New plasma source with low electron temperature for fabrication of insulating barrier in ferromagnetic tunnel junctions

Summary form only given. The quality of the tunneling barrier is the most important factor for magnetic tunnel junctions (MTJs). Plasma oxidization of metallic Al layer is a promising method to obtain a tunneling barrier, however, high-energy ions irradiated from the plasma discharging space are liable to damage the structure of the ultra-thin oxide layers. In the present study, we introduced a new plasma source for oxidization processes of ultra-thin Al layers, which reduces the electron temperature, leading to a low space potential; i.e. low accelerating energy of ions in the plasma.