Headway Technologies Inc. | Date: 2016-01-04
A design for a microwave assisted magnetic recording device is disclosed wherein a spin torque oscillator (STO) between a main pole and write shield has a spin polarization (SP) layer less than 30 Angstroms thick and perpendicular magnetic anisotropy (PMA) induced by an interface with one or two metal oxide layers. Back scattered spin polarized current from an oscillation layer is used to stabilize SP layer magnetization. One or both of the metal oxide layers may be replaced by a confining current pathway (CCP) structure. In one embodiment, the SP layer is omitted and spin polarized current is generated by a main pole/metal oxide interface. A direct current or pulsed current bias is applied across the STO. Rf current may also be injected into the STO to reduce critical current density. A write gap of 25 nm or less is achieved while maintaining good STO performance.
Headway Technologies Inc. | Date: 2015-08-10
A method of removing copper oxide from copper surfaces is disclosed that comprises application of vapor generated by an ultrasonic wave nebulizer. The energized vapor droplets include water and a weak organic acid such as acetic acid, lactic acid, citric acid, uric acid, oxalic acid, or formic acid that have a vapor pressure proximate to that of water. The weak organic acid preferably has a pKa high enough to avoid Cu etching but is sufficiently acidic to remove copper oxide at a rate that is compatible with high throughput manufacturing. In one embodiment, weak acid/water vapor is applied to a substrate in a spin bowl and is followed by a deionized water rinse step in the same spin bowl. Improved wettability results in improved uniformity in subsequently plated copper films. Considerable cost savings is realized as a result of reduced chemical consumption and higher product yields.
Headway Technologies Inc. | Date: 2015-04-29
A high performance TMR sensor is fabricated by employing a free layer comprised of CoNiFeB or CoNiFeBM where M is V, Ti, Zr, Nb, Hf, Ta, or Mo and the M content in the alloy is <10 atomic %. The free layer may have a FeCo/FeB/CoNiFeB, FeCo/CoFe/CoNiFeB, FeCo/CoFeB/CoNiFeB, or FeCo/CoNiFeB/CoFeB configuration. A CoNiFeBM layer may be formed by co-sputtering CoB with CoNiFeM. A 15 to 30% in improvement in TMR ratio over a conventional CoFe/NiFe free layer is achieved while maintaining low Hc and RA<3 ohm-um
Headway Technologies Inc. | Date: 2015-06-24
A TMR stack or a GMR stack, ultimately formed into a sensor or MRAM element, include insertion layers of Fe or iron rich layers of FeX in its ferromagnetic free layer and/or the AP1 layer of its SyAP pinned layer. X is a non-magnetic, metallic element (or elements) chosen from Ta, Hf, V, Co, Mo, Zr, Nb or Ti whose total atom percent is less than 50%. The insertion layers are between 1 and 10 angstroms in thickness, with between 2 and 5 angstroms being preferred and, in the TMR stack, they are inserted adjacent to the interfaces between a tunneling barrier layer and the ferromagnetic free layer or the tunneling barrier layer and the AP1 layer of the SyAP pinned layer in the TMR stack. The insertion layers constrain interdiffusion of B and Ni from CoFeB and NiFe layers and block NiFe crystalline growth.
Headway Technologies Inc. | Date: 2015-10-29
A magnetic sensor with increased sensitivity, lower noise, and improved frequency response is described. The sensors free layer is ribbon shaped and is closely flanked at each long edge by a ribbon of magnetically soft, high permeability material. Side stripes of soft magnetic material absorb external field flux and concentrate the flux to flow into the sensors edges to promote larger MR sensor magnetization rotation. Side stripes may be located in the plane of the free layer a maximum distance of 0.1 microns, above a plane that includes a free layer top surface, or below a plane that includes the magnetic sensor bottom surface. Edges of each side stripe may be aligned above or below a portion of the magnetic sensor. Moreover, each side stripe may have a tapered edge such that the side stripes have increasing thickness with increasing distance from the magnetic sensor.