Evolution of Electrical Properties of Magnetic Tunnel Junction through Successive Dielectric Breakdowns

Degradation of magnetic tunnel junctions with thin AlOxbarrier

“…In this study, however, much smaller MTJs have been used, and hence we believe that the observed degradation process is an intrinsic phenomenon. Our experimental results suggest that in the early stage of the degradation process the spin-dependent stressinduced leakage current could be observed, unlike with the previous observations for post-breakdown currents [10] and the leakage through extrinsic weak spots [11]. Then, however, the spin-independent component increases with stress time probably due to, e.g., the trap creation [14], which would be a precursor for the final destructive breakdown.…”

“…It has been previously reported that the excess leakage current component through the post-breakdown MTJ is independent of magnetic polarization of the electrodes, and thus its current conduction channel is considered to be unable to support the spin-polarized current [10]. On the other hand, the gradual decrease of TMR with stress time has been observed in MTJs with very large junction area of 200 mm 2 [11].…”

“…Because the thickness of the insulting films is very thin (1.0-2.0 nm), their degradation and breakdown phenomena are serious concerns for the long-term reliability of MRAMs. Although the degradation of such thin AlO x films has been studied by many groups [4][5][6][7][8][9][10][11], its mechanism has not been clarified yet.…”

Investigation of Interface Formed between Top Electrodes and Epitaxial NiO Films for Bipolar Resistance Switching

“…6(b)] results from the irreversible breakdown of the insulating interfacial oxide after electroforming; this phenomenon is similar to the dielectric breakdown of a magnetic tunnel junction and results in the formation of a metallic Al/epi-NiO contact. 24) As shown in Fig. 3(c), any interface layer is not formed at the CRO/epi-NiO interface.…”

Stress-Induced Leakage Current in Magnetic Tunnel Junctions with Thin AlOx Barrier

“…Because the thickness of the insulting films is very thin (1.0-2.0 nm), their degradation and breakdown phenomena are serious concerns for the long-term reliability of MRAMs. Although the degradation of such thin AlO x films has been studied by many groups (5)(6)(7)(8)(9)(10)(11)(12), its mechanism has not been fully clarified yet.…”