Allegro Microsystems, LLC

Samridh Jaiswal

Paolo Campiglio

Yen Ting Liu

Maxim Klebanov

Sundar Chetlur

Ronald Lehndorff

Pablo Nicolás Granell

In one aspect, a method of manufacturing a magnetoresistance (MR) element having layers include ramping up a temperature of a reference layer of the MR element to an annealing temperature of the reference layer by increasing an amplitude of laser pulses applied to the reference layer over time to an amplitude that corresponds to the annealing temperature of the reference layer; applying a magnetic field to the reference layer; and maintaining the amplitude of subsequent laser pulses over time that have the amplitude that corresponds to the annealing temperature of the reference layer until at least the reference layer is annealed.

Method of manufacturing magnetoresistance element using laser pinning process

According to one aspect of the present disclosure, a magnetic field sensor includes a magnetoresistance (MR) element. In some embodiments, the MR element includes a reference layer, a free layer, and a barrier layer. In some embodiments the free layer includes two or more cobalt iron boron (CoFeB) layers, wherein a first one of the CoFeB layers is in contact with the barrier layer, and two or more spacer layers. In some embodiments, the CoFeB layers and the spacer layers alternate to form a multilayered free layer structure. In some embodiments, the magnetic field sensor comprises an angle sensor or a current sensor. In some embodiments, the contact between the first one of the CoFeB layers and the barrier layer is configured to reduce hysteresis in the MR element. In some embodiments, the alternating CoFeB layers and spacer layers are configured to increase output amplitude of the MR element.

Magnetoresistance element including a multi-layered free layer stack to tune hysteresis and output amplitude

In one aspect, a method includes depositing magnetoresistance (MR) layers of a MR element on a semiconductor structure; depositing a first hard mask on the MR layers; depositing and patterning a first photoresist on the first hard mask using photolithography to expose portions of the first hard mask; etching the exposed portions of the first hard mask; etching a portion of the MR layers using the first hard mask; depositing a second hard mask on a first capping layer; depositing and patterning a second photoresist on the second hard mask using photolithography to expose portions of the second hard mask; etching the exposed portions of the second hard mask; etching the MR element using the second hard mask; etching portions of the first hard mask down to a top MR layer of the MR element; and depositing a conducting material on the top MR layer to form an electroconductive contact.

Fabricating an electroconductive contact on a top layer of a tunneling magnetoresistance element using two hard masks

In one aspect, manufacturing a magnetic-field angle sensor includes heating, to a first temperature, a substrate, which includes heating a first magnetoresistance (MR) element including a first type of antiferromagnetic material having a first Néel temperature and a first magnetization direction and heating a second MR element including a second type of antiferromagnetic material having a second Néel temperature and a second magnetization direction. The manufacturing also includes, after heating the substrate to the first temperature, applying a first magnetic field to the substrate in an x-direction to enable a first magnetization direction and a second magnetization direction to be in the x-direction, enabling a temperature of the substrate to be a second temperature and applying a second magnetic field to the substrate in a y-direction to enable the second magnetization direction to be in the y-direction while the first magnetization direction remains in the x-direction.

Method of manufacturing angle sensors including magnetoresistance elements including different types of antiferromagnetic materials

In one aspect, a method includes manufacturing a magnetic-field angle sensor on a wafer. The manufacturing includes forming a cosine bridge that includes forming a first magnetoresistance (MR) element. The manufacturing also includes forming a sine bridge that includes forming a second MR element. Forming the first MR element includes using a process to reduce orthogonality errors between the sine bridge and the cosine bridge caused by anisotropy present in magnetic material in the first MR element.

Reducing angle error in angle sensor due to orthogonality drift over magnetic-field

According to one aspect of the present disclosure, a magnetoresistance (MR) element includes a free layer. In some embodiments, the free layer also includes a vortex layer comprising a vortex and a skyrmion layer magnetically coupled to the vortex layer. In some embodiments, in the skyrmion layer is configured to form skyrmions that reduce annihilation of the vortex thereby increasing a linear response range of the MR element. In some embodiments, the MR element is a tunneling magnetoresistance element or a giant magnetoresistance element. In some embodiments, the MR element includes a barrier layer, wherein the vortex layer is closer to the barrier layer than the skyrmion layer.

Magnetoresistance element including a skyrmion layer and a vortex layer that are magnetically coupled to each other

Methods and apparatus for a magnetoresistive (MR) sensor a free layer with a thickness of the CoFeB material to produce out-of-plane sensing for the sensor and a reference layer magnetically coupled to the free layer. A dusting layer of an oxide material is disposed on the free layer to achieve perpendicular magnetic anisotropy for an interface of the oxide layer and the free layer for a desired sensitivity for the sensor.

Controlling out-of-plane anisotropy in an MR sensor with free layer dusting

In one aspect, a sensor includes a first metal layer portion and a second metal layer portion separated by an insulator material; a conductive material layer in electrical contact with the first metal layer portion and the second metal layer portion; and a tunnel magnetoresistance (TMR) element positioned on and in electrical contact with the conductive material layer. A first current is configured to flow from the first metal layer portion, through the conductive material layer, to the second metal layer portion, and a second current is configured to flow from the first metal layer portion, through the conductive material layer, through the TMR element, and exiting through a top of the TMR element.

Multi-terminal devices using magnetoresistance elements

Methods and apparatus for a magnetoresistive (MR) sensor including a seed layer having a CoFe layer for canceling hysteresis in the MR sensor. The MR stackup can include a free layer and a reference layer. The seed layer having CoFe provides a desired texturing of the stackup to cancel hysteresis effects.

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London, United Kingdom

Samridh Jaiswal