Semiconductor device and manufacturing method thereof

A method of manufacturing a semiconductor device, comprising:

• forming a stacked body including a plurality of first films and a plurality of second films that are alternately stacked on each other;
• forming an opening in the stacked body that extends in a thickness direction of the stacked body;
• and
• forming a first insulating film, a charge storage layer, a second insulating film, and a semiconductor layer on a side wall of the stacked body in the opening, wherein
• the charge storage layer includes a silicon nitride film,
• the second insulating film includes a silicon oxynitride film, and
• the silicon oxynitride film is formed by using a first gas containing silicon, a second gas containing nitrogen and deuterium, and a third gas containing oxygen.

A semiconductor device comprising:

• a stacked body including a plurality of first films and a plurality of second films that are alternately provided, the stacked body including an opening extending in a thickness direction;
• a first insulating film on a side wall of the stacked body in the opening;
• a charge storage layer on a surface of the first insulating film in the opening;
• a second insulating film on a surface of the charge storage layer in the opening;
• and
• a semiconductor layer on a surface of the second insulating film in the opening, wherein
• the charge storage layer includes a silicon nitride film,
• the second insulating film includes a silicon oxynitride film, and
• a hydrogen concentration of the silicon nitride film is 1.0×1019 atoms/cm3 or less in at least at a part of the silicon nitride film in a depth direction from a center of the opening towards an outside of the opening.