Method for fabricating semiconductor device with interface layer

A method for fabricating a semiconductor device, comprising:

• providing a substrate;
• forming a top inter-dielectric layer above the substrate;
• forming an opening penetrating the top inter-dielectric layer;
• forming a bottom electrode layer within the opening;
• performing an oxygen treatment to form an interface layer on the bottom electrode layer;
• performing a nitrogen treatment to turn the interface layer into a treated interface layer;
• forming a capacitor bottom dielectric layer on the treated interface layer;
• forming a capacitor top dielectric layer on the capacitor bottom dielectric layer;
• and
• forming a top electrode layer on the capacitor top dielectric layer;
• wherein the treated interface layer comprises titanium oxide nitride;
• wherein the bottom electrode layer, the treated interface layer, the capacitor bottom dielectric layer, the capacitor top dielectric layer, and the top electrode layer configure a capacitor structure.