“…14,15) However, recently, owing to the corrosion of the etched MTJ material surface and the low etch selectivity over mask materials, the etching of MTJ materials using noncorrosive gases such as CO/NH 3 , CH 3 OH, and CH 4 has been investigated by many research groups. [16][17][18][19][20][21][22][23][24][25] When noncorrosive gases are used in the etching of MTJ materials, owing to the low vapor pressures of compounds formed between the MTJ materials and the noncorrosive etching gases, the problems such as low etch rates of MTJ materials, and low etch selectivity over mask materials, low etch anisotropy still remain even though the problems related to halogen gases such as corrosion can be eliminated.…”