Lequeux S, Perrissin N, Grégoire G, Tillie L, Chavent A, Strelkov N, Vila L, Buda-Prejbeanu L D, Auffret S, Sousa R C, Prejbeanu I L, Di Russo E, Gautier E, Conlan A P, Cooper D, Dieny B
Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-SPINTEC, 38000 Grenoble, France.
Nanoscale. 2020 Mar 21;12(11):6378-6384. doi: 10.1039/c9nr10366j. Epub 2020 Mar 5.
The concept of Perpendicular Shape Anisotropy STT-MRAM (PSA-STT-MRAM) has been recently proposed as a solution to enable the downsize scalability of STT-MRAM devices beyond the sub-20 nm technology node. For conventional p-STT-MRAM devices with sub-20 nm diameters, the perpendicular anisotropy arising from the MgO/CoFeB interface becomes too weak to ensure thermal stability of the storage layer. In addition, this interfacial anisotropy rapidly decreases with increasing temperature which constitutes a drawback in applications with a large range of operating temperatures. Here, we show that by using a PSA based storage layer, the source of anisotropy is much more robust against thermal fluctuations than the interfacial anisotropy, which allows considerable reduction of the temperature dependence of the coercivity. From a practical point of view, this is very interesting for applications having to operate on a wide range of temperatures (e.g. automotive -40 °C/+150 °C).
垂直形状各向异性自旋转移力矩磁性随机存取存储器（PSA-STT-MRAM）的概念最近被提出，作为一种解决方案，以实现STT-MRAM器件在低于20纳米技术节点下的尺寸缩减可扩展性。对于直径小于20纳米的传统p-STT-MRAM器件，MgO/CoFeB界面产生的垂直各向异性变得太弱，无法确保存储层的热稳定性。此外，这种界面各向异性会随着温度升高而迅速降低，这在工作温度范围较大的应用中构成了一个缺点。在此，我们表明，通过使用基于PSA的存储层，各向异性源对热波动的抗性比界面各向异性更强，这使得矫顽力的温度依赖性能够大幅降低。从实际角度来看，这对于必须在很宽温度范围（如汽车应用中的-40°C/+150°C）下工作的应用非常有意义。
