Structure for optimizing writing performance of magnetic random access memory and preparation method thereof

Abstract

The invention discloses a structure for optimizing the writing performance of a magnetic random access memory. The structure comprises a writing accelerator, the writing accelerator is positioned on the lower side of a bottom electrode of the magnetic random access memory and the upper side of a bottom electrode through hole, and the writing accelerator is directly connected with the bottom electrode and the bottom electrode through hole. The invention further discloses a preparation method of the structure for optimizing the writing performance of the magnetic random access memory. The preparation method comprises the following steps: 1, providing a CMOS substrate with a polished surface and a metal connecting line Mx; 2, manufacturing a bottom electrode through hole in the flattened CMOSsubstrate, and grinding the bottom electrode through hole; 3, on the bottom electrode through hole, performing graphical definition and etching to manufacture writing accelerator metal, filling a writing accelerator dielectric medium, and grinding the writing accelerator dielectric medium by adopting chemical mechanical planarization; and 4, sequentially depositing a bottom electrode, a magnetictunnel junction multilayer film and a top electrode on the writing accelerator, manufacturing a magnetic tunnel junction storage unit, and finally manufacturing bit line connection on the top electrode.

Description

technical field [0001] The invention relates to the technical field of Magnetic Random Access Memory (MRAM), in particular to a structure for optimizing the writing performance of Magnetic Random Access Memory (MRAM) and a preparation method thereof. Background technique [0002] In recent years, MRAM using Magnetic Tunnel Junction (MTJ) is considered to be the future solid-state non-volatile memory, which has the characteristics of high-speed reading and writing, large capacity and low energy consumption. Ferromagnetic MTJ is usually a sandwich Structure, in which there is a magnetic free layer (Free Layer, FL), which can change the magnetization direction to record different data; the insulating tunnel barrier layer (Barrier Layer, BL) in the middle; the magnetic reference layer (Reference Layer, RL) is located On the other side of the tunnel barrier layer, its magnetization direction remains unchanged. Specifically, it can be the bottom pinning (Bottom Pinned) of the refe...

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Problems solved by technology

[0015] As mentioned above, STT-based spin transfer torque is currently the mainstream writing method for MRAM. However, it also has insurmountable speed and barrier reliability bottlenecks. The size of spin transfer torque is related to the free layer (FL) It is positively correlated with the magnetization vector product of the reference layer (RL). Before writing, the magnetization directions of the two ferromagnetic layers are almost collinear (parallel or antiparallel), mainly due to thermal fluctuations causing a small angle between them , so in the initial stage of writing, the spin transfer torque is relatively weak. As the magnetization switching process proceeds, the angle between the two magnetization vectors gradually increases, and the spin transfer torque is enhanced. At the beginning, the weak spin transfer The moment leads to an initial delay (Incubation Delay), which limits the writing speed. By increasing the writing current, the initial delay can be reduced, but at the same time it also increases the probability of potential barrier breakdown. The existence of the initial delay makes STT-MRAM currently It is also difficult to meet the performance requirements of cache (eg: SRAM)

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