Reducing or avoiding metal deposition from etching magnetic tunnel junction (MTJ) devices, including magnetic random access memory (MRAM) devices

A magnetic tunnel junction (MTJ) device, comprising:

• a bottom electrode having a width and a top surface;
• a dielectric material layer disposed adjacent to the bottom electrode and at least partially below the top surface of the bottom electrode;
• a seed layer;
• an MTJ stack pillar disposed above the dielectric material layer, the MTJ stack pillar having a width larger than the width of the bottom electrode and disposed above and in electrical contact with the bottom electrode, the MTJ stack pillar comprising:
• a pinned layer disposed above the seed layer;
• a free layer disposed above the seed layer;
• and
• a tunnel barrier disposed between the pinned layer and the free layer, the tunnel barrier configured to provide a tunnel magnetoresistance between the pinned layer and the free layer;
• and
• an over-etch trench disposed in the dielectric material layer adjacent to the MTJ stack pillar and extending below the top surface of the bottom electrode, wherein the over-etch trench does not extend into the bottom electrode.