Methods for forming structures with desired crystallinity for mram applications

Patent metadata

Field	Value
Publication number	US-2022013716-A1
Application number	US-202117486649-A
Country	US
Kind code	A1
Filing date	Sep 27, 2021
Priority date	Jul 14, 2015
Publication date	Jan 13, 2022
Grant date	—

Abstract

Embodiments of the disclosure provide methods and apparatus for fabricating magnetic tunnel junction (MTJ) structures on a substrate in for spin-transfer-torque magnetoresistive random access memory (STT-MRAM) applications. In one example, a film stack utilized to form a magnetic tunnel junction structure on a substrate includes a pinned layer disposed on a substrate, wherein the pinned layer comprises multiple layers including at least one or more of a Co containing layer, Pt containing layer, Ta containing layer, an Ru containing layer, an optional structure decoupling layer disposed on the pinned magnetic layer, a magnetic reference layer disposed on the optional structure decoupling layer, a tunneling barrier layer disposed on the magnetic reference layer, a magnetic storage layer disposed on the tunneling barrier layer, and a capping layer disposed on the magnetic storage layer.

First claim

What is claimed is:

1 . A method of forming a magnetic tunnel junction structure on a substrate, comprising:
patterning a film stack having a tunneling barrier layer disposed between a magnetic reference layer and a magnetic storage layer disposed on a substrate to remove a portion of the film stack from the substrate until an upper surface of the substrate is exposed; forming a conformal sidewall passivation layer on sidewalls of the patterned film stack wherein the sidewall passivation layer is in direct contact with a top surface of the substrate, wherein the sidewall passivation layer having a vertical portion continuously coplanar along a vertical axis normal to a major axis of the substrate and a horizontal portion in direct contact with the substrate; forming an insulation layer in direct contact with the sidewall passivation layer, and subsequently performing a thermal annealing process to the film stack wherein the insulation layer extends from a top surface of the sidewall passivation layer to the horizontal portion of the sidewall passivation layer.

2 . The method of claim 1 , wherein performing the thermal annealing process further comprises:
maintaining the substrate temperature at between about 250 degrees Celsius and about 550 degree Celsius.

3 . The method of claim 1 , wherein the film stack further comprises a capping layer disposed on the magnetic storage layer.

4 . The method of claim 1 , wherein the film stack further comprises a pinning layer disposed between the substrate and the magnetic reference layer.

5 . The method of claim 1 , wherein the film stack further comprises a structure decoupling layer disposed between the pinning layer and the magnetic reference layer.

6 . A method of forming a magnetic tunnel junction structure on a substrate, comprising:
patterning a film stack having a tunneling barrier layer disposed between a magnetic reference layer and a magnetic storage layer disposed on a substrate to remove a portion of the film stack from the substrate until an upper surface of the substrate is exposed; forming a sidewall passivation layer on sidewalls of the patterned film stack; and subsequently performing a thermal annealing process to the film stack.

7 . The method of claim 6 , wherein performing the thermal annealing process further comprises:
maintaining the substrate temperature at between about 250 degrees Celsius and about 550 degree Celsius.

8 . The method of claim 6 , wherein the film stack further comprises a capping layer disposed on the magnetic storage layer.

9 . The method of claim 6 , wherein the film stack further comprises a pinning layer disposed between the substrate and the magnetic reference layer.

10 . The method of claim 9 , wherein the film stack further comprises a structure decoupling layer disposed between the pinning layer and the magnetic reference layer.

11 . The method of claim 6 , wherein the magnetic reference layer and the magnetic storage layer are fabricated from metal alloy with boron dopants.

12 . The method of claim 6 , wherein forming the sidewall passivation layer further comprises:
forming a dielectric layer on the sidewalls of the patterned film stack by a CVD deposition process.

13 . The method of claim 12 , wherein the dielectric layer of the sidewall passivation layer is at least one of SiN, SiCN, SiO 2 , SiON, SiC, amorphous carbon, amorphous carbon, SiOC, aluminum oxide (Al 2 O 3 ) or aluminum nitride (AlN).

14 . The method of claim 6 , wherein the sidewall passivation layer is formed from by-products generated during the pattering of the film stack.

15 . The method of claim 6 , wherein forming the sidewall passivation layer further comprises:
forming an insulation layer on the substrate where the portion of the film stack is removed.

16 . The method of claim 6 , wherein performing the thermal annealing process further comprises:
altering crystalline structures of the magnetic reference layer and a magnetic storage layer.

17 . The method of claim 6 , wherein performing the thermal annealing process further comprises:
driving dopants in the magnetic reference layer and the magnetic storage layer laterally outward to the sidewall passivation layer.

18 . The method of claim 17 , wherein the dopant reacts with the sidewall passivation layer to form a dopant compound.

19 . The method of claim 15 , wherein the thermal annealing process is performed after a back end process is performed in the insulation layer or right after the insulation layer is formed on the substrate.

20 . A method of forming a magnetic tunnel junction structure on a substrate, comprising:
patterning a film stack having a tunneling barrier layer disposed between a magnetic reference layer and a magnetic storage layer disposed on a substrate to remove a portion of the film stack from the substrate until an upper surface of the substrate is exposed; forming a sidewall passivation layer on sidewalls of the patterned film stack; forming an insulation layer in contact with the sidewall passivation layer on the substrate; and driving dopants from the magnetic reference layer and the magnetic storage layer laterally outward into the sidewall passivation layer by a thermal treatment process.

Assignees

• Applied Materials Inc

Inventors

• Xue Lin
• Ahn Jaesoo
• Pakala Mahendra
• Ching Chi Hong
• Wang Rongjun

Classifications

• G11C11/16

  using elements in which the storage effect is based on magnetic spin effect · CPC title

• H10N50/01 Primary

  Manufacture or treatment · CPC title

• H10N50/80 Primary

  Constructional details · CPC title

• H10B61/00

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

• H10N50/85

  Materials of the active region · CPC title