An etchant for simultaneously etching NiFe and AlN with approximately equal etch rates that comprises phosphoric acid, acetic acid, nitric acid and deionized water. Alternating layers of NiFe and AlN may be used to form a magnetic core of a fluxgate magnetometer in an integrated circuit. The wet etch provides a good etch rate of the alternating layers with good dimensional control and with a good resulting magnetic core profile. The alternating layers of NiFe and AlN may be encapsulated with a stress relief layer. A resist pattern may be used to define the magnetic core geometry. The overetch time of the wet etch may be controlled so that the magnetic core pattern extends at least 1.5 um beyond the base of the magnetic core post etch. The photo mask used to form the resist pattern may also be used to form a stress relief etch pattern.

An etchant for simultaneously etching NiFe and AlN with approximately equal etch rates that comprises phosphoric acid, acetic acid, nitric acid and deionized water. Alternating layers of NiFe and AlN may be used to form a magnetic core of a fluxgate magnetometer in an integrated circuit. The wet etch provides a good etch rate of the alternating layers with good dimensional control and with a good resulting magnetic core profile. The alternating layers of NiFe and AlN may be encapsulated with a stress relief layer. A resist pattern may be used to define the magnetic core geometry. The overetch time of the wet etch may be controlled so that the magnetic core pattern extends at least 1.5 um beyond the base of the magnetic core post etch. The photo mask used to form the resist pattern may also be used to form a stress relief etch pattern.

Provided is a magnetic field measuring device including a first sensor unit which includes a first coil sensor configured to output a first sensor signal, a second sensor unit which includes a second coil sensor configured to output a second sensor signal and disposed in a direction perpendicular to the first coil sensor, a third sensor unit which includes a third coil sensor configured to output a third sensor signal and disposed in a direction perpendicular to the first and second coil sensors, and a digital signal processor outputs magnetic flux density based on a voltage difference between the first and fourth nodes, wherein the first to third sensor units respectively output first to third output signals in which specific voltages of the first to third sensor signals are maintained for a predetermined period of time.

A method of fabricating a semiconductor device includes aligning an alignment structure of a wafer to a direction of a magnetic field created by an external electromagnet and depositing a magnetic layer (e.g., NiFe) over the wafer in the presence of the magnetic field and while applying the magnetic field and maintaining a temperature of the wafer below 150° C. An insulation layer (e.g., AlN) is deposited on the first magnetic layer. The alignment structure of the wafer is again aligned to the direction of the magnetic field and a second magnetic layer is deposited on the insulation layer, in the presence of the magnetic field and while maintaining the temperature of the wafer below 150° C.

An apparatus includes a magnetometer-based current sensor (e.g., a Hall-effect or fluxgate-based current sensor) configured to sense a magnetic field generated by a current in at least one conductor connecting a motor drive output to a motor and to responsively produce a first current sense signal and a magnetometer-based voltage sensor (e.g., a Hall-effect or fluxgate-based voltage sensor) configured to sense a magnetic field generated in response to a voltage of the at least one conductor and to responsively produce a first voltage sense signal. The apparatus further includes a signal conversion circuit configured to receive the first current sense signal and the first voltage sense signal and to generate a second current sense input and a second voltage sense input for provision to a current sense input and a voltage sense input, respectively, of a motor protection relay that protects the motor.

In an approach to magnetic flux density based DNA sequencing, a static magnetic field is provided. A chain of nucleotides is passed through the magnetic field. A change in magnetic flux density of the static magnetic field due to an ionic voltage associated with an individual nucleotide or base pair of the chain of nucleotides is measured. An identity of the nucleotide is determined based on the change in magnetic flux density.

In an approach to magnetic flux density based DNA sequencing, a static magnetic field is provided. A chain of nucleotides is passed through the magnetic field. A change in magnetic flux density of the static magnetic field due to an ionic voltage associated with an individual nucleotide or base pair of the chain of nucleotides is measured. An identity of the nucleotide is determined based on the change in magnetic flux density.

An integrated fluxgate device has a magnetic core on a control circuit. The magnetic core has a volume and internal structure sufficient to have low magnetic noise and low non-linearity. A stress control structure is disposed proximate to the magnetic core. An excitation winding, a sense winding and a compensation winding are disposed around the magnetic core. An excitation circuit disposed in the control circuit is coupled to the excitation winding, configured to provide current at high frequency to the excitation winding sufficient to generate a saturating magnetic field in the magnetic core during each cycle at the high frequency. An isolation structure is disposed between the magnetic core and the windings, sufficient to enable operation of the excitation winding and the sense winding at the high frequency at low power.

An integrated fluxgate device has a magnetic core on a control circuit. The magnetic core has a volume and internal structure sufficient to have low magnetic noise and low non-linearity. A stress control structure is disposed proximate to the magnetic core. An excitation winding, a sense winding and a compensation winding are disposed around the magnetic core. An excitation circuit disposed in the control circuit is coupled to the excitation winding, configured to provide current at high frequency to the excitation winding sufficient to generate a saturating magnetic field in the magnetic core during each cycle at the high frequency. An isolation structure is disposed between the magnetic core and the windings, sufficient to enable operation of the excitation winding and the sense winding at the high frequency at low power.

A method of field mapping a cell under load is provided. The method comprises the steps of: providing a cell; providing a Hall effect sensor comprising a graphene conductor for measuring a magnetic field; positioning the Hall effect sensor at a first position adjacent a face of the cell; applying a load to the cell; and measuring an output of the Hall effect sensor.