Semiconductor device structure with electrode layer and method for forming the same

A method for forming a semiconductor device structure, comprising:

• forming a first electrode layer over a substrate;
• forming a capacitor dielectric layer over the first electrode layer and the substrate, wherein the capacitor dielectric layer conformally covers a top surface and a sidewall of the first electrode layer;
• depositing a second electrode layer over the capacitor dielectric layer, wherein the second electrode layer has a first top portion, a first sidewall portion, and a first bottom portion, the first top portion is over the capacitor dielectric layer over the top surface of the first electrode layer, the first sidewall portion is over the capacitor dielectric layer over the sidewall of the first electrode layer and connected between the first top portion and the first bottom portion;
• and
• bombarding the second electrode layer with ions of an inert gas to sputter first atoms from the second electrode layer, wherein
• the first atoms are deposited to the second electrode layer after the bombarding of the second electrode layer, the second electrode layer becomes a treated second electrode layer after the first atoms are deposited to the second electrode layer, the treated second electrode layer has a treated first top portion, a treated first sidewall portion, and a treated first bottom portion, the treated first sidewall portion is over the sidewall of the first electrode layer and connected between the treated first top portion and the treated first bottom portion, and the treated first sidewall portion is thicker than the first sidewall portion.