Patents by Inventor Chyu-Jiuh Torng

Chyu-Jiuh Torng has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Tunneling magneto-resistive spin valve sensor with novel composite free layer
    Patent number: 7742261
    Abstract: The conventional free layer in a TMR read head has been replaced by a composite of two or more magnetic layers, one of which is iron rich The result is an improved device that has a higher MR ratio than prior art devices, while still maintaining free layer softness and acceptable magnetostriction. A process for manufacturing the device is also described.
    Type: Grant
    Filed: January 12, 2005
    Date of Patent: June 22, 2010
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Chyu-Jiuh Torng
  • Hafnium doped cap and free layer for mram device
    Publication number: 20100136713
    Abstract: A high performance MTJ, and a process for manufacturing it, are described. A capping layer of NiFeHf is used to getter oxygen out of the free layer, thereby increasing the sharpness of the free layer-tunneling layer interface. The free layer comprises two NiFe layers whose magnetostriction constants are of opposite sign, thereby largely canceling one another.
    Type: Application
    Filed: January 27, 2010
    Publication date: June 3, 2010
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Witold Kula
  • Bottom electrode mask design for ultra-thin interlayer dielectric approach in MRAM device fabrication
    Publication number: 20100123207
    Abstract: A bottom electrode (BE) layout is disclosed that has four distinct sections repeated in a plurality of device blocks and is used to pattern a BE layer in a MRAM. A device section includes BE shapes and dummy BE shapes with essentially the same shape and size and covering a substantial portion of substrate. There is a via in a plurality of dummy BE shapes where each via will be aligned over a WL pad. A second bonding pad section comprises an opaque region having a plurality of vias. The remaining two sections relate to open field regions in the MRAM. The third section has a plurality of dummy BE shapes with a first area size. The fourth section has a plurality of dummy BE shapes with a second area size greater than the first area size to provide more complete BE coverage of an underlying etch stop ILD layer.
    Type: Application
    Filed: November 17, 2008
    Publication date: May 20, 2010
    Inventors: Tom Zhong, Chyu-Jiuh Torng, Rongfu Xiao
  • Field angle sensor fabricated using reactive ion etching
    Patent number: 7713755
    Abstract: A high-amplitude magnetic angle sensor is described along with a process for its manufacture. A thin tantalum nitride hard mask, used to pattern the device, is left in place within the completed structure but, by first converting most of it to tantalum oxide, its effect on current shunting is greatly reduced.
    Type: Grant
    Filed: December 11, 2008
    Date of Patent: May 11, 2010
    Assignee: MagIC Technologies, Inc.
    Inventors: Rongfu Xiao, Ruth Tong, Witold Kula, Chyu-Jiuh Torng
  • High density spin-transfer torque MRAM process
    Publication number: 20100109106
    Abstract: A STT-MRAM integration scheme is disclosed wherein the connection between a MTJ and CMOS metal is simplified by forming an intermediate via contact (VAC) on a CMOS landing pad, a metal (VAM) pad that contacts and covers the VAC, and a MTJ on the VAM. A dual damascene process is performed to connect BIT line metal to CMOS landing pads through VAC/VAM/MTJ stacks in a device region, and to connect BIT line connection pads to CMOS connection pads through BIT connection vias outside the device region. The VAM pad is a single layer or composite made of Ta, TaN, or other conductors which serves as a diffusion barrier, has a highly smooth surface for MTJ formation, and provides excellent selectivity with refill dielectric materials during a chemical mechanical polish process. Each VAC is from 500 to 3000 Angstroms thick to minimize additional circuit resistance and minimize etch burden.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 6, 2010
    Inventors: Tom Zhong, Chyu-Jiuh Torng, Rongfu Xiao, Adam Zhong, Wai-Ming Johnson Kan, Daniel Liu
  • Composite hard mask for the etching of nanometer size magnetic multilayer based device
    Patent number: 7696551
    Abstract: A composite hard mask is disclosed that enables sub-100 nm sized MTJ cells to be formed for advanced devices such as spin torque MRAMs. The hard mask has a lower non-magnetic metallic layer such as Ru to magnetically isolate an overlying middle metallic spacer such as MnPt from an underlying free layer. The middle metallic spacer provides a height margin during subsequent processing to avoid shorting between a bit line and the MTJ cell in the final device. An upper conductive layer may be made of Ta and is thin enough to allow a MTJ pattern in a thin overlying photoresist layer to be transferred through the Ta during a fluorocarbon etch without consuming all of the photoresist. The MTJ pattern is transferred through the remaining hard mask layers and underlying MTJ stack of layers with a second etch step using a C, H, and O etch gas composition.
    Type: Grant
    Filed: September 20, 2007
    Date of Patent: April 13, 2010
    Assignee: MagIC Technologies, Inc.
    Inventors: Rongfu Xiao, Chyu-Jiuh Torng, Tom Zhang, Witold Kula, Adam Zhang
  • Hard bias design for extra high density recording
    Patent number: 7688555
    Abstract: A hard bias structure for biasing a free layer in a MR element within a read head is comprised of a composite hard bias layer having a Co78.6Cr5.2Pt16.2/Co65Cr15Pt20 configuration. The upper Co65Cr15Pt20 layer has a larger Hc value and a thickness about 2 to 10 times greater than that of the Co78.6Cr5.2Pt16.2 layer. The hard bias structure may also include a BCC underlayer such as FeCoMo which enhances the magnetic moment of the hard bias structure. Optionally, the thickness of the Co78.6Cr5.2Pt16.2 layer is zero and the Co65Cr15Pt20 layer is formed on the BCC underlayer. The present invention also encompasses a laminated hard bias structure. The Mrt value for the hard bias structure may be optimized by adjusting the thicknesses of the BCC underlayer and CoCrPt layers. As a result, a larger process window is realized and lower asymmetry output during a read operation is achieved.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: March 30, 2010
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Yun-Fei Li, Chyu-Jiuh Torng, Chen-Jung Chien
  • Structure and method to fabricate high performance MTJ devices for spin-transfer torque (STT)-RAM
    Publication number: 20100065935
    Abstract: A STT-RAM MTJ is disclosed with a MgO tunnel barrier formed by a NOX process, a CoFeB/FeSiO/CoFeB composite free layer with a middle nanocurrent channel layer to minimize Jc0, and a Ru capping layer to enhance the spin scattering effect and increase dR/R. Good write margin is achieved by modifying the NOX process to afford a RA less than 10 ohm-?m2 and good read margin is realized with a dR/R of >100% by annealing at 330° C. or higher to form crystalline CoFeB free layers. The NCC thickness is maintained in the 6 to 10 Angstrom range to reduce Rp and avoid Fe(Si) granules from not having sufficient diameter to bridge the distance between upper and lower CoFeB layers. A FeSiO layer may be inserted below the Ru layer in the capping layer to prevent the Ru from causing a high damping constant in the upper CoFeB free layer.
    Type: Application
    Filed: September 18, 2008
    Publication date: March 18, 2010
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Po-Kang Wang, Robert Beach, Witold Kula
  • Hafnium doped cap and free layer for MRAM device
    Patent number: 7672093
    Abstract: A high performance MTJ, and a process for manufacturing it, are described. A capping layer of NiFeHf is used to getter oxygen out of the free layer, thereby increasing the sharpness of the free layer-tunneling layer interface. The free layer comprises two NiFe layers whose magnetostriction constants are of opposite sign, thereby largely canceling one another.
    Type: Grant
    Filed: October 17, 2006
    Date of Patent: March 2, 2010
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Witold Kula
  • SyAF structure to fabricate Mbit MTJ MRAM
    Patent number: 7663131
    Abstract: A MTJ that minimizes error count (EC) while achieving high MR value, low magnetostriction, and a RA of about 1100 ?-?m2 for 1 Mbit MRAM devices is disclosed. The MTJ has a composite AP1 pinned layer made of a lower amorphous Co60Fe20B20 layer and an upper crystalline Co75Fe25 layer to promote a smoother and more uniform AlOx tunnel barrier. A “stronger oxidation” state is realized in the AlOx layer by depositing a thicker than normal Al layer or extending the ROX cycle time for Al oxidation and thereby reduces tunneling hot spots. The NiFe free layer has a low Fe content of about 8 to 21 atomic % and the Hf content in the NiFeHf capping layer is from 10 to 25 atomic %. A Ta hard mask is formed on the capping layer. EC (best) is reduced from >100 ppm to <10 ppm by using the preferred MTJ configuration.
    Type: Grant
    Filed: March 8, 2007
    Date of Patent: February 16, 2010
    Assignee: MagIC Technologies, Inc.
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Guangli Liu
  • FCC-like trilayer AP2 structure for CPP GMR EM improvement
    Publication number: 20090314632
    Abstract: A method of forming a CPP-GMR spin valve having a pinned layer with an AP2/coupling/AP1 configuration is disclosed wherein the AP2 portion is a FCC-like trilayer having a composition represented by CoZFe(100-Z)/Fe(100-X)TaX/CoZFe(100-Z) or CoZFe(100-Z)/FeYCo(100-Y)/CoZFe(100-Z) where x is 3 to 30 atomic %, y is 40 to 100 atomic %, and z is 75 to 100 atomic %. Preferably, z is 90 to provide a face centered cubic structure that minimizes electromigration. Optionally, the middle layer is comprised of an Fe rich alloy such as FeCr, FeV, FeW, FeZr, FeNb, FeHf, or FeMo. EM performance is improved significantly compared to a spin valve with a conventional AP2 Co50Fe50 or Co75Fe25 single layer. MR ratio is also increased and RA is maintained at an acceptable level. The coupling layer is preferably Ru and the AP1 layer may be comprised of a lamination of CoFe and Cu layers as in [CoFe/Cu]2/CoFe.
    Type: Application
    Filed: August 25, 2009
    Publication date: December 24, 2009
    Inventors: Kunliang Zhang, Dan Abels, Min Li, Chyu-Jiuh Torng, Chen-Jung Chien, Yu-Hsia Chen
  • Seed layer for fabricating spin valve heads for ultra-high density recordings
    Patent number: 7630176
    Abstract: A method for forming a bottom spin valve sensor element with a novel seed layer and synthetic antiferromagnetic pinned layer and the sensor so formed. The novel seed layer comprises an approximately 30 angstrom thick layer of NiCr whose atomic percent of Cr is 31%. On this seed layer there can be formed either a single bottom spin valve read sensor or a symmetric dual spin valve read sensor having synthetic antiferromagnetic pinned layers. An extremely thin (approximately 80 angstroms) MnPt pinning layer can be formed directly on the seed layer and extremely thin pinned and free layers can then subsequently be formed so that the sensors can be used to read recorded media with densities exceeding 60 Gb/in2. Moreover, the high pinning field and optimum magnetostriction produces an extremely robust sensor.
    Type: Grant
    Filed: May 17, 2007
    Date of Patent: December 8, 2009
    Assignee: Headway Technologies, Inc.
    Inventors: Cheng T. Horng, Hui-Chuan Wang, Ru-Ying Tong, Chyu-Jiuh Torng
  • Tunneling magneto-resistive spin valve sensor with novel composite free layer
    Patent number: 7602590
    Abstract: The conventional free layer in a TMR read head has been replaced by a composite of two or more magnetic layers, one of which is iron rich The result is an improved device that has a higher MR ratio than prior art devices, while still maintaining free layer softness and acceptable magnetostriction. A process for manufacturing the device is also described.
    Type: Grant
    Filed: January 12, 2005
    Date of Patent: October 13, 2009
    Assignee: Headway Technologies, Inc.
    Inventors: Tong Zhao, Hui-Chuan Wang, Chyu-Jiuh Torng
  • FCC-like trilayer AP2 structure for CPP GMR EM improvement
    Patent number: 7583481
    Abstract: A CPP-GMR spin valve having a pinned layer with an AP2/coupling/AP1 configuration is disclosed wherein the AP2 portion is a FCC-like trilayer having a composition represented by CoZFe(100-Z)/Fe(100-X)TaX/CoZFe(100-Z) or CoZFe(100-Z)/FeYCo(100-Y)/CoZFe(100-Z) where x is 3 to 30 atomic %, y is 40 to 100 atomic %, and z is 75 to 100 atomic %. Preferably, z is 90 to provide a face centered cubic structure that minimizes electromigration. Optionally, the middle layer is comprised of an Fe rich alloy such as FeCr, FeV, FeW, FeZr, FeNb, FeHf, or FeMo. EM performance is improved significantly compared to a spin valve with a conventional AP2 Co50Fe5 or Co75Fe25 single layer. The MR ratio of the spin valve is also increased and the RA is maintained at an acceptable level. The coupling layer is preferably Ru and the AP1 layer may be comprised of a lamination of CoFe and Cu layers as in [CoFe/Cu]2/CoFe.
    Type: Grant
    Filed: September 23, 2005
    Date of Patent: September 1, 2009
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Dan Abels, Min Li, Chyu-Jiuh Torng, Chen-Jung Chien, Yu-Hsia Chen
  • Use of CMP to contact a MTJ structure without forming a via
    Publication number: 20090209102
    Abstract: A process is described for making contact to the buried capping layers of GMR and MTJ devices without the need to form and fill via holes. CMP is applied to the structure in three steps: (1) conventional CMP (2) a Highly Selective Slurry (HSS) is substituted for the conventional slurry to just expose the capping layer, and (3) the HSS is diluted and used to clean the surface as well as to cause a slight protrusion of the capping layers above the surrounding dielectric surface, making it easier the contact them without damaging the devices below.
    Type: Application
    Filed: February 14, 2008
    Publication date: August 20, 2009
    Inventors: Adam Zhong, Wai-Ming Kan, Tom Zhong, Chyu-Jiuh Torng
  • CoFe insertion for exchange bias and sensor improvement
    Patent number: 7564658
    Abstract: A GMR spin value structure with improved performance and a method for making the same is disclosed. A key feature is the incorporation of a thin ferromagnetic insertion layer such as a 5 Angstrom thick CoFe layer between a NiCr seed layer and an IrMn AFM layer. Lowering the Ar flow rate to 10 sccm for the NiCr sputter deposition and raising the Ar flow rate to 100 sccm for the IrMn deposition enables the seed layer to be thinned to 25 Angstroms and the AFM layer to about 40 Angstroms. As a result, HEX between the AFM and pinned layers increases by up to 200 Oe while the Tb is maintained at or above 250° C. When the seed/CoFe/AFM configuration is used in a read head sensor, a higher GMR ratio is observed in addition to smaller free layer coercivity (HCF), interlayer coupling (HE), and HK values.
    Type: Grant
    Filed: September 23, 2004
    Date of Patent: July 21, 2009
    Assignee: Headway Technologies, Inc.
    Inventors: Kunliang Zhang, Hui-Chuan Wang, Tong Zhao, Min Li, Chyu-Jiuh Torng
  • Method of MRAM fabrication with zero electrical shorting
    Publication number: 20090173977
    Abstract: An MTJ cell without footings and free from electrical short-circuits across a tunneling barrier layer is formed by using a Ta hard mask layer and a combination of etches. A first etch patterns the Ta hard mask, while a second etch uses O2 applied in a single high power process at two successive different power levels. A first power level of between approximately 200 W and 500 W removes BARC, photoresist and Ta residue from the first etch, the second power level, between approximately 400 W and 600 W continues an etch of the stack layers and forms a protective oxide around the etched sides of the stack. Finally, an etch using a carbon, hydrogen and oxygen gas completes the etch while the oxide layer protects the cell from short-circuits across the lateral edges of the barrier layer.
    Type: Application
    Filed: January 7, 2008
    Publication date: July 9, 2009
    Inventors: Rongfu Xiao, Chyu-Jiuh Torng, Tom Zhong, Witold Kula
  • Exchange bias structure for abutted junction GMR sensor
    Patent number: 7529067
    Abstract: Although it is known that exchange bias can be utilized in abutted junctions for longitudinal stabilization, a relatively large moment is needed to pin down the sensor edges effectively. Due to the inverse dependence of the exchange bias on the magnetic layer thickness, a large exchange bias has been difficult to achieve by the prior art. This problem has been solved by introducing a structure in which the magnetic moment of the bias layer has been approximately doubled by pinning it from both above and below through exchange with antiferromagnetic layers. Additionally, since the antiferromagnetic layer is in direct abutted contact with the free layer, it acts directly to help stabilize the sensor edge, which is an advantage over the traditional magnetostatic pinning that had been used.
    Type: Grant
    Filed: March 14, 2006
    Date of Patent: May 5, 2009
    Assignee: Headway Technologies, Inc.
    Inventors: Yun-Fei Li, Hui-Chuan Wang, Chyu-Jiuh Torng, Cherng-Chyi Han, Mao-Min Chen
  • High performance MTJ element for conventional MRAM and for STT-RAM and a method for making the same
    Publication number: 20090108383
    Abstract: A STT-RAM MTJ that minimizes spin-transfer magnetization switching current (Jc) is disclosed. The MTJ has a MgO tunnel barrier layer formed with a natural oxidation process to achieve a low RA (10 ohm-um2) and a Fe or Fe/CoFeB/Fe free layer which provides a lower intrinsic damping constant than a CoFeB free layer. A Fe, FeB, or Fe/CoFeB/Fe free layer when formed with a MgO tunnel barrier (radical oxidation process) and a CoFeB AP1 pinned layer in a MRAM MTJ stack annealed at 360° C. provides a high dR/R (TMR)>100% and a substantial improvement in read margin with a TMR/Rp_cov=20. High speed measurement of 100 nm×200 nm oval STT-RAM MTJs has shown a Jc0 for switching a Fe free layer is one half that for switching an amorphous CO40Fe40B20 free layer. A Fe/CoFeB/Fe free layer configuration allows the Hc value to be increased for STT-RAM applications.
    Type: Application
    Filed: October 31, 2007
    Publication date: April 30, 2009
    Inventors: Cheng T. Horng, Ru-Ying Tong, Chyu-Jiuh Torng, Witold Kula
  • Method of magnetic tunneling layer processes for spin-transfer torque MRAM
    Publication number: 20090104718
    Abstract: A method for forming a MTJ in a STT-MRAM is disclosed in which the easy-axis CD is determined independently of the hard-axis CD. One approach involves two photolithography steps and two etch steps to form a post in a hard mask which is transferred through a MTJ stack of layers by a third etch process. Optionally, the third etch may stop on the tunnel barrier or in the free layer. A second embodiment involves forming a first parallel line pattern on a hard mask layer and transferring the line pattern through the MTJ stack with a first etch step. A planar insulation layer is formed adjacent to the sidewalls in the line pattern and then a second parallel line pattern is formed which is transferred by a second etch through the MTJ stack to form a post pattern. Etch end point may be controlled independently for hard-axis and easy-axis dimensions.
    Type: Application
    Filed: October 17, 2007
    Publication date: April 23, 2009
    Inventors: Tom Zhong, Rongfu Xiao, Chyu-Jiuh Torng, Adam Zhong