Magnetic tunnel junction (MTJ) having a diffusion blocking spacer layer

A method for forming an integrated chip, the method comprising:

• forming a magnetic tunnel junction (MTJ) over a substrate, the forming of the MTJ comprising:
• depositing a reference magnetic layer over the substrate;
• depositing a barrier layer over the reference magnetic layer;
• depositing a first free magnetic layer over the barrier layer, the first free magnetic layer comprising boron;
• depositing a spacer layer over the first free magnetic layer, the spacer layer comprising magnesium and a transition metal;
• and
• depositing a second free magnetic layer over the spacer layer;
• and
• forming a plurality of metal interconnects over the MTJ, wherein the MTJ has a first energy barrier before the forming of the metal interconnects over the MTJ, and wherein the MTJ has a second energy barrier, different than the first energy barrier, after the forming of the metal interconnects over the MTJ, and wherein a difference between the first energy barrier and the second energy barrier is less than 10%,
• wherein boron atoms from the first free magnetic layer diffuse into the spacer layer after the plurality of metal interconnects are formed so that the spacer layer further comprises boron and a concentration of boron atoms in the spacer layer decreases as a distance from the first free magnetic layer increases.

A method for forming an integrated chip, the method comprising:

• depositing a reference magnetic layer on a first electrode layer;
• depositing a barrier layer on the reference magnetic layer;
• depositing a first free magnetic layer on the barrier layer;
• depositing a first spacer layer on the first free magnetic layer, the first spacer layer comprising one or both of magnesium and a first transition metal;
• depositing a second spacer layer on the first spacer layer, the second spacer layer comprising one or both of magnesium and a second transition metal, wherein at least one of the first spacer layer and the second spacer layer comprises magnesium, and wherein at least one of the first spacer layer and the second spacer layer comprises transition metal, and wherein the first spacer layer extends from a top surface of the first free magnetic layer to a bottom surface of the second spacer layer;
• depositing a second free magnetic layer over the second spacer layer;
• and
• depositing a cap layer on the second free magnetic layer;
• and
• depositing a second electrode layer on the cap layer.