Damage-free and anisotropic magnetic tunneling junction etching by pulse-time-modulated plasma

We have developed a reactive ion etching (RIE) technique for high-performance and damage-free magnetic tunneling junction devices (MTJ) using pulse-time-modulated (TM) plasma. Exposing MTJ devices to the conventional continuous-wave (CW) plasma widely used in plasma etching significantly degrades their magnetic characteristics. We found that it was caused by damaging the structure of the CoFe pinned layer. Conversely, exposure to a TM plasma does not degrades the MTJ devices' characteristics. There-fore, manufacturing processes that incorporate TM plasmas hold promise as device fabrication processes for MRAM and other magnetic devices.