Abstract: A process flow for forming a magnetic tunnel junction (MTJ) cell that is self-aligned to an underlying bottom electrode (BE) is disclosed. The BE is comprised of a lower BE layer having a first width (w1), and an upper (second) BE layer with a second width (w2) where w2>w1. Preferably, the BE has a T shape. A stack of MTJ layers including an uppermost hard mask is deposited on the BE and has width w2 because of a self-aligned deposition process. A dummy MTJ stack is also formed around the first BE layer. An ion beam etch where ions are at an incident angle <90° with respect to the substrate is used to remove extraneous material on the sidewall. Thereafter, an encapsulation layer is deposited to insulate the MTJ cell, and to fill a gap between the first BE layer and dummy MTJ stack.

Abstract: A manufacturing method for a waveguide includes forming a core including a first layer and a second layer. The first layer has a top surface including a first region with which a bottom surface of the second layer is in contact, and a second region with which the bottom surface of the second layer is not in contact. Forming the core includes the steps of: forming an initial first layer; forming an etching stopper layer on the second region of the initial first layer; forming an initial second layer on the initial first layer and the etching stopper layer; etching the initial second layer and the initial first layer so as to make the initial first layer into the first layer; and etching the initial second layer until the etching stopper layer is exposed, so as to make the initial second layer into the second layer.

Abstract: A process flow for forming magnetic tunnel junction (MTJ) nanopillars with minimal sidewall residue and damage is disclosed wherein a pattern is first formed in a hard mask or uppermost MTJ layer. Thereafter, the hard mask sidewall is etch transferred through the remaining MTJ layers with a RIE process comprising main etch and over etch portions, and a cleaning step. The RIE process features noble gas and an oxidant that is one or more of CH3OH, C2H5OH, NH3, N2O, H2O2, H2O, O2, and CO. Noble gas/oxidant flow rate ratio during over etch may be greater than during main etch to avoid chemical damage to MTJ sidewalls. The cleaning step may comprise plasma or ion beam etch with the noble gas and oxidant mixture. Highest values for magnetoresistive ratio and coercivity (Hc) are observed for noble gas/oxidant ratios from 75:25 to 90:10, especially for MTJ nanopillar sizes ?100 nm.

Abstract: A process flow for forming and encapsulating magnetic tunnel junction (MTJ) nanopillars is disclosed wherein MTJ layers including a reference layer (RL), free layer (FL), and tunnel barrier layer (TB) are first patterned by reactive ion etching or ion beam etching to form MTJ sidewalls. A plurality of MTJs on a substrate is heated (annealed) at a station in a process chamber to substantially crystallize the RL, FL, and TB to a body centered cubic (bcc) structure without recrystallization from the edge of the device before an encapsulation layer is deposited thereby ensuring lattice matching between the RL and TB, and between the FL and TB. The encapsulation layer is deposited at the same station as the anneal step without breaking vacuum, and preferably using a physical vapor deposition to prevent reactive species from attacking MTJ sidewalls. Magnetoresistive ratio is improved especially for MTJs with critical dimensions below 70 nm.

Abstract: A PMR (perpendicular magnetic recording) head includes a tapered write pole that is fully surrounded by wrapped-around magnetic shields, including laterally disposed side shields, a trailing shield and a leading shield. A layer of high magnetic saturation material (high Bs) is formed on the leading edge of the trailing shield and extends rearward, away from the ABS plane to define a cross-sectional write gap shape that is not conformal with the shape of the tapered write pole. The cross-sectional shape of this shield layer enables it to absorb flux from the write pole so that the flux for writing is enhanced and concentrated at the area of the recording medium being written upon and does not extend to adjacent tracks or to downtrack positions at which such flux is not desired.

Abstract: A magnetic tunnel junction with perpendicular magnetic anisotropy (PMA MTJ) is disclosed wherein a free layer has an interface with a tunnel barrier and a second interface with an oxide layer. A lattice-matching layer adjoins an opposite side of the oxide layer with respect to the free layer and is comprised of CoXFeYNiZLWMV or CoXFeYNiZLW wherein L is one of B, Zr, Nb, Hf, Mo, Cu, Cr, Mg, Ta, Ti, Au, Ag, or P, and M is one of Mo, Mg, Ta, Cr, W, or V, (x+y+z+w+v)=100 atomic %, x+y>0, and each of v and w are >0. The lattice-matching layer grows a BCC structure during annealing at about 400° C. thereby promoting BCC structure growth in the oxide layer. As a result, free layer PMA is enhanced and maintained to yield improved thermal stability.

Abstract: A perpendicular magnetic recording writer is disclosed with a leading shield (LS) having an upper layer that extends from an air bearing surface (ABS) to a backside at a first height (a). A LS lower layer has an upper surface that contacts the LS upper layer, a front side at the ABS, and a backside at a second height (b) where b>a. LS lower layer has a notch in the upper surface that is recessed from the ABS and has a first side aligned parallel to the ABS. The notch is aligned below the main pole and has a cross-track width that is from 1× to 11× the track width, and two sidewalls formed equidistant from a center plane wherein each sidewall intersects the first side at a 90 to 170 degree angle. Accordingly, overwrite, bit error rate (BER), and tracks per square inch capability are improved.

Abstract: A PMR writer is disclosed with an all wrap around (AWA) shield design in which one or more of the leading shield, side shields, and trailing shield (TS) structure (except the hot seed layer) at the air bearing surface (ABS) are comprised of an alloy having a damping parameter ? of ?0.04 to minimize wide area track erasure (WATE). The TS structure comprises two outer magnetic layers with an 8-16 kiloGauss (kG) saturation magnetic moment on each side of a center stack with a lower write gap, a middle hot seed layer having a 19-24 kG saturation magnetic moment, and an upper magnetic layer with a 16-24 kG saturation magnetic moment, and each having a first cross-track width. The hot seed layer, upper TS magnetic layer and an overlying PP3 trailing shield promote improved area density capability (ADC).

Abstract: A method for etching a magnetic tunneling junction (MTJ) structure is described. A bottom electrode layer is provided on a substrate. A seed layer is deposited on the bottom electrode layer. The seed layer and bottom electrode layer are patterned. A dielectric layer is deposited over the patterned seed layer and bottom electrode layer and planarized wherein the seed layer is exposed. Thereafter, a stack of MTJ layers is deposited on the patterned seed layer comprising a pinned layer, a tunnel barrier layer, and a free layer. The MTJ stack is then patterned to form a MTJ device. Because the seed layer was patterned before the MTJ patterning step, the exposure of the device to etching plasma gases is shortened and thus, etch damage is minimized.

Abstract: A magnetic tunnel junction (MTJ) is disclosed wherein first and second interfaces of a free layer (FL) with a first metal oxide (Hk enhancing layer) and second metal oxide (tunnel barrier), respectively, produce perpendicular magnetic anisotropy (PMA) to increase thermal stability. In some embodiments, metal clusters are formed in the FL and are subsequently partially or fully oxidized by scavenging oxygen to generate additional FL/oxide interfaces that enhance PMA, provide an acceptable resistance x area (RA) value, and preserve the magnetoresistive ratio. In other embodiments, a continuous or discontinuous metal (M) or MQ alloy layer within the FL reacts with scavenged oxygen to form a partially oxidized metal or alloy layer that enhances PMA and maintains acceptable RA. M is one of Mg, Al, B, Ca, Ba, Sr, Ta, Si, Mn, Ti, Zr, or Hf, and Q is a transition metal, B, C, or Al.

Abstract: 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.

Abstract: A plasmon generator including a wide portion and a narrow portion is manufactured by etching an initial plasmon generator using an etching mask. The etching mask includes a first mask layer for defining the shape of one of the narrow portion and the wide portion, and a second mask layer for defining the shape of the other of the narrow portion and the wide portion. The etching mask is formed by forming a first hard mask, a second initial mask layer and a second hard mask in this order on a first initial mask layer, and etching the first and second initial mask layers by using the first and second hard masks.

Abstract: A slider design for a hard disk drive (HDD) features an air-bearing surface (ABS) topography with arrays of micro-dots formed on bases of a multiplicity of cavities at different depths. The design eliminates the accumulation of hydrocarbons (e.g., spindle oil and disk lubricant) deposits in regions of air stagnation within the cavities where backflows and foreflows of air meet and cancel during HDD operation. The micro-dots are small raised regions of various shapes having sizes and spacings in the range between 2 and 100 microns and, in a preferred embodiment, heights of 0.15 microns above the cavity bases.

Abstract: A PMR writer is disclosed wherein magnetic flux return from a magnetic medium to a main pole is substantially greater through a trailing shield structure than through a leading return loop comprised of a leading shield, return path layer (RTP), and back gap connection (BGC). Magnetic impedance is increased between the RTP and main pole in the leading return loop by removing one or more layers in the BGC and replacing with dielectric material and non-magnetic metal to form a dielectric gap between the RTP and main pole. The non-magnetic metal may be Cu that is electrically isolated from coils within the write head. As a result, area density control and bit error rate are improved over a conventional dual write shield (DWS) structure comprising two flux return pathways. Moreover, adjacent track erasure is maintained at a level similar to a DWS design.

Abstract: A magnetic device for magnetic random access memory (MRAM), spin torque MRAM, or spin torque oscillator technology is disclosed wherein a perpendicularly magnetized magnetic tunnel junction (p-MTJ) with a sidewall is formed between a bottom electrode and a top electrode. A first dielectric layer is 3 to 400 Angstroms thick, and formed on the p-MTJ sidewall with a physical vapor deposition RF sputtering process to establish a thermally stable interface with the p-MTJ up to temperatures around 400° C. during CMOS fabrication. The first dielectric layer may comprise one or more of B, Ge, and alloys thereof, and an oxide, nitride, carbide, oxynitride, or carbonitride. The second dielectric layer is up to 2000 Angstroms thick and may be one or more of SiOYNZ, AlOYNZ, TiOYNZ, SiCYNZ, or MgO where y+z>0.

Abstract: A magnetic sensor with increased sensitivity, lower noise, and improved frequency response is described. The sensor's 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 sensor's edges to promote larger MR sensor magnetization rotation. Side stripes are located in the plane of the free layer at a maximum distance of 0.1 microns from each side of the free layer. The free layer has a width <300 nm, a length of >1 micron, and an aspect ratio (thickness/width) of at least 5. Preferably, Mfilmtfilm>Mfreetfree, where Mfilm and Mfree are the magnetization of the soft magnetic layers and free layer, respectively, and ffilm and tfree are the thickness of the soft magnetic layers and free layer, respectively.

Abstract: A slider design for a hard disk drive (HDD) features an air-bearing surface (ABS) topography with soft bumper pads (SBP) formed proximally to corners of the leading edge and the trailing edge. The bumper pads are formed by a process that combines the use of a first photomask for subtractive etching of the ABS to form pedestals, followed by additive depositions onto the pedestals using a second lift-off photomask. The additive process deposits sequences of Si layers and diamond-like carbon (DLC) layers to produce a soft bumper pad that is energy absorbing and heat conducting, thereby protecting the recording media from surface damage and thermal erasures.

Abstract: A hard mask stack for etching a magnetic tunneling junction (MTJ) structure is described. An electrode layer is deposited on a stack of MTJ layers on a bottom electrode. A photoresist mask is formed on the electrode layer. The electrode layer is etched away where it is not covered by the photoresist mask to form a metal hard mask. The metal hard mask is passivated during or after etching to form a smooth hard mask profile. Thereafter, the photoresist mask is removed and the MTJ structure is etched using the metal hard mask wherein the metal hard mask remaining acts as a top electrode. The resulting MTJ device has smooth sidewalls and uniform device shape.

Abstract: A KrF (248 nm) photoresist patterning process flow is disclosed wherein photoresist patterns having a sub-100 nm CD are formed on a dielectric antireflective coating (DARC) thereby lowering cost of ownership by replacing a more expensive ArF (193 nm) photoresist patterning process. A key feature is treatment of a DARC such as SiON with a photoresist developer solution that is 0.263 N tetramethylammonium hydroxide (TMAH) prior to treatment with hexamethyldisilazane (HMDS) in order to significantly improve adhesion of features with CD down to about 60 nm. After the HMDS treatment, a photoresist layer is coated on the DARC, patternwise exposed, and treated with the photoresist developer solution to form a pattern therein. Features that were previously resolved by KrF patterning processes but subsequently collapsed because of poor adhesion, now remain upright and intact during a subsequent etch process used to transfer the sub-100 nm features into a substrate.

Abstract: A stack of MTJ layers is provided on a substrate comprising a bottom electrode, a pinned layer, a tunnel barrier layer, a free layer, and a top electrode. The MTJ stack is patterned to form a MTJ device wherein sidewall damage is formed on its sidewalls. A dielectric spacer is formed on the MTJ device. The dielectric spacer is etched away on horizontal surfaces wherein the dielectric spacer on the sidewalls is partially etched away. The remaining dielectric spacer covers the pinned layer and bottom electrode. The dielectric spacer is removed from the free layer or is thinner on the free layer than on the pinned layer and bottom electrode. Sidewall damage is thereafter removed from the free layer by applying a horizontal etching to the MTJ device wherein the pinned layer and bottom electrode are protected from etching by the dielectric spacer layer.