Semiconductor device, memory system including the same, and method of manufacturing the same

A method of manufacturing a semiconductor device, the method comprising:

• alternately forming first material layers and second material layers to form a stacked structure;
• forming channel holes extending through the stacked structure, the channel holes including sidewalls;
• forming a charge storing layer on the side walls of the channel holes;
• forming vertical channel layers, inside the channel holes, on the charge storing layer;
• forming a slit by etching the stacked structure between the vertical channel layers;
• and
• forming insulating layer trenches configured to separate the charge storing layer into a plurality of patterns by removing the second material layers, and portions of the charge storing layer, exposed through the slit.