Method for manufacturing semiconductor device

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

• forming a first electrode over a substrate;
• forming an insulating film over the first electrode;
• forming an oxide semiconductor layer over the insulating film;
• performing a heat treatment on the oxide semiconductor layer in a chamber, whereby a hydrogen concentration of the oxide semiconductor layer is reduced;
• introducing oxygen into the chamber after the heat treatment;
• forming a source electrode and a drain electrode electrically connected to the oxide semiconductor layer;
• forming an oxide insulating film over and in contact with the oxide semiconductor layer;
• and
• forming a second electrode over the oxide insulating film,
• wherein the second electrode overlaps with the first electrode with the oxide semiconductor layer interposed therebetween, and
• wherein the heat treatment is performed under reduced pressure or performed in an inert atmosphere.

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

• forming a first electrode over a substrate;
• forming an insulating film over the first electrode;
• forming an oxide semiconductor layer over the insulating film;
• performing a heat treatment on the oxide semiconductor layer in a chamber;
• introducing oxygen into the chamber after the heat treatment;
• forming a source electrode and a drain electrode electrically connected to the oxide semiconductor layer;
• forming an oxide insulating film over and in contact with the oxide semiconductor layer;
• and
• forming a second electrode over the oxide insulating film,
• wherein the second electrode overlaps with the first electrode with the oxide semiconductor layer interposed therebetween,
• wherein the heat treatment is performed under reduced pressure or performed in an inert atmosphere, and
• wherein the heat treatment is performed at a temperature higher or equal to 400° C.

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

• forming a first electrode over a substrate;
• forming an insulating film over the first electrode;
• forming an oxide semiconductor layer over the insulating film;
• performing a heat treatment on the oxide semiconductor layer in a chamber;
• introducing oxygen into the chamber after the heat treatment;
• forming a source electrode and a drain electrode electrically connected to the oxide semiconductor layer;
• forming an oxide insulating film over and in contact with the oxide semiconductor layer;
• and
• forming a second electrode over the oxide insulating film,
• wherein the second electrode overlaps with the first electrode with the oxide semiconductor layer interposed therebetween,
• wherein the heat treatment is performed under reduced pressure or performed in an inert atmosphere, and
• wherein after the heat treatment, the oxide semiconductor layer includes crystals.