A method includes depositing a bottom electrode layer, a resistance switching element layer, and a top electrode layer over a first dielectric layer; etching the top electrode layer and the resistance switching element layer to form a resistance switching element over the bottom electrode layer and a top electrode over the resistance switching element; depositing a metal-containing compound layer over the top electrode, the resistance switching element, and the bottom electrode layer; and etching the metal-containing compound layer and the bottom electrode layer to form a bottom electrode over the first dielectric layer.