A method for fabricating a semiconductor device includes forming a structure having first surfaces at a height above a second surface, which is provided between the first surfaces, forming a first silicon layer on the structure, performing a tilt ion implantation process on the first silicon layer to form a crystalline region and an amorphous region, forming a second silicon layer on the amorphous region, removing the second silicon layer and the first silicon layer until a part of the second surface is exposed, thereby forming an etch barrier, and etching using the etch barrier to form an open part that exposes a part of a sidewall of the structure.