A memory device includes a substrate, an etch stop layer, a protective layer, and a resistance switching element. The substrate has a memory region and a logic region, and includes a metallization pattern therein. The etch stop layer is over the substrate, and has a first portion over the memory region and a second portion over the logic region. The protective layer covers the first portion of the etch stop layer. The protective layer does not cover the second portion of the etch stop layer. The resistance switching element is over the memory region, and the resistance switching element is electrically connected to the metallization pattern through the etch stop layer and the protective layer.