Passivation of Magnetic Tunnel Junction Stacks with Polydimethylsiloxane Thin Films

NMagnetoresistive random access memory (MRAM) has been extensively investigated in recent years owing to its potential importance in data storage systems. Among those, spin transfer torque MRAM (STT-MRAM) is considered as a next generation universal memory because it can operate in sub-nanometer scale. Though a conventional etching method to fabricate magnetic stacks, which constitutes STT-MRAM, with high degree of integration is a plasma-based one, it has several inherent limitations in terms of undesirable byproducts. In this study, to circumvent such drawbacks, magnetic stacks on Si wafer were successfully passivated by polydimethylsiloxane films via oxygen plasma treatment. Energy-dispersive X-ray spectroscopic result and transmission electron microscopic analysis were used for determination of stacking structure of magnetic stacks. According to scanning electron microscope measurements, the uppermost magnetic stacks could be successfully protected by PDMS films. This process is potentially applicable to the efficient wet etching of magnetic stacks in STT-MRAM.