Headway Technologies, Incorporated

Western Digital (fremont), Inc.

Fujitsu Corporation

University of Alabama

Magic Technologies, Inc.

Tong Zhao

Hui-Chuan Wang

Min Li

Kunliang Zhang

Chyu-Jiuh Torng

Yu-Hsia Chen

Yu-Chen Zhou

Yun-Fei Li

Hui Wang

Yuchen Zhou

Yuankai Zheng

Christian Kaiser

Qunwen Leng

Zhitao Diao

Xin Jiang

Ru-Ying Tong

Cheng Tzong Horng

Yimin Guo

Moris Musa Dovek

Cherng-Chyi Han

Ming Mao

Hideo Fujiwara

Hai Sun

Wei Gao

Cherng Chyi Han

Keiichi Nagasaka

Min Zheng

Shengyuan Wang

Zhipeng Li

William Hill Butler

Miao Wang

Jianxin Fang

Minghui Yu

Amrit Bandyopadhyay

Hui-Chaun Wang

Yu-Hsai Chen

Julian Velev

A TMR sensor that includes a free layer having at least one B-containing (BC) layer made of CoFeB, CoFeBM, CoB, CoBM, or CoBLM, and a plurality of non-B containing (NBC) layers made of CoFe, CoFeM, or CoFeLM is disclosed where L and M are one of Ni, Ta, Ti, W, Zr, Hf, Tb, or Nb. One embodiment is represented by (NBC/BC)where n&#x2267;2. A second embodiment is represented by (NBC/BC)/NBC where n&#x2267;1. In every embodiment, a NBC layer contacts the tunnel barrier and NBC layers each with a thickness from 2 to 8 Angstroms are formed in alternating fashion with one or more BC layers each 10 to 80 Angstroms thick. Total free layer thickness is &#x3c;100 Angstroms. The free layer configuration described herein enables a significant noise reduction (SNR enhancement) while realizing a high TMR ratio, low magnetostriction, low RA, and low Hc values.

TMR device with novel free layer structure

A magnetic read apparatus has an air-bearing surface (ABS) and includes a shield, a crystal decoupling structure on the shield and a read sensor on the crystal decoupling structure. The crystal decoupling structure includes at least one of a magnetic high crystalline temperature amorphous alloy layer and a combination of a high crystalline temperature amorphous layer and an amorphous magnetic layer. The high crystalline temperature amorphous layer has a crystalline temperature of at least three hundred degrees Celsius. The amorphous magnetic layer is amorphous as-deposited.

Magnetic reader having a crystal decoupling structure

A TMR sensor with a free layer having a FL1/FL2/FL3 configuration is disclosed in which FL1 is FeCo or a FeCo alloy with a thickness between 2 and 15 Angstroms. The FL2 layer is made of CoFeB or a CoFeB alloy having a thickness from 2 to 10 Angstroms. The FL3 layer is from 10 to 100 Angstroms thick and has a negative &#x3bb; to offset the positive &#x3bb; from FL1 and FL2 layers and is comprised of CoB or a CoBQ alloy where Q is one of Ni, Mn, Tb, W, Hf, Zr, Nb, and Si. Alternatively, the FL3 layer may be a composite such as CoB/CoFe, (CoB/CoFe)where n is &#x2267;2 or (CoB/CoFe)/CoB where m is &#x2267;1. The free layer described herein affords a high TMR ratio above 60% while achieving low values for &#x3bb; (&#x3c;5&#xd7;10), RA (1.5 ohm/&#x3bc;m), and Hc (&#x3c;6 Oe).

TMR device with novel free layer

A method of fabricating a TMR sensor that includes a free layer having at least one B-containing (BC) layer made of CoFeB, CoFeBM, CoB, CoBM, or CoBLM, and a plurality of non-B containing (NBC) layers made of CoFe, CoFeM, or CoFeLM is disclosed where L and M are one of Ni, Ta, Ti, W, Zr, Hf, Tb, or Nb. In every embodiment, a NBC layer contacts the tunnel barrier and NBC layers each with a thickness from 2 to 8 Angstroms are formed in alternating fashion with one or more BC layers each 10 to 80 Angstroms thick. Total free layer thickness is &#x3c;100 Angstroms. The TMR sensor may be annealed with a one step or two step process. The free layer configuration described herein enables a significant noise reduction (SNR enhancement) while realizing a high TMR ratio, low magnetostriction, low RA, and low Hc values.

A high performance TMR sensor is fabricated by employing a free layer comprised of CoNiFeB or CoNiFeBM where M is V, Ti, Zr, Nb, Hf, Ta, or Mo and the M content in the alloy is &#x3c;10 atomic %. The free layer may have a FeCo/FeB/CoNiFeB, FeCo/CoFe/CoNiFeB, FeCo/CoFeB/CoNiFeB, or FeCo/CoNiFeB/CoFeB configuration. A CoNiFeBM layer may be formed by co-sputtering CoB with CoNiFeM. A 15 to 30% in improvement in TMR ratio over a conventional CoFe/NiFe free layer is achieved while maintaining low Hc and RA&#x3c;3 ohm-um. The CoNiFeB or CoNiFeBM layer has a magnetostriction (&#x3bb;) value between &#x2212;5&#xd7;10and 5&#xd7;10.

TMR device with low magnetostriction free layer

Systems and methods are provided for manufacturing a magnetic recording sensor for use in a magnetic reader, such as a tunneling magnetoresistance (TMR) readers. The magnetic recording sensor can be manufactured by heating a substrate in a first chamber and depositing an antiferromagnetic (AFM) layer on the heated substrate. Additionally, a first pinned layer is added onto the AFM layer, and the substrate is subsequently cooled.

Heated AFM layer deposition and cooling process for TMR magnetic recording sensor with high pinning field

A TMR sensor that includes a free layer having at least one B-containing (BC) layer made of CoFeB, CoFeBM, CoB, COBM, or CoBLM, and a plurality of non-B containing (NBC) layers made of CoFe, CoFeM, or CoFeLM is disclosed where L and M are one of Ni, Ta, Ti, W, Zr, Hf, Tb, or Nb. One embodiment is represented by (NBC/BC)where n&#x2267;2. A second embodiment is represented by (NBC/BC)/NBC where n&#x2267;1. In every embodiment, a NBC layer contacts the tunnel barrier and NBC layers each with a thickness from 2 to 8 Angstroms are formed in alternating fashion with one or more BC layers each 10 to 80 Angstroms thick. Total free layer thickness is &#x3c;100 Angstroms. The free layer configuration described herein enables a significant noise reduction (SNR enhancement) while realizing a high TMR ratio, low magnetostriction, low RA, and low Hc values.

Disclosed are methods for making read sensors using developable bottom anti-reflective coating and amorphous carbon (a-C) layers as junction milling masks. The methods described herein provide an excellent chemical mechanical polishing or planarization (CMP) stop, and improve control in reader critical physical parameters, shield to shield spacing (SSS) and free layer track width (FLTW).

Reader fabrication method employing developable bottom anti-reflective coating

An annealing process for a TMR or GMR sensor having an amorphous free layer is disclosed and employs at least two annealing steps. A first anneal at a temperature Tof 200&#xb0; C. to 270&#xb0; C. and for a tof 0.5 to 15 hours is employed to develop the pinning in the AFM and pinned layers. A second anneal at a temperature Tof 260&#xb0; C. to 400&#xb0; C. where T&#x3e;Tand t&#x3e;tis used to crystallize the amorphous free layer and complete the pinning. An applied magnetic field of about 8000 Oe is used during both anneal steps. The mechanism for forming a sensor with high MR and robust pinning may involve structural change in the tunnel barrier or at an interface between two of the layers in the spin valve stack. A MgO tunnel barrier and a CoFe/CoB free layer are preferred.

Two step annealing process for TMR device with amorphous free layer

A magneto-resistive device having a large output signal as well as a high signal-to-noise ratio is described along with a process for forming it. This improved performance was accomplished by expanding the free layer into a multilayer laminate comprising at least three ferromagnetic layers separated from one another by antiparallel coupling layers. The ferromagnetic layer closest to the transition layer must include CoFeB while the furthermost layer is required to have low Hc as well as a low and negative lambda value. One possibility for the central ferromagnetic layer is NiFe but this is not mandatory.

MR device with synthetic free layer structure

A three step ion beam etch (IBE) sequence involving low energy (&#x3c;300 eV) is disclosed for trimming a sensor critical dimension (free layer width=FLW) to less than 50 nm. A first IBE step has a steep incident angle with respect to the sensor sidewall and accounts for 60% to 90% of the FLW reduction. The second IBE step has a shallow incident angle and a sweeping motion to remove residue from the first IBE step and further trim the sidewall. The third IBE step has a steep incident angle to remove damaged sidewall portions from the second step and accounts for 10% to 40% of the FLW reduction. As a result, FLW approaching 30 nm is realized while maintaining high MR ratio of over 60% and low RA of 1.2 ohm-&#x3bc;m. Sidewall angle is manipulated by changing one or more ion beam incident angles.

Method to fabricate small dimension devices for magnetic recording applications

A CPP MR sensor interposes a tapered soft magnetic flux guide (FG) layer between a hard magnetic biasing layer (HB) and the free layer of the sensor stack. The flux guide channels the flux of the hard magnetic biasing layer to effectively bias the free layer, while eliminating instability problems associated with magnetostatic coupling between the hard bias layers and the upper and lower shields surrounding the sensor when the reader-shield-spacing (RSS) is small.

MR sensor with flux guide enhanced hard bias structure

A high performance TMR sensor is fabricated by incorporating a tunnel barrier having a Mg/MgO/Mg configuration. The 4 to 14 Angstroms thick lower Mg layer and 2 to 8 Angstroms thick upper Mg layer are deposited by a DC sputtering method while the MgO layer is formed by a NOX process involving oxygen pressure from 0.1 mTorr to 1 Torr for 15 to 300 seconds. NOX time and pressure may be varied to achieve a MR ratio of at least 34% and a RA value of 2.1 ohm-um. The NOX process provides a more uniform MgO layer than sputtering methods. The second Mg layer is employed to prevent oxidation of an adjacent ferromagnetic layer. In a bottom spin valve configuration, a Ta/Ru seed layer, IrMn AFM layer, CoFe/Ru/CoFeB pinned layer, Mg/MgO/Mg barrier, CoFe/NiFe free layer, and a cap layer are sequentially formed on a bottom shield in a read head.

Low resistance tunneling magnetoresistive sensor with natural oxidized double MgO barrier

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Fremont, CA, United States of America

Tong Zhao