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.

A storage element includes a storage layer having a magnetization perpendicular to a layer surface and storing information according to a magnetization state of a magnetic material; a fixed magnetization layer having the magnetization as a reference of the information of the storage layer and perpendicular to the layer surface; an interlayer formed of a nonmagnetic material and interposed between the storage layer and the fixed magnetization layer; a coercive force enhancement layer adjacent to the storage layer, opposite to the interlayer, and formed of Cr, Ru, W, Si, or Mn; and a spin barrier layer formed of an oxide, adjacent to the coercive force enhancement layer, and opposite to the storage layer. The storage layer magnetization is reversed using spin torque magnetization reversal caused by a current in a lamination direction of a layer structure including the storage layer, the interlayer, and the fixed magnetization layer, thereby storing information.

A storage element includes a storage layer, a fixed magnetization layer, a spin barrier layer, and a spin absorption layer. The storage layer stores information based on a magnetization state of a magnetic material. The fixed magnetization layer is provided for the storage layer through a tunnel insulating layer. The spin barrier layer suppresses diffusion of spin-polarized electrons and is provided on the side of the storage layer opposite the fixed magnetization layer. The spin absorption layer is formed of a nonmagnetic metal layer causing spin pumping and provided on the side of the spin barrier layer opposite the storage layer. A direction of magnetization in the storage layer is changed by passing current in a layering direction to inject spin-polarized electrons so that information is recorded in the storage layer and the spin barrier layer includes at least a material selected from oxides, nitrides, and fluorides.

A storage element includes a storage layer, a fixed magnetization layer, a spin barrier layer, and a spin absorption layer. The storage layer stores information based on a magnetization state of a magnetic material. The fixed magnetization layer is provided for the storage layer through a tunnel insulating layer. The spin barrier layer suppresses diffusion of spin-polarized electrons and is provided on the side of the storage layer opposite the fixed magnetization layer. The spin absorption layer is formed of a nonmagnetic metal layer causing spin pumping and provided on the side of the spin barrier layer opposite the storage layer. A direction of magnetization in the storage layer is changed by passing current in a layering direction to inject spin-polarized electrons so that information is recorded in the storage layer and the spin barrier layer includes at least a material selected from oxides, nitrides, and fluorides.

A storage element includes a storage layer, a fixed magnetization layer, a spin barrier layer, and a spin absorption layer. The storage layer stores information based on a magnetization state of a magnetic material. The fixed magnetization layer is provided for the storage layer through a tunnel insulating layer. The spin barrier layer suppresses diffusion of spin-polarized electrons and is provided on the side of the storage layer opposite the fixed magnetization layer. The spin absorption layer is formed of a nonmagnetic metal layer causing spin pumping and provided on the side of the spin barrier layer opposite the storage layer. A direction of magnetization in the storage layer is changed by passing current in a layering direction to inject spin-polarized electrons so that information is recorded in the storage layer and the spin barrier layer includes at least a material selected from oxides, nitrides, and fluorides.

A semiconductor memory structure includes a substrate, a magnetic tunneling junction (MTJ) stack disposed on the substrate, and an encapsulation layer surrounding the MTJ stack. The encapsulation layer comprises an outer silicon oxynitride layer with a composition of SiO.sub.x1N.sub.y1 and an inner silicon oxynitride layer with a composition of SiO.sub.x2N.sub.y2, wherein x1/y1>x2/y2.

A semiconductor memory structure includes a substrate, a magnetic tunneling junction (MTJ) stack disposed on the substrate, and an encapsulation layer surrounding the MTJ stack. The encapsulation layer comprises an outer silicon oxynitride layer with a composition of SiO.sub.x1N.sub.y1 and an inner silicon oxynitride layer with a composition of SiO.sub.x2N.sub.y2, wherein x1/y1>x2/y2.

A magnetic tunneling junction (MTJ) element includes a reference layer, a tunnel barrier layer on the reference layer, a free layer on the tunnel barrier layer, and a composite capping layer on the free layer. The composite capping layer comprises a diffusion-stop layer on the free layer, a light-element sink layer on the diffusion-stop layer, and an amorphous layer on the light-element sink layer.

A magnetic tunnel junction stack includes: a pinned layer; a main oxide barrier layer on the pinned layer; a free layer on the main oxide barrier layer; and a hybrid oxide/metal cap layer on the free layer. The hybrid oxide/metal cap layer includes: a first oxide layer on the free layer; a second oxide layer on the first oxide layer; and a metallic cap layer on the second oxide layer, wherein the free layer is free of boron (B).

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.