摘要:
An all (111) MTJ stack is disclosed in which there are no transitions between different crystalline orientations when going from layer to layer. This is accomplished by providing strongly (111)-textured layers immediately below the MgO tunnel barrier to induce a (111) orientation therein.
摘要:
An all (111) MTJ stack is disclosed in which there are no transitions between different crystalline orientations when going from layer to layer. This is accomplished by providing strongly (111)-textured layers immediately below the MgO tunnel barrier to induce a (111) orientation therein.
摘要:
A boron or boron containing dusting layer such as CoB or FeB is formed along one or both of top and bottom surfaces of a free layer at interfaces with a tunnel barrier layer and capping layer to improve thermal stability while maintaining other magnetic properties of a MTJ stack. Each dusting layer has a thickness from 0.2 to 20 Angstroms and may be used as deposited, or at temperatures up to 400° C. or higher, or following a subsequent anneal at 400° C. or higher. The free layer may be a single layer of CoFe, Co, CoFeB or CoFeNiB, or may include a non-magnetic insertion layer. The resulting MTJ is suitable for STT-MRAM memory elements or spintronic devices. Perpendicular magnetic anisotropy is maintained in the free layer at temperatures up to 400° C. or higher. Ku enhancement is achieved and the retention time of a memory cell for STT-MRAM designs is increased.
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. 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. Dusting layers and a similar SAF design may be employed in a free layer for Ku enhancement and to increase the retention time of a memory cell.
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. 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. Dusting layers and a similar SAF design may be employed in a free layer for Ku enhancement and to increase the retention time of a memory cell.
摘要:
An improved PMA STT MTJ storage element, and a method for forming it, are described. By inserting a suitable oxide layer between the storage and cap layers, improved PMA properties are obtained, increasing the potential for a larger Eb/kT thermal factor as well as a larger MR. Another important advantage is better compatibility with high processing temperatures, potentially facilitating integration with CMOS.
摘要:
A boron or boron containing dusting layer such as CoB or FeB is formed along one or both of top and bottom surfaces of a free layer at interfaces with a tunnel barrier layer and capping layer to improve thermal stability while maintaining other magnetic properties of a MTJ stack. Each dusting layer has a thickness from 0.2 to 20 Angstroms and may be used as deposited, or at temperatures up to 400° C. or higher, or following a subsequent anneal at 400° C. or higher. The free layer may be a single layer of CoFe, Co, CoFeB or CoFeNiB, or may include a non-magnetic insertion layer. The resulting MTJ is suitable for STT-MRAM memory elements or spintronic devices. Perpendicular magnetic anisotropy is maintained in the free layer at temperatures up to 400° C. or higher. Ku enhancement is achieved and the retention time of a memory cell for STT-MRAM designs is increased.
摘要:
An improved PMA STT MTJ storage element, and a method for forming it, are described. By inserting a suitable oxide layer between the storage and cap layers, improved PMA properties are obtained, increasing the potential for a larger Eb/kT thermal factor as well as a larger MR. Another important advantage is better compatibility with high processing temperatures, potentially facilitating integration with CMOS.
摘要:
A magnetic element in a spintronic device or serving as a propagation medium in a domain wall motion device is disclosed wherein first and second interfaces of a free layer with a perpendicular Hk enhancing layer and tunnel barrier, respectively, produce enhanced surface perpendicular anisotropy to increase thermal stability in a magnetic tunnel junction. The free layer may be a single layer or a composite and is comprised of a glassing agent that has a first concentration in a middle portion thereof and a second concentration less than the first concentration in regions near first and second interfaces. A CoFeB free layer selectively crystallizes along first and second interfaces but maintains an amorphous character in a middle region containing a glass agent providing the annealing temperature is less than the crystallization temperature of the middle region.
摘要:
A synthetic antiferromagnetic (SAF) structure for a spintronic device is disclosed and has an AP2/antiferromagnetic (AF) coupling/CoFeB configuration. The SAF structure is thinned to reduce the fringing (Ho) field while maintaining high coercivity. The AP2 reference layer has intrinsic perpendicular magnetic anisotropy (PMA) and induces PMA in a thin CoFeB layer through AF coupling. In one embodiment, AF coupling is improved by inserting a Co dusting layer on top and bottom surfaces of a Ru AF coupling layer. When AP2 is (Co/Ni)4, and CoFeB thickness is 7.5 Angstroms, Ho is reduced to 125 Oe, Hc is 1000 Oe, and a balanced saturation magnetization-thickness product (Mst)=0.99 is achieved. The SAF structure may also be represented as FL2/AF coupling/CoFeB where FL2 is a ferromagnetic layer with intrinsic PMA.