JP4383796B2 - Nanostructure and manufacturing method thereof - Google Patents

Description

  The present invention relates to a quantum device, a nanostructure used as a mold for nanoimprinting, a manufacturing method thereof, and a magnetic recording medium.

  Metal and semiconductor thin films, thin wires, dots, and the like may exhibit unique electrical, optical, and chemical properties by confining the movement of electrons in a size smaller than a certain characteristic length. From such a viewpoint, as a functional material, interest in a material (nanostructure) having a structure finer than 100 nanometers (nm) is increasing.

  Examples of the manufacturing method of the nanostructure include fabrication by semiconductor processing techniques including fine pattern drawing techniques such as photolithography, electron beam exposure, and X-ray exposure.

  In addition to such a manufacturing method, there is an attempt to realize a novel nanostructure based on a regular structure that is naturally formed, that is, a self-organized structure. Many of these methods have begun to be studied because there is a possibility that a fine and special structure can be produced that exceeds the conventional method depending on the fine structure used as a base.

  An example of a unique structure formed in a self-organized manner, in particular, pores in the vertical direction from the sample surface, is an anodized alumina film (see, for example, Non-Patent Document 1 below). When an Al plate is anodized in an acidic electrolyte, a porous oxide film is formed. The characteristic of this porous oxide film is that the extremely fine pores (cylindrical nanoholes) having a diameter (2r) of several nanometers to several hundreds of nanometers are arranged in parallel at intervals (2R) of several tens of nanometers to several hundreds of nanometers It has a simple geometric structure. This cylindrical pore has a high aspect ratio and is excellent in the uniformity of the cross-sectional diameter. The diameter 2r and the interval 2R of the pores can be controlled to some extent by adjusting the current and voltage during anodization.

  In addition, in the anodization of silicon, when viewed macroscopically, the pores are formed perpendicular to the film surface. However, when observed in more detail, the pores are random or dendritic structures. For this reason, the shape of the pores is not constant, which causes inconvenience when applied to quantum effect devices such as single-electron memories and single-electron transistors (see Non-Patent Document 2 below).

  On the other hand, with the dramatic increase in information processing in recent years, information recording technology such as a magnetic disk device is also required to have a large capacity. Particularly in hard disks, the amount of recorded information per unit area is increasing at a rate exceeding 60% per year. In the future, it is desired to increase the amount of information recorded, and it is also desired to reduce the size and increase the density of portable recording devices.

  Conventionally used magnetic recording media for hard disks are of the horizontal magnetic recording system, and the magnetization is recorded parallel to the disk surface. In this horizontal magnetic recording system, it is necessary to reduce the thickness of the magnetic recording layer in order to suppress the demagnetizing field in the magnetic domain as the density increases and to detect the magnetic state above the medium in order to detect the magnetization state. Therefore, the volume per magnetic fine particle becomes extremely small, and the superparamagnetic effect tends to occur easily. That is, the energy that stabilizes the magnetization direction becomes smaller than the thermal energy, the recorded magnetization changes with time, and the recording is erased. For this reason, in recent years, research has been actively conducted to shift to a perpendicular magnetic recording method in which the thickness of the recording layer can be increased in place of horizontal magnetic recording.

In the perpendicular magnetic recording medium, it is important to uniformly reduce the magnetic particles, in particular, to uniformly disperse magnetic particles having a particle diameter of 10 nm or less, preferably 4 to 8 nm on the substrate through thin partition walls. ing. In addition, efforts are made to direct a specific crystal axis in the direction perpendicular to the substrate in order to have the effect of magnetocrystalline anisotropy. The magnetization is directed in the direction perpendicular to the substrate surface. CoPt Examples, FePt, and granular the L1 ₀ ordered alloy such FePd, medium withstand superparamagnetic effect due to miniaturization of magnetic particles has been proposed (see Patent Document 1). And here L1 ₀ ordered alloy, such as Co and Pt has a lined structure alternately [100] plane, the crystal magnetic anisotropy is one that is resistant to stacking and vertically.
JP 2001-273622 A RCFurneaux, WRRigby & APDavidson NATURE Vol.337 p.147 (1989) MIJBe Al e, NGChew, MJUren, AGCullis, JDBenjamin: Appl.Phys.Lett.46,86 (1985)

  In the above prior art, it is difficult to produce dots or wires of 20 nm or less such as Al. Even if the lithography technique is used, it has been very difficult to form a fine protruding columnar structure having a diameter of 10 nm or less uniformly and at a high density.

  The present invention provides a nanometer-sized dot or wire structure or manufacturing method. The present invention also provides a mold and a magnetic recording medium using this structure.

The present invention is a nanostructure formed on a substrate or a substrate having an underlayer, and includes a columnar first member containing Al and a second member formed so as to surround the first member. The second member contains two or more materials capable of forming a eutectic, and one of the materials is either Si or Ge, and the first member is more than the second member. It also provides projecting nanostructures.

Further, the present invention includes a columnar first member containing Al and a second member formed so as to surround the first member on a substrate or a substrate having an underlayer, and the second member Forming a structure in which the member contains two or more kinds of materials capable of forming a eutectic and one of the materials is either Si or Ge by sputtering; and part of the second member Alternatively, the present invention provides a method for producing a nanostructure comprising a step of removing all of them.

Nanodots and nanowires can be formed by the nanostructure of the present invention. Such a nanostructure can be used not only as an electronic device but also as a magnetic recording medium by forming a magnetic film on the upper part, and can drive a magnetic recording / reproducing apparatus and an information processing apparatus. In addition, a nano-sized structure that has been considered difficult can be obtained relatively easily, and can be used as a mold by forming a hard material such as Ni on the surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Configuration of nanostructure>
FIG. 1 is a schematic diagram illustrating an example of a nanostructure in an embodiment of the present invention.

  FIG. 1A shows a case where the columnar structure having Al as a main component is cylindrical, and FIG. 1B shows a case where the projecting portion is conical. In FIG. 1, reference numeral 1 denotes an Al— (Si, Ge) nanostructure, 11 denotes a columnar structure having Al as a main component, and 12 denotes a matrix having (Si, Ge) as a main component surrounding the columnar structure 11. 13 is a substrate, 14 is a columnar structure embedded portion, 15 is a columnar structure protruding portion, and 16 is a deformed columnar structure protruding portion.

  In the structure of the present invention formed on the substrate 13, the film-like Al— (Si, Ge) nanostructure 1 excluding the Al protruding portion has a total ratio of Si and Ge to the total amount of 20 atomic. % To 70 atomic%. Preferably, they are 25 atomic% or more and 65 atomic% or less, More preferably, they are 30 atomic% or more and 60 atomic% or less. If the ratio of Si + Ge is within the above range, an Al— (Si, Ge) mixed film in which the columnar structures 11 are dispersed in the matrix region 12 is obtained.

  The above ratio (atomic%) is an atomic weight ratio, for example, a value when the amounts of Si, Ge and Al in the Al— (Si, Ge) mixed film are quantitatively analyzed by inductively coupled plasma emission spectrometry. . When using wt% as a unit, for example, 20 atomic% or more and 70 atomic% or less is 20.65 wt% or more and 70.84 wt% or less (converted assuming that the atomic weight of Al is 26.982 and the atomic weight of Si is 28.086). is doing).

  The ratio of the total amount of Si and Ge to the total amount of Si, Al, and Ge is a value represented by a molar ratio of (Si + Ge) / (Si + Ge + Al) × 100. That is, when Si + Ge + Al is 100 atomic%, the ratio is Si + Ge.

  The composition of the columnar structure 11 is mainly composed of Al. However, if a microstructure having a columnar structure is obtained, it contains other elements such as Si, Ge, oxygen, argon, nitrogen and hydrogen. Also good.

  Further, the composition of the (Si, Ge) region portion surrounding the periphery of the columnar structure is mainly composed of Si or Ge, but only has to surround the periphery of the columnar structure mainly composed of Al. Various elements such as Al, oxygen, argon, nitrogen, and hydrogen may be contained.

  The matrix region 12 can be amorphous or fine (poly) crystal. However, the matrix region 12 is preferably amorphous (Si, Ge) from the viewpoint of insulation. The reason is that by using amorphous (Si, Ge), the band gap is increased as compared with crystalline Si and Ge, and the electrical insulation of the base material separating the columnar structures is improved. . In consideration of insulation and chemical resistance, it is effective that the matrix region is Si or Si containing Al.

  In addition, the mixture used here has shown the state which the columnar structure has grown in the matrix area | region and it.

  The columnar structure 11 containing Al has a circular shape or an elliptical shape as viewed from above the film. Of course, as long as the columnar structures 11 are appropriately dispersed in the matrix 12, any shape may be employed.

  The diameter of the columnar structure 11 in the nanostructure according to the present invention is 20 nm or less, preferably 10 nm or less, and more preferably 8 nm or less. In the case of an ellipse or the like, the longest outer diameter portion may be within the above range.

  Also, the average diameter of the columnar structures 11 tends to decrease as the total amount of (Si, Ge) increases, and when the total amount of (Si, Ge) is the same, the larger the ratio of Si, the finer the columnar structure Become a body. Therefore, when the total amount of (Si, Ge) or a mixture of Si and Ge is used for the matrix region, the diameter of the columnar structure can be controlled by controlling the ratio of Si.

  By the way, nanometer-sized nanostructures (substantially in the range of sub-nm to 100 nm) are smaller in size than a certain characteristic length (mean free path, etc.), and thus have unique electrical, optical, and chemical properties. May exhibit specific properties. From this point of view, the nanostructure is useful as a functional material, and also in the nanostructure according to the present invention, the diameter of the columnar structure constituting the mixture is 20 nm or less, particularly 10 nm or less. Can be used in various ways as a nanostructure.

  The interval between the plurality of columnar structures 11, that is, the center-to-center distance may be 30 nm or less, preferably 15 nm or less, more preferably 10 nm.

  Of course, the interval has an interval at which the columnar structures do not contact each other. For example, the diameter of the Al columnar structure having a columnar structure is 1 to 20 nm, the interval between the Al columnar structures is 5 to 30 nm, and the ratio between the height and the diameter of the Al columnar structure, That is, a fine structure having an aspect ratio of 0.1 to 100,000 and having the Al columnar structure substantially perpendicular to the substrate can be used.

  Further, the shape of the columnar structure 11 viewed from the cross section of the substrate may be a rectangular shape as shown in FIG. 1A, or may be a square shape or a trapezoidal shape. The length of the columnar structure 11 can be applied in the range of 1 nm to 100 μm.

  In particular, let us consider a case where the length is controlled in the range of 1 nm to several μm when the diameter of the columnar structure 11 is, for example, 1 to 10 nm and the center-to-center distance is 10 nm to 15 nm. When the length is several nanometers to several tens of nanometers (when the ratio of length to diameter is low), the columnar structure 1 acts as an aluminum quantum dot (0 dimension), and when larger than that, the aluminum quantum wire (one dimension) ).

  The aluminum-containing columnar structures 11 are separated from each other by a matrix 12 containing (Si, Ge) as a main component as shown in FIG. That is, the plurality of columnar structures 11 are dispersed in the (Si, Ge) region.

  The columnar structures 11 are preferably aligned in a specific direction. As shown in FIG. 1 (a), it is particularly preferable to align in a direction perpendicular to the substrate.

  In addition, the columnar protruding portion 15 containing Al as a main component may protrude to any extent depending on the purpose, but if it is 50 nm or less, the shape is not easily broken. The tip of the protrusion may be deformed as shown in FIG.

  FIG. 2 is a schematic view showing another example of the nanostructure in the embodiment of the present invention.

  The thickness of the matrix portion only needs to be thinner than the columnar structure 11 as shown in FIG. 2A, and may not be as shown in FIG. In this case, the matrix 12 is obtained by etching away.

  Further, as shown in FIG. 2D, even when the substrate is etched by using the columnar structure 11 as a mask as shown in FIG. The columnar structure on the substrate surface remaining after removing the columnar structure as a main component can also be used.

  In the present invention, the substrate includes those having a film formed on the surface. That is, as shown in FIG. 2E, the substrate surface layer can be used as the substrate surface layer convex portion 22 to form a columnar structure.

  The substrate 13 is not particularly limited, but is mixed on an insulating substrate such as quartz glass or plastic, a semiconductor substrate such as a silicon substrate, germanium substrate, gallium arsenide, or indium phosphorus, or a substrate as a support member. If a film can be formed, a flexible substrate (for example, a polyimide resin) can also be used. Further, a substrate in which one or more films are formed on the support substrate may be used.

<Method for producing nanostructure>
Next, a method for producing a nanostructure according to the present invention will be described.

  FIG. 3 is a schematic view showing an example of a method for producing a nanostructure of the present invention.

  In the figure, 13 is a substrate, 31 is a columnar structure, 32 is an Al- (Si, Ge) mixed film, 33 is a matrix mainly composed of Si and Ge, 34 is a columnar structure embedded portion, and 35 is a columnar structure protruding portion. , 36 are substrate projections.

  First, an example in which an Al— (Si, Ge) mixed film is formed by magnetron sputtering, which is a film forming method for forming a substance in a non-equilibrium state, will be described.

  The target as a raw material is achieved by arranging a Si chip or a Ge chip on an Al target substrate. The Si chip or the Ge chip can be divided into a plurality of parts, but is not limited to this. Alternatively, an Al- (Si, Ge) fired product prepared by firing a predetermined amount of Al and (Si, Ge) powder can be used as a film forming target material. By using such a target, it is possible to form a homogeneous film with little variation in film composition.

  Alternatively, a method of separately preparing an Al target, a Si target, and a Ge target and simultaneously sputtering each target may be used.

  The total total amount of (Si, Ge) in the formed film is 20 atomic% or more and 70 atomic% or less, preferably 25 atomic% or more and 65 atomic% or less, more preferably 30 atomic%, based on the total amount of Al and (Si, Ge). % Or more and 60 atomic% or less.

  The substrate temperature is 300 ° C. or lower, preferably 200 ° C. or lower. Further, it may be room temperature or lower. If the total amount of (Si, Ge) is produced within such a temperature range, a nanostructure in which columnar structures are dispersed in the (Si, Ge) region can be obtained. The Al— (Si, Ge) mixed film formed by forming the material in a non-equilibrium state at a substrate temperature of 300 ° C. or lower is formed using Al— (Si, Ge) mixed film. , Ge) becomes a structure similar to the eutectic structure, Al forms a nano-columnar structure having a level of several nanometers, and is separated from the (Si, Ge) region in a self-forming manner. The reason why it is similar to a eutectic here is that (Si, Ge) is often amorphous and does not always exist as a crystal. It is also important for the present invention that the composition contains more (Si, Ge) than the so-called eutectic point. Further, when Al— (Si, Ge) is deposited at a sample temperature of at least 300 ° C., the Al— (Si, Ge) mixed film is formed at a temperature of 300 ° C. or less. It starts to grow into a large crystal with a smaller area of a more stable interface than the structure to be formed, and does not form a nano-columnar structure of several nm level.

  The total amount of (Si, Ge) in the Al- (Si, Ge) mixture can be changed, for example, by changing the amount of Si chip or Ge chip placed on the Al target, or mixing of Al and Al- (Si, Ge) powder. It can be controlled by using a target prepared by changing the amount.

  When film formation is performed in a non-equilibrium state, particularly in the case of sputtering, the pressure in the reaction apparatus when argon gas is flowed is preferably about 0.2 to 1 Pa. However, it is not particularly limited to this, and any pressure may be used as long as argon plasma is stably formed.

  Examples of the substrate 13 include a substrate such as an insulating substrate such as quartz glass, a semiconductor substrate such as silicon or gallium arsenide, and a substrate in which one or more layers are formed on these substrates. The substrate material, thickness, mechanical strength, and the like are not particularly limited as long as there is no problem in forming the Al columnar structure. In addition, the shape of the substrate is not limited to a flat plate-like shape, but includes a curved surface, a surface having a certain degree of irregularities and steps, etc., but if there is no problem with the aluminum nanocolumnar structure, It is not particularly limited.

  The film forming method for forming the material in a non-equilibrium state is preferably a sputtering method, but the material is formed in any non-equilibrium state including a vapor deposition method (resistance heating vapor deposition, electron beam vapor deposition, etc.) and an ion plating method. A membrane method is applicable.

  As a method of film formation, a simultaneous film formation process in which Al and (Si, Ge) are simultaneously formed may be used, or a layer film formation process in which several atomic layers of Al and (Si, Ge) are stacked. You can use it.

Next, a method of projecting the Al columnar structure 31 from the Al- (Si, Ge) film will be described. A dry etch process is effective for forming this protrusion. In the dry etching process, the etching rate of Si and Ge with respect to Al may be fast, but it is preferable that the difference in etching rate is large. For this etching, plasma etching using CF ₄ or plasma etching using SF ₆ is effective. The etching rate varies greatly depending on the apparatus and plasma conditions. For example, in the case of CF ₄ , the ratio of the Si etching rate to the Al etching rate is about 10 times, and in the case of SF ₆ it is increased to about 100 times. It is possible.

  As shown in FIG. 3A, the columnar structure 31 mainly composed of Al is formed in the flat film 32 by dry etching before the etching. On the other hand, when etching is started, FIG. As shown in FIG. 5, the Si and Ge matrix 33 is etched more preferentially than the columnar structure 31. Finally, the Si and Ge matrix 33 disappears and only the columnar structure 31 mainly composed of Al remains on the substrate surface as shown in FIG.

  When the etching is further advanced from this state, for example, when the substrate 13 is a Si substrate, the columnar structure 31 serves as a mask to form the substrate convex portion 36 on the substrate surface as shown in FIG. . Here, the etching gas may be switched. When the etching is further advanced, or only the columnar structure is wet-etched, only the substrate convex portion 36 is obtained on the substrate surface as shown in FIG.

  The nanostructure thus produced has a function as an Al quantum dot or Al nanowire as it is, but the functionality can be enhanced by growing a more functional film on the structure. For example, a medium having a uniform particle diameter can be produced by forming a thin film for magnetic recording.

  FIG. 4 is a schematic diagram showing a nanostructure when a thin film is formed on the surface of the present invention.

  4A, 4B, 4C, and 4D show the case where the thin film 41 is formed on the surface corresponding to FIGS. 3B, 3C, 3D, and 3E. Is.

  As such a film, a Co alloy film, a Co / Pt, Co / Pd laminated film, an ordered alloy film of FePt or CoPt, and the like are effective.

  In the present invention, a magnetic thin film formed on the nanostructure is effective as a magnetic recording medium. Such a magnetic recording medium can also be used in a magnetic recording / reproducing apparatus.

  FIG. 6 is a schematic diagram showing a magnetic recording / reproducing apparatus using the magnetic recording medium of the present invention.

  In addition to the magnetic recording medium 61, it is necessary to incorporate a magnetic recording medium driving unit 62 such as a motor, a read / write magnetic head 63, a magnetic head driving unit 64, a signal processing unit 65, a dustproof case, and the like. However, in the magnetic recording / reproducing apparatus, the driving of the magnetic recording medium is not limited to the rotation, and the driving of the magnetic head is not limited to the slide on the circumference.

  Further, an information processing apparatus can be configured using such a magnetic recording / reproducing apparatus.

  FIG. 7 is a conceptual diagram of an information processing apparatus using the magnetic recording / reproducing apparatus of the present invention.

  It is possible to configure an information processing apparatus in which the magnetic recording / reproducing device unit 72, the calculation unit 73, the memory unit 74, the power source 75, the external input / output unit 76 and the wiring 77 connecting them are housed in the storage container 71.

  Further, it can be applied to a nanoimprint method in which a minute hole is formed on another substrate by a transfer method.

  FIG. 5 is a schematic view when the nanostructure of the present invention is used as a mold.

  By using the nanostructure obtained in the present invention as a mold 51 and pressing a resist 52 formed on a substrate 53, transfer holes 54 are formed on the resist surface. In this case, it is effective to form the hard film 56 on the columnar structure or to attach a release agent.

  In addition, the present invention makes it possible to apply aluminum nanocolumnar structures such as quantum dots and quantum wires in various forms, and remarkably expand the application range. Although the structure in the present invention can be used as a functional material itself, it can also be used as a base material, a template, or the like of a further novel nanostructure.

  Hereinafter, the present invention will be described with reference to examples.

"Example 1"
The present embodiment relates to a method for producing a columnar structure mainly composed of Al from an Al- (Si, Ge) film.

  The nanostructure of this invention and its manufacturing method are demonstrated using FIG. In FIG. 3, 13 is a substrate, 32 is an Al— (Si, Ge) mixed film, and 31 is a nano-columnar structure mainly composed of Al. Reference numeral 33 denotes a (Si, Ge) matrix, 34 and 35 denote columnar structure embedded portions and columnar structure protruding portions of nanocolumnar structures each having Al as a main component, and 36 denotes a substrate convex portion.

<Al- (Si, Ge) film formation>
A Si wafer is used as the substrate, and a composition ratio of x = 0.0, _0.2 , _0.4 , _0.6, 0.8, 1.0 in Al _0.6 (Si _1-x Ge _x ) _0.4 is formed thereon. This film was formed. Here, Al was used as a target, and Si and Ge chips were placed thereon to change the composition. The sputtering conditions were an RF power source, an Ar flow rate of 50 sccm, a discharge pressure of 0.7 Pa, an input power of 300 W, a substrate temperature of room temperature, and a film thickness of about 100 nm.

  As a result, as shown in FIG. 3A, the Al— (Si, Ge) mixed film 32 has (Si, Ge) matrix 33 and (Si, Ge) matrix mainly composed of amorphous (Si, Ge). A columnar structure 31 mainly composed of Al grown in the direction perpendicular to the substrate was grown in 33. The diameter of the columnar structures 31 was about 3 to 20 nm, and the interval between the columnar structures was about 6 to 30 nm. Here, the diameter of the columnar structure 31 depends on the ratio of Si and Ge, and the diameter of the columnar structure 31 tends to decrease as the composition ratio of Si increases.

  Here, the target may not be a target on which a chip is placed, but the composition ratio may be a desired value even if simultaneous sputtering is performed using a mixed target or Al, Si, and Ge targets.

  Furthermore, although the RF sputtering method is used here as the sputtering method, the present invention is not limited to this, and an ECR sputtering method, a DC sputtering method, or an ion beam sputtering method may be used. Furthermore, the sputtering conditions depend on the apparatus, and are not limited thereto.

<Etching>
Next, the obtained Al— (Si, Ge) film 32 was dry-etched with an etching apparatus. As etching conditions, the CF ₄ flow rate was 20 sccm, the input power was 150 W, and the pressure was 4.5 Pa.

  First, when etching was performed for 2 minutes, about half of the (Si, Ge) matrix 33 was etched, and the columnar structure 31 containing Al as a main component was hardly changed, and FIG. It became the structure shown in.

  Further etching for 3 minutes revealed that most of the (Si, Ge) matrix 33 was etched, resulting in the structure shown in FIG. At this time, the tip of the columnar structure 31 may be sharpened.

  When the etching is further continued, the columnar structure 31 is used as a mask, and the Si substrate in the portion where the columnar structure 31 is not formed is etched to obtain the structure shown in FIG.

  Further, the columnar structure 31 can be removed by etching or wet etching with phosphoric acid or the like, and the structure shown in FIG. 3E is obtained.

  Here, when the protruding portion 35 of the columnar structure exceeds 50 nm, the columnar structure protruding portion 35 may be slightly bent depending on conditions.

  In addition, the (Si, Ge) matrix is almost in an amorphous state and may contain Al.

(Comparative example)
Further, as a comparative sample A, a similar experiment was performed using a film having an Al _1-y Si _y composition. As a result, a columnar structure cannot be obtained with a film having y other than 0.2 to 0.7, and the target protruding structure cannot be obtained. This was the same result even when the mixed composition of Si and Ge or only Ge was used. By adjusting the content of Si and Ge with respect to the total amount of Al, Si and Ge to at least 20 atomic% to 70 atomic%, it is possible to form an Al columnar structure in (Si, Ge). This makes it possible to produce an Al thin wire having excellent linearity.

Further, as a comparative sample B, a mixed film of about 200 nm was formed on a Si substrate using a target having a composition ratio of Al ₆₀ Si ₄₀ . Here, the substrate temperature was 320 ° C. A circular or elliptical aluminum columnar structure could not be confirmed on the sample surface when the sample was viewed from directly above the substrate. That is, an Al columnar structure could not be confirmed. That is, if the substrate temperature is too high, the state changes to a more stable state, and it is considered that the film growth for forming the Al columnar structure as shown in FIG. 3 is not completed.

"Example 2"
In this embodiment, the case where the etching conditions are changed will be described. Here, the Al- (Si, Ge) mixed film 32 has an Al _0.6 Si _0.4 composition.

The obtained AlSi film 32 was dry-etched with an etching apparatus. As etching conditions, the SF ₆ flow rate was 20 sccm, the input power was 150 W, and the pressure was 5.0 Pa.

  First, when etching was performed for 20 seconds, about half of the Si matrix 33 was etched, and the main component of Al and the columnar structure 31 remained almost unchanged, resulting in the structure shown in FIG. It was.

  Further etching for 20 minutes revealed that most of the Si matrix 33 was etched, resulting in the structure shown in FIG.

  When the etching is further continued, the columnar structure 31 is used as a mask, and the Si substrate in the portion where the columnar structure 31 is not formed is etched to obtain the structure shown in FIG.

As described above, the SF ₆ flow gas can shorten the etching time.

  Here, as a comparative example, etching was performed by an ion milling method of Ar. As a result, the columnar structure 31 did not form a protrusion.

"Example 3"
Next, an example in which a film is formed on the columnar structure protrusion will be described.

In this example, the Al— (Si, Ge) mixed film 32 having an Al _0.6 Si _0.4 composition is used for the Al— (Si, Ge) mixed film 32 as in Example 2, and the substrate is dry-etched with SF ₆ to the nanostructure shown in FIG. Was made.

  Then, a Co / Pt laminated film was formed to a thickness of 30 nm with a thickness of Co = 0.5 nm and Pt = 1.0 nm.

  When the magnetic properties of the obtained film were measured, it was confirmed that there was an easy axis of magnetization in the direction perpendicular to the substrate.

  When observed with a scanning electron microscope, the crystal grains were uniformly miniaturized reflecting the convex portions of the substrate.

From the above, it can be seen that the nanostructure of the present invention is effective as a magnetic device, particularly as a magnetic recording medium. Further, instead of the Co / Pt laminated film, a Co / Pd laminated film, or Pt (001) is formed on the substrate to form a nano-sized columnar structure of Pt (001), and FePt or it is also effective as a magnetic recording medium to be formed of the magnetic film of the L1 ₀ structure such as CoPt.

  FIG. 8 is a diagram illustrating an example of a nanostructure in which a Pt layer is formed on a substrate.

  As shown in FIG. 8A, after a Pt layer 83a is formed on the substrate 83 and Al is the main component and the columnar structure 81 is formed, as shown in FIG. By using the structure 81 as a mask, the Pt layer 83a is removed by etching, and finally the columnar structure 81 is removed to produce a nanostructure.

  It is also possible to form a soft magnetic layer on the upper part of the substrate and arrange the soft magnetic layer on the lower part of the columnar structure.

Example 4
The present embodiment relates to a magnetic recording / reproducing apparatus. Since the magnetic recording medium described in the third embodiment has recording and reproducing characteristics, the magnetic recording medium 61 includes a magnetic recording medium driving unit 62, a magnetic head 63, a magnetic head driving unit 64, a signal, as shown in FIG. The present invention can be used in a magnetic recording / reproducing apparatus including a processing unit 65 and the like.

"Example 5"
The present embodiment relates to an information processing apparatus.

  Since the magnetic recording / reproducing apparatus described in the fourth embodiment can input and output information, as shown in FIG. 7, the magnetic recording / reproducing apparatus part 72, the calculation part 73, the memory part 74, the power supply 75, the external input / output, and the like. It is possible to constitute an information processing apparatus in which the output unit 76 and the wiring 77 connecting them are housed in the storage container 71.

"Example 6"
In this example, an example using the nanostructure of the present invention as a mold will be described.

  FIG. 9 is a diagram showing an example of a nanostructure used as a mold of the present invention.

An Al— (Si, Ge) mixed film 32 having a thickness of 100 nm was formed on a glass substrate in the same manner as in Example 1. Here, an Al (Si, Ge) mixed film having an Al _0.6 Si _0.4 composition was used, and the Si matrix portion was dry-etched with CF ₄ by about 50 nm to produce about 40 nm of columnar structure protrusions 85 containing Al as a main component. At this time, the diameter of the columnar structure protrusions 95 was about 5 nm, and the interval was about 9 nm. A Ni layer 96 as a hard film is formed to a thickness of about 15 nm on the columnar structure projecting portion 35 to obtain the structure shown in FIG.

  As shown in FIG. 5, a release agent was applied to the surface of the obtained nanostructure and pressed against a substrate 53 having a PMMA coating of 30 nm as a resist 52 on a Si substrate 53.

  When the mold was taken and the surface of the PMMA on the substrate was observed with a scanning probe microscope, traces of nano-sized protrusions on the surface of the mold remained as fine holes in the PMMA.

The schematic diagram which shows an example of the nanostructure in embodiment of this invention Schematic diagram showing other examples of nanostructures Schematic diagram showing an example of a method for producing nanostructures Schematic showing a nanostructure when a thin film is formed on the surface of the present invention Schematic diagram when the nanostructure of the present invention is used as a mold Schematic diagram showing a magnetic recording / reproducing apparatus using the magnetic recording medium of the present invention. Conceptual diagram of information processing apparatus using magnetic recording / reproducing apparatus of the present invention The figure which shows the example of the nanostructure which formed Pt layer on the board | substrate of this invention The figure which shows the example of the nanostructure used as a mold of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nanostructure 11 Columnar structure 12 Matrix 13 Substrate 14 Columnar structure embedding part 15 Columnar structure protrusion 16 Deformation columnar structure protrusion 21 Substrate convex part 22 Substrate surface layer convex part 31 Columnar structure 32 Al- (Si, Ge) Mixed film 33 (Si, Ge) matrix 34 Columnar structure embedded portion 35 Columnar structure projecting portion 36 Substrate convex portion 41 Surface film 51 Mold 52 Resist 53 Substrate 56 Hard film 61 Magnetic recording medium 81 Columnar structure 83 Substrate 83a Pt layer 91 Mold 95 Columnar structure protrusion 96 Ni layer

Claims (7)

A nanostructure formed on a substrate or a substrate having an underlayer,
Si , Ge, or those having a columnar first member containing Al as a main component and a second member formed so as to surround the first member, the second member being capable of forming a eutectic with Al A nanostructure characterized in that the first member protrudes more than the second member.   The nanostructure according to claim 1, wherein an average diameter of the first member is 20 nm or less.   The nanostructure according to claim 1 or 2, wherein a height of the first member protruding from the second member is 50 nm or less.   A mold using the nanostructure according to any one of claims 1 to 3. A columnar first member containing Al as a main component and a second member formed so as to surround the first member are provided on a substrate or a substrate having a base layer, and the second member is made of Al. And a step of forming a structure containing Si , Ge or a mixture thereof, which can form a eutectic as a main component, by sputtering, and a step of removing part or all of the second member. A method for producing a nanostructure. The step of removing part or all of the second member is a step of removing the second member to expose the substrate or the substrate having the base layer, and partially or partially removing the second member. 6. The method for producing a nanostructure according to claim 5, further comprising a step of removing a part of the substrate or the substrate having an underlayer after the step of removing all. After the step of removing the first member from the substrate or the substrate having the underlayer,
The method for producing a nanostructure according to claim 6, further comprising a step of forming a laminated film on the substrate or a substrate having a base layer.

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