摘要:
Formation of a bottom electrode for an MTJ device on a silicon nitride substrate is facilitated by including a layer of ruthenium near the silicon nitride surface. The ruthenium is a good electrical conductor and it responds differently from Ta and TaN to certain etchants. Adhesion to SiN is enhanced by using a TaN/NiCr bilayer as “glue”. Thus, said included layer of ruthenium may be used as an etch stop layer during the etching of Ta and/or TaN while the latter materials may be used to form a hard mask for etching the ruthenium without significant corrosion of the silicon nitride surface.
摘要:
A method and system for fabricating a magnetic recording device are described. The method and system include providing a mask layer on the magnetic recording device and imprinting a pattern in the mask layer to form a mask. The method and system also include transferring the pattern from the mask to the magnetic recording device. In another aspect, the method and system include providing a malleable mask layer on the magnetic recording device. In this aspect, the method and system also include depressing an imprint mask into the mask layer and curing the mask layer while the imprint mask is depressed into the mask layer to provide a mask having a pattern. The pattern may correspond to a read sensor and/or a perpendicular magnetic recording pole. The method and system also include transferring the pattern from the mask to the magnetic recording device.
摘要:
A method to fabricate an MTJ device and its connections to a CMOS integrated circuit is described. The device is built out of three layers. The bottom layer serves as a seed layer for the center layer, which is alpha tantalum, while the third, topmost, layer is selected for its smoothness, its compatibility with the inter-layer dielectric materials, and its ability to protect the underlying tantalum.
摘要:
An MTJ (magnetic tunneling junction) device particularly suitable for use as an MRAM (magnetic random access memory) or a tunneling magnetoresistive (TMR) read sensor, is formed on a seed layer which allows the tunneling barrier layer to be ultra-thin, smooth, and to have a high breakdown voltage. The seed layer is a layer of NiCr which is formed on a sputter-etched layer of Ta. The tunneling barrier layer for the MRAM is formed from a thin layer of Al which is radically oxidized (ROX), in-situ, to form the layer with characteristics described above. The tunneling barrier layer for the read sensor formed from a thin layer of Al or a HfAl bilayer which is naturally oxidized (NOX), in-situ, to form the barrier layer. The resulting device has generally improved performance characteristics in terms of GMR ratio and junction resistance.
摘要:
An MTJ (magnetic tunneling junction) MRAM (magnetic random access memory) cell is formed on a conducting lead and magnetic keeper layer that is capped by a sputter-etched Ta layer. The Ta capping layer has a smooth surface as a result of the sputter-etching and that smooth surface promotes the subsequent formation of a lower electrode (pinning/pinned layer) with smooth, flat layers and a radical oxidized (ROX) Al tunneling barrier layer which is ultra-thin, smooth, and to has a high breakdown voltage. A seed layer of NiCr is formed on the sputter-etched capping layer of Ta. The resulting device has generally improved performance characteristics in terms of its switching characteristics, GMR ratio and junction resistance.
摘要:
A high performance MTJ in an MRAM array is disclosed in which the bottom conductor has an amorphous Ta capping layer. A key feature is a surfactant layer comprised of oxygen that is formed on the Ta surface. The resulting smooth and flat Ta capping layer promotes a smooth and flat surface in the MTJ layers which are subsequently formed on the surfactant layer. For a 0.3×0.6 micron MTJ bit size, a 35 to 40 Angstrom thick NiFe(18%) free layer, an AlOx barrier layer generated from a ROX oxidation of an 9 to 10 Angstrom thick Al layer, and a Ru/Ta/Ru capping layer are employed to give a dR/R of >40% and an RA of about 4000 ohm-μm2. The MTJ configuraton is extendable to a 0.2×0.4 micron MTJ bit size.
摘要:
A magnetoresistive (MR) transducer has at least one insulative layer made of tetrahedral amorphous carbon (ta-C). The ta-C layer is formed by filtered cathodic arc deposition, has an essentially zero concentration of hydrogen and can serve as a read gap for the transducer. The hydrogen-free t-aC read gap has high thermal conductivity, keeping an adjoining MR sensor from overheating during operation. This extends sensor lifetimes and/or improves sensor performance. The read gap also has low defects and porosity, preventing unwanted electrical conduction or shorting between a sensor and a shield. The high hardness of the read gap resists plasma and chemical etching processes such as ion milling that are used to form the sensor. The increased hardness and reduced defects and porosity allow the read gaps to be made thinner without risking electrical shorting. Other hydrogen-free t-aC layers are employed for other sensor elements where electrical insulation and reduced thickness are important.
摘要:
The preferred embodiment of the present invention provides a write head having an interlaced conductor coil winding and method of fabrication. The interlaced winding of the present invention may have alternating turns of a first and a second coil. In the preferred embodiment, the side walls of successive coil turns are separated by an ultra thin inorganic insulation which defines the distance between successive turns of the first and second coil. In one method of fabrication, a conductive seed layer is deposited on a generally planar insulative surface, a resist mask is formed on the seed layer, and a conductive material deposited on the exposed seed layer to form the turns of the first coil. The masked portions of the seed layer are removed, after resist mask removal, to electrically isolate the turns of the first coil. The inorganic insulation may be formed in a layer conformal with the first coil. The second coil is formed between the turns of the first coil. A seed layer and mask may be used to facilitate second coil deposition. Etching, or planarization, may be used to electrically isolate the turns of the second coil. A capping layer may be formed over any exposed conductor material to insulate the winding from an upper pole structure or other overlying structure. Embodiments of the present invention may have multiple layers of conductor winding having some conventional, or all interlaced coil structure.
摘要:
A magnetoresistive sensor has a read gap that is made of a slow ion milling rate material. The slow milling rate read gap allows a blunt end to be formed for the sensor without excessive overmilling into the read gap. The read gap may also be formed of plural layers with at least one of the layers having a low milling rate. This allows the other read gap layer to have complimentary attributes, such as high thermal conductivity, low stress, less pinholes and/or better dielectric properties. The electromagnetic characteristics of MR sensors having such steeply sloped ends are enhanced both in reading signals and reducing noise. The track width of such a sensor can be more accurately formed due to the blunt shape of the contiguous junction, quantizing signals and reducing errors from reading adjacent tracks. The sensor can also be made to have a sharper linear bit resolution, due to a thinner, high-integrity read gap. Barkhausen noise is reduced, as well as signal biasing improved, with blunt contiguous junctions formed between the sensor ends and lead or bias layers.
摘要:
A method provides a PMR transducer. In one aspect, the method includes forming a trench in an intermediate layer using reactive ion etch(es). The trench top is wider than its bottom. In this aspect, the method also includes providing a seed layer using atomic layer deposition and providing a PMR pole on the seed layer. Portion(s) of the seed layer and PMR pole reside in the trench. In another aspect, the method includes providing a mask including a trench having a top wider than its bottom. In this aspect, the method includes providing mask material in the trench, providing an intermediate layer on the mask material and removing the mask material to provide another trench in the intermediate layer. In this aspect, the method also includes providing a PMR pole in the additional trench.