Spin orbit torque magnetoresistive random access memory containing composite spin hall effect layer including beta phase tungsten

Abstract

A spin orbit torque magnetoresistive random access memory (SOT MRAM) cell includes a magnetic tunnel junction that contains a free layer having two bi-stable magnetization directions, a reference magnetic layer having a fixed magnetization direction, and a tunnel barrier layer located between the free layer and the reference layer, and a nonmagnetic spin Hall effect layer. The spin Hall effect layer may include an alternating stack of beta phase tungsten layers and noble metal nonmagnetic dusting layers. Alternatively or in addition, a hafnium layer may be located between the nonmagnetic spin Hall effect layer and the free layer.

Description

FIELD[0001]The present disclosure relates generally to the field of magnetic storage elements, and particularly to spin orbit torque (SOT) magnetoresistive memory cells.BACKGROUND[0002]Magnetoresistive random access memory (MRAM) is a non-volatile random-access memory technology. Unlike conventional random access memory (RAM), data in MRAM devices are not stored as electric charge or current flows. Instead, data is stored by magnetic storage elements. MRAM devices include cells or elements having a magnetically hard layer (i.e., a “reference” layer) and a magnetically soft layer (i.e., the “free” layer). Writing to MRAM is performed by passing current through current leads that are formed on either side of each memory element in order to create a local induced magnetic field, which sets the direction of the soft layer magnetization. Significant problems arise when scaling these devices to high densities. Particularly, the currents required to generate sufficient field to switch the ...

AI Technical Summary

Benefits of technology

This patent describes a new type of memory called Spin Orbit Torque Magnetoresistive Random Access Memory (SOT MRAM). It includes a special layer called a tunnel barrier layer, which is made up of a stack of layers called beta phase tungsten layers and noble metal nonmagnetic dusting layers. This layer helps to control the movement of electrical current in the memory cell. The patent also mentions the use of a hafnium layer between the nonmagnetic spin Hall effect layer and the free layer, which may help to improve the functionality of the memory. Overall, this technology could improve the speed and reliability of MRAM memory cells.

Problems solved by technology

Significant problems arise when scaling these devices to high densities.

Particularly, the currents required to generate sufficient field to switch the free layer become prohibitively large, and disturbances to neighboring cells or elements can occur during writing, which in turn may cause a neighboring cell to be erroneously written.

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