JP2010287664A - Spin conduction element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spin conduction element capable of preventing charges from accumulating on a channel layer more than is necessary and preventing elements from damages. <P>SOLUTION: The spin conduction element 100 includes: a channel 7 extending in a predetermined direction and made of a semiconductor material; a magnetization fixed layer 12B disposed on the channel 7 via a first insulation layer 81; a magnetization free layer 12C, disposed on the channel 7 via a second insulation layer 82; and a first electrode 20A and a second electrode 20D disposed on the channel layer 7. The first electrode 20A, the magnetization fixed layer 12B, the magnetization free layer 12C and the second electrode 20D are disposed on the channel 7, in this order, along a predetermined direction, and the channel 7 extends to the outside from at least any one of the first electrode 20A and the second electrode 20D in the predetermined direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a spin transport device.

  A spin transport element is known in which a magnetization free layer and a magnetization fixed layer are provided on a channel layer for accumulating or conducting spin. In recent years, a spin transport element using a semiconductor material for a channel layer has attracted much attention in place of a spin transport element using a metal material for a channel layer (see, for example, Patent Document 1 and Patent Document 2). A spin transport element using a semiconductor material for the channel layer has a longer spin diffusion length than a spin transport element using a metal material for the channel layer.

JP 2007-299467 A Japanese Patent No. 4029772

  As a spin transport element, a so-called Schottky junction type in which a magnetization free layer and a magnetization fixed layer made of a ferromagnetic material and a channel layer made of a semiconductor material are connected is known. In the case of the Schottky junction type, there is a tendency that the characteristic variation due to the influence of the interface is large. On the other hand, a method is known in which a tunnel insulating layer is inserted between a magnetization free layer and a magnetization fixed layer made of a ferromagnetic material and a channel layer made of a semiconductor material. When a tunnel insulating layer is inserted, there is an advantage that characteristics are stabilized.

  Further, the surface of the channel layer is covered with a film having high spin resistance or an insulating film so that the spin current does not leak outside the channel layer. That is, the channel layer is separated from the outer region by a tunnel insulating layer, a film having high spin resistance, or an insulating film.

  However, if the channel layer is electrically isolated from the outer region, charges may be accumulated in the channel layer when an element is formed or a circuit is formed. When charge accumulation in the channel layer exceeds an allowable amount, there is a problem that element destruction occurs.

  Accordingly, an object of the present invention is to provide a spin transport device that can suppress the accumulation of charges more than necessary in a channel layer made of a semiconductor material and can suppress device breakdown.

  In order to solve the above-described problems, a spin transport device according to the present invention includes a channel made of a semiconductor material extending in a predetermined direction, a magnetization fixed layer disposed on the channel via a first insulating layer, and a first channel on the channel. Comprising a magnetization free layer disposed via two insulating layers, and a first electrode and a second electrode disposed on the channel, the first electrode, the magnetization fixed layer, the magnetization free layer, and the second electrode, It arrange | positions in this order along a predetermined direction on a channel, and the channel is extended to the outer side rather than at least one of the 1st electrode and the 2nd electrode in the predetermined direction.

  In the spin transport device of the present invention, the channel made of a semiconductor material extends outward from at least one of the first electrode and the second electrode. Therefore, the portion of the channel extending outside at least one of the first electrode and the second electrode can be grounded (grounded). Therefore, it is possible to suppress the charge from being accumulated more than necessary in the channel. Therefore, it is possible to suppress the destruction of the element at the time of element creation or circuit formation. In addition, since the ground portion is a portion of the channel that extends outward from at least one of the first electrode and the second electrode, spin current leakage and current leakage are suppressed, and the spin transport element Hard to adversely affect operation.

  Further, it is preferable that a ground electrode is further provided, and the ground electrode is provided on a portion of the channel that extends outward from at least one of the first electrode and the second electrode. Thereby, the electric charge accumulated in the channel can be suitably released from the ground electrode to the outside of the channel.

  The third insulating layer further includes a channel, a magnetization fixed layer, a magnetization free layer, side surfaces of the first electrode, the second electrode, and the ground electrode, and a magnetization fixed layer and a magnetization free layer. Between the first electrode and the magnetization fixed layer, between the second electrode and the magnetization free layer, and between the ground electrode and the first electrode or the second electrode. . As a result, the electric charge can be released to the outside of the channel while preventing the spin current from leaking to the outside of the channel. Therefore, element breakdown can be suppressed while maintaining good spin conduction.

  The third insulating layer is preferably an oxide film. The oxide film can be easily formed on the channel.

  Moreover, it is preferable to further include an annular peripheral layer that is connected to a portion of the channel that extends outward from at least one of the first electrode and the second electrode, and is disposed around the channel. Thereby, it can earth | ground easily from a cyclic | annular surrounding layer.

  The first and second insulating layers are preferably made of magnesium oxide. By using magnesium oxide for the first and second insulating layers, the spin injection efficiency is improved.

  Further, the material of the magnetization free layer and the magnetization fixed layer may be a metal selected from the group consisting of Ti, V, Cr, Mn, Co, Fe, and Ni, an alloy containing one or more elements of the group, or the group It is preferable to use an alloy containing one or more elements selected from the group consisting of B, C, and N. Since these materials are soft magnetic materials, the function as a magnetization free layer can be suitably realized. In addition, since these materials are ferromagnetic materials having a high spin polarizability, it is possible to suitably realize the function as a magnetization fixed layer.

  Moreover, it is preferable to give a coercive force difference to the magnetization free layer and the magnetization fixed layer by shape anisotropy. Thereby, it is possible to omit an antiferromagnetic layer for providing a coercive force difference.

  Moreover, it is preferable to make the coercive force of the magnetization fixed layer larger than the coercivity of the magnetization free layer. Thereby, it is possible to suitably realize the functions as the magnetization fixed layer and the magnetization free layer in the spin transport element.

  Further, it is preferable to further include an antiferromagnetic layer formed on the magnetization fixed layer, and to fix the magnetization direction of the magnetization fixed layer by the antiferromagnetic layer. When the antiferromagnetic layer is exchange-coupled with the magnetization fixed layer, it is possible to impart unidirectional anisotropy to the magnetization direction of the magnetization fixed layer. In this case, a magnetization fixed layer having a higher coercive force in one direction can be obtained than when no antiferromagnetic layer is provided.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an electric charge accumulate | stores more than necessary in the channel which consists of semiconductor materials, and can provide the spin transport element which can suppress element destruction.

1 is a perspective view showing a spin transport element according to a first embodiment. It is sectional drawing along the II-II line in FIG. It is sectional drawing along the III-III line in FIG. FIG. 3A is a top view showing the spin transport device according to the first embodiment. (B) is the figure which expanded the area | region B in (a). It is sectional drawing which shows the modification of a spin transport element. It is a perspective view which shows the spin transport element concerning 2nd Embodiment. It is a top view which shows the spin transport element concerning 2nd Embodiment. It is a top view of the mask used when patterning a silicon film.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
(First embodiment)

  In the first embodiment, an example in which the channel of the spin transport element 100 is an island shape or a thin line shape is shown. FIG. 1 is a perspective view of the spin transport device 100. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG.

  As shown in FIG. 2, in the case where silicon is used as a semiconductor, the spin transport device 100 includes a silicon substrate 1, an insulating layer 2, a silicon channel 7, an insulating layer 8, a magnetization fixed layer 12B, a magnetization free layer 12C, and a first magnetization layer. It mainly includes an electrode 20A and a second electrode 20D.

  An insulating layer 2 and a silicon channel 7 are provided in this order on the silicon substrate 1. Examples of the insulating layer 2 include silicon oxide and silicon nitride. As the silicon substrate 1, the insulating layer 2, and the silicon channel 7, for example, an SOI (Silicon On Insulator) substrate can be used.

  The insulating layer 8 is an insulating film for expressing the tunnel magnetoresistive effect. The insulating layer 8 is provided in contact with the silicon channel 7. In the example shown in FIG. 2, the insulating layer 8 includes a first insulating layer 81 and a second insulating layer 82.

  The magnetization fixed layer 12 </ b> B is provided on the silicon channel 7 via the first insulating layer 81. The magnetization free layer 12 </ b> C is provided on the silicon channel 7 via the second insulating layer 82.

  The first electrode 20A and the second electrode 20D are disposed on the silicon channel 7. The magnetization fixed layer 12B and the magnetization free layer 12C are disposed between the first electrode 20A and the second electrode 20D.

  The silicon channel 7 functions as a layer that conducts and diffuses spin. The silicon channel 7 includes, for example, silicon. The silicon channel 7 extends in the predetermined direction Ax. The predetermined direction Ax is parallel to the Y-axis direction.

  FIG. 2 shows an example in which the first electrode 20A, the magnetization fixed layer 12B, the magnetization free layer 12C, and the second electrode 20D are arranged in this order on the silicon channel 7 along the predetermined direction Ax.

  The silicon channel 7 extends outside the first electrode 20A and the second electrode 20D. Therefore, since the silicon channel 7 can be grounded (grounded), it is possible to suppress accumulation of charges in the silicon channel 7 more than necessary. Therefore, it is possible to suppress the destruction of the element at the time of element creation or circuit formation. In addition, since a portion of the silicon channel that extends outside at least one of the first electrode and the second electrode can be a grounded portion, spin current and current leakage are suppressed, and the spin transport device It is hard to adversely affect the operation.

  Hereinafter, the silicon channel 7 will be described more specifically. The silicon channel 7 faces the opposite side of the first electrode 20A and the second electrode 20D from the side where the magnetization fixed layer 12B and the magnetization free layer 12C are provided, than the first electrode 20A and the second electrode 20D. It extends outward. One end P of the silicon channel 7 extends outside the end 51 of the first electrode 20A opposite to the magnetization fixed layer 12B side. The other end Q of the silicon channel 7 extends outside the end 53 of the second electrode 20D on the side opposite to the magnetization free layer 12C side.

  The silicon channel 7 has, for example, an island shape, a rectangular parallelepiped shape, or a fine line shape with a predetermined direction Ax as a major axis. The total length L1 of the silicon channel 7 is the length from the end 51 of the first electrode 20A opposite to the magnetization fixed layer 12B to the end 53 of the second electrode 20D opposite to the magnetization free layer 12C. Longer than L2. As a result, in the silicon channel 7, in the end portion of the first electrode 20A, the portion outside the end portion 51 opposite to the magnetization fixed layer 12B side, or the end portion of the second electrode 20D, the magnetization free A portion outside the end portion 53 on the side opposite to the layer 12C side can be used as a portion for grounding. The total length L1 of the silicon channel 7 is the length from one end P to the other end Q of the silicon channel 7.

  The grounding electrode S1 is provided on a portion of the silicon channel 7 that extends outward from the first electrode 20A. Specifically, the grounding electrode S1 is provided on the upper surface of the upper surface of the silicon channel 7 on the outer side of the end portion 51 of the first electrode 20A on the side opposite to the magnetization fixed layer 12B side. The grounding electrode S1 is connected to the grounding circuit 61. Therefore, the electric charge accumulated in the silicon channel 7 can be released to the grounding circuit 61. In FIG. 2, on the silicon channel 7, the ground electrode S1, the first electrode 20A, the magnetization fixed layer 12B, the magnetization free layer 12C, and the second electrode 20D are arranged in this order in a predetermined direction Ax. Indicates.

  As shown in FIG. 3, the silicon channel 7 has an inclined portion on the side surface, and the inclination angle θ is 50 degrees to 60 degrees. Here, the inclination angle θ is an angle formed by the bottom of the silicon channel 7 and the side surface. The silicon channel 7 can be formed by wet etching, and the upper surface of the silicon channel 7 is preferably a (100) plane.

  From the viewpoint of suppressing an increase in resistance and functioning as a tunnel insulating layer, the thickness of the first insulating layer 81 and the second insulating layer 82 shown in FIG. 2 is preferably 3 nm or less. The film thicknesses of the first insulating layer 81 and the second insulating layer 82 are preferably 0.4 nm or more in consideration of the thickness of one atomic layer. For example, magnesium oxide is used as the first insulating layer 81 and the second insulating layer 82. By using magnesium oxide for the first insulating layer 81 and the second insulating layer 82, the spin injection efficiency is improved.

  The magnetization fixed layer 12B and the magnetization free layer 12C are made of a ferromagnetic material. As a material of the magnetization fixed layer 12B and the magnetization free layer 12C, for example, a metal selected from the group consisting of Ti, V, Cr, Mn, Co, Fe, and Ni, an alloy including one or more elements of the group, or Examples include alloys containing one or more elements selected from the group and one or more elements selected from the group consisting of B, C, and N. Since these materials are soft magnetic materials, the function as the magnetization free layer 12C can be suitably realized. Further, since these materials are ferromagnetic materials having a high spin polarizability, the function as the magnetization fixed layer 12B can be suitably realized.

  As the first electrode 20A and the second electrode 20D, for example, a nonmagnetic metal having low resistance to Si such as Al can be used. A conductive material is used for the ground electrode S1.

  A side insulating layer 7 a is formed on the side surface of the silicon channel 7. Further, the third insulating layer 7b is formed on the side surfaces of the silicon channel 7, the magnetization fixed layer 12B, the magnetization free layer 12C, the first electrode 20A, the second electrode 20D, and the ground electrode S1, and the magnetization fixed layer 12B and the magnetization free layer. Provided between the layers 12C, between the first electrode 20A and the magnetization fixed layer 12B, between the second electrode 20D and the magnetization free layer 12C, and between the ground electrode S1 and the first electrode 20A. Yes. As a result, most of the silicon channel 7 other than that required for grounding is covered with the insulating layer. Therefore, electric charges can be released to the outside of the silicon channel while preventing the spin current from leaking to the outside of the silicon channel. Therefore, element breakdown can be suppressed while maintaining good spin conduction.

  Further, the third insulating layer 7b allows the silicon channel 7, the first insulating layer 81, the second insulating layer 82, the magnetization fixed layer 12B, the magnetization free layer 12C, the first electrode 20A, the second electrode 20D, and the grounding electrode S1. Can be protected and deterioration can be suppressed. An insulating material is used for the side insulating layer 7a and the third insulating layer 7b. For example, an oxide film such as silicon oxide or a nitride film such as silicon nitride is used. The third insulating layer 7b such as silicon oxide is suitable as a protective film. The silicon oxide film can be easily formed on the silicon channel 7 made of silicon.

  A wiring 18A is provided on the first electrode 20A and the third insulating layer 7b (the inclined side surface of the silicon channel 7). Similarly, the wiring 18B is provided on the magnetization fixed layer 12B and the third insulating layer 7b (the inclined side surface of the silicon channel 7). Similarly, the wiring 18C is provided on the magnetization free layer 12C and the third insulating layer 7b (the inclined side surface of the silicon channel 7). Similarly, the wiring 18D is provided on the second electrode 20D and the third insulating layer 7b (the inclined side surface of the silicon channel 7). The wirings 18A to 18D are made of a conductive material such as Cu. By providing the wiring on the third insulating layer 7b, it is possible to suppress the spin of the silicon channel 7 from being absorbed by this wiring. Further, by providing the wiring on the third insulating layer 7b, it is possible to suppress a current from flowing from the wiring to the silicon channel 7, and to improve the spin injection efficiency.

  Measurement electrode pads E1 to E4 are provided at the ends of the wirings 18A to 18D, respectively. End portions of the wirings 18 </ b> A to 18 </ b> D and measurement electrode pads E <b> 1 to E <b> 4 are formed on the insulating layer 2. The electrode pads E1 to E4 are made of a conductive material such as Au.

  FIG. 4A is a top view showing the spin transport device according to the present invention. FIG. 4B is an enlarged view of the region B in FIG. As shown in FIG. 4A, the silicon channel 7 has a rectangular parallelepiped shape with the major axis in the Y direction. A grounding electrode S1 provided outside the first electrode 20A is connected to the grounding circuit 61.

  As shown in FIG. 4B, a magnetization fixed layer 12B is provided under the wiring 18B. A magnetization free layer 12C is provided under the wiring 18C. Each of the magnetization fixed layer 12B and the magnetization free layer 12C has a rectangular parallelepiped shape with the major axis in the X direction. The width in the Y direction is larger in the magnetization free layer 12C than in the magnetization fixed layer 12B. The magnetization fixed layer 12 </ b> B and the magnetization free layer 12 </ b> C are provided with a difference in reversal magnetic field due to a difference in aspect ratio between the X direction and the Y direction. Thus, the magnetization fixed layer 12B and the magnetization free layer 12C have a coercive force difference due to shape anisotropy, and the magnetization fixed layer 12B has a coercive force larger than that of the magnetization free layer 12C.

  Hereinafter, the operation of the spin transport device 100 will be described. As shown in FIG. 1, by connecting the electrode pads E1 and E3 to a current source 70, a detection current can be passed through the magnetization fixed layer 12B. When a detection current flows from the magnetization fixed layer 12B, which is a ferromagnetic material, to the nonmagnetic silicon channel 7 through the insulating layer 8, electrons having a spin corresponding to the magnetization direction of the magnetization fixed layer 12B are converted into silicon. Injected into channel 7. The injected spin diffuses toward the magnetization free layer 12C. In this way, the current and spin current flowing through the silicon channel 7 can be structured to flow mainly in the Y direction. Then, due to the interaction between the magnetization direction of the magnetization free layer 12C changed by an external magnetic field, that is, the electron spin and the electron spin of the portion of the silicon channel 7 in contact with the magnetization free layer 12C, A voltage output is generated between the magnetization free layers 12C. This voltage output can be detected by a voltage measuring device 80 connected to the electrode pads E2 and E4.

  The effect of the spin transport device 100 according to the first embodiment will be described. In the spin transport device 100 according to the first embodiment, the silicon channel 7 extends outside the first electrode 20A and the second electrode 20D. Therefore, since the silicon channel 7 can be grounded (grounded), it is possible to suppress accumulation of charges in the silicon channel 7 more than necessary. Therefore, it is possible to suppress the destruction of the element at the time of element creation or circuit formation. In addition, since a portion of the silicon channel that extends outside at least one of the first electrode and the second electrode can be a grounded portion, spin current and current leakage are suppressed, and the spin transport device It is hard to adversely affect the operation.

  Although the spin transport device according to the first embodiment has been described above, the present invention is not limited to this.

  In the present embodiment, an example in which the silicon channel 7 extends outward from both the first electrode 20A and the second electrode 20D has been described. However, the silicon channel 7 includes the first electrode 20A and the second electrode 20D. It suffices if it extends outside at least one of them. Therefore, the portion of the silicon channel that extends outside at least one of the first electrode and the second electrode can be grounded (grounded). Therefore, it is possible to suppress the charge from being accumulated more than necessary in the silicon channel. Therefore, it is possible to suppress the destruction of the element at the time of element creation or circuit formation. In addition, since the ground portion is a portion of the silicon channel that extends outward from at least one of the first electrode and the second electrode, spin current and current leakage are suppressed, and the operation of the spin transport device is performed. Is difficult to adversely affect.

  Further, for example, in the first embodiment, an example in which there is one grounding electrode is shown, but a plurality of grounding electrodes may be provided. The grounding electrode may be provided on a portion of the silicon channel 7 that extends outward from at least one of the first electrode 20A and the second electrode 20D. For example, a grounding electrode (first grounding electrode) S1 is provided on a portion of the silicon channel 7 that extends outside the first electrode 20A, and the second electrode of the silicon channel 7 is further provided. Another grounding electrode (second grounding electrode) S2 (see FIG. 1) may be provided on a portion extending outside 20D. In this configuration, the third insulating layer is on the side surfaces of the silicon channel 7, the magnetization fixed layer 12B, the magnetization free layer 12C, the first electrode 20A, the second electrode 20D, the first grounding electrode, and the second grounding electrode. Between the magnetization fixed layer 12B and the magnetization free layer 12C, between the first electrode 20A and the magnetization fixed layer 12B, between the second electrode 20D and the magnetization free layer 12C, and the first grounding electrode and the first electrode. And between the second grounding electrode and the second electrode. As a result, charges can be released to the outside of the silicon channel while preventing the spin current from leaking to the outside of the silicon channel. Therefore, element breakdown can be suppressed while maintaining good spin conduction.

  When a plurality of spin transport elements 100 are arranged, the plurality of spin transport elements 100 may be grounded simultaneously. FIG. 5 shows a modification of the spin transport device. FIG. 5 shows an example in which three spin transport elements 100 are grounded simultaneously. For the sake of convenience, in FIG. 5, the third insulating layer 7 b on the silicon channel 7 is omitted, but the third insulating layer 7 b is provided other than the portion necessary for grounding on the silicon channel 7. Preferably it is.

  In each spin transport device 100, the silicon channel 7 can be connected to the common electrode C1 and the common electrode C2. More specifically, in each spin transport device 100, the common electrode C1 is connected to a portion of the silicon channel 7 outside the first electrode 20A, and the common electrode C2 is connected to the second electrode 20D of the silicon channel 7. Connect to the outer part.

That is, the common electrode C1 may be connected to the upper surface of the silicon channel 7 on the one end P side, and the common electrode C2 may be connected to the upper surface of the silicon channel 7 on the other end Q side. The common electrode C1 can be connected to the grounding circuit 63, and the common electrode C2 can be connected to the grounding circuit 64. Therefore, in each spin transport device 100, the charge accumulated more than necessary in the silicon channel 7 can be released to the outside of the silicon channel 7 by the common electrode C1 and the common electrode C2. Alternatively, only one of the common electrode C1 and the common electrode C2 may be connected to the silicon channel 7.
(Second Embodiment)

  In the second embodiment, an example is shown in which a silicon channel of a spin transport element is not an isolated island shape, but an annular silicon layer is connected around the silicon channel. FIG. 6 is a perspective view showing a spin transport device 200 according to the second embodiment. FIG. 7 is a top view showing the spin transport device 200 according to the second embodiment.

  The spin transport device 200 of the second embodiment includes the silicon substrate 1, the insulating layer 2, the silicon channel 7, the first insulating layer 81, the second insulating layer 82, and the magnetization described in the spin transport device 100 of the first embodiment. The fixed layer 12B, the magnetization free layer 12C, the first electrode 20A, the second electrode 20D, the side surface insulating layer 7a, the third insulating layer 7b, the wirings 18A to 18D, and the electrode pads E1 to E4 can be similarly applied.

  However, in the spin transport device 200 of the second embodiment, the grounding electrode S1 in the spin transport device 100 of the first embodiment is not provided on the silicon channel 7. Instead, in the spin transport device 200, the silicon channel 7 is connected to a portion extending outside of at least one of the first electrode 20A and the second electrode 20D and is disposed around the silicon channel 7. An annular silicon layer (annular surrounding layer) 71 is further provided. The grounding electrode S3 is provided on a part of the annular silicon layer 71. Therefore, the charge more than necessary stored in the silicon channel 7 can be easily released to the outside through the annular silicon layer and the ground electrode S3. In addition, since the grounded portion is an annular silicon layer connected to the silicon channel 7, the spin current and current leakage are suppressed, and it is difficult to adversely affect the operation of the spin transport element. Further, the annular silicon layer 71 can also function as a noise shield pattern by imparting predetermined conductivity.

  In FIG. 6, the spin transport element 200 is connected to two portions of the silicon channel 7 that extend outside the first electrode 20 </ b> A and the second electrode 20 </ b> D and is disposed around the silicon channel 7. An example in which an annular silicon layer 71 is further provided will be described.

  The annular silicon layer 71 is connected to the grounding circuit 65 through the grounding electrode S3. Thereby, the silicon channel 7 can be easily grounded through the annular silicon layer.

  Further, a fourth insulating layer 7 c is provided on the side surface and the upper surface of the annular silicon layer 71. Since the silicon channel 7 is surrounded by the annular silicon layer 71 covered with the fourth insulating layer 7c, the silicon channel 7 can be shielded from external magnetism. Therefore, good spin conduction can be maintained in the silicon channel 7. The silicon channel 7 and the annular silicon layer 71 are not separated and can be composed of the same layer. Further, the third insulating layer 7b and the fourth insulating layer 7c are also not separated and can be composed of the same layer.

  As mentioned above, although this invention was demonstrated by 1st and 2nd embodiment, this invention is not limited to this. In the first and second embodiments, an example in which a channel made of silicon is used as the channel has been shown, but the channel may be made of a semiconductor material. For example, a compound semiconductor such as GaAs or a carbon-based material may be used as the channel made of a semiconductor material. Further, instead of the annular silicon layer 71 in the second embodiment, a surrounding layer made of an annular semiconductor material such as an annular surrounding layer made of GaAs or an annular surrounding layer made of a carbon-based material may be used. it can.

  Further, for example, the magnetization free layer 12C and the second electrode side can function for current input, and the magnetization fixed layer 12B and the first electrode side can function for voltage output. Further, for example, instead of giving a coercive force difference to the magnetization fixed layer 12B and the magnetization free layer 12C by shape anisotropy, for example, an antiferromagnetic layer may be further provided on the magnetization fixed layer 12B. The antiferromagnetic layer functions to fix the magnetization direction of the magnetization fixed layer 12B. When the antiferromagnetic layer is exchange-coupled with the magnetization fixed layer, it is possible to impart unidirectional anisotropy to the magnetization direction of the magnetization fixed layer. In this case, a magnetization fixed layer having a higher coercive force in one direction can be obtained than when no antiferromagnetic layer is provided. The material used for the antiferromagnetic layer is selected according to the material used for the magnetization fixed layer. For example, as an antiferromagnetic layer, an alloy exhibiting antiferromagnetism using Mn, specifically, Mn and at least one element selected from Pt, Ir, Fe, Ru, Cr, Pd, and Ni An alloy containing Specific examples include IrMn and PtMn.

Hereinafter, the present invention will be described more specifically based on Example 1, but the present invention is not limited to Example 1 below.
Example 1

  An SOI substrate comprising a silicon substrate, a silicon oxide film (thickness 200 nm), and a silicon film (thickness 100 nm) was prepared. An alignment mark was formed on the SOI substrate by photolithography. Ion implantation for imparting n-type conductivity to the silicon film was performed. Then, impurities were diffused by annealing. The annealing temperature was 900 ° C. Thereafter, the deposits, organic substances, oxide film, and mask on the surface of the silicon film were removed by cleaning. HF was used as the cleaning liquid.

  Subsequently, a magnesium oxide film (thickness 0.8 nm) was formed on the silicon film by an ultrahigh vacuum electron beam evaporation method. Further, an iron film (thickness 10 nm), a titanium film, and a tantalum film were formed in this order on the magnesium oxide film by the MBE method. The titanium film and the tantalum film are cap layers for suppressing characteristic deterioration due to oxidation of the iron film serving as the magnetization fixed layer. Since the titanium film and the tantalum film are amorphous, the influence on the crystallinity of the iron film is small.

  Thereafter, the magnesium oxide film, iron film, titanium film, and tantalum film were patterned by ion milling. Using the aluminum oxide film, magnesium oxide film, iron film, titanium film, tantalum film, and resist as a mask, the silicon film was patterned by anisotropic wet etching.

  8A and 8B are top views of masks used when patterning a silicon film. As shown in FIGS. 8A and 8B, masks M <b> 1 and M <b> 2 having a main portion 20 and corner portions 21 and 22 protruding from the main portion 20 are used. At this time, it is preferable to use a mask in which the corner portions 21 and 22 have an area smaller than the area of the main portion 20. Moreover, when the main part 20 is a rectangle, the protruded corner | angular parts 21 and 22 are arrange | positioned at the four corners of a rectangle. As shown in FIG. 8A, the corner portion 21 of the mask M1 may be a square including a range overlapping the main portion 20 of the mask M1. Further, as shown in FIG. 8B, the corner portion 22 of the mask M2 may be circular including a range overlapping the main portion 20 of the mask M2. In addition, the corner portion of the mask may be, for example, a rectangle or a triangle including a range overlapping with the main portion of the mask. Note that the present invention can also be implemented using a mask having no corners.

  As a result, a silicon channel having a rectangular parallelepiped shape and an inclined portion on the side surface was obtained. At this time, the size of the silicon channel was 23 μm × 300 μm. Further, the side surface of the obtained silicon channel was oxidized to form a silicon oxide film (side insulating layer).

  Thereafter, the iron film was patterned by ion milling and chemical etching to obtain a magnetization fixed layer and a magnetization free layer, respectively. The magnesium oxide film located other than between the magnetization fixed layer and the magnetization free layer and the silicon channel was removed. Thereby, the first insulating layer and the second insulating layer were obtained. Among the exposed silicon channels, Al films were formed on the outside of the magnetization fixed layer and the outside of the magnetization free layer, respectively, to obtain a first electrode and a second electrode. Also, a conductive material was deposited on the outside of the first electrode to obtain a grounding electrode.

  Further, on the side surfaces of the silicon oxide film (side insulating layer) on the side wall of the silicon channel, the first insulating layer, the second insulating layer, the magnetization fixed layer, the magnetization free layer, the first electrode, the second electrode, and the ground electrode A silicon oxide film (third insulating layer) was formed on a portion of the upper surface of the silicon channel where the magnetization fixed layer, the magnetization free layer, the first electrode, the second electrode, and the ground electrode were not formed.

  Next, wirings were formed on the first electrode, the magnetization fixed layer, the magnetization free layer, and the second electrode, respectively. As the wiring, a stacked structure of Ta (thickness 10 nm), Cu (thickness 50 nm), and Ta (thickness 10 nm) was used. Furthermore, an electrode pad was formed at each end of each wiring. A laminated structure of Cr (thickness 50 nm) and Au (thickness 150 nm) was used as the electrode pad. Finally, the grounding electrode was connected to the grounding circuit. Thus, the spin transport device of Example 1 having the same configuration as the spin transport device 100 shown in FIGS.

  DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Insulating layer, 7 ... Silicon channel (channel which consists of semiconductor materials), 7a ... Insulating layer for side surfaces, 7b ... 3rd insulating layer, 81 ... 1st insulating layer, 82 ... 2nd insulating layer, 12B ... Magnetization fixed layer, 12C ... Magnetization free layer, 18A-18D ... Wiring, 20A ... First electrode, 20D ... Second electrode, S1 ... Grounding electrode, 61 ... Grounding circuit, 100 ... Spin conduction element, E1- E4 ... Electrode pad.

Claims (10)

A channel made of a semiconductor material extending in a predetermined direction;
A magnetization fixed layer disposed on the channel via a first insulating layer;
A magnetization free layer disposed on the channel via a second insulating layer;
A first electrode and a second electrode disposed on the channel;
The first electrode, the magnetization fixed layer, the magnetization free layer, and the second electrode are arranged in this order along the predetermined direction on the channel,
The spin transport element, wherein the channel extends to the outside of at least one of the first electrode and the second electrode in the predetermined direction. A ground electrode;
3. The spin transport device according to claim 1, wherein the grounding electrode is provided on a portion of the channel that extends outward from at least one of the first electrode and the second electrode. . A third insulating layer;
The third insulating layer includes
On the side surfaces of the channel, the magnetization fixed layer, the magnetization free layer, the first electrode, the second electrode, and the ground electrode;
Between the magnetization fixed layer and the magnetization free layer;
Between the first electrode and the magnetization fixed layer;
The spin transport device according to claim 3, provided between the second electrode and the magnetization free layer, and between the ground electrode and the first electrode or the second electrode.   The spin transport device according to claim 3, wherein the third insulating layer is an oxide film.   The ring further includes an annular peripheral layer connected to a portion of the channel that extends outward from at least one of the first electrode and the second electrode and disposed around the channel. Or the spin transport device according to 2;   The spin transport device according to any one of claims 1 to 5, wherein the first insulating layer and the second insulating layer are magnesium oxide.   The material of the magnetization free layer and the magnetization fixed layer is a metal selected from the group consisting of Ti, V, Cr, Mn, Co, Fe, and Ni, an alloy containing one or more elements of the group, or the group The spin transport device according to any one of claims 1 to 6, wherein the spin transport device is an alloy containing one or more elements selected from the group consisting of B, C, and N.   The spin transport device according to claim 1, wherein a coercive force difference is given to the magnetization free layer and the magnetization fixed layer by shape anisotropy.   The spin transport element according to claim 1, wherein the magnetization fixed layer has a coercive force larger than that of the magnetization free layer. An antiferromagnetic layer formed on the magnetization fixed layer;
The spin transport device according to any one of claims 1 to 9, wherein the antiferromagnetic layer fixes the magnetization direction of the magnetization fixed layer.

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