Semiconductor device and method for fabricating the same

A method for fabricating a semiconductor device including a plurality of memory cells, the method comprising:

• forming a first electrode layer over a substrate;
• forming an initial buffer layer over the first electrode pattern;
• forming an initial Si-containing layer over the initial buffer layer;
• performing a radical oxidation process to form an oxide layer including SiO2, the oxide layer converted from at least a portion of the initial Si-containing layer and any remaining portion of the initial Si-containing layer forming a Si-containing layer;
• and
• incorporating a dopant into the oxide layer by an ion implantation process to form a selector pattern.