Abstract: A high performance TMR sensor is fabricated by employing a free layer with a trilayer configurations represented by FeCo/CoFeB/CoB, FeCo/CoB/CoFeB, FeCo/CoFe/CoB, or FeCo/FeB/CoB may also be employed. Alternatively, CoNiFeB or CoNiFeBM formed by co-sputtering CoB with CoNiFe or CoNiFeM, respectively, where M is V, Ti, Zr, Nb, Hf, Ta, or Mo may be included in a composite free layer or as a single free layer in the case of CoNiFeBM. A 15 to 30% in improvement in TMR ratio over a conventional CoFe/NiFe free layer is achieved while maintaining low Hc and RA <3 ohm-um2. In bilayer or trilayer embodiments, magnetostriction (?) between ?5×10?6 and 5×10?6 is achieved by combining CoB (??) and one or more layers having a positive ?.

Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.

Abstract: A method of forming a high performance magnetic tunnel junction (MTJ) is disclosed wherein the tunnel barrier includes at least three metal oxide layers. The tunnel barrier stack is partially built by depositing a first metal layer, performing a natural oxidation (NOX) process, depositing a second metal layer, and performing a second NOX process to give a MOX1/MOX2 configuration. An uppermost metal layer on the MOX2 layer is not oxidized until after the MTJ stack is completely formed and an annealing process is performed to drive unreacted oxygen in the MOX1 and MOX2 layers into the uppermost metal layer. In an alternative embodiment, a plurality of metal oxide layers is formed on the MOX1 layer before the uppermost metal layer is deposited. The resulting MTJ stack has an ultralow RA around 1 ohm-?m2 and maintains a high magnetoresistive ratio characteristic of a single metal oxide tunnel barrier layer.

Abstract: A composite seed layer that reduces the shield to shield distance in a read head while improving Hex (exchange coupling field) and Hex/Hc (Hc=coercivity) is disclosed and has a SM/A/SM/B configuration in which the SM layers are soft magnetic layers, the A (amorphous) layer is made of at least one of Co, Fe, Ni, and includes one or more amorphous elements, and the B layer is a buffer layer that contacts the AFM (anti-ferromagnetic) layer in the spin valve. The SM/A/SM stack together with the S1 (bottom) shield forms an effective shield such that the buffer layer serves as the effective seed layer while maintaining a blocking temperature of 260° C. in the AFM layer. The lower SM layer may be omitted. Examples of the amorphous layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr while the buffer layer may be Cu, Ru, Cr, Al, or NiFeCr.

Abstract: A composite free layer having a FL1/insertion/FL2 configuration is disclosed for achieving high dR/R, low RA, and low ? in TMR or GMR sensors. Ferromagnetic FL1 and FL2 layers have (+) ? and (?) ? values, respectively. FL1 may be CoFe, CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb. FL2 may be CoFe, NiFe, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, Nb, or B. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. In a TMR stack with a MgO tunnel barrier, dR/R>60%, ?˜1+10?6, and RA=1.2 ohm-um2 when FL1 is CoFe/CoFeB/CoFe, FL2 is CoFe/NiFe/CoFe, and the insertion layer is CoTa or CoFeBTa.

Abstract: The conventional free layer in a CPP GMR or TMR read head has been replaced by a tri-layer laminate comprising Co rich CoFe, moderately Fe rich NiFe, and heavily Fe rich NiFe. 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 described.

Abstract: The invention discloses how the insertion of a layer of CoFeB serves to increase the robustness of an MTF device by smoothing the interface between the tunnel barrier and the pinned layer.

Abstract: A composite free layer having a FL1/insertion/FL2 configuration is disclosed for achieving high dR/R, low RA, and low ? in TMR or GMR sensors. Ferromagnetic FL1 and FL2 layers have (+) ? and (?) ? values, respectively. FL1 may be CoFe, CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb. FL2 may be CoFe, NiFe, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, Nb, or B. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. In a TMR stack with a MgO tunnel barrier, dR/R>60%, ?˜1×10?6, and RA=1.2 ohm-um2 when FL1 is CoFe/CoFeB/CoFe, FL2 is CoFe/NiFe/CoFe, and the insertion layer is CoTa or CoFeBTa.

Abstract: An insertion layer is provided between an AFM layer and an AP2 pinned layer in a GMR or TMR element to improve exchange coupling properties by increasing Hex and the Hex/Hc ratio without degrading the MR ratio. The insertion layer may be a 1 to 15 Angstrom thick amorphous magnetic layer comprised of at least one element of Co, Fe, or Ni, and at least one element having an amorphous character selected from B, Zr, Hf, Nb, Ta, Si, or P, or a 1 to 5 Angstrom thick non-magnetic layer comprised of Cu, Ru, Mn, Hf, or Cr. Preferably, the content of the one or more amorphous elements in the amorphous magnetic layer is less than 40 atomic %. Optionally, the insertion layer may be formed within the AP2 pinned layer. Examples of an insertion layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr.

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.

Abstract: A high performance TMR sensor is fabricated by employing a composite inner pinned (AP1) layer in an AP2/Ru/AP1 pinned layer configuration. In one embodiment, there is a 10 to 80 Angstrom thick lower CoFeB or CoFeB alloy layer on the Ru coupling layer, a and 5 to 50 Angstrom thick Fe or Fe alloy layer on the CoFeB or CoFeB alloy, and a 5 to 30 Angstrom thick Co or Co rich alloy layer formed on the Fe or Fe alloy. A MR ratio of about 48% with a RA of <2 ohm-um2 is achieved when a CoFe AP2 layer, MgO (NOX) tunnel barrier, and CoFe/NiFe free layer are used in the TMR stack. Improved RA uniformity and less head noise are observed. Optionally, a CoFe layer may be inserted between the coupling layer and CoFeB or CoFeB alloy layer to improve pinning strength and enhance crystallization.

Abstract: A three step ion beam etch (IBE) sequence involving low energy (<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-?m2. Sidewall angle is manipulated by changing one or more ion beam incident angles.

Abstract: A composite free layer having a FL1/insertion/FL2 configuration where a top surface of FL1 is treated with a weak plasma etch is disclosed for achieving enhanced dR/R while maintaining low RA, and low ? in TMR or GMR sensors. The weak plasma etch removes less than about 0.2 Angstroms of FL1 and is believed to modify surface structure and possibly increase surface energy. FL1 may be CoFe, CoFe/CoFeB, or alloys thereof with Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, or Nb having a (+) ? value. FL2 may be CoFe, NiFe, or alloys thereof having a (?) ? value. The thin insertion layer includes at least one magnetic element such as Co, Fe, and Ni, and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Cr, or B. When CoFeBTa is selected as insertion layer, the CoFeB:Ta ratio is from 1:1 to 4:1.

Abstract: A high performance TMR element is fabricated by inserting an oxygen surfactant layer (OSL) between a pinned layer and AlOx tunnel barrier layer in a bottom spin valve configuration. The pinned layer preferably has a SyAP configuration with an outer pinned layer, a Ru coupling layer, and an inner pinned layer comprised of CoFeXBY/CoFeZ wherein x=0 to 70 atomic %, y=0 to 30 atomic %, and z=0 to 100 atomic %. The OSL is formed by treating the CoFeZ layer with oxygen plasma. The AlOx tunnel barrier has improved uniformity of about 2% across a 6 inch wafer and can be formed from an Al layer as thin as 5 Angstroms. As a result, the Hin value can be decreased by ? to about 32 Oe. A dR/R of 25% and a RA of 3 ohm-cm2 have been achieved for TMR read head applications.

Abstract: A TMR read head with improved voltage breakdown is formed by laying down the AP1 layer as two or more layers. Each AP1 sub-layer is exposed to a low energy plasma for a short time before the next layer is deposited. This results in a smooth surface, onto which to deposit the tunneling barrier layer, with no disruption of the surface crystal structure of the completed AP1 layer.

Abstract: An insertion layer is provided between an AFM layer and an AP2 pinned layer in a GMR or TMR element to improve exchange coupling properties by increasing Hex and the Hex/Hc ratio without degrading the MR ratio. The insertion layer may be a 1 to 15 Angstrom thick amorphous magnetic layer comprised of at least one element of Co, Fe, or Ni, and at least one element having an amorphous character selected from B, Zr, Hf, Nb, Ta, Si, or P, or a 1 to 5 Angstrom thick non-magnetic layer comprised of Cu, Ru, Mn, Hf, or Cr. Preferably, the content of the one or more amorphous elements in the amorphous magnetic layer is less than 40 atomic %. Optionally, the insertion layer may be formed within the AP2 pinned layer. Examples of an insertion layer are CoFeB, CoFeZr, CoFeNb, CoFeHf, CoFeNiZr, CoFeNiHf, and CoFeNiNbZr.

Abstract: A process to manufacturing a TMR read head with improved voltage breakdown is performed by laying down the AP1 layer as two or more layers. Each AP1 sub-layer is exposed to a low energy plasma for a short time before the next layer is deposited. This results in a smooth surface, onto which to deposit the tunneling barrier layer, with no disruption of the surface crystal structure of the completed AP1 layer.

Abstract: A high performance TMR element is fabricated by inserting an oxygen surfactant layer (OSL) between a pinned layer and AlOx tunnel barrier layer in a bottom spin valve configuration. The pinned layer preferably has a SyAP configuration with an outer pinned layer, a Ru coupling layer, and an inner pinned layer comprised of CoFeXBY/CoFeZ wherein x=0 to 70 atomic %, y=0 to 30 atomic %, and z=0 to 100 atomic %. The OSL is formed by treating the CoFeZ layer with oxygen plasma. The AlOx tunnel barrier has improved uniformity of about 2% across a 6 inch wafer and can be formed from an Al layer as thin as 5 Angstroms. As a result, the Hin value can be decreased by ? to about 32 Oe. A dR/R of 25% and a RA of 3 ohm-cm2 have been achieved for TMR read head applications.

Abstract: 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-um2. 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.

Abstract: 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-um2. 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.