Perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy

An anisotropic, enhancement-layer technology used in the field of spin-transfer torque magnetic random access memory

Inactive Publication Date: 2016-10-05
HITACHI GLOBAL STORAGE TECH NETHERLANDS BV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this type of structure requires precise growth of the MgO layer while preventing Ta diffusion into the MgO layer during the annealing process.

Method used

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  • Perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy
  • Perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy
  • Perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy

Examples

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Embodiment Construction

[0011] figure 2 is a cross-sectional view of layers constituting an MTJ according to an embodiment of the present invention. The MTJ is largely identical to the MTJ described in the previously cited Sato et al. article, except for the CoFeB alloy reinforcement layer between the MgO capping layer and the Ta capping layer.

[0012] MTJ 100 includes: a substrate, which may be formed from any suitable material, such as semiconductor-grade silicon, silicon oxide, or titanium aluminum carbide; a magnetization 103; a ferromagnetic free layer 104 having a magnetization 105 capable of switching between magnetizations parallel and antiparallel to the reference layer; and an insulating oxide barrier layer 106, typically MgO, at the reference between layer 102 and free layer 104 .

[0013] In this example, reference layer 102 is the AP2 layer portion of an antiparallel (AP) pinning structure. AP pinning structures are well known and include a first (AP1) ferromagnetic layer and a seco...

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Abstract

A perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy. A magnetic tunnel junction (MTJ) for use in a magnetoresistive random access memory (MRAM) has a CoFeB alloy free layer located between the MgO tunnel barrier layer and an upper MgO capping layer, and a CoFeB alloy enhancement layer between the MgO capping layer and a Ta cap. The CoFeB alloy free layer has high Fe content to induce perpendicular magnetic anisotropy (PMA) at the interfaces with the MgO layers. To avoid creating unnecessary PMA in the enhancement layer due to its interface with the MgO capping layer, the enhancement layer has low Fe content. After all of the layers have been deposited on the substrate, the structure is annealed to crystallize the MgO. The CoFeB alloy enhancement layer inhibits diffusion of Ta from the Ta cap layer into the MgO capping layer and creates good crystallinity of the MgO by providing CoFeB at the MgO interface.

Description

technical field [0001] The present invention relates generally to spin-transfer torque magnetic random access memory (SST-MRAM) with perpendicular magnetic anisotropy (PMA), and more particularly to PMA STT memory elements with double MgO interfaces. Background technique [0002] Spin-transfer torque magnetic random access memory (SST-MRAM) comprising a magnetic tunnel junction (MTJ) with perpendicular magnetic anisotropy (PMA) is a strong candidate for future non-volatile memory. An MTJ storage element has a free ferromagnetic layer (also called recording layer or storage layer) and a reference ferromagnetic layer (also called pinned layer) separated by a thin insulating tunnel barrier (usually MgO). The free layer and the reference layer have PMAs, magnetized perpendicular to the surface of the layers. The magnetization of the reference layer is pinned, but switching the current through the MTJ causes the magnetization of the free layer to change at a value corresponding ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L43/08H01L43/10H01L27/22
CPCH10B61/00H10N50/85H10N50/10G11C11/161H01F10/32H10B61/22
Inventor 吴相文高峥朱克强
Owner HITACHI GLOBAL STORAGE TECH NETHERLANDS BV
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