Effect of nitrogen incorporation to oxidation process on the reliability of magnetic tunnel junctions

In this study, nitrogen atoms are added in a post-oxidation process of a thin Al metal layer to enhance the stability of magnetic tunnel junctions (MTJs). Al-N bonds in the tunnel barrier were detected by XPS measurements. The MTJs fabricated by an ultra-high vacuum magnetron sputtering system consisted of Si(100)/SiO/sub 2//CoFeB(100 /spl Aring/)/Cu(250 /spl Aring/)/CoFe(50 /spl Aring/)/AIO/sub x/ or AlO/sub x/N/sub y/(20 /spl Aring/)/CoFe(25 /spl Aring/)/IrMn(200 /spl Aring/)/Cu(300 /spl Aring/). The lifetimes of the two barriers were predicted in order to see the nitrogen effect on the reliability. Under the lifetime specification of 1 MTJ failure out of 10/sup 12/ junctions, the operating voltage of 0.24 V was obtained for the purely oxidized barriers while 0.42 V of operating voltages for the oxy-nitrided barriers.