Mg discontinuous insertion layer for improving MTJ shunt

摘要

A MTJ is disclosed with a discontinuous Mg or Mg alloy layer having a thickness from 1 to 3 Angstroms between a free layer and a capping layer in a bottom spin valve configuration. It is believed the discontinuous Mg layer serves to block conductive material in the capping layer from diffusing through the free layer and into the tunnel barrier layer thereby preventing the formation of conductive channels that function as electrical shunts within the insulation matrix of the tunnel barrier. As a result, the “low tail” percentage in a plot of magnetoresistive ratio vs Rp is minimized which means the number of high performance MTJ elements in a MTJ array is significantly increased, especially when a high temperature anneal is included in the MTJ fabrication process. The discontinuous layer is formed by a low power physical vapor deposition process.

主权项

1. A magnetic tunnel junction (MTJ), comprising:
(a) a free layer having perpendicular magnetic anisotropy (PMA) that contacts a top surface of a tunnel barrier layer; (b) a non-magnetic capping layer as the uppermost layer in the MTJ; and (c) a discontinuous Mg or MgM alloy insertion layer that contacts a top surface of the free layer and a bottom surface of the non-magnetic capping layer where M is one of Ta, Ti, V, Mo, Zr, Hf, Pt Pd, W, Nb, Rh, Ru, Cu, Cr, or Ir, and M has a content less than about 5 atomic % in the MgM alloy.