International Business Machines Corporation

Aakash Pushp

Timothy Phung

Benjamin Madon

M A Mueed

Martin Michael Frank

Masatoshi Ishii

Gregory Michael Wallraff

Heike E Riel

Jin Ping Han

Pritish Narayanan

Krystelle Lionti

Stuart P Parkin

Brian Peter Hughes

Stuart Sp Parkin

Vincent Ouazan-Reboul

Forming a hardmask layer for reactive ion etching includes depositing a hardmask above an underlayer. The hardmask includes a layer of magnesium oxide having a thickness of up to 10 nm. A resist layer is deposited above the hardmask and developed to form a pattern that exposes portions of the hardmask. The pattern is transferred from the resist layer to the hardmask by rinsing exposed portions of the hardmask with a deionized water solution.

Magnesium oxide based hardmask for reactive ion etching

A method of forming a composite crystalline nitride structure is provided. The method includes depositing a first crystalline nitride layer on a substrate, patterning the first crystalline nitride layer to form a patterned crystalline nitride layer having a top surface and that includes undulations, annealing the patterned crystalline nitride layer at a temperature between 300&#xb0; C. to 850&#xb0; C. to form an annealed patterned crystalline nitride layer, and depositing a second crystalline nitride layer on the annealed patterned crystalline nitride layer. The second crystalline nitride layer is lattice-matched to the underlying annealed patterned crystalline nitride layer to within 2%, thereby forming the composite crystalline nitride structure.

Obtaining a clean nitride surface by annealing

Various devices are described (along with methods for making them), where the device has a tunnel barrier sandwiched between two magnetic layers (one of the magnetic layers functioning as a free layer and the other of the magnetic layers functioning as a reference layer). One magnetic layer underlies the tunnel barrier and the other magnetic layer overlies the tunnel barrier, thereby permitting spin-polarized current to pass across the magnetic layers and through the tunnel barrier. At least one of the magnetic layers includes a metal oxide sublayer (e.g., an MgO sublayer) sandwiched between magnetic material.

Magnetic multi-layers containing MgO sublayers as perpendicularly magnetized magnetic electrodes for magnetic memory technology

A magnetic double tunnel junction (MDTJ) (which, preferably, has a large aspect ratio, wherein length L of the MDTJ&#x3e;&#x3e;width w of the MDTJ) has magnetic domain wall(s) or DW(s) in the free layer of the MDTJ, wherein controlled movement of the DW(s) across the free layer is effected in response to the polarity, magnitude, and duration of a voltage pulse across the MDTJ. The motion and relative position of DW(s) causes the conductance of the MDTJ (that is measured across the MDTJ) to change in a symmetric and linear fashion. By reversing the polarity of the bias voltage, the creation and/or direction of the DW(s) motion can be reversed, thereby allowing for a bi-directional response to the input pulse.

Magnetic domain wall-based non-volatile, linear and bi-directional synaptic weight element

A titanium (Ti) seed layer is formed from a Ti source directly on a surface of a substrate, where the surface is substantially free of oxide and nitride, and a reactive nitrogen species is introduced from a nitrogen plasma source and additional Ti is introduced from the Ti source, wherein the nitrogen plasma: (a) reacts with the Ti seed layer to form TiN and (b) reacts with the additional Ti to form additional TiN. The TiN and additional TiN collectively form a TiN superconducting layer that directly contacts the surface of the substrate.

Method of growing titanium nitride on silicon substrate free from silicon nitride interface by using a titanium seed layer

A hybrid template assisted selective epitaxy (HTASE) process is described comprising the steps of: depositing a template oxide layer on top of a silicon fin; opening a via in a selected portion of the template oxide to expose a portion of the encapsulated silicon fin and subsequently growing a nitride superconductor layer on top of the exposed silicon fin thereby forming a hybrid encapsulation of the silicon fin; performing a back-etch of the silicon fin to remove a portion (e.g., 5 nm-20 um) of the silicon fin; growing a layer formed from a group III/group V compound within an area where the silicon fin was removed via the back-etch; and if needed, removing the template oxide layer.

Hybrid template area selective epitaxy (HTASE)

A device comprising a first magnetic layer (e.g., CoMnSi Heusler alloy or a tetragonally distorted perpendicularly magnetized (PMA) Heusler alloy such as MnGa, MnGe, etc.) and a second magnetic layer (e.g., CoMnSi Heusler alloy or a tetragonally distorted perpendicularly magnetized (PMA) Heusler alloy such as MnGa, MnGe, etc.), and a metal halide tunnel barrier in between the first and second magnetic layers, wherein the metal halide tunnel barrier (e.g., NaF, NaCl, NaBr, LiF, LiCl, and LiBr or their combination) is lattice matched within a predetermined limit (e.g. 5%) of both the first and second magnetic layers.

Lattice matched tunnel barriers for perpendicularly magnetized Heusler alloys

A tunable resistance device and methods of forming the same include a magnetic fixed layer having a fixed magnetization, a magnetic free layer, and a non-magnetic conductive layer directly between the magnetic fixed layer and the magnetic free layer. The magnetic fixed layer, the magnetic free layer, and the non-magnetic conductive layer are formed in a lattice of wires, with each wire in the lattice being formed from a stack of the magnetic fixed layer, the magnetic free layer, and the non-magnetic conductive layer.

Racetrack synapse for neuromorphic applications

A device comprising a control unit and a plurality of resistive cells. The plurality of resistive cells each comprises a first terminal, a second terminal and a polymorphic layer comprising a polymorphic material. The polymorphic layer is configured to form a tunnel barrier. The polymorphic layer is arranged between the first terminal and the second terminal. The first terminal, the second terminal and the polymorphic layer form a tunnel junction.

Device comprising polymorphic resistive cells

Thermal-spin-torque (TST) in a magnetic tunnel junction (MTJ) is demonstrated by generating large temperature gradients across ultrathin MgO tunnel barriers, with this TST being significant enough to considerably affect the magnitude of the switching field of the MTJ. The origin of the TST is attributed to an asymmetry of the tunneling conductance across the zero-bias voltage of the MTJ. Through magneto-Seebeck voltage measurements, it is estimated that the charge-current that would be generated due to the temperature gradient would give rise to spin-transfer-torque (STT) that is a thousand times too small to account for the observed changes in switching fields, indicating the presence of large TST.

Magnetic tunnel junction switching assisted by temperature-gradient induced spin torque

A domain wall injector device uses electrical current passed across an interface between two magnetic regions whose magnetizations are aligned non-collinearly to create a domain wall or a series of domain walls in one of the magnetic regions. The method relies on a combination of innate fringing fields from the magnetic regions and the spin-transfer torque derived from the charge current. The device may be used to store data that are subsequently read out.

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Santa Clara, CA, United States of America

Aakash Pushp