JP2009043848A - Magnetic recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording device which is improved in use efficiency as a recording device by improving a data transfer rate with a relatively simple configuration by drastically shortening a readout time of data and preferably further a write time of data, and also securing a sufficient storage area for data. <P>SOLUTION: Two read elements 2 and two write elements 3 each are disposed on a data storage area 1a of a magnetic thin line 1 (illustrated as read elements 2a and 2b and write elements 3a and 3b), and the data storage area 1a is divided into divided areas 1a<SB>1</SB>and 1a<SB>2</SB>. When the two read elements 2 and two write elements 3 are thus arranged, a data readout time and a write time are shortened to halves respectively as compared with arrangement of one read element 2 and one write element 3 because the number (n) of element groups is 2. Similarly, the ratio of occupation by a buffer area 1b needed for the magnetic thin line 1 is 1/3 (≈33%) (the ratio of occupation by a data storage area 1a is 2/3 (≈67%)). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic storage device that performs magnetic storage using reversal magnetization.

  One of the nonvolatile memory elements whose memory is not lost even when the power is turned off is a magnetic random access memory (MRAM). The MRAM is a memory device that utilizes a change in resistance value depending on the spin direction of a magnetic material. In MRAM, a method of writing and reading data is mainly used due to a complicated configuration in which TMR which is a magnetoresistive element and orthogonal wirings (bit lines and write word lines) are arranged above and below this TMR (for example, (See Patent Documents 1 and 2).

  Recently, there is an increasing demand for higher density and higher capacity (over Gbit) of MRAM, and miniaturization of the TMR film is being promoted. However, if the TMR film is miniaturized, the demagnetizing field of the free layer increases, the current required for magnetization reversal increases and power consumption increases, and the combined magnetic field affects adjacent elements. There are issues to be addressed.

As a technique for solving these problems, a technique of “spin injection magnetization reversal method” in which a spin-polarized current (spin current) is injected has been proposed (see Non-Patent Document 1).
However, in the present technology, at present, the current density required for magnetization reversal is as large as about 10 ⁷ [A / cm ² ], for example. Also, in the magnetic memory, in order to aim for a higher-density storage memory, a multi-value recording method realized by a flash memory or the like will be essential in the future.

  Therefore, as a new memory system aiming at a large-capacity memory exceeding Gbit, a domain wall motion storage memory using a domain wall current drive phenomenon (see Non-Patent Document 2) by a spin transfer effect has been proposed (Patent Document 3). See).

Japanese Patent Laid-Open No. 11-317071 JP 2002-246666 A JP 2006-237183 A Research Trend of Spin Injection Magnetization Reversal, Kojiro Rooftop, Yoshishige Suzuki, Japan Society of Applied Magnetics Vol.28 No.9, 2004 Yamaguchi, Ono; Physical Review Letters V92, Number.7 077205-1

  However, the domain wall motion type storage memory has a problem that it takes a long time to read data and a sufficient data storage area cannot be secured.

  The present invention has been made in view of the above-mentioned problems. With a relatively simple configuration, the data reading time, preferably further, the data writing time is greatly shortened to improve the data transfer speed, and the data An object of the present invention is to provide a highly reliable magnetic recording apparatus that can secure a sufficient storage area and improve the use efficiency of the recording apparatus.

  The magnetic recording apparatus of the present invention has a strip shape arranged in parallel to a horizontal plane, and a plurality of magnetic domains can be formed freely. The magnetic fine wire for recording data corresponding to the magnetization direction of the magnetic domain, and the magnetic domain And a plurality of reading elements for reading the data recorded in the magnetic domain by detecting the magnetization direction in the desired magnetic domain, and the magnetic wire includes a first area in which the data is recorded And a second region for holding the magnetic domain that moves when reading the data, and each reading element is disposed on the first region at a predetermined interval. The first area is divided and the data is read from the corresponding divided portion.

  According to the present invention, with a relatively simple configuration, it is possible to significantly reduce the data reading time, preferably further the data writing time, thereby improving the data transfer speed and securing a sufficient data storage area. A highly reliable magnetic recording apparatus that can improve the use efficiency of the recording apparatus as possible is realized.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[Configuration of domain wall motion storage memory]
In the present embodiment, a multi-value type domain wall motion storage memory having a basic configuration of memory cells as shown in FIG. 1 is presented.
The basic configuration of this memory cell is a magnetic thin wire 1 for recording data corresponding to the magnetization direction of the magnetic domain, and a part of a data reading unit for reading data recorded on the magnetic thin wire 1 above a substrate (not shown). A reading element 2 connected on the magnetic wire 1 and a data writing unit for writing data on the magnetic wire 1 and a writing element 3 connected on the magnetic wire 1 are provided.

  The magnetic wire 1 has a laminated structure of a ferromagnetic material, for example, NiFe and CoFeB, and has a band shape of, for example, a width of 300 nm or less arranged in parallel to the substrate surface (horizontal plane), and the magnetostatic energy is minimized. Thus, a plurality of minute magnetic domains 11 and 12 can be formed freely, and a domain wall (Domain Wall: DW) 13 is formed at the boundary between the magnetic domains 11 and 12. Here, the minute magnetic domain 11 is magnetized in the direction indicated by the arrow M (parallel direction), and the minute magnetic domain 12 is magnetized in the direction indicated by the arrow N (anti-parallel direction). Note that the lower electrode formed under the magnetic wire 1 is not illustrated here, and will be illustrated and described in the manufacturing method described later.

In the magnetic wire 1, the magnetization difficult direction and the magnetization easy direction are controlled by the shape thereof, and single minute magnetic domains 11 and 12 are formed in the longitudinal direction. When a pulse current is applied to the magnetic wire 1, when the conduction electrons cross the domain wall 13, the spins of the conduction electrons rotate along the magnetic moment by the sd interaction. At this time, the spin angular momentum of the mission electrons is absorbed into the magnetic moment by the conservation of angular momentum. As a result, the magnetic moment rotates and the domain wall 13 moves. That is, the domain wall can be moved by current drive by the spin torque transfer effect. For example, according to the experimental results shown in Non-Patent Document 2, for example, J = 1.2 × 10 ¹² A / cm ² , and the domain wall 13 is moved at a speed of about 3 m / s by a pulse current of 0.5 μs to 5 μs. Migration is demonstrated from MFM measurements. As described above, in the magnetic wire 1, the tiny magnetic domains 11 and 12 in a single direction can be formed, and the domain wall 13 (magnetic domains 11 and 12) can be moved by current drive. A pulse current Iv, which is a domain wall motion current for performing this current drive, is supplied to the magnetic wire 1 from a wiring (not shown).

  In the magnetic wire 1, for example, 1-bit (“0” or “1”) data is recorded in one recording area. Here, since the domain walls 13 are formed adjacent to each other in the different magnetization directions, the minute magnetic domains 11 and 12 in FIG. 1 are set as one recording area. When recording areas having the same magnetization direction are adjacent to each other, a domain wall 13 is not formed between the recording areas, and a minute magnetic domain composed of two recording areas is formed. As an example of this, a minute magnetic domain consisting of two recording areas having the same magnetization direction (parallel direction here) is shown as 11a. In this way, multivalued data can be recorded on one magnetic wire 1.

  In the illustrated example, the right side portion of the reading element 2 is a data storage area 1a, and the left side portion of the reading element 2 is a minute magnetic domain for reading data in a desired recording area in the data storage area 1a. A buffer region 1b (a part of which is shown) is provided for holding the minute magnetic domains 11 and 12 that have moved beyond the reading element 2 when the 11, 12 is moved. In consideration of the efficiency of data writing and reading, it is preferable that the data storage area is arranged at the center of the magnetic wire 1 and a pair of buffer areas are arranged at both ends.

  The reading element 2 is formed on one end of the recording region 1a of the magnetic wire 1 and has an insulating layer 14 made of, for example, MgO and functioning as a tunnel insulating film, and a laminated structure of, for example, CoFeB, Ru, CoFe, and PtMn. A fixed magnetization layer 15 having a magnetization direction fixed (here, fixed in a parallel direction, for example) is sequentially laminated. An upper electrode 16 is stacked on the reading element 2. The upper surface of the upper electrode 16 is connected to the reading electrode 4. The reading element 2 functions as a so-called TMR (Tunneling Magneto Resistance) reading element integrally with the magnetic wire 1.

  The writing element 3 is formed on the other end of the recording region 1a of the magnetic wire 1 and has an insulating layer 17 made of, for example, MgO and functioning as a tunnel insulating film, and a laminated structure of, for example, CoFeB, Ru, CoFe, and PtMn. Thus, a fixed magnetization layer 18 having a magnetization direction fixed (here, fixed in a parallel direction, for example) is sequentially laminated. An upper electrode 19 is stacked on the write element 3. The upper surface of the upper electrode 19 is connected to the write electrode 5. The write element 3 functions as a so-called TMR write element integrally with the magnetic wire 1.

Here, in the reading element 2 and the writing element 3, the insulating layers 14 and 17, the fixed magnetization layers 15 and 18, and the upper electrodes 16 and 19 are formed in the same layer, that is, in the same layer position with the same material.
A memory cell array (not shown) is configured by arranging a plurality of memory cells configured as described above so that, for example, a plurality of magnetic thin wires 1 are arranged in parallel.

  When reading the recorded data, a predetermined pulse current Iv as a domain wall motion current is supplied from an Iv supply electrode (not shown) to the magnetic wire 1 (described in the manufacturing method), and a desired recording area (single or A plurality of continuous recording areas) are moved to a position immediately below the reading element 2, and a reading current is supplied to the reading element 2 by the reading electrode 4. The fixed magnetization layer 15 of the reading element 2 is magnetized in, for example, a parallel direction, and the resistance value of the reading element 2 when the magnetization direction of the recording area is parallel is the anti-parallel direction of the magnetization direction of the recording area. It becomes lower than the resistance value of the reading element 2 in some cases. Thus, by detecting the resistance value corresponding to the magnetization direction of the recording area as the read voltage Vsp, the magnetization direction of the minute magnetic domain corresponding to the recording area is read as data. The data read operation after this read operation will be described later.

  On the other hand, when writing data, a spin current is supplied from the write electrode 5 to the write element 3. Corresponding to the direction in which the spin current is applied, the recording region of the magnetic wire 1 positioned immediately above the writing element 3 is magnetized in the parallel direction or antiparallel direction. The magnetized recording area is moved by supplying a predetermined pulse current Iv as a domain wall moving current from an Iv supply electrode (not shown) to the magnetic thin wire 1 (described in the manufacturing method), and the desired recording area continues to be described above. It is magnetized like

Here, the result of trial calculation of the recording capacity in this memory cell is shown.
For example, the length of the recording area is 60 nm, the length of the magnetic wire 1 is 1.4 mm (memory length 1.4 mm (track length)), the width of the magnetic wire 1 is 50 nm (the separation distance between adjacent magnetic wires 1 is also 50 nm). In the case where 100,000 magnetic thin wires 1 (a structure in which the reading element 2 and the writing element 3 are formed on each magnetic thin wire 1) are formed, the memory portion size is 1.4 mm × 1.1 mm. A large capacity of about 1.2 Gbit is realized.

FIG. 2 shows another configuration example of the basic configuration of the memory cell shown in FIG.
This memory cell has the same functions, operations and effects as the memory cell shown in FIG. 1, but is different in that the configuration of the data writing unit is different.

In this memory cell, the data writing section is composed of a write wiring 6 disposed close to the magnetic wire 1 (disposed electrically separated by an insulating layer).
When writing data, a magnetic field is generated by applying a current to the write wiring 6, and the recording area of the magnetic wire 1 is magnetized by this magnetic field. Corresponding to the direction in which the current is applied, the recording region of the magnetic wire 1 positioned immediately above the writing element 3 is magnetized in the parallel or antiparallel direction. The magnetized recording area is moved by supplying a predetermined pulse current Iv as a domain wall motion current from a wiring (not shown) to the magnetic thin wire 1, and the desired recording area is subsequently magnetized as described above.

  As described above, in this domain wall motion type storage memory, the magnetic wire 1 is used to hold the data storage region 1a that is the target of data writing and reading and the micro magnetic domains 11 and 12 that move when data is read. And a buffer area 1b. As described below, in the domain wall motion storage memory, it is essential to provide the buffer area 1b together with the data storage area 1a, and various problems arise from this point.

FIG. 3 is a schematic diagram showing the basic arrangement relationship between the magnetic wire 1, the reading element 2 and the writing element 2.
When the reading element 2 and the writing element 3 are arranged as shown in the figure, the data reading time Tr or the writing time Tw is the number of stored data in the data storage area 1a of the magnetic wire 1 (data is recorded as follows). The number of recorded areas is increased by N and the pulse time t of the pulse current which is the domain wall motion current becomes longer.
Tr = Tw = N × t

  Further, as shown in the drawing, the magnetic wire 1 requires a buffer area 1b having a size corresponding to the number N of stored data, that is, the same size as the data storage area 1a. This means that the ratio of the buffer area 1b that is not the target of data writing and reading in the magnetic thin wire 1 is 50%, and it must be said that the usage efficiency as the recording apparatus is low. .

Therefore, the present inventor has intensively studied to solve the above problems and has come up with an apparatus configuration as shown below.
In the present invention, the basic configuration of the domain wall motion storage memory shown in FIG. 1 (or FIG. 2), that is, the strip-shaped magnetic wire 1 arranged in parallel to the horizontal plane, the reading element 2 and the writing element 3 ( Alternatively, on the premise of a basic configuration provided with a write wiring 6: the following is omitted), a plurality of reading elements 2 are provided, and each reading element 2 is arranged on the data storage area 1a at a predetermined interval so that the data storage area 1a is provided. The data is divided and data reading processing is performed on the corresponding divided portion. More preferably, a domain wall motion storage memory having a configuration in which a plurality of write elements 3 are provided adjacent to each read element 2 and data write processing is performed on the divided portion corresponding to each write element 3 is presented.

By arranging a plurality of element groups each consisting of one read element 2 and one write element 3 on the data storage area 1a of the magnetic wire 1 at equal intervals, for example, the data storage area 1a is divided by the number n of element groups (here Is divided equally). In this case, the reading process and the writing process can be simultaneously performed on at least two, for example, all element groups. Accordingly, the data reading time Tr or the writing time Tw is shortened as follows.
Tr = Tw = (N / n) × t

In the magnetic wire 1, the required ratio R of the buffer region 1b to the entire magnetic wire 1 (the total of the data storage region 1a and the buffer region 1b) is also shortened as follows.
R = [1 / (n + 1)] × 100 (%)

FIG. 4 is a schematic diagram showing the basic arrangement relationship between the magnetic wire 1 and the reading element 2 and writing element 2 in the present invention.
Here, two reading elements 2 and two writing elements 3 are provided on the data storage region 1a of the magnetic thin wire 1 (each shown as reading elements 2a, 2b and writing elements 3a, 3b) to store data. The case where the area 1a is divided into the divided areas 1a ₁ and 1a ₂ will be exemplified. When each of the two reading elements 2 and the writing elements 3 is arranged in this way, the number of element groups is n = 2. Therefore, when the reading elements 2 and the writing elements 3 are arranged one by one (see FIG. Compared with 3), the data reading time and the writing time are each halved. Similarly, the ratio of the buffer area 1b required for the magnetic wire 1 is 1/3 (≈33%) (the ratio of the data storage area 1a is 2/3 (≈67%)).

  Here, Patent Document 3 discloses a domain wall motion storage memory provided with a U-shaped magnetic shift register having a data area and a storage unit, and having a reading element and a writing element at the bottom of the U-shape. In paragraph [0031] of Patent Document 3, it is described that the storage unit can be made smaller than the data area by providing two or more reading elements and writing elements. However, with this U-shaped magnetic shift register, it is impossible to realize the reading element and writing element other than the bottom part of the U-shape, and therefore the reduction effect of the storage part is hardly expected. Conceivable. In this regard, Patent Document 3 does not describe or suggest any further reading element and writing element installation sites and installation (formation) methods. Therefore, the above description in paragraph [0031] of Patent Document 3 is not sufficient for obtaining the reduction effect of the storage section, and does not disclose the configuration of the invention.

  On the other hand, in the present invention, as in the above-described embodiment, in order to easily and surely realize the reduction effect of the buffer region 1b, the magnetic thin wire 1 having a strip shape arranged in parallel to the horizontal plane is used. As a premise, an element group composed of one reading element 2 and one writing element 3 is arranged on the magnetic wire 1 at equal intervals, for example.

  As described above, in the present invention, as the number of element groups is increased, the data reading time and the writing time are shortened, and the proportion of the data storage region 1a occupied by the magnetic thin wire 1 is increased. According to the present invention, such a relatively simple configuration greatly reduces the data reading time and writing time, thereby improving the data transfer speed, and recording the data storage area 1a sufficiently. A highly reliable domain wall motion storage memory that improves the usage efficiency of the apparatus is realized.

Furthermore, in this embodiment, as shown in FIG. 5, a memory cell array including a plurality of the above-described memory cells is presented.
The memory cell array 10 includes a plurality of the above-described memory cells arranged in parallel.
That is, in the memory cell array 10, a plurality of magnetic wires 1 (four magnetic wires 1 arranged in parallel in the illustrated example) are arranged in parallel, and each magnetic wire 1 has a plurality of magnetic wires 1 as described above. A plurality of reading elements 2 and writing elements 3 (two reading elements 2 (reading elements 2a and 2b) and one writing element 3 in the illustrated example) are arranged on the data storage region 1a. Each magnetic wire 1 is configured such that a domain wall motion current Iv (pulse current) is supplied simultaneously. For the convenience of illustration, the reading electrode 4 disposed on the reading elements 2a and 2b and the writing electrode 5 disposed on the writing element 3 are not shown.

Here, reading element blocks 31 and 32 are constituted by reading elements 2 a and 2 b provided on each magnetic thin wire 1, and writing element block 33 is constituted by writing element 3 provided on each magnetic thin wire 1.
In the memory cell array 10, a reading selector 34 that can simultaneously perform reading operations of reading elements for each reading element block, and a data reference unit 35 that generates a reference voltage for determining data read by the reading elements, Further, a write selector 36 for appropriately supplying a spin current to each write element 3 of the write element block 33 is further provided.

  The reading selector 34 has a data reading unit 34 a having terminals 35 connected to the reading elements 2 a of the reading element block 31 and a data reading unit having terminals 34 c connected to the reading elements 2 b of the reading element block 31. 34b, and is configured such that one of the data reading units 34a and 34b can be selected at the time of data reading.

  The data reference unit 35 includes a reference voltage generation unit 35a that generates a reference voltage at the time of data reading corresponding to each reading element. In the illustrated example, four reference voltage generators 35a are provided. As described above, in this embodiment, as the data reference unit 35, only the reference voltage generation unit 35a corresponding to the number of reading elements (four in the illustrated example) constituting the reading element block may be provided. The area occupied by can be reduced.

  The reference voltage is a voltage Vl corresponding to the resistance value when the magnetization direction of the recording area of the magnetic wire 1 is parallel in the reading elements 2a and 2b, and the magnetization direction of the recording area of the magnetic wire 1 is opposite to that of the reading element 2. A value intermediate between the resistance value Vh (Vl <Vh) in the parallel direction, for example, Vref≈1 / 2 (Vl + Vh).

  The reference voltage generator 35a may be configured to generate the reference voltage Vref independently of the magnetic wire 1 and the reading elements 2a and 2b, or may be the same layer as each layer constituting the magnetic wire 1 and the reading elements 2a and 2b. That is, it may be configured by reference elements formed of the same material at the same layer position.

An example of the reference element will be described with reference to FIG.
In this case, each reference voltage generator 35a includes a pair of reference elements 20a and 20b.
The reference element 20a includes a lower magnetization layer 21a whose magnetization direction is, for example, a parallel direction, an insulating layer 22a made of, for example, MgO, and a magnetization direction that is the same as the magnetization direction of the lower magnetization layer 21a, here a parallel direction. The upper magnetic layer 23a thus formed is sequentially stacked.
The reference element 20b includes a lower magnetization layer 21b whose magnetization direction is, for example, a parallel direction, an insulating layer 22b made of, for example, MgO, and a magnetization direction that is opposite to the magnetization direction of the lower magnetization layer 21b. The upper magnetic layer 23b thus formed is sequentially stacked.

  Here, the lower magnetization layers 21a and 21b are each formed from a magnetization switching layer whose magnetization direction can be freely changed, and the upper magnetization layers 23a and 23b are each formed from a magnetization fixed layer whose magnetization direction is fixed.

  The resistance value when the read current Ir similar to that of the read element 2 is supplied to the reference element 20a is the same as the resistance value when the magnetization direction of the recording region of the magnetic wire 1 is parallel to the read element 2. On the other hand, the resistance value when the reading current Ir similar to that of the reading element 2 is supplied to the reference element 20b is the same as the resistance value when the magnetization direction of the recording region of the magnetic wire 1 is antiparallel in the reading element 2. It is. That is, the voltage corresponding to the former resistance value is Vl, and the voltage corresponding to the latter resistance value is Vh (Vl <Vh).

  In this example, a current source 24 that supplies the read current Ir and a 1/2 voltage circuit 25 that outputs the input voltage by halving, for example, are provided, and a voltage (Vl + Vh) formed by connecting the reference elements 20a and 20b in series. ) Generates a reference voltage Vref≈1 / 2 (Vl + Vh).

  Here, the lower magnetization layers 21a and 21b are formed from a magnetization switching layer whose magnetization direction can be freely changed, and the upper magnetization layers 23a and 23b are each formed from a magnetization fixed layer whose magnetization direction is fixed. The lower magnetic layers 21a and 21b, the insulating layer 14 and the insulating layer 22, the fixed magnetic layer 15 and the upper magnetic layers 23a and 23b are formed in the same layer, that is, in the same layer position with the same material.

  In the present embodiment, the read voltage Vsp of one of the read element blocks 31 and 32 selected by the read selector 34 is compared with the reference voltage Vref of the data reference unit 35 and recorded in each read element. Data is determined. That is, for example, a differential amplifier (not shown) is provided, and the read voltage Vsp and the reference voltage Vref are respectively input to the differential amplifier, and the magnitudes of both are compared from the positive and negative of the difference value. If Vsp> Vref, the magnetization direction of the recording area of the magnetic wire 1 is antiparallel, and if Vsp <Vref, the magnetization direction of the recording area of the magnetic wire 1 is determined to be parallel. For example, when the magnetization direction is parallel to the data “0” and when the magnetization direction is anti-parallel, the data “1” corresponds to the data “1”. In this case, data “0” is read out.

  Thus, in the present embodiment, the reference operation with the data reference unit 35 is performed for each reading element block, and each reading element constituting the reading element block (if the reading element block 31, each reading element 2a, the reading element block). If it is 32, data reading is performed simultaneously for each reading element 2b). In the example shown in the figure, data reading is simultaneously performed on four reading elements in the four magnetic thin wires 1, so that the reading speed is four times faster than when data reading is performed for each reading element (the reading time is 1). / 4).

The write selector 36 has terminals 36a connected to the write elements 3 constituting the write element block 33. For each terminal 36a, a spin current Is in a direction corresponding to the data to be recorded. Is configured to supply.
As described above, in the present embodiment, data writing is performed on all the write elements 3 constituting the write element block 33 all at once. In the illustrated example, data writing is simultaneously performed on the four write elements 3 in the four magnetic thin wires 1, so that the write speed is four times faster than when data is written for each write element 3 ( The writing time is 1/4).

In the above example, four memory cells are shown among the memory cells constituting the memory cell array, but the present invention is not limited to this.
For example, K memory cells constituting the memory cell array (that is, a configuration in which K magnetic thin wires 1 are arranged in parallel), and the number of reading elements constituting the reading element block is L (K and L are each 2 or more). If it is a natural number and L ≦ K), the reading speed is L times (reading time is 1 / L) compared to the case where data reading is performed for each reading element.
Similarly, if the number of write elements constituting the write element block is L (K and L are natural numbers of 2 or more and L ≦ K), data writing is performed for each write element. Compared to the case, the writing speed is L times (writing time is 1 / L).

[Method of manufacturing domain wall moving storage memory]
Hereinafter, a manufacturing method of the multi-value type domain wall motion storage memory according to the present embodiment will be described.
7 and 8 are schematic cross-sectional views showing the method of manufacturing the multi-value domain wall motion storage memory according to this embodiment in the order of steps.

First, as shown in FIG. 7A, a lower electrode 53 embedded in an insulating film 52 is formed on a silicon substrate 51.
Specifically, an insulating film 52, here a silicon oxide film, is deposited on the silicon substrate 51 by, for example, a CVD method to a thickness of about 200 nm, for example.
Next, the insulating film 52 is processed by lithography and dry etching to form a groove 52a for forming each electrode, and in order to embed each groove 52a, a conductive material, for example, Cu here has a film thickness of 400 nm, for example, by sputtering. Deposit to a degree. Then, the deposited Cu is polished and planarized by a chemical mechanical polishing (CMP) method until the surface of the insulating film 52 is exposed, and a lower electrode 53 is formed by filling each groove 52a with Cu.

Subsequently, as shown in FIG. 7B, the magnetic wire 1 is formed.
Specifically, as the lower magnetic film, for example, a stacked structure of NiFe having a thickness of about 30 nm and CoFeB having a thickness of about 2 nm is deposited. Then, the lower magnetic film is processed by lithography and dry etching by lithography and dry etching, and a plurality of stripe-shaped magnetic thin wires 1 are arranged in parallel so as to be L & S (line and space) having a width and a pitch of about 50 nm, for example. Set up.

Subsequently, as illustrated in FIG. 7C, an insulating film 55, an upper magnetic film 56, and a conductive film 57 are sequentially stacked so as to cover the magnetic wire 1.
Specifically, the insulating film 55 is made of MgO having a thickness of about 1 nm, for example, and the upper magnetic film 56 is made of CoFeB having a thickness of about 2.3 nm, Ru having a thickness of about 0.8 nm, and having a thickness of about 1.7 nm. A stacked structure of PtMn having a thickness of about 100 nm is sequentially formed as CoFe and an antiferromagnetic layer, and Ta having a thickness of, for example, about 50 nm is sequentially formed as the conductive film 57.

Subsequently, as shown in FIG. 8A, the reading elements 2a and 2b, the writing element 3 and the upper electrodes 16 and 19 are formed.
Specifically, the laminated body including the conductive film 57, the upper magnetic film 56, and the insulating film 55 is processed into a shape required for the upper magnetic film 56 by lithography and dry etching. In this dry etching, the surface of the magnetic wire 1 is used as an etching stopper. That is, the stacked body is left in the portions where the reading elements 2 a and 2 b and the writing element 3 are formed, corresponding to the upper part of each lower electrode 53 on the magnetic wire 1.

  As described above, the reading elements 2a and 2b in which the insulating layer 14 and the fixed magnetic layer 15 are sequentially laminated on the portion corresponding to the upper part of each lower electrode 53 on the magnetic wire 1 and the insulating layer 17 and the fixed magnetic layer 18 are provided. A memory portion (basic configuration of the memory cell) including the write elements 3 sequentially stacked is formed. Here, the upper electrodes 16 are formed on the reading elements 2 a and 2 b, and the upper electrode 19 is formed on the writing element 3.

Subsequently, as shown in FIG. 8B, an interlayer insulating film 58 and a contact plug 59 are formed.
Specifically, for example, an insulating film, here, a silicon oxide film having a thickness of about 200 nm is formed on the entire surface by CVD, and an interlayer insulating film 58 is formed.
Next, the interlayer insulating film 58 is polished and planarized by the CMP method until the surfaces of the upper electrodes 16 and 19 are exposed.

Next, the interlayer insulating film 58 is processed so as to expose one end of the surface of the magnetic wire 1 by lithography and dry etching, and a via hole 58 a is formed in the interlayer insulating film 58.
Then, for example, a CVD method is used to deposit a TiN film so as to cover the inner wall surface of the via hole 58a to form a barrier metal film (not shown), and then the via hole 58a is embedded via the barrier metal film by the CVD method. A tungsten (W) film is deposited as described above. Etch back or polish back the W film and the barrier metal film until the surface of the interlayer insulating film 58 is exposed, fill the via hole 58a with W through the barrier metal film, and be electrically connected to the magnetic wire 1 at one end. The contact plug 59 is formed.

Subsequently, as shown in FIG. 8C, each read electrode 4, write electrode 5, and Iv supply electrode 61 are formed. Here, the Iv supply electrode 61 is an electrode for supplying a domain wall motion current to the magnetic wire 1.
Specifically, a conductive material, here Cu, is deposited to a thickness of about 200 nm on the interlayer insulating film 58 from which the surfaces of the contact plug 59, each upper electrode 16, and each upper electrode 19 are exposed. This Cu is processed by lithography and dry etching, and on each surface of the exposed contact plug 59, each upper electrode 16, and the upper electrode 19, in this order, the Iv supply electrode 61, each read electrode 4, and the write electrode 5 Are formed simultaneously.

Thereafter, an insulating film, here a silicon oxide film, is deposited to a thickness of about 400 nm so as to cover the read electrode 4, the write electrode 5 and the Iv supply electrode 61 by, for example, a CVD method, and a protective film 62 is formed. To do.
Through the above steps, the multi-value domain wall motion storage memory according to the present embodiment having the basic configuration of the memory cell as shown in FIG. 1 is completed.

  Here, the manufacturing method of the domain wall motion type storage memory having the basic configuration of the memory cell as shown in FIG. 1 is illustrated, but the domain wall motion type storage memory having the basic configuration of the memory cell as shown in FIG. Instead of forming the writing element 2, for example, Cu is separated from the magnetic wire 1 by a predetermined distance in the interlayer insulating film 58 at a position aligned above the magnetic wire 1 and above the lower electrode 53. What is necessary is just to form the write wiring 6 as a material. Other steps are the same as above.

  In the above-described embodiment, the case where the TMR type spin injection element is used as the reading elements 2a and 2b and the writing element 3 is exemplified, but a GMR type element may be used.

  In the above-described embodiment, the magnetic thin wire 1 is exemplified by a laminated structure of NiFe and CoFeB. However, as these ferromagnetic layers, a ferromagnetic material such as Co, Ni, Fe, or an alloy thereof is used. You may comprise by the ferromagnetic material which consists of (CoFe, NiFe, CoFeB etc.).

Further, the case where the antiferromagnetic layers of the pinned magnetic layers 15 and 18 are made of PtMn has been exemplified, but the antiferromagnetic layer may be made of an antiferromagnetic material such as IrMn or PdPtMn.
Although the case where the nonmagnetic layers of the fixed magnetization layers 15 and 18 are made of Ru has been illustrated, these nonmagnetic layers may be made of a nonmagnetic material such as Rh, Cu, Al, or Au.

  Further, although the case where the insulating layers 14 and 17 are made of MgO has been exemplified, the tunnel insulating film may be made of an insulating material such as AlOx, HfOx, TiOx, TaOx (1 ≦ x ≦ 2).

  As described above, according to the present embodiment, with a relatively simple configuration, the data reading time, preferably further the data writing time is greatly shortened to improve the data transfer speed, and the data storage area Therefore, a highly-reliable domain wall motion storage memory is realized that can sufficiently ensure the above-mentioned and improve the usage efficiency of the recording apparatus.

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

(Appendix 1) It is a strip shape arranged in parallel to a horizontal plane, and a plurality of magnetic domains can be freely formed, and a magnetic wire for recording data corresponding to the magnetization direction of the magnetic domain;
A plurality of reading elements that read the data recorded in the magnetic domain by moving the magnetic domain and detecting the magnetization direction in the desired magnetic domain;
The magnetic wire has a first area in which the data is recorded, and a second area for holding the magnetic domain that moves when the data is read.
Each of the reading elements is disposed on the first area at a predetermined interval, divides the first area, and performs the data reading process on a corresponding divided portion. apparatus.

  (Supplementary note 2) The supplementary note 1, wherein at least two of the plurality of reading elements simultaneously perform the data reading process on the divided portions corresponding to the reading elements. Magnetic recording device.

(Appendix 3) A plurality of the magnetic thin wires are juxtaposed,
The supplementary note 1 or 2, wherein the data reading process by at least one reading element among the plurality of reading elements arranged on each magnetic thin line is performed simultaneously on at least two of the magnetic thin lines. 2. A magnetic recording apparatus according to 2.

(Additional remark 4) The data reference part which generates the reference voltage for judging the data read by the reading element further is included,
4. The magnetic recording apparatus according to appendix 3, wherein the data is determined by comparing the reference voltage generated by the data reference unit with the voltages read simultaneously by the reading elements.

(Additional remark 5) It further includes the writing part which writes data in the said 1st area | region of the said magnetic wire,
5. The magnetic recording apparatus according to any one of appendices 1 to 4, wherein the writing unit is disposed on the first region.

(Appendix 6) including a plurality of writing units,
6. The magnetic recording apparatus according to appendix 5, wherein the writing unit is disposed adjacent to each reading element on the first region.

  (Supplementary note 7) The magnetic recording apparatus according to supplementary note 5 or 6, wherein the writing unit includes a writing element connected to the magnetic wire.

  (Supplementary note 8) The magnetic recording apparatus according to supplementary note 5 or 6, wherein the writing section includes a write wiring provided in proximity to the magnetic thin wire.

(Appendix 9) A plurality of the magnetic thin wires are juxtaposed,
9. The data writing process according to any one of appendices 5 to 8, wherein the data writing process by the data writing unit disposed in each of the magnetic thin wires is performed simultaneously for at least two of the magnetic thin wires. Magnetic recording device.

1 is a schematic perspective view showing a multi-value type domain wall motion storage memory having a basic configuration of a memory cell according to the present invention. It is a schematic perspective view which shows the other example of the multi-value type domain wall motion type storage memory which has the basic composition of the memory cell in this invention. It is a schematic diagram which shows the fundamental arrangement | positioning relationship between a magnetic thin wire | line, a reading element, and a writing element. It is a schematic diagram which shows the fundamental arrangement | positioning relationship between the magnetic wire in this invention, a reading element, and a writing element. FIG. 5 is a schematic diagram showing a memory cell array including a plurality of memory cells adopting the principle of FIG. 4. It is a schematic diagram which shows an example of a reference element. It is a schematic sectional view showing a manufacturing method of a multi-value type domain wall motion type storage memory according to this embodiment in the order of steps. FIG. 8 is a schematic cross-sectional view illustrating the manufacturing method of the multi-value domain wall motion storage memory according to the present embodiment in order of processes following FIG. 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic thin wire | line 1a Data storage area 1b Buffer area | region 2 (2a, 2b) Read element 3 (3a, 3b) Write element 4 Read electrode 5 Write electrode 6 Write wiring 11, 11a, 12 Micro magnetic domain 13 Domain wall 14, 17 , 22a, 22b Insulating layers 15, 18 Fixed magnetization layers 16, 19 Upper electrodes 21a, 21b Lower magnetization layers 23a, 23b Upper magnetization layer 24 Current source 25 1/2 voltage circuit 50a Memory formation region 50b Reference element formation region 51 Silicon substrate 52, 55 Insulating film 52a Groove 53 Lower electrode 56 Upper magnetic film 57 Conductive film 58 Interlayer insulating film 58a Via hole 59 Contact plug 61 Iv supply electrode 62 Protective film

Claims (5)

A strip shape arranged parallel to the horizontal plane, and a plurality of magnetic domains can be freely formed, and a magnetic wire for recording data corresponding to the magnetization direction of the magnetic domain;
A plurality of reading elements that read the data recorded in the magnetic domain by moving the magnetic domain and detecting the magnetization direction in the desired magnetic domain;
The magnetic wire has a first area in which the data is recorded, and a second area for holding the magnetic domain that moves when the data is read.
Each of the reading elements is disposed on the first area at a predetermined interval, divides the first area, and performs the data reading process on a corresponding divided portion. apparatus.   2. The magnetic recording apparatus according to claim 1, wherein at least two of the plurality of reading elements simultaneously perform the data reading process on the divided portions corresponding to the reading elements. . A plurality of the magnetic thin wires are juxtaposed,
2. The data reading process by at least one reading element among the plurality of reading elements arranged on each magnetic thin line is performed simultaneously on at least two magnetic thin lines. Or a magnetic recording apparatus according to 2; A writing unit for writing data in the first region of the magnetic wire;
The magnetic recording apparatus according to claim 1, wherein the writing unit is disposed on the first region. A plurality of the magnetic thin wires are juxtaposed,
5. The magnetic recording apparatus according to claim 4, wherein the data writing process by the data writing unit disposed in each of the magnetic thin wires is performed simultaneously for at least two of the magnetic thin wires.

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