Multilayer structure with vertical magnetic anisotropy at interface and magnetic random access memory

Abstract

The embodiment of the invention provides a multilayer structure with vertical magnetic anisotropy at the interface and a magnetic random access memory. The whole multilayer structure is annealed at atemperature of above 500 DEG C after growth, which ensures good thermal stability. In the annealing process, the crystallization of chromium metal in a buffer layer promotes the formation of the crystal orientation of the whole structure. At the same time, charge trapping is formed between a ferromagnetic layer and a first oxide barrier layer due to annealing, which enhances the vertical magneticanisotropy at the interface formed by interlayer coupling between the two layers. Because the layers are at a nanometer scale, the obtained multilayer structure also has the advantage of small size. The magnetic tunnel junction in the magnetic random access memory provided by the embodiment of the invention is a multilayer structure with vertical magnetic anisotropy at the interface, which can increase the storage density of the magnetic random access memory.

Description

technical field [0001] The invention relates to the technical field of magnetic random access memory, and more specifically, relates to a multi-film layer structure with interface perpendicular magnetic anisotropy and magnetic random access memory. Background technique [0002] At present, magnetic random access memory (MRAM) and magnetic logic have the advantages of non-volatility, fast read and write speed, low power consumption and unlimited erasing and rewriting, and have attracted extensive attention from industry and academia. [0003] The core device of magnetic random access memory and magnetic logic is the magnetic tunnel junction (Magnetic Tunnel Junction, MTJ). The basic structure of the magnetic tunnel junction is a three-layer thin film structure, which specifically includes: a reference layer, a barrier layer and a free layer. Wherein, both the reference layer and the free layer are ferromagnetic materials. When the magnetization directions of the two layers a...

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Problems solved by technology

[0006] However, the structure of Ta(Mo,Hf) / CoFeB / MgO / CoFeB / Ta(Mo,Hf) still has obvious shortcomings

First, the interface perpendicular magnetic anisotropy of the structure is weak, resulting in low thermal stability of the structure; secondly, because of the weak interface perpendicular magnetic anisotropy, in order to make the easy axis of magnetization perpendicular to the interface direction, it is necessary A thinner CoFeB layer reduces the demagnetization field, which leads to a larger magnetic damping coefficient and thus a larger critical switching current for the structure

Finally, the thermal stability will decrease when the cross-sectional size is reduced. In order to maintain sufficient thermal stability, the size of the structure will be increased, which will lead to a lower storage density of the MRAM using this structure.

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