A via structure, a MRAM device using the via structure and a method for fabricating the MRAM device are provided. In the method for fabricating the MRAM device, at first, a first dielectric layer is deposited over a transistor. Then, a contact is formed in the first dielectric layer and electrically connected to the transistor. Thereafter, a metal nitride layer is deposited over the first dielectric layer and the contact. Then, an etch stop layer is deposited over the metal nitride layer. Thereafter, a second dielectric layer is deposited over the etch stop layer. Then, a via structure is formed in the second dielectric layer, the etch stop layer, and the metal nitride layer and landing on the contact. Thereafter, a memory stack is formed over the via structure.