Semiconductor device and method for manufacturing semiconductor device
According to one embodiment, a semiconductor device includes a foundation layer, a stacked body provided on the foundation layer, the stacked body including a plurality of electrode layers stacked with an insulator interposed, a semiconductor body extending through the stacked body in a stacking direction of the stacked body, and a charge storage portion provided between the semiconductor body and the electrode layers. The semiconductor body includes a first semiconductor film, and a second semiconductor film provided between the first semiconductor film and the charge storage portion. An average grain size of a crystal of the second semiconductor film is larger than an average grain size of a crystal of the first semiconductor film.
1. A method for manufacturing a semiconductor device, comprising:
forming a stacked body on a foundation layer, the stacked body including a plurality of first layers and a plurality of second layers, the first layers and the second layers including a first layer and a second layer stacked alternately;
forming a stacked film on a bottom and side surface of a hole, the hole extending through the stacked body in a stacking direction of the stacked body;
forming a cover film inside the hole on a side surface of the stacked film and on the stacked film at the bottom, a gap remaining on an inner side of the cover film, the cover film being a silicon film;
annealing the cover film to crystallize the cover film after forming the cover film to be amorphous;
exposing the foundation layer at the bottom of the hole by removing the stacked film and the cover film at the bottom of the hole by reactive ion etching (RIE);
removing a portion of the cover film at the side surface of the hole adjacent to the gap after the removing of the stacked film and the cover film at the bottom; and
forming a semiconductor film on aside surface of the cover film and on the bottom of the hole after the removing of the portion of the cover film adjacent to the gap,
a portion of the crystallized cover film adjacent to the gap being amorphized in the RIE, and
the amorphized portion of the cover film being removed by etching using a gas including a halogen.