Abstract: Patterned, longitudinally and transversely antiferromagnetically exchange biased GMR sensors are provided which have narrow effective trackwidths and reduced side reading. The exchange biasing significantly reduces signals produced by the portion of the ferromagnetic free layer that is underneath the conducting leads while still providing a strong pinning field to maintain sensor stability. In the case of the transversely biased sensor, the magnetization of the free and biasing layers in the same direction as the pinned layer simplifies the fabrication process and permits the formation of thinner leads by eliminating the necessity for current shunting.

Abstract: By using a free layer that includes a NiFe layer containing between 65 and 72 atomic percent iron, an improved CPP GMR device has been created. The resulting structure yields a higher CPP GMR ratio than prior art devices, while maintaining free layer softness and acceptable magnetostriction. A process for manufacturing the device is also described.

Abstract: A trimmed upper pole piece for a magnetic write head, said pole piece having a tapered profile that is widest at its trailing edge. Such a pole piece is capable of writing narrow tracks with sharply and well defined patterns and minimal overwriting of adjacent tracks. The necessary taper is produced by using NiCr, NiFeCr, Rh or Ru as write gap filling materials which have an etch rate which is substantially equal to the etch rate of the other layers forming the pole piece and are highly corrosion resistant. As a result, the write gap does not protrude to mask the effects of the ion-beam etch used to form the taper.

Abstract: A perpendicular magnetic recording (PMR) head with single or double coil layers has a small write shield stitched onto a main write shield. The stitched shield allows the main write pole to produce a vertical write field with sharp vertical gradients that is reduced on both sides of the write pole so that adjacent track erasures are eliminated. From a fabrication point of view, both the main pole and the stitched shield are defined and formed using a single photolithographic process, a trim mask and CMP lapping process so that the main shield can be stitched onto a self-aligned main pole and stitched shield.

Abstract: A method of making a perpendicular magnetic recording (PMR) head with single or double coil layers and with a small write shield stitched onto a main write shield. The stitched shield allows the main write pole to produce a vertical write field with sharp vertical gradients that is reduced on both sides of the write pole so that adjacent track erasures are eliminated. From a fabrication point of view, both the main pole and the stitched shield are defined and formed using a single photolithographic process, a trim mask and CMP lapping process so that the main shield can be stitched onto a self-aligned main pole and stitched shield.

Abstract: A trimmed upper pole piece for a magnetic write head is presented, said pole piece having a uniform width above and below a write gap layer and said pole piece being formed on a pedestal of uniform width projecting from a planar surface of a magnetic shield layer. Prior art methods of trimming pole pieces to a final width using ion-beam etches produce pole pieces with thickness differentials due to the etch resistant nature of the typical alumina write-gap filling material. The present pole piece uses NiCr, NiFeCr or Ru as write gap filling materials because they have an etch rate which is substantially equal to the etch rate of the other layers forming the pole piece and allow a uniform trimming to occur.

Abstract: For high track density recording, tighter reader and writer track width control are essential. This has been achieved by using the write gap layer as the plating seed on which the upper pole was electro-formed so that the width of the GMR pedestal serves to define the device's write track width.

Abstract: A method for forming MRAM cell structures wherein the topography of the cell is substantially flat and the distance between a bit line and a magnetic free layer, a word line and a magnetic free layer or a word line and a bit line and a magnetic free layer is precise and well controlled. The method includes the formation of an MTJ film stack over which is formed both a capping and sacrificial layer. The stack is patterned by conventional means, then is covered by a layer of insulation which is thinned by CMP to expose a remaining portion of the sacrificial layer. The remaining portion of the sacrificial layer can be precisely removed by an etching process, leaving only the well dimensioned capping layer to separate the bit line from the magnetic free layer and the capping layer. The bit line and an intervening layer of insulation separate the free layer from a word line in an equally precise and controlled manner.

Abstract: An improved seed/AFM structure is formed by first depositing a layer of tantalum on the lower shield. A NiCr layer is then deposited on the Ta followed by a layer of IrMn. The latter functions effectively as an AFM for thicknesses in the 40-80 Angstrom range, enabling a reduced shield-to-shield spacing.

Abstract: Problems such as thermal pole tip protrusion result from thermal mismatch between the alumina and pole material during the writing process. This, and similar problems due to inadequate heat dissipation, have been overcome by dividing the bottom shield into two pieces both of which sit on top of a non-magnetic heat sink. Heat generated by the coil during writing is transferred to the non-magnetic heat sink whence it gets transferred to the substrate. With this approach, the head not only benefits from less field disturbance due to the small shield but also improves heat dissipation from the additional heat sink.

Abstract: A perpendicular magnetic recording (PMR) head with single or double coil layers has a small write shield stitched onto a main write shield. The stitched shield allows the main write pole to produce a vertical write field with sharp vertical gradients that is reduced on both sides of the write pole so that adjacent track erasures are eliminated. From a fabrication point of view, both the main pole and the stitched shield are defined and formed using a single photolithographic process, a trim mask and CMP lapping process so that the main shield can be stitched onto a self-aligned main pole and stitched shield.

Abstract: Aggressive (i.e. tight tolerance) stitching offers several advantages for magnetic write heads but at the cost of some losses during pole trimming. This problem has been overcome by replacing the alumina filler layer, that is used to protect the stitched pole during trimming, with a layer of electro-plated material. Because of the superior step coverage associated with the plating method of deposition, pole trimming can then proceed without the introduction of stresses to the stitched pole while it is being trimmed.

Abstract: Aggressive (i.e. tight tolerance) stitching offers several advantages for magnetic write heads but at the cost of some losses during pole trimming. This problem has been overcome by replacing the alumina filler layer, that is used to protect the stitched pole during trimming, with a layer of electroplated material. Because of the superior step coverage associated with the plating method of deposition, pole trimming can then proceed without the introduction of stresses to the stitched pole while it is being trimmed.

Abstract: A process is described for the fabrication, through electrodeposition, of FexCoyNiz (x=60-71, y=25-35, z=0-5) films that have, in their as-deposited form, a saturation magnetization of at least 24 kG and a coercivity of less than 0.3 Oe. A key feature is the addition of aryl sulfinates to the plating bath along with a suitable seed layer.

Abstract: A process for achieving tighter reader and writer track width control is disclosed. The write gap layer is used as the plating seed on which the upper pole is electro-formed. This allows the write gap layer to then be deposited through a precisely controllable process such as sputtering. Since less material needs to be removed during pole trimming, a thinner layer of photoresist may be used, resulting in improved dimensional control.

Abstract: One of the major requirements for higher frequency extendability is to reduce yoke length and inductance in order to have fast saturation. This has been accomplished by using a design that provides a cavity in the lower pole piece inside which is located at least two coils, one on top of the other. A process for manufacturing the device is also described.

Abstract: A perpendicular magnetic recording (PMR) head is fabricated with a pole tip shielded laterally by a separated pair of side shields and shielded from above by an upper shield. The side shields are formed by a RIE process using specific gases applied to a shield layer through a masking layer formed of material that has a slower etch rate than the shield material. A masking layer of Ta, Ru/Ta, TaN or Ti, formed on a shield layer of NiFe and using RIE gases of CH3OH, CO or NH3 or their combinations, produces the desired result. The differential in etch rates maintains the opening dimension within the mask and allows the formation of a wedge-shaped trench within the shield layer that separates the layer into two shields. The pole tip is then plated within the trench and, being aligned by the trench, acquires the wedge-shaped cross-section of the trench. An upper shield is then formed above the side shields and pole.

Abstract: Aggressive (i.e. tight tolerance) stitching offers several advantages for magnetic write heads but at the cost of some losses during pole trimming. This problem has been overcome by replacing the alumina filler layer, that is used to protect the stitched pole during trimming, with a layer of electro-plated material. Because of the superior step coverage associated with the plating method of deposition, pole trimming can then proceed without the introduction of stresses to the stitched pole while it is being trimmed.

Abstract: Improved magnetic devices have been fabricated by replacing the conventional seed layer (typically Ta) with a bilayer of Ru on Ta. Although both Ru and Ta layers are ultra thin (between 5 and 20 Angstroms), good exchange bias between the seed and the AFM layer (IrMn about 70 Angstroms thick) is retained. This arrangement facilitates minimum shield-to-shield spacing and gives excellent performance in CPP, CCP-CPP, or TMR configurations.

Abstract: A PMR write head has a stitched shield formation which results in a strong perpendicular write field with sharp vertical gradients. The shape of the stitched shield is determined by two design parameters, d=½(WSWSLE?WMPTE), and TSWS, where WSWSLE is the width of the leading edge of the stitched shield in the ABS plane, WMPTE is the width of the trailing edge of the main magnetic pole in the ABS plane and TSWS is the thickness of the stitched shield. By a proper choice of these parameters, the write field of the head is sharply limited in the cross-track direction, so that adjacent track erasures are eliminated.