Abstract: This invention comprises a method to make small MTJ element using hybrid etching and oxygen plasma immersion ion implantation. The method has no removal of the magnetic free layer (or memory layer) and hence prevents any possible physical damage near the free layer edges. After photolithography patterning, alternative Ta, Ru, Ta etchings are performed before it stops on an MgO intermediate layer above the free layer. Then an oxygen plasma immersion ion implantation is performed to completely oxidize the exposed portion of the free layer, leaving the hard mask covered portion unchanged which define the lateral width of the MTJ element.

Abstract: A STT-MRAM comprises apparatus, a method of operating and a method of manufacturing a self-referenced magnetoresistive memory and a plurality of magnetoresistive memory element including a self-referenced read scheme through a write/read circuitry coupled to the bit line positioned adjacent to selected ones of the plurality of magnetoresistive memory elements to supply bi-directional spin-transfer recording and reading currents across the MTJ stack. Thus magnetization of a recording layer can be readily switched or reversed to the direction in accordance with a direction of a current across the MTJ stack by applying a spin transfer current, and the magnetization of a reference layer can be readily rotated to two reading directions subsequently in accordance with directions of currents across the MTJ stack by applying low spin transfer currents.

Abstract: This invention comprises methods to form isolated magnetic tunneling junction (MTJ) memory element with small footprint using oxygen-ion implantation. After patterned resist is form on an MTJ film, the substrate is subject to a series of ion implantations outside the mask areas to subsequently implant Mg and oxygen ions into the exposed MTJ junction region, followed by high temperature rapid thermal annealing. Using such a process, implanted oxygen ions, Mg ions and non-oxidized Mg atoms in MTJ stack form highly resistive MgO crystalline and the ion implanted area is converted into electrically insulated metal oxide, creating a shape well-defined MTJ memory element with ultra-small dimensions and vertical edges.

Abstract: A STT-MRAM comprises apparatus, and method of operating a double-MTJ magnetoresistive memory and a plurality of magnetoresistive memory element having a first recording layer which has an interface interaction with an underneath dielectric functional layer and having a second recording layer which has no interface interaction with an underneath dielectric functional layer. The energy switch barrier of the first recording layer is reduced under an electric field applying along a perpendicular direction of the functional with a proper voltage on a digital line from a control circuitry; accordingly, the magnetization of the first recording layer is readily reversible in a low spin-transfer switching current while the magnetization of the second recording layer is readily reversible in a high spin-transfer switching current, enabling two separate bits recording in a double MTJ stack.

Abstract: A spin-transfer-torque magnetoresistive memory comprises apparatus and method of manufacturing a three terminal magnetoresistive memory element having highly conductive bottom electrodes overlaid on top of a SHE-metal layer in the regions outside of an MTJ stack. The memory cell comprises a bit line positioned adjacent to selected ones of the plurality of magnetoresistive memory elements to supply a reading current across the magnetoresistive element stack and two highly conductive bottom electrodes overlaid and electrically contacting on top of a SHE-metal layer in the outside of an MTJ region and to supply a bi-directional spin Hall effect recording current, and accordingly to switch the magnetization of the recording layer. Thus magnetization of a recording layer can be readily switched or reversed to the direction in accordance with a direction of a current along the SHE-metal layer by applying a low write current.

Abstract: A STT-MRAM comprises apparatus and a method of manufacturing a spin-torque magnetoresistive memory and a plurality of a three-terminal magnetoresistive memory element having a voltage-gated recording. The first terminal, a bit line, is connected to the top magnetic reference layer, and the second terminal is located at the middle recording layer which is connected to the underneath select CMOS transistor through a VIA and the third one, a digital line, is a voltage gate with a narrow pillar underneath the memory layer across an insulating functional layer which is used to reduce the write current by manipulating the perpendicular anisotropy of the recording layer. The fabrication includes formation of a bottom electrode, formation of digital line, formation of memory cell & VIA connection and formation of the top bit line. Photolithography patterning and hard mask etch are used to form the digital line pillar and small memory pillar.

Abstract: A STT-MRAM comprises apparatus and a method of manufacturing a spin-torque magnetoresistive memory and a plurality of a three-terminal magnetoresistive memory element having a voltage-gated recording. A bit line is coupled to the memory element through an upper electrode provided on the top surface of a reference layer, a select CMOS is coupled to the recording layer of the memory element through a middle second electrode and a VIA and a digital line is coupled to a voltage gate which is insulated from the recording layer by a dielectric layer and is used to adjust the switching write current. The fabrication includes formation of bottom digital line, formation of memory cell & VIA connection, formation of top bit line. Dual photolithography patterning and hard mask etch are used to form a small memory pillar. Ion implantation is used to convert a buried dielectric VIA into an electrical conducting path between middle memory cell and underneath CMOS device.

Abstract: A perpendicular magnetoresistive element comprises anovel buffer layer provided on a surface of the recording layer, which is opposite to a surface of the recording layer where the tunnel barrier layer is provided, wherein at least the portion of the buffer layer interfacing to the recording layer contains a rocksalt crystal structure having the (100) plane parallel to the substrate plane and at least a portion of the buffer layer comprises a doped element having conductivity enhancement and the perpendicular resistance of the buffer layer is relatively small than that of the tunnel barrier layer.

Abstract: A STT-MRAM comprises a method to form magnetic random access memory (MRAM) element array having ultra small dimensions using double photo exposures and etch of their hard masks. The memory cells are located at the cross section of two ultra-narrow photo-resist lines suspended between two large photo-resist bases. Array of MRAM cells with small dimension is formed by a third magnetic etch.

Abstract: A planar STT-MRAM comprises apparatus, a method of operating a spin-torque magnetoresistive memory and a plurality of magnetoresistive memory element having spin-transfer torques acting on a recording layer from a MTJ stack and a novel magnetoresistance with a spin-valve layer. The spin-valve layer is field-reversible between two stable magnetization states either parallel or anti-parallel to the fixed reference layer magnetization through a set/reset current pulse along a conductive line provided by a control circuitry, accordingly, the magnetoresistive element is pre-configured into a reading mode having canceled spin-transfer torques or a recording mode having additive spin-transfer torques.

Abstract: A STT-MRAM comprises apparatus, a method of operating a spin-torque magnetoresistive memory and a plurality of magnetoresistive memory element having a bias voltage controlled perpendicular anisotropy of a recording layer through an interlayer interaction to achieve a lower spin-transfer switching current. The anisotropy modification layer is under an electric field along a perpendicular direction with a proper voltage between a digital line and a bit line from a control circuitry, accordingly, the energy switch barrier is reduced in the spin-transfer recording while maintaining a high thermal stability and a good retention.

Abstract: A perpendicular magnetoresistive memory element comprises a three-terminal structure having a thick multilayered recording layer connected to a middle electrode and a functional layer having rocksalt crystal structure interfacing to the recording layer. The interface crystal grain structures between the functional layer and the recording layer provides an electric field manipulated perpendicular anisotropy enabling a low spin transfer write current.

Abstract: A perpendicular STT-MRAM comprises apparatus, a method of operating and a method of manufacturing a spin-torque magnetoresistive memory and a plurality of magnetoresistive memory element having a recording layer which has an interface interaction with an underneath dielectric functional layer. The energy switch barrier of the recording layer is reduced under an electric field applying along a perpendicular direction of the functional with a proper voltage on a digital line from a control circuitry; accordingly, the perpendicular magnetization of the recording layer is readily reversible in a low spin-transfer switching current.

Abstract: A planar STT-MRAM comprises apparatus, a method of operating and a method of manufacturing a spin-torque magnetoresistive memory and a plurality of magnetoresistive memory element having a ferromagnetic recording layer forming a flux closure with a self-aligned ferromagnetic soft adjacent layer which has an electric field enhanced perpendicular anisotropy through an interface interaction with a dielectric functional layer. The energy switch barrier of the soft adjacent layer is reduced under an electric field along a perpendicular direction with a proper voltage on a digital line from a control circuitry; accordingly, the in-plane magnetization of the recording layer is readily reversible in a low spin-transfer switching current.

Abstract: A magnetoresistive element comprises a novel Boron-absorbing cap multilayer provided on the top surface of an amorphous CoFeB (or CoB, FeB) ferromagnetic recording layer. As the magnetoresistive film is thermally annealed, a crystallization process occurs to form bcc CoFe grains having epitaxial growth with (100) plane parallel to the surface of the tunnel barrier layer as Boron elements migrate into the novel cap layer. Removing the top portion of the cap layer by means of sputtering etch or RIE etch processes followed by optional oxidization process, a thin thermally stable portion of cap layer is remained on top of the recording layer with low damping constant. Accordingly, a reduced write current is achieved for spin-transfer torque MRAM application.

Abstract: A perpendicular magnetoresistive element comprises a novel buffer layer having rocksalt crystal structure interfacing to a CoFeB-based recording layer has (100) plane parallel to the substrate plane and with {110} lattice parameter being slightly larger than the bcc CoFe lattice parameter along {100} direction, and crystallization process of amorphous CoFeB material in the recording layer during thermal annealing leads to form bcc CoFe grains having epitaxial growth with in-plane expansion and out-of-plane contraction. Accordingly, a perpendicular anisotropy, as well as a perpendicular magnetization, is induced in the recording layer. The invention preferably includes materials, configurations and processes of perpendicular magnetoresistive elements suitable for perpendicular spin-transfer torque MRAM applications.