Semiconductor device and method of manufacturing the same

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

• forming alternating layers, where a silicon germanium layer and a silicon layer are alternately stacked, on a substrate;
• patterning and etching the alternating layers to form a fin structure protruding onto the substrate, and then, forming a silicon nitride film on a surface and a sidewall of each of the alternating layers having the fin structure;
• sequentially forming a dummy gate and a silicon oxide film on the alternating layers with the silicon nitride film therebetween, and then, forming a gate spacer on a sidewall of the dummy gate;
• etching the silicon nitride film upward exposed, and then, etching the alternating layers by using the silicon oxide film as a hard mask;
• and
• selectively forming an inner spacer in a sidewall of each of silicon germanium layers among the silicon germanium layers and silicon layers of the etched alternating layers by etching a silicon oxide film formed on sidewalls of the silicon germanium layers and the silicon layers until the sidewalls of the silicon layers are exposed,
• wherein, when etching the silicon oxide film, the silicon nitride film is hardly etched based on an etching selectivity between the silicon nitride film and the silicon oxide film, such that both end portions of the un-etched silicon nitride film protrude with respect to the sidewalls of each of the silicon layers.