Co/Ni Multilayers with Improved Out-of-Plane Anisotropy for Magnetic Device Applications

• US 20140217531A1
• Filed: 04/04/2014
• Published: 08/07/2014
• Est. Priority Date: 05/10/2011
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Headway Technologies Incorporated
• Inventors: Jan, Guenole, Tong, Ru-Ying, Wang, Yu-Jen
• Granted Patent: US 8,987,849 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: H01F 10/30 characterised by the composition of the intermediate layers , e.g. seed, buffer, template, diffusion preventing, cap layers H01F10/06 and H01F10/32 take precedence
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 41/307 insulating or semiconductive spacer
• CPC Class Codes: H01L 29/66007 Multistep manufacturing processes
• CPC Class Codes: H01L 29/66984 Devices using spin polarized carriers
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

A MTJ for a spintronic device is disclosed and includes a thin seed layer that enhances perpendicular magnetic anisotropy (PMA) in an overlying laminated layer with a (Co/X)_n or (CoX)_n composition where n is from 2 to 30, X is one of V, Rh, Ir, Os, Ru, Au, Cr, Mo, Cu, Ti, Re, Mg, or Si, and CoX is a disordered alloy. The seed layer is preferably NiCr, NiFeCr, Hf, or a composite thereof with a thickness from 10 to 100 Angstroms. Furthermore, a magnetic layer such as CoFeB may be formed between the laminated layer and a tunnel barrier layer to serve as a transitional layer between a (111) laminate and (100) MgO tunnel barrier. The laminated layer may be used as a reference layer, dipole layer, or free layer in a MTJ. Annealing between 300° C. and 400° C. may be used to further enhance PMA in the laminated layer.

Claims

1. A magnetic element, comprising:

(a) a seed layer comprising one or more of Hf, NiCr, and NiFeCr that enhances perpendicular magnetic anisotropy (PMA) in an overlying laminated layer; and

(b) a layer having intrinsic PMA and comprising pure Co or a laminated stack represented by (Fe/V)_n where n is the number of laminates in the stack, and the Co or (Fe/V)_n laminated stack contacts a top surface of the seed layer.

2. The magnetic element of claim 1 wherein the seed layer and Co layer or Fe/V)_n laminated stack are formed in a magnetic tunnel junction (MTJ) having a seed layer/reference layer/tunnel barrier/free layer configuration, the Co layer or (Fe/V)_n laminated stack is part of the reference layer.

3. The magnetic element of claim 2 wherein the reference layer further comprises a magnetic layer formed between the Co layer or (Fe/V)_n laminated stack and the tunnel barrier to increase a magnetoresistive (MR) ratio in the MTJ, the magnetic layer interfaces with the tunnel barrier and has PMA with a magnetic moment in a same direction as the PMA in the Co layer or (Fe/V)_n laminated stack.

4. The magnetic element of claim 1 wherein the seed layer and Co layer or (Fe/V)_n laminated stack are formed in a MTJ having a reference layer/tunnel barrier/free layer/spacer/seed layer/dipole layer configuration and the Co layer or (Fe/V)_n laminated stack is the dipole layer.

5. The magnetic element of claim 1 wherein the seed layer and the Co layer or (Fe/V)_n laminated stack are formed in a MTJ having a seed layer/composite free layer/tunnel barrier/reference layer configuration and the Co layer or (Fe/V)_n laminated stack is part of the composite free layer.

6. The magnetic element of claim 5 wherein the composite free layer further comprises a magnetic layer formed between the Co layer or (Fe/V)_n laminated stack and the tunnel barrier to increase a magnetoresistive (MR) ratio in the MTJ, the magnetic layer interfaces with the tunnel barrier and has PMA with a magnetic moment in a same direction as the PMA in the Co layer or (Fe/V)_n laminated stack.