A semiconductor device is provided. The semiconductor device according to an implementation of the disclosed technology may include a variable resistance layer; a selector layer disposed over or under the variable resistance layer; a first protective layer disposed on sidewalls of the variable resistance layer and sidewalls of the selector layer, the first protective layer including silicon (Si) and nitrogen (N) and having a nitrogen (N) content higher than a silicon (Si) content; and a second protective layer disposed over the first protective layer, the second protective layer including silicon (Si) and nitrogen (N) and having a silicon (Si) content higher than a nitrogen (N) content.