High retention storage layer using ultra-low RA MgO process in perpendicular magnetic tunnel junctions for MRAM devices

Patent metadata

Field	Value
Publication number	US-11264557-B2
Application number	US-201715859458-A
Country	US
Kind code	B2
Filing date	Dec 30, 2017
Priority date	Dec 30, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A method for manufacturing a magnetic random access memory element having increased retention and low resistance area product (RA). A MgO layer is deposited to contact a magnetic free layer of the memory element. The MgO layer is deposited in a sputter deposition chamber using a DC power and a Mg target to deposit Mg. The deposition of Mg is periodically stopped and oxygen introduced into the deposition chamber. This process is repeated a desired number of times, resulting in a multi-layer structure. The resulting MgO layer provides excellent interfacial perpendicular magnetic anisotropy to the magnetic free layer while also having a low RA.

First claim

What is claimed is:

1. A method for manufacturing a magnetic randomaccess memory element, the method comprising:
forming a magnetic tunnel junction (MTJ) that includes a magnetic reference layer, a magnetic free layer over the magnetic reference layer in an element height direction, and a thin, non-magnetic, electrically-insulating magnetic barrier layer positioned between the reference layer and the free layer;
forming a capping layer comprising multiple homogeneous layers of MgO, to cover the magnetic tunnel junction, the multiple layers of MgO being formed through alternating DC sputtering and oxidation; and
controlling one or more of the following parameters to maintain a thickness of the capping layer over 1 nanometer and an area resistance of less than 1.5Ωμm 2 : deposition time; oxygen flowrate; Mg thickness; and number of multi-layers.

2. The method as in claim 1 , wherein the oxidation comprises introducing oxygen into a sputter deposition chamber.

3. The method as in claim 1 , wherein the DC sputtering comprises depositing Mg from a Mg target in a deposition chamber using DC power.

4. The method as in claim 1 wherein the MgO is deposited after the magnetic free layer.

5. The method as in claim 1 , further comprising depositing a non-magnetic barrier layer.

6. The method as in claim 5 , wherein the non-magnetic barrier layer comprises MgO.

7. The method as in claim 5 , wherein the non-magnetic barrier layer is deposited before the magnetic free layer and the MgO layer is deposited after the magnetic free layer.

Assignees

• Integrated Silicon Solution Cayman Inc

Inventors

• KARDASZ Bartlomiej Adam
• Vasquez Jorge
• Pinarbasi Mustafa
• Wolf Georg

Classifications

• H01F10/3286 Primary

  Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy · CPC title

• H01F10/3272

  by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets · CPC title

• G11C11/161

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title

• H01F41/307

  insulating or semiconductive spacer · CPC title

• H01F10/329

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title