Method for manufacturing oxide film, method for manufacturing semiconductor memory device, semiconductor device, and semiconductor memory device

A method for manufacturing a semiconductor memory device, comprising:

• forming a stacked structure in which an oxide layer and a nitride layer are alternately stacked in a first direction;
• forming a hole extending in the first direction in the stacked structure;
• forming a charge storage layer inside the hole;
• forming a first insulating film inside the hole;
• forming a semiconductor layer inside the hole;
• selectively removing the nitride layer with respect to the oxide layer;
• forming an aluminum nitride film in a region where the nitride layer is removed;
• forming an aluminum oxide film by oxidizing the aluminum nitride film in an atmosphere containing heavy water (D2O);
• and
• forming a conductive film in the region,
• wherein the aluminum nitride film is oxidized at a temperature of 950° C. or more in the forming the aluminum oxide film.