Patents by Inventor Kunliang Zhang
Kunliang Zhang 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).
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Patent number: 12266384Abstract: The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.Type: GrantFiled: January 5, 2023Date of Patent: April 1, 2025Assignee: Headway Technologies, Inc.Inventors: Hui-Chuan Wang, Shohei Kawasaki, Kunliang Zhang, Sangmun Oh, Zheng Gao
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Patent number: 12254908Abstract: Systems and methods for controlling a critical dimension (CD) uniformity of a magnetic head device are described. A film stack that is part of a system for controlling a critical dimension (CD) uniformity of a magnetic head device can include a substrate, a magnetoresistive (MR) sensor layer, and a hard mask layer. The system can also include a first mask that defines critical shape patterns other than the CD. The hard mask layer can be patterned using the first mask. The system can also include a second mask that defines the CD. A mandrel pattern can be formed on the hard mask layer using the second mask.Type: GrantFiled: June 28, 2023Date of Patent: March 18, 2025Assignee: Headway Technologies, Inc.Inventors: Tom Zhong, Hiroshi Omine, Jianing Zhou, Kunliang Zhang, Ruhang Ding, Min Li
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Patent number: 12211526Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.Type: GrantFiled: October 30, 2023Date of Patent: January 28, 2025Assignee: Headway Technologies, Inc.Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Publication number: 20240233999Abstract: The present embodiments relate to a tunnel magnetoresistance (TMR) element. The TMR element can include a free layer comprising a metallic alloy that is doped using a dopant element. In some instances, the metallic alloy comprises a cobalt-iron (CoFe) alloy. The present embodiments relate to doping a small amount of an element (e.g., hafnium (Hf), tantalum (Ta), Yttrium (Y)) in a high flux CoFe layer of a tunnel magnetoresistance (TMR) element. The small amount of dopant can suppress a long-range order in the CoFe film. The amorphous state of a CoFe alloy can be induced by the dopant and result in a magnetically soft layer. A resistance of the TMR element can be modified based on an application of an external magnetic field to the free layer and the pin layer.Type: ApplicationFiled: January 5, 2023Publication date: July 11, 2024Inventors: Hui-Chuan Wang, Shohei Kawasaki, Kunliang Zhang, Sangmun Oh, Zheng Gao
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Publication number: 20240071414Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.Type: ApplicationFiled: October 30, 2023Publication date: February 29, 2024Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Patent number: 11887635Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.Type: GrantFiled: July 1, 2022Date of Patent: January 30, 2024Assignee: Headway Technologies, Inc.Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Publication number: 20230343362Abstract: Methods of critical dimension (CD) uniformity control for magnetic head devices are disclosed. In some embodiments, a method can include providing a film stack, the film stack including a substrate, a magnetoresistive (MR) sensor layer, and a hard mask layer, patterning the hard mask layer using a first mask that defines critical shape patterns other than the CD, forming a mandrel pattern using a second mask that defines the CD, and forming a sidewall spacer pattern on sidewalls of the mandrel pattern, and removing the mandrel pattern.Type: ApplicationFiled: June 28, 2023Publication date: October 26, 2023Inventors: Tom Zhong, Hiroshi Omine, Jianing Zhou, Kunliang Zhang, Ruhang Ding, Min Li
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Patent number: 11715491Abstract: Methods of critical dimension (CD) uniformity control for magnetic head devices are disclosed. In some embodiments, a method can include providing a film stack, the film stack including a substrate, a magnetoresistive (MR) sensor layer, and a hard mask layer, patterning the hard mask layer using a first mask that defines critical shape patterns other than the CD, forming a mandrel pattern using a second mask that defines the CD, and forming a sidewall spacer pattern on sidewalls of the mandrel pattern, and removing the mandrel pattern.Type: GrantFiled: June 30, 2021Date of Patent: August 1, 2023Assignee: Headway Technologies, Inc.Inventors: Tom Zhong, Hiroshi Omine, Jianing Zhou, Kunliang Zhang, Ruhang Ding, Min Li
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Publication number: 20230005500Abstract: Methods of critical dimension (CD) uniformity control for magnetic head devices are disclosed. In some embodiments, a method can include providing a film stack, the film stack including a substrate, a magnetoresistive (MR) sensor layer, and a hard mask layer, patterning the hard mask layer using a first mask that defines critical shape patterns other than the CD, forming a mandrel pattern using a second mask that defines the CD, and forming a sidewall spacer pattern on sidewalls of the mandrel pattern, and removing the mandrel pattern.Type: ApplicationFiled: June 30, 2021Publication date: January 5, 2023Inventors: Tom Zhong, Hiroshi Omine, Jianing Zhou, Kunliang Zhang, Ruhang Ding, Min Li
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Publication number: 20220335969Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or in another embodiment, the PM layer adjoins a backside of the top shield and has a width equal to or greater than that of the FL.Type: ApplicationFiled: July 1, 2022Publication date: October 20, 2022Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Patent number: 11380355Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or a width equal to the cross-track distance between outer sides of the longitudinal bias layers. In another embodiment, the PM layer adjoins a backside of the top shield.Type: GrantFiled: October 27, 2020Date of Patent: July 5, 2022Assignee: Headway Technologies, Inc.Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Publication number: 20220130419Abstract: A read head includes a permanent magnet (PM) layer formed up to 100 nm behind a free layer where PM layer magnetization may be initialized in a direction that adjusts free layer (FL) bias point, and shifts sensor asymmetry (Asym) closer to 0% for individual heads at slider or Head Gimbal Assembly level to provide a significant improvement in device yield. Asym is adjusted using different initialization schemes and initialization directions. With individual heads, initialization direction is selected based on a prior measurement of asymmetry. The PM layer is CoPt or CoCrPt and has coercivity from 500 Oersted to 1000 Oersted. The PM layer may have a width equal to the FL, or a width equal to the cross-track distance between outer sides of the longitudinal bias layers. In another embodiment, the PM layer adjoins a backside of the top shield.Type: ApplicationFiled: October 27, 2020Publication date: April 28, 2022Inventors: Glen Garfunkel, Yan Wu, Wenyu Chen, Kunliang Zhang, Min Li, Shohei Kawasaki
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Patent number: 11217274Abstract: A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100° C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.Type: GrantFiled: February 7, 2020Date of Patent: January 4, 2022Assignee: Headway Technologies, Inc.Inventors: Junjie Quan, Glen Garfunkel, Yewhee Chye, Kunliang Zhang, Min Li
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Patent number: 10950261Abstract: The use of supermalloy-like materials such as NiFeMe where Me is one or more of Mo, Cr, and Cu for the side and top shields of a magnetic bit sensor is shown to provide better shielding protection from stray fields because of their extremely high permeability. Moreover, the side shield may comprise a stack in which a Ni, Fe, Co, FeNi, CoFe, or FeCo is sandwiched between two NiFeMe layers to enhance the bias field on an adjacent free layer. Including NiFeMe in a side shield results in an increase in readback amplitude under the same asymmetric sigma. For these sensors, the signal to noise ratio was higher and the bit error rate was lower than with conventional materials in the side shield. A method is disclosed for forming a magnetic bit sensor having supermalloy-like materials in the side shields.Type: GrantFiled: August 28, 2018Date of Patent: March 16, 2021Assignee: Headway Technologies, Inc.Inventors: Yewhee Chye, Kunliang Zhang, Min Li
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Publication number: 20200176024Abstract: A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100° C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.Type: ApplicationFiled: February 7, 2020Publication date: June 4, 2020Inventors: Junjie Quan, Glen Garfunkel, Yewhee Chye, Kunliang Zhang, Min Li
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Patent number: 10593357Abstract: A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100° C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.Type: GrantFiled: October 16, 2018Date of Patent: March 17, 2020Assignee: Headway Technologies, Inc.Inventors: Junjie Quan, Glen Garfunkel, Yewhee Chye, Kunliang Zhang, Min Li
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Patent number: 10586560Abstract: A PMR (perpendicular magnetic recording) head is configured for thermally assisted magnetic recording (TAMR). The thermal energy is supplied by the near-fields of plasmons and the near-fields are directed to a magnetic recording medium by a PPG layer. The PPG layer is Rhodium (Rh) whose small-grained crystal structure normally makes it subject to thermal deformations and other weaknesses. By growing the PPG layer on a thin template layer (TTL), the portion of the PPG layer adjacent to the air-bearing surface (ABS) develops a larger grain size and stronger forces between its atomic constituents which makes it resistant to those deformations.Type: GrantFiled: March 5, 2019Date of Patent: March 10, 2020Assignee: Headway Technologies, Inc.Inventors: Shengyuan Wang, Weihao Xu, Cherng-Chyi Han, Xuhui Jin, Min Li, Kunliang Zhang
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Patent number: 10354707Abstract: A seed layer stack with a smooth top surface having a peak to peak film thickness variation of about 0.5 nm is formed by sputter depositing a second seed layer on a first seed layer that is Mg, MgN, or an alloy thereof where the second seed layer has a bond energy substantially greater than that of the first seed layer. The second seed layer may be Ta or NiCr. In some embodiments, an uppermost seed layer that is one or both of Ru and Cu is deposited on the second seed layer. Higher coercivity (Hc) and perpendicular magnetic anisotropy (Hk) is observed in an overlying ferromagnetic layer than when a prior art seed layer stack is employed. The first seed layer has a thickness from 2 to 20 Angstroms and has a resputtering rate about 2 to 40 times that of the second seed layer.Type: GrantFiled: April 14, 2016Date of Patent: July 16, 2019Assignee: Headway Technologies, Inc.Inventors: Kunliang Zhang, Ruhang Ding, Min Li, Wenyu Chen
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Publication number: 20190051321Abstract: A hard magnet stabilization scheme is disclosed for a top shield and junction shields for double or triple dimension magnetic reader structures. In one design, the hard magnet (HM) adjoins a top or bottom surface of all or part of a shield domain such that the HM is recessed from the air bearing surface to satisfy reader-to-reader spacing requirements and stabilizes a closed loop magnetization in the top shield. The HM may have a height and width greater than that of the top shield. The top shield may have a ring shape with a HM formed above, below, or within the ring shape, and wherein the HM stabilizes a vortex magnetization. HM magnetization is set or reset from room temperature to 100° C. to maintain a desired magnetization direction in the top shield, junction shield, and free layer in the sensor.Type: ApplicationFiled: October 16, 2018Publication date: February 14, 2019Inventors: Junjie Quan, Glen Garfunkel, Yewhee Chye, Kunliang Zhang, Min Li
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Publication number: 20190013041Abstract: The use of supermalloy-like materials such as NiFeMe where Me is one or more of Mo, Cr, and Cu for the side and top shields of a magnetic bit sensor is shown to provide better shielding protection from stray fields because of their extremely high permeability. Moreover, the side shield may comprise a stack in which a Ni, Fe, Co, FeNi, CoFe, or FeCo is sandwiched between two NiFeMe layers to enhance the bias field on an adjacent free layer. Including NiFeMe in a side shield results in an increase in readback amplitude under the same asymmetric sigma. For these sensors, the signal to noise ratio was higher and the bit error rate was lower than with conventional materials in the side shield. A method is disclosed for forming a magnetic bit sensor having supermalloy-like materials in the side shields.Type: ApplicationFiled: August 28, 2018Publication date: January 10, 2019Inventors: Yewhee Chye, Kunliang Zhang, Min Li