Mtj structure having vertical magnetic anisotropy

Patent metadata

Field	Value
Publication number	US-2016359102-A1
Application number	US-201515117905-A
Country	US
Kind code	A1
Filing date	Jan 29, 2015
Priority date	Feb 11, 2014
Publication date	Dec 8, 2016
Grant date	—

Abstract

Provided is a magnetic tunneling junction (MTJ) structure having (PMA). The MJT structure includes a seed layer including a tungsten-based substance, a first ferromagnetic layer that is positioned on the seed layer, includes a boron-based ferromagnetic material and has PMA, a tunneling barrier layer positioned on the first ferromagnetic layer, and a second ferromagnetic layer that is positioned on the tunneling barrier layer and has PMA, wherein the seed layer has a thickness in a range of 1 nm to 10 nm. Accordingly, by using the tungsten-based substance as a seed layer substance, the MTJ structure may be provided in which crystallinity of the first ferromagnetic layer is maintained even at a high temperature in a range of 350° C. to 400° C., a problem of the PMA reduction is prevented, and therefore, thermal stability is improved.

First claim

1 . A magnetic tunneling junction (MTJ) structure having perpendicular magnetic anisotropy (PMA), comprising:
a seed layer including a tungsten-based material; a first ferromagnetic layer that is positioned on the seed layer, includes a boron-based ferromagnetic material, and has PMA; a tunneling barrier layer positioned on the first ferromagnetic layer; and a second ferromagnetic layer that is positioned on the tunneling barrier layer and has PMA, wherein the seed layer has a thickness in a range of 1 nm to 10 nm.

2 . The MTJ structure of claim 1 , wherein the tungsten-based material includes W or WB.

3 . The MTJ structure of claim 1 , wherein the boron-based ferromagnetic material includes CoFeB.

4 . The MTJ structure of claim 1 , wherein the tunneling barrier layer includes at least one selected from the group consisting of MgO, Al 2 O 3 , HfO 2 , TiO 2 , Y 2 O 3 , and Yb 2 O 3 .

5 . The MTJ structure of claim 1 , wherein the first ferromagnetic layer maintains PMA even after a heat treatment is performed at a temperature in a range of 350° C. to 400° C.

6 . The MTJ structure of claim 1 , wherein the tungsten-based substance of the seed layer has a beta phase or a mixed phase in which alpha and beta phases are mixed after a heat treatment is performed at a temperature in a range of 350° C. to 400° C.

7 . A magnetic device comprising:
a plurality of digit lines; a plurality bit lines crossing upper portions of the digit lines; and the magnetic tunneling junction (MTJ) structure of any one of claims 1 to 6 that is interposed between the digit lines and the bit lines.

Assignees

• Industry-Univ Coop Found Hanyang Univ

Inventors

• Hong Jinpyo
• Lee Jabin

Classifications

• H01F10/3286

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

• H10B61/00

  Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices · CPC title

• H10N50/01

  Manufacture or treatment · CPC title

• H10N50/80

  Constructional details · CPC title

• G11C11/161 Primary

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