Elongated magnetoresistive tunnel junction structure

A Magnetic Tunnel Junction (MTJ) memory array, the memory array comprising:

• a number of elongated MTJ line structures formed onto a substrate, each elongate MTJ line structure comprising:
• a magnetic reference layer extending across the entire length of each elongated MTJ structure;
• a tunnel barrier layer;
• and
• a number of separate free magnetic regions formed along the tunnel barrier layer, each free magnetic region forming a memory cell, wherein one of the separate free magnetic regions has a top surface facing away from the tunnel barrier layer;
• wherein a ratio of length to width of each elongated MTJ line structure is such that the magnetic field of the magnetic reference layer is pinned in a single direction across the entire length of each elongated MTJ line structure, and
• wherein one of the elongated line structures is free of an anti-ferromagnetic pinning layer, wherein the one of the elongated MTJ line structures includes a patterned buffer layer physically contacting the semiconductor substrate, wherein the patterned buffer layer has a profile shape in a top view of the elongated MTJ structure, and wherein the tunnel barrier layer of the one of the elongated MJT line structures is a patterned tunnel barrier layer having the profile shape in the top view of the elongated MTJ structure, and
• wherein a contact physically contacting the one of the separate free magnetic regions such that a first portion of the top surface of the one of the separate free magnetic regions is covered by the contact and a second portion of the top surface of the one of the separate free magnetic regions is not covered by the contact, and
• wherein opposing ends of the one of the elongated MTJ line structures includes reservoir regions, the reservoir regions having a greater width than the width of the one of the elongated MTJ line structures, the reservoir regions being free of any free magnetic material layer and configured to make magnetic moment circular.

A device comprising:

• an MTJ structure disposed over a semiconductor substrate, the MTJ structure comprising:
• a buffer layer disposed directly on the semiconductor substrate such that the buffer layer physically contacts the semiconductor substrate;
• a magnetic reference layer disposed directly on the buffer layer such that the magnetic reference layer physically contacts the buffer layer and extends across the entire length of the MTJ structure;
• a tunnel barrier layer disposed directly on the magnetic reference layer such that the tunnel barrier layer physically contacts the magnetic reference layer;
• and
• a free magnetic region disposed directly on the tunnel barrier layer such that the free magnetic region physically contacts the tunnel barrier layer;
• and
• a contact extending through the semiconductor substrate and the buffer layer to the magnetic reference layer, and
• wherein the MTJ structure is without an anti-ferromagnetic pinning layer, and
• wherein the MTJ structure includes opposing ends disposed on either side of an elongated body of the MTJ structure, the opposing ends each including a reservoir region having a greater width than the elongated body, the reservoir regions being free of any free magnetic regions and configured to make magnetic moment circular, and
• wherein a ratio of length to width of the MTJ structure is such that the magnetic field of the magnetic reference layer is pinned in a single direction across the entire length of the MTJ structure.