A semiconductor device structure is provided. The structure includes a semiconductor substrate and a data storage element over the semiconductor substrate. The structure also includes an ion diffusion barrier element over the data storage element and a protective element extending along a sidewall of the ion diffusion barrier element. A bottom surface of the protective element is between a top surface of the data storage element and a bottom surface of the data storage element. The structure further includes a first electrode electrically connected to the data storage element and a second electrode electrically connected to the data storage element.