Enhancement of switching margin by utilizing superior pinned layer stability for sub-20nm perpendicular STT-MRAM

We report enhanced switching margin in perpendicular MTJ cells at 20nm node. By introducing a novel structure with superior pinned layer stability, stable magnetization switching without magnetostatic interference has been achieved. Wide switching field margins over 40s have been secured for reproducible STT switching as well as a tightly controlled Hoffset below 100Oe. Switching voltage margin of the novel structure are also wide enough to show definite STT switching.