Perpendicular magnetic tunnel junction (pMTJ) devices employing a thin pinned layer stack and providing a transitioning start to a body-centered cubic (BCC) crystalline / amorphous structure below an upper anti-parallel (AP) layer

摘要

Perpendicular magnetic tunnel junction (pMTJ) devices employing a pinned layer stack with a thin top anti-parallel (AP2) layer and having a transitioning layer providing a transitioning start to a body-centered cubic (BCC) crystalline/amorphous structure below the top anti-parallel (AP2) layer, to promote a high tunnel magnetoresistance ratio (TMR) with reduced pinned layer thickness are disclosed. A first anti-parallel (AP) ferromagnetic (AP1) layer in a pinned layer has a face-centered cubic (FCC) or hexagonal closed packed (HCP) crystalline structure. A transitioning material (e.g., Iron (Fe)) is provided in a transitioning layer between the AP1 layer and an AFC layer (e.g., Chromium (Cr)) that starts a transition from a FCC or HCP crystalline structure, to a BCC crystalline/amorphous structure. In this manner, a second AP ferromagnetic (AP2) layer disposed on the AFC layer can be provided in a reduced thickness BCC crystalline or amorphous structure to provide a high TMR with a reduced pinned layer thickness.

主权项

1. A perpendicular magnetic tunnel junction (pMTJ), comprising:
a bottom electrode and a top electrode; a pinned layer disposed between the bottom electrode and the top electrode; a free layer disposed between the pinned layer and the top electrode; and a tunnel barrier layer disposed between the pinned layer and the free layer, the tunnel barrier layer configured to provide a tunnel magnetoresistance between the pinned layer and the free layer; the pinned layer comprising a synthetic anti-ferromagnetic (SAF) structure, comprising:
a first anti-parallel (AP) layer having a first reference magnetic orientation, the first AP layer comprising a face-centered cubic (FCC) or hexagonal closed packed (HCP) crystalline structure material;an anti-ferromagnetic coupling (AFC) layer disposed above the first AP layer;a second AP layer disposed above the AFC layer, the second AP layer having a second reference magnetic orientation opposite of the first reference magnetic orientation, the second AP layer comprising a body-centered cubic (BCC) crystalline or amorphous structure; anda transitioning layer disposed below the second AP layer, in the first AP layer as an interface between the first AP layer and the AFC layer to provide a transitioning start to the BCC crystalline or amorphous structure of the second AP layer.