Lee Seung-Eun, Baek Jong-Ung, Park Jea-Gun
MRAM Center, Department of Electronics and Computer Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
MRAM Center Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
Sci Rep. 2017 Sep 19;7(1):11907. doi: 10.1038/s41598-017-10967-x.
For double MgO-based p-MTJ spin-valves with a top CoFeB free layer ex-situ annealed at 400 °C, the insertion of a nanoscale-thickness Fe diffusion barrier between the tungsten (W) capping layer and MgO capping layer improved the face-centered-cubic (f.c.c.) crystallinity of both the MgO capping layer and tunneling barrier by dramatically reducing diffusion of W atoms from the W capping layer into the MgO capping layer and tunneling barrier, thereby enhancing the TMR ratio and thermal stability (Δ). In particular, the TMR ratio was extremely sensitive to the thickness of the Fe barrier; it peaked (154%) at about 0.3 nm (the thickness of only two atomic Fe layers). The effect of the diffusion barrier originated from interface strain.
对于顶部CoFeB自由层在400 °C进行异位退火的双氧化镁基p型磁性隧道结（p-MTJ）自旋阀，在钨（W）覆盖层和氧化镁覆盖层之间插入纳米级厚度的铁扩散阻挡层，通过显著减少W原子从W覆盖层扩散到氧化镁覆盖层和隧道势垒中，改善了氧化镁覆盖层和隧道势垒的面心立方（f.c.c.）结晶度，从而提高了隧道磁电阻（TMR）比率和热稳定性（Δ）。特别是，TMR比率对铁阻挡层的厚度极为敏感；在约0.3 nm（仅为两层原子厚度的铁）时达到峰值（154%）。扩散阻挡层的作用源于界面应变。
