JP4331437B2 - Method for producing compound / alloy structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a compound / alloy structure, and in particular, a recording device such as a magnetic recording medium or a magnetic head, an electronic device such as LSI, a display device using field emission or field ionization, charge injection, etc. The present invention relates to a method for producing a compound / alloy structure characterized by a method for producing a fine structure constituting a molecular device or the like.
[0002]
[Prior art]
At present, device structure fabrication by optical lithography is industrially the mainstream, but material is cut using electron beam (EB) lithography and focused ion beam (FIB) for experimental microstructure fabrication. Method, Method of Evaporating Material Using High Energy EB, Ion Beam Chemical Vapor Deposition (CVD) Method or EB Chemical Vapor Deposition Method of Decomposing Material Gas Introduced into Device by Ion Beam or EB such as FIB May be used.
[0003]
On the other hand, several structural fabrication methods using a scanning tunneling microscope (STM) have been proposed with the aim of further miniaturizing the structure. As a fabrication method using this STM, a “microfabrication method and apparatus” (Japanese Patent Laid-Open No. 2-173278), “Micropart Processing Method and Apparatus and Micropart Analysis Method and Apparatus” (Japanese Patent Laid-Open No. 4-34824), “Ultra Fine Processing Method Using Scanning Tunneling Microscope” As seen in Kaihei 4-368762), a method using electric field evaporation of the material to be processed, a method of processing the material using a chemical reaction in combination with electric field evaporation, and conversely, evaporating the probe material of STM by electric field evaporation. There are a method of depositing on a substrate and a kind of EB-CVD method using a tunnel current or a field emission current from a probe.
[0004]
Furthermore, a method of using a chemical reaction or phase change due to the tunnel current of STM is proposed as a resist production or exposure method of lithography, as in “Lithography mask manufacturing method and lithography apparatus” (Japanese Patent Laid-Open No. 3-41449). ing.
[0005]
[Problems to be solved by the invention]
However, the currently mainstream lithography method requires multi-step operations such as pattern production, exposure, development, and etching, and is currently anisotropic when the material to be processed is a metal rather than a semiconductor. Since it is difficult to perform etching, there is a problem that it is difficult to produce a fine structure with a high aspect ratio.
[0006]
In addition, in FIB cutting, there is a problem that if the ion convergence is increased to increase the resolution, the ion current is drastically reduced and the processing speed becomes very small. In addition, the FIB uses ions used for both cutting and deposition. For example, there is a problem that contamination by Ga ions occurs.
[0007]
On the other hand, the method of evaporating using EB has a problem that it takes a lot of time to try to evaporate other parts while leaving a part of the material. Since a high-pressure material gas is introduced, there is a problem that contamination occurs due to the incorporation of the material gas or residual gas in the apparatus.
[0008]
Furthermore, among the microstructural fabrication methods using STM that have been proposed to date, the method using electric field evaporation of a material to be processed is very large when a part of the material is left as in the case of evaporation by EB. There is a problem that it takes a long time.
[0009]
In addition, the STM probe material deposition method consumes the probe as it evaporates, making it difficult to control the tunnel current, which greatly depends on the probe state, and requiring frequent replacement of the probe. There is a problem of becoming.
[0010]
Further, in the case of the EB-CVD method using STM, there is a problem that the same contamination problem as in the normal EB-CVD method cannot be avoided.
[0011]
Further, in the formation of a lithography pattern using STM, there is a problem that a multi-step operation is not different from that of normal lithography, and the same problem occurs when the material is a metal.
[0012]
Accordingly, an object of the present invention is to selectively form a fine compound / alloy structure by a simple process.
[0013]
[Means for Solving the Problems]
FIG. 1 is an explanatory diagram of the principle configuration of the present invention. Here, means for solving the problems in the present invention will be described with reference to FIG.
See FIG. 1 In order to solve the above-mentioned problem, the present invention provides a method for producing a compound / alloy structure in which a plurality of material substances 2 and 3 deposited on a substrate are locally provided in a region having a diameter of 1 μm or less. After heating and melting to form a structure 6 made of either a compound or an alloy , the material materials 2 and 3 are further deposited on the structure 6 and then a local heat treatment is performed . Features.
[0014]
In this manner, by locally heating, it is possible to selectively form the structure 6 made of any compound or alloy having a predetermined composition with an arbitrary fine shape without mask.
In particular, by depositing the material substances 2 and 3 on the structure 6 and performing local heat treatment, it is possible to form a configuration such as a fine heterojunction in which the different substances 2 and 3 are in contact with the boundary. Become.
[0015]
The size of such a fine structure 6 is 1 μm or less, more preferably 100 nm or less as the maximum diameter, which is difficult to process by lithography.
In this case, the material substances 2 and 3 may be directly deposited on the substrate, or may be deposited on the substrate via the base 1.
[0016]
In this case, when the probe 4 such as STM is used, since the position of the structure 6 can be confirmed by observing by STM before reworking, alignment at the time of reworking becomes easy.
[0017]
As the local heating means in this case, any one of a tunnel current 5 using a probe 4 such as STM, a contact current, or a field emission current may be used, or an electron beam, a laser beam, or a synchrotron. Any energy beam of tron radiation may be used. The magnitude of energy applied to the material substances 2 and 3, for example, the amount of current to be applied, or in the case of an energy beam, the energy of the beam itself By controlling the number of beams and changes with time, it is possible to form a structure 6 having an arbitrary shape and composition.
[0018]
In this case, since the operations from film formation to processing of the material substances 2 and 3 can be performed in a high vacuum, contamination derived from the production atmosphere can be avoided, and the probe 4 such as STM can be attached. When used, the probe 4 is not consumed because the material is supplied not from the probe 4 but from the substrate, and problems due to consumption can be avoided.
[0019]
As the structure 6 formed in this way, a group III-V compound semiconductor structure using a material substance 2, 3 composed of a group III element and a material substance 2, 3 composed of a group V element, a material composed of a group II element A compound structure such as an 11-VI compound semiconductor structure using the materials 2 and 3 composed of the materials 2 and 3 and a group VI element, or a material material 2 and 3 composed of a magnetic metal or a nonmagnetic metal was used. An alloy structure such as a nonmagnetic alloy structure, a ferromagnetic alloy structure, or an antiferromagnetic alloy structure is typical.
[0020]
Further, the composition of the structure 6 can be arbitrarily controlled by changing the ratio of the thicknesses of the plurality of material substances 2 and 3, whereby a mixed crystal compound semiconductor structure or alloy structure having an arbitrary composition can be obtained. Can be formed.
[0021]
Further, by utilizing the difference in physical or chemical properties between the material substances 2 and 3 and the formed structure 6, unnecessary portions other than the structure are removed, thereby performing a selective evaporation method by lithography or EB. Without use, only a fine structure 6 can be formed at an arbitrary position by a simple maskless etching process.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Here, with reference to FIG. 2 thru | or FIG. 4, the manufacturing process of the fine heterojunction structure of the 1st Embodiment of this invention is demonstrated.
2A. First, an Sb thin film 12 having a thickness of 100 nm or less, for example, 10 nm, and a thickness of 100 nm or less, for example, 10 nm, are formed on the Al ₂ O ₃ substrate 11 by vacuum deposition. A thin film 13 is sequentially deposited to form a multilayer film.
[0023]
Next, referring to FIG. 2B, the STM probe 14 is brought close to the multilayer film to the extent that the tunnel current flows, and the heated portions of the In thin film 13 and the Sb thin film 12 are heated by locally flowing the tunnel current. The InSb dots 15 are formed by melting and alloying.
In this case, although the size of the InSb dots 15 depends on the amount of tunnel current, for example, by flowing about several μA, the InSb dots 15 having a maximum diameter of 100 nm or less, for example, 20-30 nm can be obtained.
[0024]
Next, referring to FIG. 3C, an Al thin film 16 having a thickness of 100 nm or less, for example, 10 nm is deposited on the entire surface again by using the vacuum evaporation method.
[0025]
Next, referring again to FIG. 3D, again, the Al thin film 16 corresponding to the InSb dots 15 is again brought close enough to the tunnel current to flow, and the Al thin film is locally heated by locally passing the tunnel current. An InAlSb / InSb heterojunction can be formed by melting and alloying the heated portions of 16 and InSb dots 15 to form InAlSb dots 17.
In this case, since the STM probe 14 is used, since the position of the InSb dot 15 can be confirmed by performing observation with the STM before reprocessing, alignment during reprocessing is easy.
[0026]
Next, referring to FIG. 4F, unreacted Al thin film 16 and In thin film 13 are selectively removed by etching using an etchant made of dilute hydrochloric acid with a small etching rate for InAlSb dots 17.
[0027]
Finally, referring to FIG. 4G, an isolated InAlSb / InSb heterojunction can be formed by removing the unreacted Sb thin film 12 by lightly etching with aqua regia.
In this case, the exposed portions of the InAlSb dots 17 and InSb dots 15 are also etched.
[0028]
As described above, in the first embodiment of the present invention, since a tunnel current is used to locally heat an STM probe, a fine heterojunction junction structure is formed at an arbitrary location. It becomes possible to do.
[0029]
It is possible to form a pn junction heterodiode by doping In and Sb with an n-type impurity such as Si and doping Al with a p-type impurity such as Zn when depositing the thin film. become.
[0030]
In this case, a refractory metal wiring pattern such as W is provided on the Al ₂ O ₃ substrate, and an InSb dot is formed on the refractory metal wiring pattern, whereby one electrode of the pn junction heterodiode can be obtained. .
[0031]
For the other electrode, for example, an Al thin film is deposited again on the entire surface including the pn junction heterodiode, and then local heating is repeated until the pn junction heterodiode is reached while moving the STM probe to melt the Al. -By solidifying, a thicker Al wiring pattern than other parts can be formed, and then the other electrode can be formed by removing the remainder of the Al film by lightly etching with dilute acid .
In this case, it is necessary to consider the location where the InSb tod is formed so that the Al wiring and the W wiring are not short-circuited.
[0032]
Next, with reference to FIG. 5, the manufacturing process of the nonmagnetic alloy dot of the 2nd Embodiment of this invention is demonstrated.
5A. First, a Cu thin film 22 having a thickness of 100 nm or less, for example, 12 nm, and a Ni thin film 23 having a thickness of 100 nm or less, for example, 8 nm are formed on the Ta substrate 21 by vacuum deposition. A multilayer film is formed by sequentially depositing.
[0033]
Next, refer to FIG. 5B. Next, the STM probe 24 is brought close to the multilayer film to the extent that the tunnel current flows, and the Ni thin film 23 and the Cu thin film 22 are heated by locally heating the tunnel current. By melting and alloying, Cu _0.6 Ni _0.4 dots 25 are formed.
[0034]
Thus, in the second embodiment of the present invention, Cu _0.6 Ni _0.4 dots 25, which are nonmagnetic alloys, are scattered in arbitrary positions in the Ni thin film 23, which is a ferromagnetic metal, in an isolated state. Can do.
Note that the composition ratio of the alloy dots substantially depends on the film thickness ratio of the Cu thin film 22 and the Ni thin film 23 deposited first.
[0035]
Next, with reference to FIG. 6, the manufacturing process of the ferromagnetic alloy dot of the 3rd Embodiment of this invention is demonstrated.
First, referring to FIG. 6A, using a vacuum deposition method on the Ta substrate 31, a Cu thin film 32 having a thickness of 100 nm or less, for example, 12 nm, a Al thin film 33 having a thickness of 100 nm or less, for example, 6 nm, and A multilayer film is formed by sequentially depositing a Mn thin film 34 having a thickness of 100 nm or less, for example, 6 nm.
[0036]
Next, referring to FIG. 6B, the MTM thin film 34 to the Cu thin film 32 are heated by bringing the STM probe 35 close to the multilayer film to the extent that the tunnel current flows, and locally heating the tunnel current. Cu ₂ AlMn dots 36 are formed by melting and alloying.
[0037]
As described above, in the third embodiment of the present invention, Cu ₂ AlMn dots 36, which are ferromagnetic alloys, are isolated at arbitrary positions in the Cu thin film 32, Al thin film 33, and Mn thin film 34 that are nonmagnetic metals. Can be scattered in the state.
In this case, the film thicknesses of the Cu thin film 32, the Al thin film 33, and the Mn thin film 34 to be deposited are set so as to correspond to the composition ratio of Cu ₂ AlMn.
[0038]
Next, with reference to FIG. 7, the manufacturing process of the antiferromagnetic alloy dot of the 4th Embodiment of this invention is demonstrated.
First, referring to FIG. 7A, using a vacuum deposition method on the Ta substrate 41, a Pt thin film 42 having a thickness of 100 nm or less, for example, 6 nm, a Pd thin film 43 having a thickness of 100 nm or less, for example, 6 nm, and A multilayer film is formed by sequentially depositing a Mn thin film 44 having a thickness of 100 nm or less, for example, 12 nm.
[0039]
Next, referring to FIG. 7B, the MTM thin film 44 to the Pt thin film 42 are heated by bringing the STM probe 45 close enough to the tunnel current to flow on the multilayer film and locally heating the tunnel current. PtPdMn ₂ dots 46 are formed by melting and alloying.
[0040]
As described above, in the fourth embodiment of the present invention, the PtPdMn ₂ dots 46, which are antiferromagnetic alloys, are isolated in arbitrary positions in the Pt thin film 42, the Pd thin film 43, and the Mn thin film 44 that are nonmagnetic metals. Can be scattered in the state.
Also in this case, the film thicknesses of the Pt thin film 42, the Pd thin film 43, and the Mn thin film 44 to be deposited are set so as to correspond to the composition ratio of PtPdMn ₂ .
[0041]
As mentioned above, although each embodiment of the present invention has been described, the present invention is not limited to the configuration described in each embodiment, and various modifications can be made.
For example, in the description of each of the above embodiments, the tunnel current from the STM probe is used to melt the multilayer film. However, the present invention is not limited to the tunnel current, and a field emission current or a contact current is used. May be used.
Needless to say.
[0042]
That is, the “tunnel current” is formed between the positive and negative electrodes by applying a voltage that does not exceed the work function of the material constituting each electrode, for example, a voltage of about 5 to 6 V or less. The potential barrier is about 1 nm between the positive and negative electrodes, and almost no current flows away from 1 nm.
[0043]
On the other hand, the “field emission current” is due to electrons emitted into free space by applying a voltage higher than the work function of the material constituting each electrode between the positive and negative electrodes. Although current can flow even at intervals of nm to μm, if the applied voltage is increased too much, the resolution becomes worse.
[0044]
The “contact current” is a current that flows in the state where the positive and negative electrodes are in contact and electrons move between the electrodes and there is no potential barrier. The resolution depends on the contact area of the probe. The resolution is worse.
For example, when the size of the structure is about several nanometers or more, it is desirable to use a probe made of a refractory metal of a contact type AFM (atomic force microscope).
[0045]
Further, the local heating means is not limited to such a current, and an electron beam, laser light, or synchrotron radiation light may be used, and the structure is relatively large in size. Becomes effective.
[0046]
In the first embodiment, the unreacted Sb thin film is removed using aqua regia, but the whole is lightened by sputter etching using a rare gas such as Ar gas in a vacuum. It may be etched.
[0047]
In each of the above embodiments, binary and ternary compounds or alloys are formed, but a multilayer film is formed of four or more layers to form a quaternary mixed crystal compound or alloy. Is also good.
[0048]
In the first embodiment, the manufacturing process of the group III-V compound semiconductor is described. However, the manufacturing process is not limited to the group III-V compound semiconductor, and thin film materials such as Hg and Cd are used. A II-VI compound semiconductor such as HgCdTe may be formed using a II group element and a VI group element such as Te, and further, a compound semiconductor of another group may be formed. .
[0049]
Here, the detailed configuration of the present invention will be described again with reference to FIG. 1 again.
See FIG. 1 again. (Appendix 1) A structure made of either a compound or an alloy by locally heating and melting a region having a diameter of 1 μm or less of a plurality of material substances 2 and 3 deposited on a substrate. After forming 6 , the material substances 2 and 3 are further deposited on the structure 6, and then a local heat treatment is performed .
In (Supplementary Note 2) the step of locally heating the plurality of the material 2, a tunnel current 5, contact current, or a compound according to Appendix 1, which comprises using one of the field emission current and A method for manufacturing an alloy structure.
(Supplementary Note 3) In the step of locally heating the plurality of the material 2, process for the preparation of a compound-alloy structure according to Note 1, which comprises using the energy beam irradiation.
(Additional remark 4 ) The said energy beam is either an electron beam, a laser beam, or synchrotron radiation light, The manufacturing method of the compound and alloy structure of Additional remark 3 characterized by the above-mentioned.
(Supplementary Note 5) In the case of a plurality of the material 2,3 material substance 2 is made of a Group III element (3) and consisting of the V group element material substance 3 (2), the structure 6 is group III-V compound semiconductor 5. The method for producing a compound / alloy structure according to any one of appendices 1 to 4 , wherein the compound / alloy structure is a structure.
(Supplementary Note 6) In the case of a plurality of the material 2,3 material substance 2 is made of a group II element (3) and consisting of a group VI element material substance 3 (2), the structure 6 is 11-VI group compound semiconductor 5. The method for producing a compound / alloy structure according to any one of appendices 1 to 4 , wherein the compound / alloy structure is a structure.
(Supplementary Note 7) The plurality of the material 2 is made of a magnetic metal or a magnetic metal, and the structure 6 are non-magnetic alloy structure, the ferromagnetic alloy structure, or of an antiferromagnetic structure The method for producing a compound / alloy structure according to any one of supplementary notes 1 to 4 , wherein the method is any one.
(Supplementary Note 8) The compound, alloy structure according to any one of Supplementary Notes 1 to 7, characterized in that changing the composition of the structure 6 by varying the ratio of said plurality of thickness of the material 2, 3 Manufacturing method.
After formation of the (Supplementary Note 9) The structure 6, by utilizing a difference in physical or chemical properties of the structure 6 formed with the material substance 2, the unnecessary portion other than the structure 6 The method for producing a compound / alloy structure according to any one of appendices 1 to 8 , wherein the compound / alloy structure is removed.
[0050]
【The invention's effect】
According to the present invention, after forming a multilayer film with different material substances, it is locally heated and melted to be alloyed. Therefore, in an electronic device, a magnetic device, etc., an alloy having an arbitrary size of nanometer size or more or A fine structure of a compound can be directly produced on a substrate, and as a result, it greatly contributes to ultra-miniaturization exceeding the lithography limit of electronic devices and magnetic devices.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a basic configuration of the present invention.
FIG. 2 is an explanatory diagram of the manufacturing process up to the middle of the first embodiment of the present invention.
FIG. 3 is an explanatory diagram of the manufacturing process until the middle of FIG. 2 and subsequent steps of the first embodiment of the present invention.
FIG. 4 is an explanatory diagram of the manufacturing process after FIG. 3 according to the first embodiment of the present invention.
FIG. 5 is an explanatory diagram of a manufacturing process according to the second embodiment of this invention.
FIG. 6 is an explanatory diagram of the manufacturing process of the third embodiment of the present invention.
FIG. 7 is an explanatory diagram of the manufacturing process of the fourth embodiment of the present invention.
[Explanation of symbols]
1 base 2 material substance 3 material substance 4 probe 5 tunneling current 6 structure 11 Al ₂ O ₃ substrate 12 Sb thin film 13 probe 15 of In film 14 STM InSb dots 16 Al thin film 17 InAlSb dots 21 Ta substrate 22 Cu thin film 23 Ni thin film 24 STM probe 25 Cu _0.6 Ni _0.4 dot 31 Ta substrate 32 Cu thin film 33 Al thin film 34 Mn thin film 35 STM probe 36 Cu ₂ AlMn dot 41 Ta substrate 42 Pt thin film 43 Pd thin film 44 Mn thin film 45 STM Probe 46 PtPdMn ₂ dots

Claims (4)

Locally heating the diameters 1μm or less in the range of a plurality of the material which had been deposited on the substrate, after forming the structure made of any of the compounds or alloys are melted, on the structure, further A method for producing a compound / alloy structure, comprising depositing a material substance and performing a local heat treatment . 2. The method for producing a compound / alloy structure according to claim 1, wherein in the step of locally heating the plurality of material substances, any one of a tunnel current, a contact current, and a field emission current is used. 2. The method for producing a compound / alloy structure according to claim 1, wherein irradiation of an energy beam is used in the step of locally heating the plurality of material substances. Wherein after formation of the structure to utilize the difference in physical or chemical properties of the structures formed with the material substance, according to claim 1, characterized in that the removal of unnecessary portions other than the structure 4. The method for producing a compound / alloy structure according to any one of items 1 to 3 .

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