Gradient protection layer in MTJ manufacturing

Patent metadata

Field	Value
Publication number	US-11411176-B2
Application number	US-202017120613-A
Country	US
Kind code	B2
Filing date	Dec 14, 2020
Priority date	Oct 25, 2018
Publication date	Aug 9, 2022
Grant date	Aug 9, 2022

Abstract

A method includes forming Magnetic Tunnel Junction (MTJ) stack layers, which includes depositing a bottom electrode layer; depositing a bottom magnetic electrode layer over the bottom electrode layer; depositing a tunnel barrier layer over the bottom magnetic electrode layer; depositing a top magnetic electrode layer over the tunnel barrier layer; and depositing a top electrode layer over the top magnetic electrode layer. The method further includes patterning the MTJ stack layers to form a MTJ; and performing a passivation process on a sidewall of the MTJ to form a protection layer. The passivation process includes reacting sidewall surface portions of the MTJ with a process gas comprising elements selected from the group consisting of oxygen, nitrogen, carbon, and combinations thereof.

First claim

What is claimed is:

1. A device comprising:
a Magnetic Tunnel Junction (MTJ) stack comprising:
a bottom electrode;
a bottom magnetic electrode over the bottom electrode;
a tunnel barrier over the bottom magnetic electrode;
a top magnetic electrode over the tunnel barrier; and
a top electrode over the top magnetic electrode;

a dielectric protection layer on a sidewall of the MTJ, wherein the dielectric protection layer comprises:
a first portion on a sidewall of the top magnetic electrode, wherein the first portion comprises first materials of the top magnetic electrode and a first additional element;
a second portion on a sidewall of the barrier tunnel, wherein the second portion comprises second materials of the barrier tunnel and a second additional element; and
a third portion on a sidewall of a top portion of the bottom magnetic electrode, wherein the third portion comprises third materials of the bottom magnetic electrode and a third additional element.

2. The device of claim 1 , wherein the third portion of the dielectric protection layer further extends to a level lower than a bottom surface of the bottom magnetic electrode, wherein the third portion has a thickness smaller than thicknesses of the first portion and the second portion.

3. The device of claim 2 , wherein the dielectric protection layer further comprises a fourth portion on a sidewall of the bottom electrode, wherein the fourth portion has a thickness smaller than the thickness of the third portion.

4. The device of claim 1 , wherein the dielectric protection layer extends on, and forms a horizontal interface with, a top surface of the top electrode.

5. The device of claim 4 further comprising a conductive feature over and contacting the top electrode, wherein the conductive feature penetrates through the dielectric protection layer.

6. The device of claim 1 , wherein the first additional element and the second additional element are a same element selected from oxygen, carbon, and nitrogen, and combinations thereof.

7. The device of claim 1 , wherein the first additional element and the second additional element are different elements selected from oxygen, carbon, and nitrogen.

8. The device of claim 1 , wherein the third portion of the dielectric protection layer extends to a bottom surface of the bottom electrode.

9. The device of claim 1 , wherein the dielectric protection layer has a bottom higher than a bottom surface of the bottom electrode.

10. A device comprising:
a bottom electrode;
a top electrode over the bottom electrode, wherein the top electrode comprises a first material;
a Magnetic Tunnel Junction (MTJ) between the bottom electrode and the top electrode, the MTJ comprising:
a bottom magnetic electrode over the bottom electrode;
a tunnel barrier over the bottom magnetic electrode; and
a top magnetic electrode over the tunnel barrier; and

a first protection layer on a surface of the MTJ, wherein the first protection layer comprises a compound of a material of the MTJ and a first element, wherein the first element is selected from the group consisting of oxygen, nitrogen, carbon, and combinations thereof, and wherein the first protection layer comprises an inner surface contacting the MTJ, and an outer surface opposing to the inner surface, and wherein both of the material of the MTJ and the first element extend from the inner surface to the outer surface.

11. The device of claim 10 , wherein the first protection layer contacts sidewalls of the top magnetic electrode, the tunnel barrier, and a top portion of the bottom magnetic electrode.

12. The device of claim 10 , wherein the first protection layer has a bottom lower than the tunnel barrier, and higher than a bottom surface of the bottom magnetic electrode.

13. The device of claim 10 further comprising a second protection layer on the first protection layer, wherein the second protection layer comprises the material of the MTJ and a second element different from the first element.

14. The device of claim 13 , wherein the second protection layer extends lower than the first protection layer.

15. The device of claim 13 , wherein the second protection layer extends lower than a bottom surface of the bottom magnetic electrode.

16. A device comprising:
a Magnetic Tunnel Junction (MTJ) comprising:
a bottom magnetic electrode;
a tunnel barrier over the bottom magnetic electrode; and
a top magnetic electrode over the tunnel barrier; and

a protection layer extending on a sidewall of the MTJ, wherein the protection layer comprises a first portion contacting a sidewall of the top magnetic electrode, and the first portion comprises a first compound material of:
a doping element selected from the group consisting of oxygen, nitrogen, carbon, and combinations thereof; and
all elements of the top magnetic electrode, wherein both of the doping element and the all elements of the top magnetic electrode are distributed throughout the first portion.

17. The device of claim 16 , wherein the protection layer further comprises a second portion contacting a sidewall of a lower portion of the bottom magnetic electrode, wherein the second portion is thinner than the first portion.

18. The device of claim 16 , wherein the protection layer further comprises a third portion contacting a sidewall of the tunnel barrier, wherein the third portion further comprises a second compound material of the doping element and all elements of the tunnel barrier.

19. The device of claim 16 , wherein the protection layer has an upper portion having a first thickness, and a lower portion having a second thickness smaller than the first thickness.

20. The device of claim 16 further comprising a bottom electrode and a top electrode over the bottom electrode, wherein the MTJ is between the bottom electrode and the top electrode, and wherein the protection layer extends to a level between a top surface and a bottom surface of the bottom electrode.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Peng Tai-Yen
• Chen Yu-Shu
• Yang Sin-Yi
• Wang Chen-Jung
• Huang Chien Chung
• Lin Han-Ting
• Shieh Jyu-Horng
• Fu Qiang

Classifications

• H10B61/00

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

• H01L43/02

  Electricity · mapped topic

• H01L43/12 Primary

  Electricity · mapped topic

• H10N50/01 Primary

  Manufacture or treatment · CPC title

• H10N50/85

  Materials of the active region · CPC title