JPWO2010026704A1 - Magnetoresistive element, manufacturing method thereof, and storage medium used in the manufacturing method - Google Patents

Abstract

A magnetoresistive element having a higher MR ratio than the conventional one and a method for manufacturing the same are provided. In a magnetoresistive element having a substrate, a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer, the magnetization free layer is made of Co atoms, Fe atoms, and B atoms And a crystalline second ferromagnetic layer made of an alloy containing Ni atoms, Fe atoms and B atoms.

Description

  The present invention relates to a magnetoresistive element used in a magnetic reproducing head of a magnetic disk drive, a storage element of a magnetic random access memory, and a magnetic sensor, preferably a tunnel magnetoresistive element (particularly, a spin valve type tunnel magnetoresistive element). Furthermore, the present invention relates to a method of manufacturing a magnetoresistive element and a storage medium used for the manufacturing method.

  Patent Documents 1 to 6 and Non-Patent Documents 1 and 2 describe a TMR (Tunneling Magneto Resistance) effect element including a tunnel barrier layer and first and second ferromagnetic layers disposed on both sides thereof. Is described. As the first and / or second ferromagnetic layers constituting this element, an alloy containing Co atoms, Fe atoms and B atoms (hereinafter referred to as a CoFeB alloy) is used. In addition, a polycrystalline structure is described as the CoFeB alloy layer.

  Patent Documents 2 to 5, Patent Document 7, and Non-Patent Documents 1 to 5 describe TMR elements using a crystalline magnesium oxide film made of single crystal or polycrystal as a tunnel barrier film. ing.

JP 2002-204004 A International Publication No. 2005/088745 Pamphlet JP 2003-304010 A JP 2006-080116 A US Patent Application Publication No. 2006/0056115 US Pat. No. 7,252,852 JP 2003-318465 A

D. D. “Applied Physics Letters”, 86,092502 (2005) by Djayapraira et al. "Japan Journal of Applied Physics" by Shinji Yuasa et al., Vol. 43, no. 48, pp 588-590, issued April 2, 2004 C. L. Platt et al., “J. Appl. Phys.” 81 (8), 15 April 1997. W. H. Butler et al., “The American Physical Society” (Physical Review Vol. 63, 0544416) 8, January 2001. S. P. Published by Parkin et al., "2004 Nature Publishing Group" Letters, pp 862-887, published October 31, 2004.

  An object of the present invention is to provide a magnetoresistive element having a further improved high MR ratio, a manufacturing method thereof, and a storage medium used in the manufacturing method as compared with the prior art.

A first aspect of the present invention is a magnetoresistive element having a substrate, a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer.
The magnetization free layer includes a crystalline first ferromagnetic layer made of an alloy containing Co atoms, Fe atoms and B atoms, and a crystalline second ferromagnetic made of an alloy containing Ni atoms, Fe atoms and B atoms. A magnetoresistive element having a body layer.

  In the first aspect of the present invention, the tunnel barrier layer preferably has a crystalline magnesium oxide layer or a crystalline boron magnesium oxide layer.

A second aspect of the present invention is a process of forming a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer on a substrate by using a sputtering method. In the manufacturing method of the magnetoresistive element having
In the step of forming the magnetization free layer, an alloy layer containing Co atoms, Fe atoms and B atoms is formed by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. And a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms by a sputtering method using a target made of an alloy containing Ni atoms, Fe atoms and B atoms. This is a method for manufacturing a magnetoresistive element.

  In the first and second aspects of the present invention, the tunnel barrier layer preferably has a crystalline magnesium oxide layer or a crystalline boron magnesium oxide layer.

A third aspect of the present invention uses a step of forming a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer on a substrate by a sputtering method. In the storage medium storing the control program for executing the manufacture of the magnetoresistive element,
The control program for executing the step of forming the magnetization free layer includes an alloy containing Co atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. A step of forming a layer, and a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Ni atoms, Fe atoms and B atoms. And a storage medium storing a control program for executing the formation of the magnetization free layer.

  According to the present invention, the MR ratio achieved by a conventional tunnel magnetoresistive element (hereinafter referred to as a TMR element) can be greatly improved. Further, the present invention can be mass-produced and has high practicality. Therefore, by using the present invention, a memory element of MRAM (Magnetic Resistive Random Access Memory) capable of ultra-high integration can be efficiently provided. .

It is a cross-sectional schematic diagram of an example of the magnetoresistive element of this invention. It is a figure which shows typically the structure of an example of the film-forming apparatus which manufactures the magnetoresistive element of this invention. FIG. 3 is a block diagram of the apparatus of FIG. It is a model perspective view of MRAM comprised using the magnetoresistive element of this invention. It is an equivalent circuit diagram of MRAM comprised using the magnetoresistive element of this invention. It is sectional drawing of another tunnel barrier layer of this invention. It is a model perspective view of the columnar crystal structure concerning the magnetoresistive element of this invention. It is sectional drawing of the TMR element of the other structure of the magnetoresistive element of this invention.

  The magnetoresistive element of the present invention has a substrate, a magnetization fixed layer, a tunnel barrier layer, and a magnetization free layer. The magnetization free layer contains a crystalline first ferromagnetic layer made of an alloy containing Co atoms, Fe atoms and B atoms (hereinafter referred to as CoFeB), and Ni atoms, Fe atoms and B atoms. It has a crystalline second ferromagnetic layer made of an alloy (hereinafter referred to as NiFeB). The tunnel barrier layer preferably includes a crystalline magnesium oxide (hereinafter referred to as Mg oxide) layer or a crystalline boron magnesium oxide (hereinafter referred to as BMg oxide) layer.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  FIG. 1 shows an example of the laminated structure of the magnetoresistive element 10 according to the present invention, and shows the laminated structure of the magnetoresistive element 10 using the TMR element 12. According to the magnetoresistive element 10, for example, a multilayer film of 10 layers including the TMR element 12 is formed on the substrate 11. This 10-layer multilayer film has a multilayer film structure from the lowermost first layer (Ta layer) to the uppermost 10th layer (Ru layer). Specifically, the PtMn layer 14, the CoFe layer 15, the nonmagnetic Ru layer 16, the CoFeB layer 121, the nonmagnetic polycrystalline Mg oxide layer or BMg oxide layer 122 that is a tunnel barrier layer, the CoFeB layer 1232, and the NiFeB layer 1231. Are stacked. Further thereon, a nonmagnetic Ta layer 17 and a nonmagnetic Ru layer 18 are stacked in this order, and a magnetic layer and a nonmagnetic layer are stacked as a whole. In addition, the numerical value in the bracket | parenthesis of each layer in a figure shows the thickness of each layer, and a unit is nm. The said thickness is an example and is not limited to this. The PtMn layer is an alloy layer containing Pt atoms and Mn atoms, the CoFe layer is an alloy layer containing Co atoms and Fe atoms, and the NiFeB layer is an alloy layer containing Ni atoms, Fe atoms, and B atoms.

  In the present invention, a CoFeB layer 121 and another ferromagnetic layer, for example, a CoFe layer, a CoFeNi layer, or the like may be laminated.

  Reference numeral 11 denotes a substrate such as a wafer substrate, a glass substrate, or a sapphire substrate.

  A TMR element 12 is a ferromagnetic layer 121 made of a polycrystalline CoFeB layer, a tunnel barrier layer 122, a first ferromagnetic layer 1232 made of a polycrystalline CoFeB layer, and a second ferromagnetic layer 1231 made of a polycrystalline NiFeB layer. It is comprised by the laminated film layer structure of this. The tunnel barrier layer 122 is made of a polycrystalline Mg oxide layer or a polycrystalline BMg oxide layer.

  In the present invention, the CoFeB layer of the first ferromagnetic layer 1232 contains a small amount of other atoms such as Pt, Ni, Mn, etc. (5 atomic% or less, preferably 0.01 to 1 atomic%). Can be made. The content of Ni atoms when Ni atoms are contained as a minor component is 5 atomic% or less, preferably 0.01 to 1.0 atomic, with respect to the content of Ni atoms in the NiFeB layer of the second ferromagnetic layer 1231. %, But not limited to this range.

  In the present invention, the NiFeB layer of the second ferromagnetic layer 1231 contains a small amount of other atoms such as Pt, Co, Mn, etc. (5 atomic% or less, preferably 0.01 to 1 atomic%). be able to. When Co atoms are contained as a minor component, the Co atom content is 5 atomic% or less, preferably 0.01 to 1.% with respect to the Co atom content in the CoFeB layer of the first ferromagnetic layer 1232. Although it is 0 atomic%, it is not limited to this range.

  Reference numeral 13 denotes a lower electrode layer (underlayer) of the first layer (Ta layer), and reference numeral 14 denotes an antiferromagnetic layer of the second layer (PtMn layer). 15 is a ferromagnetic layer of the third layer (CoFe layer), and 16 is a non-magnetic layer for exchange coupling of the fourth layer (Ru layer).

  The fifth layer is a ferromagnetic layer made of the crystalline CoFeB layer 121. The B atom content in the crystalline CoFeB layer 121 is preferably set in the range of 0.1 atomic% to 60 atomic%, more preferably 10 atomic% to 50 atomic%. The crystalline CoFeB layer 121 can contain a small amount (5 atomic% or less, preferably 0.01 to 1 atomic%) of other atoms such as Pt, Ni, and Mn.

  The layer composed of the third layer, the fourth layer, and the fifth layer described above is the magnetization fixed layer 19. The substantial magnetization fixed layer 19 is a ferromagnetic layer of the fifth crystalline CoFeB layer 121.

  A tunnel barrier layer 122 is a sixth layer (polycrystalline Mg oxide layer or BMg oxide layer), and is an insulating layer. The tunnel barrier layer 122 may be a single polycrystalline Mg oxide layer or a polycrystalline BMG oxide layer.

  Further, according to the present invention, the tunnel barrier layer 122 can be configured as shown in FIG. That is, the polycrystalline Mg oxide layer 1221 or the polycrystalline BMg oxide layer 1221, the polycrystalline Mg (metallic magnesium) layer 1222 or the polycrystalline BMg (boron magnesium alloy) layer 1222, and the polycrystalline Mg oxide layer 1223 or polycrystalline BMg A stacked structure of the oxide layer 1223 is shown. Furthermore, a laminated structure in which a plurality of three layers including the laminated films 1221, 1222 and 1223 illustrated in FIG. 6 are provided may be used.

  FIG. 8 is an example of another TMR element 12 of the present invention. Reference numerals 12, 121, 122, 1231 and 1232 in FIG. 8 are the same members as described above. In this example, the tunnel barrier layer 122 is a laminated film including a polycrystalline Mg oxide layer or polycrystalline BMg oxide layer 82 and Mg layers or BMg layers 81 and 83 on both sides of the layer 82. In the present invention, the use of the layer 81 can be omitted, and the layer 82 can be disposed adjacent to the crystalline CoFeB layer 1232. Alternatively, the use of the layer 83 can be omitted and the layer 82 can be disposed adjacent to the crystalline CoFeB layer 121.

  FIG. 7 is a schematic perspective view of a polycrystalline structure composed of a BMg oxide layer or an aggregate 71 of columnar crystals 72 of the Mg oxide layer. The polycrystalline structure also includes a structure of a polycrystalline-amorphous mixed region including a partial amorphous region in the polycrystalline region. The column crystal is preferably a single crystal in which (001) crystal planes are preferentially oriented in the film thickness direction for each column. The average diameter of the columnar single crystal is preferably 10 nm or less, more preferably in the range of 2 nm to 5 nm, and the film thickness is preferably 10 nm or less, more preferably 0.5 nm. It is in the range of 5 nm.

Further, the BMg oxide used in the present invention has a general formula B _x Mg _y O _z (0.7 ≦ Z / (X + Y) ≦ 1.3, preferably 0.8 ≦ Z / (X + Y) <. 1.0). In the present invention, it is preferable to use a stoichiometric amount of BMg oxide, but a high MR ratio can be obtained even with an oxygen-deficient BMg oxide.

The Mg oxide used in the present invention has a general formula Mg _y O _z (0.7 ≦ Z / Y ≦ 1.3, preferably 0.8 ≦ Z / Y <1.0). Indicated by In the present invention, it is preferable to use a stoichiometric amount of Mg oxide, but even with an oxygen-deficient Mg oxide, a high MR ratio can be obtained.

  The polycrystalline Mg oxide or polycrystalline BMg oxide used in the present invention contains various trace components such as Zn atom, C atom, Al atom, Ca atom, Si atom and the like in the range of 10 ppm to 100 ppm. be able to.

  The seventh layer and the eighth layer can function as a magnetization free layer. The crystalline CoFeB layer 1232 constituting the seventh layer can be formed by sputtering using a CoFeB target. The crystalline NiFeB layer 1231 constituting the eighth layer can be formed by sputtering using a NiFeB alloy target.

  The crystalline CoFeB layer 121, the CoFeB layer 1232, and the NiFeB layer 1231 described above may have a crystal structure having the same structure as the aggregate 71 including the column crystal structure 72 illustrated in FIG.

  The crystalline CoFeB layer 121 and the CoFeB layer 1232 are preferably provided adjacent to the tunnel barrier layer 122 located in the middle. In the manufacturing apparatus, these three layers are sequentially stacked without breaking the vacuum.

  Reference numeral 17 denotes an electrode layer of a ninth layer (Ta layer).

  Reference numeral 18 denotes a hard mask layer of the tenth layer (Ru layer). The tenth layer may be removed from the magnetoresistive element when used as a hard mask.

  Next, with reference to FIG. 2, an apparatus and a manufacturing method for manufacturing the magnetoresistive element 10 having the above laminated structure will be described. FIG. 2 is a schematic plan view of an apparatus for manufacturing the magnetoresistive element 10, which is an apparatus capable of producing a multilayer film including a plurality of magnetic layers and a nonmagnetic layer, and is a mass production type sputtering film formation. Device.

  The magnetic multilayer film manufacturing apparatus 200 shown in FIG. 2 is a cluster type manufacturing apparatus and includes three film forming chambers based on a sputtering method. In this apparatus 200, a transfer chamber 202 provided with a robot transfer apparatus (not shown) is installed at a central position. Two load lock / unload lock chambers 205 and 206 are provided in the transfer chamber 202 of the manufacturing apparatus 200 for manufacturing the magnetoresistive element, and the substrate (for example, silicon substrate) 11 is carried in and out, respectively. . By alternately loading and unloading the substrate between these load lock / unload lock chambers 205 and 206, the tact time is shortened and a magnetoresistive element can be manufactured with high productivity.

  In the manufacturing apparatus 200 for manufacturing a magnetoresistive element, three film forming magnetron sputtering chambers 201 </ b> A to 201 </ b> C and one etching chamber 203 are provided around a transfer chamber 202. In the etching chamber 203, a required surface of the TMR element 10 is etched. A gate valve 204 that can be opened and closed is provided between each of the chambers 201A to 201C and 203 and the transfer chamber 202. Each chamber 201A to 201C and 202 is provided with an unillustrated evacuation mechanism, gas introduction mechanism, power supply mechanism, and the like. The magnetron sputtering chambers 201A to 201C for film formation can sequentially deposit each film from the first layer to the tenth layer on the substrate 11 using a high frequency sputtering method without breaking the vacuum. it can.

  Four or five cathodes 31 to 35, 41 to 45, 51 to 54 are arranged on an appropriate circumference on the ceiling of the magnetron sputtering chambers 201A to 201C for film formation. Further, the substrate 11 is disposed on a substrate holder located coaxially with the circumference. Further, a magnetron sputtering apparatus in which a magnet is disposed behind the targets mounted on the cathodes 31 to 35, 41 to 45, 51 to 54 is preferable.

  In the apparatus, high-frequency power such as a radio frequency (RF frequency) is applied to the cathodes 31 to 35, 41 to 45, 51 to 54 from the power input means 207A to 207C. As the high frequency power, a frequency in the range of 0.3 MHz to 10 GHz, preferably a frequency in the range of 5 MHz to 5 GHz and a power in the range of 10 W to 500 W, preferably in the range of 100 W to 300 W can be used.

  In the above, for example, a Ta target is attached to the cathode 31, a PtMn target is attached to the cathode 32, a CoFeB target is attached to the cathode 33, a CoFe target is attached to the cathode 34, and a Ru target is attached to the cathode 35.

  The cathode 41 is equipped with a Mg oxide target, and the cathode 42 is fitted with a BMg oxide target.

  If necessary, an Mg target can be attached to the cathode 43, and a BMg target can be attached to the cathode 44. The tunnel barrier layer 122 having the structure shown in FIG. 8 can be produced by using the cathode 43 or 44.

  The cathode 51 is a CoFeB target for the seventh layer, the cathode 52 is a Ta target for the ninth Ta layer, the cathode 53 is a Ru target for the tenth layer, and the cathode 54 is NiFeB targets for 8 layers are each mounted.

  The in-plane directions of the targets mounted on the cathodes 31 to 35, 41 to 45, and 51 to 54 are preferably arranged non-parallel to each other. By using the non-parallel arrangement, a magnetic film and a nonmagnetic film having the same composition as the target composition can be deposited by sputtering while rotating a target having a smaller diameter than the substrate diameter.

  In the non-parallel arrangement, for example, they can be arranged non-parallel so that the crossing angle between the target central axis and the substrate central axis is 45 ° or less, preferably 5 ° to 30 °. Further, the substrate at this time can use a rotation speed of 10 rpm to 500 rpm, preferably a rotation speed of 50 rpm to 200 rpm.

  FIG. 3 is a block diagram of a film forming apparatus used in the present invention. In the figure, 301 is a transfer chamber corresponding to the transfer chamber 202 in FIG. 2, 302 is a film forming chamber corresponding to the film forming magnetron sputtering chamber 201A, and 303 is a film forming chamber corresponding to the film forming magnetron sputtering chamber 201B. is there. Reference numeral 304 denotes a film forming chamber corresponding to the film forming magnetron sputtering chamber 201C, and reference numeral 305 denotes a load lock / unload lock chamber corresponding to the load lock / unload lock chambers 205 and 206. Reference numeral 306 denotes a central processing unit (CPU) having a built-in storage medium 312. Reference numerals 309 to 311 denote bus lines that connect the CPU 306 and the processing chambers 301 to 305, and control signals for controlling the operations of the processing chambers 301 to 305 are transmitted from the CPU 306 to the processing chambers 301 to 305.

  In the manufacture of the magnetoresistive element of the present invention, for example, a substrate (not shown) in the load lock / unload lock chamber 305 is carried out to the transfer chamber 301. This substrate unloading step is calculated based on a control program stored in the storage medium 312 by the CPU 306. A control signal based on the calculation result is executed by controlling the execution of various devices mounted in the load lock / unload lock chamber 305 and the transfer chamber 301 through the bus lines 307 and 311. Examples of the various devices include a gate valve (not shown), a robot mechanism, a transport mechanism, and a drive system, and the storage medium 312 corresponds to the storage medium of the present invention described above.

  The substrate transferred to the transfer chamber 301 is transferred to the film formation chamber 302. Here, the first layer 13 to the fifth layer (CoFeB layer) in FIG. 1 are sequentially stacked on the substrate carried into the film forming chamber 302. The CoFeB layer 121 of the fifth layer at this stage preferably has an amorphous structure, but may have a polycrystalline structure.

  In the stacking process, control signals calculated based on the control program stored in the storage medium 312 in the CPU 306 execute various apparatuses mounted on the transfer chamber 301 and the film forming chamber 302 through the bus lines 307 and 308. Implemented by controlling. Examples of such various devices include a power supply mechanism to a cathode (not shown), a substrate rotation mechanism, a gas introduction mechanism, an exhaust mechanism, a gate valve, a robot mechanism, a transport mechanism, and a drive system.

  The substrate having the laminated film up to the fifth layer is once returned to the transfer chamber 301 and then transferred into the film formation chamber 303.

  In the film formation chamber 303, a polycrystalline Mg oxide layer 122 or a polycrystalline BMg oxide layer 122 is formed as a sixth layer on the fifth CoFeB 121 layer. In the sixth layer deposition, various control signals calculated based on the control program stored in the storage medium 312 in the CPU 306 are mounted on the transfer chamber 301 and the deposition chamber 303 through the bus lines 307 and 309. This is done by controlling the execution of the device. Examples of the various devices include a power supply mechanism to a cathode (not shown), a substrate rotation mechanism, a gas introduction mechanism, an exhaust mechanism, a gate valve, a robot mechanism, a transport mechanism, and a drive system.

  The substrate having the laminated film up to the sixth Mg oxide layer 122 or BMg oxide layer 122 is once again returned to the transfer chamber 301 and then transferred into the film formation chamber 304.

  In the film forming chamber 304, the seventh layer (CoFeB layer 1232), the eighth layer (NiFeB layer 1231), and the ninth layer are formed on the polycrystalline Mg oxide layer 122 or the BMg oxide layer 122 of the sixth layer. The (Ta layer 17) and the tenth layer (Ru layer 18) are sequentially stacked. The seventh CoFeB layer 1232 and the eighth NiFeB layer 1231 at this stage preferably have an amorphous structure, but may have a polycrystalline structure.

  In the above-described stacking, the control signals calculated based on the control program stored in the storage medium 312 in the CPU 306 execute various apparatuses mounted on the transfer chamber 301 and the film forming chamber 304 through the bus lines 307 and 310. Implemented by controlling. Examples of the various devices include a power supply mechanism to a cathode (not shown), a substrate rotation mechanism, a gas introduction mechanism, an exhaust mechanism, a gate valve, a robot mechanism, a transport mechanism, and a drive system.

  The storage medium 312 is a storage medium of the present invention, and a control program for executing manufacture of the magnetoresistive element is stored in the storage medium.

  Examples of the storage medium 312 used in the present invention include a hard disk medium, a magneto-optical disk medium, a floppy (registered trademark) disk medium, and a nonvolatile memory such as a flash memory and an MRAM. .

  Further, the amorphous state of the fifth layer 121, the seventh layer 1232, and the eighth layer 1231 immediately after the film formation can be made into the polycrystalline structure shown in FIG. 7 by annealing. For this reason, in the manufacturing method of the present invention, the magnetoresistive element 10 immediately after film formation is carried into an annealing furnace (not shown), where the fifth layer 121, the seventh layer 1232, and the eighth layer 1231 are in an amorphous state. The phase can be changed to a crystalline state. At this time, magnetism can be imparted to the PtMn layer 14 as the second layer.

  The storage medium 312 stores a control program for performing the process in the annealing furnace. Therefore, the annealing process can be executed by controlling various devices (for example, a heater mechanism, an exhaust mechanism, a transport mechanism, etc.) in the annealing furnace by a control signal obtained by calculation of the CPU 306 based on the control program.

  Further, instead of the fifth CoFeB layer 121, a crystalline ferromagnetic layer made of an alloy layer such as a CoFeTaZr layer, a CoTaZr layer, a CoFeNbZr layer, a CoFeZr layer, a FeTaC layer, a FeTaN layer, or a FeC layer may be used. it can.

  In the present invention, an Rh layer or an Ir layer can be used instead of the Ru layer of the fourth layer 16.

  In the present invention, an alloy layer such as an IrMn layer, an IrMnCr layer, a NiMn layer, a PdPtMn layer, a RuRhMn layer, or OsMn is preferably used instead of the second PtMn14 layer. The film thickness is preferably 10 to 30 nm.

  FIG. 4 is a schematic diagram of an MRAM 401 using the magnetoresistive element of the present invention as a memory element. In the MRAM 401, 402 is a memory element of the present invention, 403 is a word line, and 404 is a bit line. Each of the large number of memory elements 402 is arranged at each intersection position of a plurality of word lines 403 and a plurality of bit lines 404, and is arranged in a lattice-like positional relationship. Each of the large number of memory elements 402 can store 1-bit information.

  FIG. 5 is an equivalent circuit diagram including the TMR element 10 that stores 1-bit information and the transistor 501 having a switch function at the intersection of the word line 403 and the bit line 404 of the MRAM 401.

  The magnetoresistive element shown in FIG. 1 was produced using the film forming apparatus shown in FIG. The film forming conditions of the TMR element 12 which is the main part are as follows.

  For the CoFeB layer 121, a target having a CoFeB composition ratio (atomic ratio) of 60/20/20 was used. In the CoFeB layer 121, Ar was used as a sputtering gas, and its pressure was set to 0.03 Pa. The CoFeB layer 121 was formed by magnetron DC sputtering (chamber 201A) at a sputtering rate of 0.64 nm / sec. At this time, the CoFeB layer 121 had an amorphous structure.

  Subsequently, a target with an MgO composition ratio (atomic ratio) of 50/50 was used instead of the sputtering apparatus (chamber 201B). Ar is used as a sputtering gas, and a pressure of 0.2 Pa is used in a pressure range of 0.01 to 0.4 Pa, and magnetron RF sputtering (13.56 MHz) is used to form a sixth Mg oxide layer. A certain tunnel barrier layer 122 was formed. At this time, the Mg oxide layer (tunnel barrier layer 122) had a polycrystalline structure composed of the aggregate 71 of columnar crystals 72 shown in FIG. Further, the deposition rate of magnetron RF sputtering (13.56 MHz) at this time was 0.14 nm / sec.

  Subsequently, instead of the sputtering apparatus (chamber 201C), a ferromagnetic layer which is a magnetization free layer (seventh CoFeB layer 1232) was formed. In the CoFeB layer 1232, Ar was used as a sputtering gas, and its pressure was set to 0.03 Pa. The CoFeB layer 1232 was formed at a sputtering rate of 0.64 nm / sec. At this time, the CoFeB layer 1232 was a target having a CoFeB composition ratio (atomic ratio) of 40/40/20. Immediately after the film formation, the CoFeB layer 1232 had an amorphous structure.

  Subsequently, in the same chamber 201C, a ferromagnetic layer which is a magnetization free layer (eighth NiFeB layer 1231) was formed. In the NiFeB layer 1231, Ar was used as a sputtering gas, and its pressure was set to 0.03 Pa. The NiFeB layer 1231 was formed at a sputtering rate of 0.64 nm / sec. At this time, the NiFeB layer 1231 used a target having an NiFeB composition ratio (atomic ratio) of 40/40/20. Immediately after this film formation, the NiFeB layer 1231 had an amorphous structure.

  In this embodiment, the deposition rate of the MgO film was 0.14 nm / sec, but there is no problem even if it is deposited in the range of 0.01 nm to 1.0 nm / sec.

  The magnetoresistive element 10 which has been laminated by performing sputtering film formation in each of the magnetron sputtering chambers 201A to 201C for film formation is subjected to an annealing process in a magnetic field of 8 kOe in a heat treatment furnace at about 300 ° C. for 4 hours. did. As a result, it was confirmed that the CoFeB layer 121, the CoFeB layer 1232, and the NiFeB layer 1231 having an amorphous structure had a polycrystalline structure composed of the aggregates 71 of the columnar crystals 72 illustrated in FIG.

  By this annealing step, the magnetoresistive element 10 can act as a magnetoresistive element having a TMR effect. Also, by this annealing step, predetermined magnetization was imparted to the antiferromagnetic material layer 14 which is the second PtMn layer.

  As a comparative example of the present invention, a magnetoresistive element was manufactured using the same method as in the above example except that the use of the NiFeB layer as the eighth layer was omitted.

  When the MR ratio of the magnetoresistive element of the example and the magnetoresistive element of the comparative example were measured and compared, the MR ratio of the magnetoresistive element of the example was compared with the MR ratio of the magnetoresistive element of the comparative example. The numerical value was improved by 2 times to 1.5 times or more.

  The MR ratio is a parameter related to the magnetoresistive effect in which the electric resistance of the film also changes as the magnetization direction of the magnetic film or the magnetic multilayer film changes in response to an external magnetic field. Rate (MR ratio).

  In addition, the magnetoresistive resistance was changed in the same manner as in the above example except that the polycrystalline Mg oxide tunnel barrier layer 122 was used instead of the polycrystalline Mg oxide tunnel barrier layer 122 used in the above example. An element was fabricated and the MR ratio was measured. A target having a BMgO composition ratio (atomic ratio) of 25/25/50 was used. As a result, as compared with the example using the polycrystalline Mg oxide layer, the MR ratio was remarkably improved (1.5 times the MR ratio according to the example using the polycrystalline Mg oxide layer). The above MR ratio) was obtained.

  10: magnetoresistive element, 11: substrate, 12: TMR element, 121: CoFeB ferromagnetic layer (fifth layer), 122: tunnel barrier layer (sixth layer), 1231: NiFeB ferromagnetic layer (eighth layer) Magnetization free layer), 1232: CoFeB ferromagnetic layer (seventh layer; magnetization free layer), 13: lower electrode layer (first layer; underlayer), 14: antiferromagnetic layer (second layer), 15 : Ferromagnetic layer (third layer), 16: nonmagnetic layer for exchange coupling (fourth layer), 17: upper electrode layer (9th layer), 18: hard mask layer (10th layer), 19: magnetization Fixed layer, 200: magnetoresistive element creation apparatus, 201A to 201C: film forming chamber, 202: transfer chamber, 203: etching chamber, 204: gate valve, 205, 206: load lock / unload lock chamber, 31 to 35, 41 to 45, 51 54: cathode, 207A to 207C: power input unit, 301: transfer chamber, 302 to 304, film forming chamber, 305: load lock / unload lock chamber, 306: central processing unit (CPU), 307 to 311: bus line 312: Storage medium, 401: MRAM, 402: Memory element, 403: Word line, 404: Bit line, 501: Transistor, 71: Aggregation of columnar crystal, 72: Columnar crystal, 81: Mg layer or BMg Layer, 82: Mg oxide layer or BMg oxide layer, 83: Mg layer or BMg layer

The first of the present invention is a substrate, an antiferromagnetic layer, a magnetization fixed layer positioned adjacent to the antiferromagnetic layer, a magnetization free layer, and a tunnel positioned between the magnetization fixed layer and the magnetization free layer In a magnetoresistive element having a barrier layer,
The magnetization free layer includes a crystalline first ferromagnetic layer made of an alloy containing Co atoms, Fe atoms and B atoms, and a crystalline second ferromagnetic made of an alloy containing Ni atoms, Fe atoms and B atoms. It has a body layer,
The tunnel barrier layer is a magnetoresistive element including crystalline magnesium oxide or crystalline boron magnesium oxide .

According to a second aspect of the present invention, an antiferromagnetic layer, a magnetization fixed layer positioned adjacent to the antiferromagnetic layer, a magnetization free layer, and the magnetization fixed layer and the magnetization are formed on a substrate by using a sputtering method. In the method of manufacturing a magnetoresistive element, including the step of forming a tunnel barrier layer positioned between the free layer and
In the step of forming the magnetization free layer, an alloy layer containing Co atoms, Fe atoms and B atoms is formed by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. step, and, by a sputtering method using a target made of an alloy containing Ni atoms, Fe atoms and B atoms, have a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms,
The step of forming the tunnel barrier layer includes a step of forming crystalline magnesium oxide or crystalline boron magnesium oxide by a sputtering method. .

According to a third aspect of the present invention, an antiferromagnetic layer, a magnetization fixed layer positioned adjacent to the antiferromagnetic layer, a magnetization free layer, and the magnetization fixed layer and the magnetization free layer are formed on a substrate by sputtering. In a storage medium storing a control program for executing manufacture of a magnetoresistive element by using a step of forming a tunnel barrier layer positioned between
The control program for executing the step of forming the magnetization free layer includes an alloy containing Co atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. A step of forming a layer, and a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Ni atoms, Fe atoms and B atoms. And a control program for executing the film formation of the magnetization free layer ,
The control program for executing the step of forming the tunnel barrier layer is a control program for executing the step of forming crystalline magnesium oxide or crystalline boron magnesium oxide by a sputtering method. It is a storage medium.

Claims (5)

In a magnetoresistive element having a substrate, a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer,
The magnetization free layer includes a crystalline first ferromagnetic layer made of an alloy containing Co atoms, Fe atoms and B atoms, and a crystalline second ferromagnetic made of an alloy containing Ni atoms, Fe atoms and B atoms. A magnetoresistive element comprising a body layer.   The magnetoresistive element according to claim 1, wherein the tunnel barrier layer includes a crystalline magnesium oxide layer or a crystalline boron magnesium oxide layer. Production of magnetoresistive element having a step of forming a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer on a substrate using a sputtering method In the method
In the step of forming the magnetization free layer, an alloy layer containing Co atoms, Fe atoms and B atoms is formed by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. And a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms by a sputtering method using a target made of an alloy containing Ni atoms, Fe atoms and B atoms. A method for manufacturing a magnetoresistive element.   4. The method of manufacturing a magnetoresistive element according to claim 3, wherein the tunnel barrier layer has a crystalline magnesium oxide layer or a crystalline boron magnesium oxide layer. By using a step of forming a magnetization fixed layer, a magnetization free layer, and a tunnel barrier layer positioned between the magnetization fixed layer and the magnetization free layer on a substrate by a sputtering method, In a storage medium storing a control program for executing manufacture,
The control program for executing the step of forming the magnetization free layer includes an alloy containing Co atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Co atoms, Fe atoms and B atoms. A step of forming a layer, and a step of forming an alloy layer containing Ni atoms, Fe atoms and B atoms by sputtering using a target made of an alloy containing Ni atoms, Fe atoms and B atoms. A storage medium characterized by storing a control program for executing film formation of the magnetization free layer.

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