In-Situ Formed Capping Layer in MTJ Devices

• US 20100193891A1
• Filed: 04/08/2010
• Published: 08/05/2010
• Est. Priority Date: 02/18/2008
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Tsai, Chia-Shiung, Wang, Yu-Jen, Wang, Yung-Hung, Juang, Mark
• Granted Patent: US 8,143,683 B2
• Time in Patent Office: Days
• US Class Current: 257/421
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1657 Word-line or row circuits
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A method of forming an integrated circuit includes forming magnetic tunnel junction (MTJ) layers; etching the MTJ layers to form a MTJ cell; and forming a dielectric capping layer on sidewalls of the MTJ cell, wherein the step of forming the dielectric capping layer is in-situ performed with the step of etching the MTJ layers.

Claims

1. A device comprising:

a magnetic tunnel junction (MTJ) cell comprising;

a pinning layer;

a tunnel barrier layer; and

a free layer; and

a dielectric capping layer on sidewalls of the MTJ cell comprising sidewalls of the pinning layer, the tunnel barrier layer, and the free layer, wherein the dielectric capping layer has a non-neutral stress.

2. The device of claim 1, wherein an internal stress of the MTJ cell is no greater than about 1 MPa.

3. The device of claim 1, wherein the non-neutral stress in the dielectric capping layer has a magnitude less than about 3 GPa.

4. The device of claim 1 further comprising a top electrode over the MTJ cell, wherein a top edge of the dielectric capping layer is lower than a top surface of the top electrode, and higher than a bottom surface of the top electrode.

5. The device of claim 1, wherein the dielectric capping layer comprises materials selected the group consisting essentially of nitrogen-containing compounds and carbon-containing compounds.

6. The device of claim 1, wherein the dielectric capping layer is a composite layer comprising more than one layer formed of different materials.

7. The device of claim 1, wherein the dielectric capping layer has a thickness no greater than about two times a width of the MTJ cell.

8. The device of claim 1, wherein edges of the MTJ cell are substantially free from oxidation.

9. The device of claim 1, wherein the dielectric capping layer further comprises a portion directly over and vertically aligned to the tunnel barrier layer.

10. The device of claim 1 further comprising a bottom electrode underlying and electrically coupled to the MTJ cell, wherein the dielectric capping layer further comprises a portion directly over and contacting the bottom electrode.

11. A device comprising:

a magnetic tunnel junction (MTJ) cell comprising;

a pinning layer;

a tunnel barrier layer; and

a free layer;

a top electrode overlying the MTJ cell; and

a dielectric capping layer on sidewalls of the MTJ cell comprising sidewalls of the pinning layer, the tunnel barrier layer, and the free layer, wherein the sidewalls of the MTJ cell are substantially un-oxidized.

12. The device of claim 11, wherein the dielectric capping layer is a composite layer comprising more than one layer formed of different materials.

13. The device of claim 11, wherein the dielectric capping layer has a non-neutral stress.

14. The device of claim 13, wherein the non-neutral stress in the dielectric capping layer has a magnitude less than about 3 GPa.

15. A device comprising:

a bottom electrode;

a magnetic tunnel junction (MTJ) cell over the bottom electrode;

a top electrode over the MTJ cell; and

a dielectric capping layer comprising;

a top portion directly over the top electrode;

a sidewall portion on a sidewall of the MTJ cell; and

a bottom portion directly over the bottom electrode and vertically misaligned with the top portion and the sidewall portion, wherein the top portion, the sidewall portion, and the bottom portion form a continuous region.

16. The device of claim 15 further comprising;

a pinning layer;

a tunnel barrier layer; and

a free layer, wherein the pinning layer, the tunnel barrier layer, the free layer, and the top electrode are substantially co-terminus with respective edges vertically aligned to each other.

17. The device of claim 15, wherein a bottom surface of the top portion contacts a top surface of the top electrode, and a bottom surface of the bottom portion contacts a top surface of the bottom electrode.

18. The device of claim 15, wherein the dielectric capping layer has a thickness no greater than about two times a width of the MTJ cell.

19. The device of claim 15, wherein edges of the MTJ cell are substantially free from oxidation.

20. The device of claim 15, wherein an internal stress of the MTJ cell is no greater than about 1 MPa.