Embodiments of the disclosure provide methods and apparatus for fabricating magnetic tunnel junction (MTJ) structures on a substrate for MRAM applications. In one embodiment, a magnetic tunnel junction (MTJ) device structure includes a junction structure disposed on a substrate, the junction structure comprising a first ferromagnetic layer and a second ferromagnetic layer sandwiching a tunneling barrier layer, a dielectric capping layer disposed on the junction structure, a metal capping layer disposed on the junction structure, and a top buffer layer disposed on the metal capping layer.