.

A method for manufacturing a semiconductor device, comprising the steps of:

• forming a gate electrode over a substrate;
• forming a gate insulating film over the gate electrode;
• forming an oxide semiconductor film overlapping with the gate electrode with the gate insulating film interposed therebetween;
• performing first heat treatment on the oxide semiconductor film, the first heat treatment including heating in an inert atmosphere and cooling in an oxygen atmosphere;
• forming a source electrode and a drain electrode over the oxide semiconductor film;
• forming a metal oxide film over the source electrode and the drain electrode, the metal oxide film being in contact with the oxide semiconductor film;
• forming an insulating film over the metal oxide film;
• introducing oxygen to at least one of the oxide semiconductor film, the metal oxide film, and an interface between the oxide semiconductor film and the metal oxide film through the insulating film;
• and
• performing second heat treatment after the step of introducing oxygen.