Method of making a high thermal stability reference structure with out-of-plane anisotropy for magnetic device applications

摘要

Enhanced Hc and Hk in addition to higher thermal stability to 400° C. are achieved in magnetic devices by adding dusting layers on top and bottom surfaces of a spacer in a synthetic antiferromagnetic (SAF) structure to give a RL1/DL1/spacer/DL2/RL2 reference layer configuration where RL1 and RL2 layers exhibit perpendicular magnetic anisotropy (PMA), the spacer induces antiferromagnetic coupling between RL1 and RL2, and DL1 and DL2 are dusting layers that enhance PMA. Dusting layers are deposited at room temperature to 400° C. RL1 and RL2 layers are selected from laminates such as (Ni/Co)n, L10 alloys, or rare earth-transition metal alloys. The reference layer may be incorporated in STT-MRAM memory elements or in spintronic devices including a spin transfer oscillator. A transition layer such as CoFeB/Co may be formed between the RL2 reference layer and tunnel barrier layer in a bottom spin valve design.

主权项

1. A method of forming a magnetic device having high perpendicular magnetic anisotropy (PMA) comprising:
(a) depositing a seed layer on a substrate; (b) forming a reference layer on the seed layer wherein the reference layer has a RL1/DL1/spacer/DL2/RL2 configuration in which the RL1 and RL2 layers exhibit perpendicular magnetic anisotropy, the spacer induces RKKY (antiferromagnetic coupling) between the RL1 and RL2 layers, and DL1 and DL2 are dusting layers which enhance the RKKY coupling between the RL1 and RL2 layers; (c) forming a CoFeB/Co transitional layer on the RL2 layer; (d) forming a non-magnetic spacer on the reference layer; (e) depositing a free layer on the non-magnetic spacer; (f) depositing a cap layer on the free layer to give a multilayer stack with a seed/reference layer/non-magnetic spacer/free layer/cap layer configuration; and (g) annealing the multilayer stack.