425 results about "Magnetic tunnelling" patented technology

A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.

A magnetoresistive random-access memory device with a magnetic tunnel junction stack having a significantly improved performance of the free layer in the magnetic tunnel junction structure. The memory device includes an antiferromagnetic structure and a magnetic tunnel junction structure disposed on the antiferromagnetic structure. The magnetic tunnel junction structure includes a reference layer and a free layer with a barrier layer sandwiched therebetween. Furthermore, a capping layer including a tantalum nitride film is disposed on the free layer of the magnetic tunnel junction structure.

Integrated circuits with magnetic tunnel junction (MTJ) structures and methods for fabricating integrated circuits with MTJ structures are provided. An exemplary method for fabricating an integrated circuit includes forming a first conductive line in electrical connection with an underlying semiconductor device. The method exposes a surface of the first conductive line. Further, the method selectively deposits a conductive material on the surface of the first conductive line to form an electrode contact. The method includes forming a MTJ structure over the electrode contact.

Provided are a perpendicular magnetic tunnel junction (MTJ), a magnetic device including the same, and a method of manufacturing the MTJ, the perpendicular MTJ includes a lower magnetic layer; a tunnelling layer on the lower magnetic layer; and an upper magnetic layer on the tunnelling layer. One of the upper and lower magnetic layers includes a free magnetic layer that exhibits perpendicular magnetic anisotropy, wherein the magnetizing direction of the free magnetic layer is changed by a spin polarization current. A polarization enhancing layer (PEL) and an exchange blocking layer (EBL) are stacked between the tunnelling layer and the free magnetic layer.

A magnetic memory is described. The magnetic memory includes dual magnetic junctions and spin-orbit interaction (SO) active layer(s). Each dual magnetic junction includes first and second reference layers, first and second nonmagnetic spacer layers and a free layer. The free layer is magnetic and between the nonmagnetic spacer layers. The nonmagnetic spacer layers are between the corresponding reference layers and the free layer. The SO active layer(s) are adjacent to the first reference layer of each dual magnetic junction. The SO active layer(s) exert a SO torque on the first reference layer due to a current passing through the SO active layer(s) substantially perpendicular to a direction between the SO active layer(s) and the first reference layer. The first reference layer has a magnetic moment changeable by at least the SO torque. The free layer is switchable using a spin transfer write current driven through the dual magnetic junction.

A magnetic field sensing device for determining the strength of a magnetic field, includes four magnetic tunnel junction elements or element arrays (100) configured as a bridge (200). A current source is coupled to a current line (116) disposed near each of the four magnetic tunnel junction elements (100) for selectively supplying temporally spaced first and second currents. Sampling circuitry (412, 414) coupled to the current source samples the bridge output during the first and second currents and determines the value of the magnetic field from the difference of the first and second values. A method for sensing the magnetic field includes supplying a first current to the current line (116), supplying a second current the current line (116), sampling the value at the output for each of the first and second currents, determining the difference between the sampled values during each of the first and second currents, and determining a measured magnetic field based on the determined difference.

A magnetic tunnel junction (MTJ) for use in a magnetoresistive random access memory (MRAM) has a CoFeB alloy free layer located between the MgO tunnel barrier layer and an upper MgO capping layer, and a CoFeB alloy enhancement layer between the MgO capping layer and a Ta cap. The CoFeB alloy free layer has high Fe content to induce perpendicular magnetic anisotropy (PMA) at the interfaces with the MgO layers. To avoid creating unnecessary PMA in the enhancement layer due to its interface with the MgO capping layer, the enhancement layer has low Fe content. After all of the layers have been deposited on the substrate, the structure is annealed to crystallize the MgO. The CoFeB alloy enhancement layer inhibits diffusion of Ta from the Ta cap layer into the MgO capping layer and creates good crystallinity of the MgO by providing CoFeB at the MgO interface.

Reading margin is improved in a MTJ designed for MRAM applications by employing a pinned layer with an AP2 / Ru / AP1 configuration wherein the AP1 layer is a CoFeB / CoFe composite and by forming a MgO tunnel barrier adjacent to the CoFe AP1 layer by a sequence that involves depositing and oxidizing a first Mg layer with a radical oxidation (ROX) process, depositing and oxidizing a second Mg layer with a ROX method, and depositing a third Mg layer on the oxidized second Mg layer. The third Mg layer becomes oxidized during a subsequent anneal. MTJ performance may be further improved by selecting a composite free layer having a Fe / NiFeHf or CoFe / Fe / NiFeHf configuration where the NiFeHf layer adjoins a capping layer in a bottom spin valve configuration. As a result, read margin is optimized simultaneously with improved MR ratio, a reduction in bit line switching current, and a lower number of shorted bits.

Orthogonal spin-transfer magnetic random access memory (OST-MRAM) uses a spin-polarizing layer magnetized perpendicularly to the free layer to achieve large spin-transfer torques and ultra-fast energy efficient switching. OST-MRAM devices that incorporate a perpendicularly magnetized spin-polarizing layer and a magnetic tunnel junction, which consists of an in-plane magnetized free layer and synthetic antiferromagnetic reference layer, exhibit improved performance over prior art devices. The switching is bipolar, occurring for positive and negative polarity pulses, consistent with a precessional reversal mechanism, and requires an energy less than 450 fJ and may be reliably observed at room temperature with 0.7 V amplitude pulses of 500 ps duration.

A method and system for providing a magnetic memory is disclosed. The method and system include providing a plurality of magnetic elements and a plurality of reference layers. Each of the magnetic elements includes a free layer and a spacer layer. Each of the reference layers is coupled with a corresponding portion of the magnetic elements. The reference layers are ferromagnetic. A portion of each reference layer functions as at least a portion of a pinned layer for each of the corresponding portion of the magnetic elements. The portion of each of the plurality of reference layers also functions as a write line for the corresponding portion of the plurality of magnetic elements. The spacer layer resides between the free layer of each of the plurality of magnetic elements and the reference layer.

A method for forming a MTJ in a STT-MRAM is disclosed in which the easy-axis CD is determined independently of the hard-axis CD. One approach involves two photolithography steps and two etch steps to form a post in a hard mask which is transferred through a MTJ stack of layers by a third etch process. Optionally, the third etch may stop on the tunnel barrier or in the free layer. A second embodiment involves forming a first parallel line pattern on a hard mask layer and transferring the line pattern through the MTJ stack with a first etch step. A planar insulation layer is formed adjacent to the sidewalls in the line pattern and then a second parallel line pattern is formed which is transferred by a second etch through the MTJ stack to form a post pattern. Etch end point may be controlled independently for hard-axis and easy-axis dimensions.

The invention discloses a monolithic reference full bridge magnetic field sensor. The magnetic field sensor is a Wheatstone bridge formed by a magneto-resistor reference element and a sensing element. Both a sensing arm and a reference arm are magnetic tunnel junction resistance or giant magnetoresistance material. According to the invention, the sensitivity of the sensing element and the reference element are adjusted through one or one set of magnetic bias combination, exchange bias, magnetic shielding or shape anisotropy performance. In addition, bridge output offset and symmetry can be optimized through presetting and adjusting a resistance value ratio of the reference element to the sensing element. Through using the technology, the magnetic field sensor presents excellent temperature stability, low offset voltage and excellent voltage symmetry.

A magnetic memory cell is formed including a magneto tunnel junction (MTJ) and an access transistor, which is used to access the MTJ in operation. The access transistor, which is formed on a silicon substrate, includes a gate, drain and source with the gate position substantially perpendicular to the plane of the silicon substrate thereby burying the gate and allowing more surface area on the silicon substrate for formation of additional memory cells.

An information sensing and storing device has a dual-MTJ (Magnetic Tunnel Junction) structure, and comprises a bottom electrode, an MTJ 1, a non-ferromagnetic metal isolation layer, an MTJ 2 and a top electrode sequentially from bottom to top, wherein a metal wire is arranged at one side of the device. A fabrication method of the information sensing and storing device comprises the five steps of: 1, depositing a magnetic multi-layer film material on a substrate; 2, performing annealing through an ultrahigh magnetic field vacuum annealing apparatus to fix the magnetization direction of a reference layer; 3, finishing shape fabrication of the dual-MTJ structure by using traditional nanometer device processing technologies such as photoetching, etching and magnetron sputtering; 4, depositing an isolation layer at the outer side of the dual-MTJ structure, and configuring the metal wire near the dual-MTJ structure through the technologies such as photoetching, etching and inlaying; and 5, forming a metal electrode at the top of the dual-MTJ structure by using the processing technologies such as photoetching, etching and inlaying for subsequent integration or test.

Methods and apparatus relating to spin-orbit-torque magnetoresistive random access memory with voltage-controlled anisotropy are disclosed. In an example, disclosed is a three-terminal magnetic tunnel junction (MTJ) storage element that is programmed via a combination of voltage-controlled magnetic anisotropy (VCMA) and spin-orbit torque (SOT) techniques. Also disclosed is a memory controller configured to program the three-terminal MTJ storage element via VCMA and SOT techniques. The disclosed devices improve efficiency over conventional devices by using less write energy, while having a design that is simpler and more scalable than conventional devices. The disclosed devices also have increased thermal stability without increasing required switching current, as critical switching current between states is essentially the same

A magnetic memory device including a Magnetic Tunnel Junction (MTJ) device comprises a substrate and Front End of Line (FEOL) circuitry. A Via level (VA) InterLayer Dielectric (ILD) layer, a bottom conductor layer, and an MTJ device formed over the top surface of the VA ILD layer are formed over a portion of the substrate. An alignment region including alignment marks extends through the bottom conductor layer and extends down into the device below the top surface of the VA ILD layers is juxtaposed with the MJT device.

A perpendicular spin transfer torque (STT) memory cell with double MgO interface and CoFeB layer for enhancement of perpendicular magnetic anisotropy. A magnetic tunnel junction (MTJ) for use in a magnetoresistive random access memory (MRAM) has a CoFeB alloy free layer located between the MgO tunnel barrier layer and an upper MgO capping layer, and a CoFeB alloy enhancement layer between the MgO capping layer and a Ta cap. The CoFeB alloy free layer has high Fe content to induce perpendicular magnetic anisotropy (PMA) at the interfaces with the MgO layers. To avoid creating unnecessary PMA in the enhancement layer due to its interface with the MgO capping layer, the enhancement layer has low Fe content. After all of the layers have been deposited on the substrate, the structure is annealed to crystallize the MgO. The CoFeB alloy enhancement layer inhibits diffusion of Ta from the Ta cap layer into the MgO capping layer and creates good crystallinity of the MgO by providing CoFeB at the MgO interface.

Magneto-resistive devices with lower power consumption and higher stability are provided. The magneto-resistive devices may include a pinned layer, a free layer and an insulating layer between the pinned layer and the free layer. The pinned layer, the free layer and the insulating layer may constitute a magnetic tunnel junction. The free layer may include a first magnetic layer and a second magnetic layer that has a Curie temperature lower than a Curie temperature of the first magnetic layer.

Aspects disclosed include spin-orbit torque (SOT) magnetic tunnel junction (MTJ) (SOT-MTJ) devices employing perpendicular and in-plane free layer magnetic anisotropy to facilitate perpendicular magnetic orientation switching. A free layer in a MTJ in the SOT-MTJ device includes both a perpendicular magnetic anisotropy (PMA) region(s) and an in-plane magnetic anisotropy (IMA) region(s). A spin torque is generated in the free layer when a SOT switching current flows through an electrode adjacent to the free layer sufficient to switch the magnetic moment of the free layer to an in-plane magnetic orientation. To prevent a non-deterministic perpendicular magnetic orientation after the SOT switching current is removed, the free layer also includes the IMA region(s) to provide an in-plane magnetization to generate an effective magnetic field in the free layer to assist in switching the magnetic moment of the free layer past an in-plane magnetic orientation to a perpendicular magnetic orientation.

Embodiments described herein are related to contactless data communication. Related systems and methods for contactless data communication are disclosed herein. For example, a magnetic field-based contactless transmitter is disclosed that includes a substrate, a pair of dipole coils disposed on the substrate, and a drive circuit electrically coupled to the pair of dipole coils. To transmit data to a magnetic tunnel junction (MTJ) receiver disposed on a second substrate, the drive circuit is configured to drive the pair of dipole coils so as to generate a magnetic field in-plane to the MTJ receiver. Data can be transmitted from the magnetic field-based contactless transmitter to the MTJ receiver using the magnetic field.

The invention provides an MRAM storage unit. The unit comprises two magnetic tunnel junctions and a spin orbital moment providing line, the two magnetic tunnel junctions are located on the surface ofthe same side of the spin orbital moment providing line, wherein the free layer of each magnetic tunnel junction is close to the spin orbital moment providing line, the magnetization directions of thereference layers of the two magnetic tunnel junctions are the same, and the spin orbital moment providing line is used for applying spin magnetic moments in opposite directions to the two magnetic tunnel junctions, so that the free layers of the two magnetic tunnel junctions have opposite magnetization directions. According to the MRAM storage unit, complementary resistance states can be stored,differential signals are formed during state reading, the reading error rate is reduced, and the data reading speed can be remarkably increased.

A magnetic memory device comprises a magnetic tunnel junction (MTJ) (37) connecting to a bit line (31) to a sense line (49) through an isolation transistor (81). The MTJ (37) includes a ferromagnetic layer having a magnetic hard axis. An assist current line (33) overlies the bit line (31) and is insulated from the bit line (31). The MTJ (37) is switchable between a first, relatively high resistance state and a second, relatively low resistance state. The assist current line (33) applies a magnetic field along the magnetic hard axis in the ferromagnetic layer, independently of current flow through the MTJ (37) for assisting switching of the MTJ (37) between the first and second states.

A spin-torque transfer magnetic random access memory (STTMRAM) element employed to store a state based on the magnetic orientation of a free layer, the STTMRAM element is made of a first perpendicular free layer (PFL) including a first perpendicular enhancement layer (PEL). The first PFL is formed on top of a seed layer. The STTMRAM element further includes a barrier layer formed on top of the first PFL and a second perpendicular reference layer (PRL) that has a second PEL, the second PRL is formed on top of the barrier layer. The STTMRAM element further includes a capping layer that is formed on top of the second PRL.

A method of manufacturing a magnetic memory cell, including a magnetic tunnel junction (MTJ), includes using silicon nitride layer and silicon oxide layer to form a trench for depositing copper to be employed for connecting the MTJ to other circuitry without the use of a via.

A Magnetic Random Access Memory (MRAM) array has a plurality of main MRAM bitcells and a plurality of canary MRAM bitcells in which a first Magnetic Tunnel Junction (MTJ) diameter of each of the main MRAM bitcells is larger than any second MTJ diameter of any of the canary bitcells. Test circuitry is configured to periodically poll the canary bitcells to determine if values stored at the canary bitcells match expected canary values. When the values do not match the expected canary values, the test circuitry is configured to indicate a presence of a magnetic field, and in response to determining the presence of the magnetic field, continue to poll the canary bitcells until the values match the expected canary values which indicates the magnetic field is no longer present.

The bottom-pinned spin-orbit torque (SOT) MRAM devices are fabricated to form high quality interfaces between layers including the spin-orbit torque (SOT) layer and the free layer of the magnetic tunnel junction (MTJ) by forming those layers under vacuum, without breaking vacuum in between formation of the layers. An encapsulation layer is used as an etch stop and to protect the free layer. The encapsulation layer is etched back prior to the deposition of a metal layer. The metal layer forms a plurality of metal lines that are electrically connected to two or more sides of the SOT layer and are electrically coupled to the SOT layer to transfer current through the SOT layer. The metal lines are not in contact with a top surface of the SOT layer which has a dielectric layer disposed thereon.

A dual-cell spin-transfer torque random-access memory including a first magnetic tunneling junction and a second magnetic tunneling junction. An access circuit is coupled to the first and second magnetic tunneling junctions such that independent read and write access is provided to bits stored in the first and second magnetic tunneling junctions.