WO2003080902A1

WO2003080902A1 - METHOD OF MICROFABRICATING CRYSTAL TiO2 AND MICROFABRICATED CRYSTAL TiO2

Info

Publication number: WO2003080902A1
Application number: PCT/JP2003/003499
Authority: WO
Inventors: Yoshimichi Ohki; Tetsuya Nakanishi; Kenichi Nomura; Kunihiro Shima; Satoshi Ishii; Koichi Awazu; Makoto Fujimaki
Original assignee: Waseda University; National Institute Of Advanced Industrial Science And Technology
Priority date: 2002-03-26
Filing date: 2003-03-24
Publication date: 2003-10-02
Also published as: JP2003279766A; AU2003220980A1; JP4025886B2

Abstract

A method of microfabricating crystal TiO2 wherein deep patterns can be formed and wherein sharp and accurate fabrication can be effected, and microfabricated crystal TiO2. A substrate of rutile crystal TiO2 with a mask (3) of desired pattern formed over an upper surface thereof is irradiated with accelerated ion. Parts (2a) irradiated with ion are leached by hydrofluoric acid. Thus, an etching reflecting the pattern of the mask (3) is carried out. Further, a microstructure wherein rutile crystal TiO2 and anatase crystal TiO2 are mixed can be formed by effecting a heat treatment of parts (2a) irradiated with ion at 900 ° C or below so as to convert the same to anatase crystal TiO2.

Description

Bright fine manual crystal T i 0 ₂ micromachining methods and microfabricated crystal T i O 2 art

The present invention, concerning a fine machining method crystals T i O _2. The present invention also rutile crystal T i 0 ₂ and anatase T i 0 ₂ crystals and are mixed T io ₂ relates microfabrication methods. Further, the present invention relates to a crystal processed by these fine processing methods.

T i 0 ₂ Background art

Crystal T i 0 ₂ is the infrared - near-ultraviolet region (1 2 0 0 0 nm~ 4 0 0 nm) transparent in, since a large birefringence has a high refractive index, the prism, Henkomoto Widely applied to optical elements such as elements. In recent years, it has also been used for photocatalytic materials and solar cell materials. Furthermore, crystalline T i 〇 ₂ has attracted attention as a material of the photonic crystal has a high dielectric constant. This photonic crystal is an artificial, very fine structure with a high contrast that periodically changes the dielectric constant, and has attracted attention as a structure that can bend and guide light. ing.

In application to these applications, crystal i 0 ₂ has been performed is subjected to microfabrication, conventional, reactive gas-phase etching method (R eactiveionetching, RIE) has been used. The RIE is a method of processing the front surface of the crystal T i 0 ₂ By corrode crystalline T io ₂ by corrosive gas plasma shape (etching), a portion that does not corrode the registry ( 'mask) by exposure to plasma was covered by port Rimmer or metal called, to form a desired pattern on the crystalline T io ₂ surface. In this method, it is necessary to prolong the time of plasma exposure in order to deepen the pattern to be formed. However, since the resist is also corroded by corrosive plasma and cannot be processed for a long time, it is difficult to process the resist for a long time. There was a problem that it was difficult to form a pattern. In addition, since this is a processing method that utilizes the corrosive action, the surface exposed to the plasma may be roughened, However, there is a problem that the shape is not always sharply reflected in + minutes. Furthermore, in the conventional crystal T i 0 ₂ microfabrication method by etching such as RIE, it was not possible to impart i 0 ₂ inside a fine pattern in the crystal.

On the other hand, crystalline T i 0 ₂ of the sheet is also as high utility value, as a method for forming the crystalline T i 〇 _second sheet is conventional, crystalline T i 0 ₂ mechanically polishing methods rows cracking ing. However, in forming a thin plate of the crystal Ti 0 ₂ by polishing, it was difficult to reduce the thickness of the thin plate to several tens μm or less due to mechanical impact.

Incidentally, the crystal T i 0 _2, there are rutile and anatase one peptidase type, as such photocatalyst materials and solar cells materials are useful anatase. As a manufacturing method of the conventional anatase T i 0 _2, include CVD or sol-gel method. However, the CVD method or the sol-gel method can only integrally manufactured child anatase crystal T i 0 _2, can not partially anatase child in rutile crystal T i O ₂ surface Was. If it can be expected to further expand the use of crystalline T i 0 ₂ If possible provide a crystalline T i 0 ₂ subjected to such a fine processing.

The present invention has been made in view of these problems, and an object thereof is to provide a can and sharp and can be accurately etched crystal T i 0 ₂ microfabrication method to form a deep pattern. The present invention also aims to provide a crystalline T i 0 ₂ microfabrication method capable of forming a 1 0 m or less crystalline T i 0 ₂ of the sheet. The present invention aims at providing a crystal T i O ₂ inside capable of giving a fine pattern crystal T i 0 ₂ microfabrication methods. The present invention aims at providing a rutile crystal T i 0 ₂ and anatase T i 0 ₂ and the possible crystal T i 0 ₂ microfabrication methods be mixed in the desired position. Furthermore, the invention purpose is to provide a crystalline T io ₂ that these microfabricated methods microfabricated. Disclosure of the invention

Crystal T i 0 ₂ microfabrication method of the present invention, the ion shines the ions accelerated in the crystal T i 0 ₂ irradiation is irradiated portion is soluble in the solution, part fraction the ion is irradiated Is a method of processing the crystal T io ₂ by removing like this By adopting the configuration, the crystal Ti 0 ₂ is insoluble in acids and the like, but after masking the desired portion with ions and then irradiating with accelerated ions, the portion irradiated with ions Only becomes amorphous. Since the amorphous portion is dissolved in an acid or the like, the crystal Ti 0 2 can be processed by dissolving and removing (etching) this. At this time, since the accelerated ions may be advanced deep in the adjusting child its energy one, it is possible to form a deep pattern, is sharp and precise microfabrication crystal T i 0 ₂ It is possible.

Further, the fine processing method of the present invention is a method of irradiating by setting the ion so soluble in the solution from the surface side of the crystal T io _2. As a result, the crystal T i O

Etching can be performed from the surface of ₂ .

The method of micromachining crystal T io ₂ of the present invention is higher in the inner portion of the ions that electronic stopping power enters into the crystal T io ₂ than crystalline T i 0 ₂ surface, with the inner side partial the crystalline T io ₂ is a method of irradiating set to be soluble in the solution. This enables hollow microfabrication crystal T i 0 _2, also, it is possible to process to a thickness of 1 0 At _m or less thin plate.

Crystal T i 0 ₂ microfabrication method of the present invention, the ion is the way an ion of atomic number 1 0 or more atom. By irradiating accelerating such ions can allow dissolve the crystals T i 0 ₂ like acid.

Crystal T i 0 ₂ microfabrication method of the present invention, the crystalline T i O ₂ is a method of having a rutile crystal structure. For this reason, a crystal T i に₂ which is excellent in optical properties and has a high dielectric constant and is suitable as a photonic crystal can be processed. Further, it is possible than § anatase type crystal T io ₂ exhibit good selectivity.

The fine processing method of the crystal T io ₂ of the present invention comprises irradiating the ion to the crystal T i 0 ₂ through a mask having a desired shape, thereby changing the shape of the mask to the surface or the inside of the crystal T io ₂ It is a method of forming in a part. For this reason, it is a method for fine processing of the crystal T i 0 ₂ with high accuracy, in which the shape of the mask is sharply reproduced.

The method of micromachining crystal T io ₂ of the present invention, the solution to melt-a portion in which the ions are irradiated is the way an acid. Therefore, it is easy to handle and has excellent versatility. The crystal T i 0 ₂ microfabrication method of the present invention, after irradiation with ions accelerated to the rutile type crystal T i 0 _2, by heating in 9 0 0 ° C or less temperature, ions are irradiated In the anatase crystal T i 02. Therefore, it is possible and Ruchi Le-type crystal T i 0 ₂ and anatase crystal T io ₂ is readily pressurized E the microstructure mixed.

The method of micromachining crystal T io ₂ of the present invention, the ion is the way an atomic number 1 0 or more I ON. Therefore, by irradiating accelerating the ions, it can be amorphous crystals T i 〇 _2.

Crystal T i 0 ₂ microfabrication method of the present invention, by irradiating the ions to the rutile type crystal T i 0 ₂ through a mask having a desired shape, ANATA only parts of the other than the mask This is a method for forming a mono-type crystal T i 0 ₂ . Therefore, it is possible to process the microstructure with mixed anatase T i O 2 was reproduced sharply rutile crystal T io ₂ the shape of the mask.

The method of micromachining crystal T io ₂ of the present invention, the crystalline T i 0 ₂ is the way of a single crystal or polycrystalline. Therefore, it can be applied to a wide range of applications.

The finely-processed crystal Ti 0 ₂ of the present invention is obtained by irradiating accelerated ions to make the irradiated portions soluble in a solution and removing the irradiated portions. For this reason, the crystal T i 0 ₂ has a sharp and accurate fine processing with a deep pattern.

Crystal T i 0 ₂ microfabricated of the present invention irradiates by setting the ion so soluble in the solution from the front surface of the crystal T i 0 _2, is obtained by removing from the surface side

. Thus, sharp and accurate micromachining a deep pattern from the crystal T i 0 ₂ surface is in the crystal T io ₂ was made.

Crystal T io ₂ microfabricated of the present invention is higher in the inner portion of the ions that electronic stopping power enters the crystal T i 0 in ₂ than the surface of the crystal T i O _2, the inner side min Irradiation is performed by setting the crystal T i 0 ₂ so as to be soluble in the solution, so that a portion inside the surface of the crystal τ i 0 ₂ is soluble in the solution and the inside portion is removed. is there. Therefore, it has a crystal T i O ₂ of the hollow and thin plate.

Crystal T i 0 ₂ microfabricated of the present invention, Ma said ion having a desired shape By irradiating the crystal T i 0 ₂ through the disk, in which the shape of the mask was formed on the crystal T i 0 ₂ surface or inner portion. Therefore, accurate fine processing that reproduces the shape of the mask sheet Jaap has become crystal T i ◦ ₂ was made. Crystal T i 0 ₂ microfabricated of the present invention, after irradiation with I-on accelerated rutile crystal T i 0 _2, by heating in 9 0 0 ° C or less temperature, ions are irradiated the part is obtained by the anatase T i 0 _2. Therefore, it has a crystal T io ₂ having a rutile type crystal T i 0 ₂ and anatase T i 0 ₂ and has a mixed microstructure.

Crystal T i 0 ₂ microfabricated of the present invention, by irradiating the rutile crystal T io ₂ the ions through a mask having a desired shape, only ANATA foremost parts of the other than the mask This is a zeolite crystal T i 0 ₂ formed. Therefore, has a microstructure rutile crystal T i 0 ₂ shape reproduced sharply of the mask and the anatase T io ₂ are mixed.

Further, the micro-processed crystal T io ₂ of the present invention is one wherein the crystal T io ₂ is a single crystal or a polycrystal. This makes it applicable to a wide range of applications. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a schematic diagram illustrating an apparatus for performing crystallization T i 0 ₂ microfabrication method according to the first embodiment of the present invention.

FIG. 2 is a schematic view showing a method for microfabrication of the crystal TiO ₂ of the first embodiment. Figure 3 is a graph showing that amorphous crystalline T i 0 ₂ is the ion irradiation.

Figure 4 is a graph showing the depth and value of the etching depth of the various ions from ESP and the sample table surface when irradiated rutile crystal T i 0 _2.

Figure 5 is a graph showing the relationship between the depth from ESP and the sample surface when the C 1 ions having each acceleration energy was irradiated to the rutile crystal T i 0 _2.

Figure 6 is a cross-sectional view schematically showing the crystal T i 0 that obtained by ₂ microfabrication methods crystals T i 0 ₂ of the basic structure according to a second embodiment of the present invention. Figure 7 is a schematic diagram showing a crystal T i 0 ₂ microfabrication method of the second embodiment. Figure 8 is a schematic schematic representation of crystalline T i 0 ₂ microfabricated obtained by the process shown in FIG.

9, ions are irradiated to the rutile crystal T i 0 _2, is a graph showing the XRD spectrum in the case of heat-treated at then in air.

Figure 1 0 is a schematic diagram showing a crystal T i 0 ₂ microfabrication method according to a third embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of a crystal T i 0 ₂ microfabrication method of the present invention with reference to the accompanying drawings will be described in detail. FIG. 1 schematically shows an apparatus capable of performing the microfabrication method of the present embodiment. In the figure, reference numeral 1 denotes an ion accelerator, and the ion irradiation direction of the ion accelerator 1 is such that a rutile crystal T i O ₂ plate 2 is installed. The rutile crystal T i 0 ₂ is also sulfuric acid or highly corrosive aqueous HF solution (hydrofluoric acid) of which the acid is a strong acid is insoluble and therefore is conventionally have been performed etching by RIE, which microfabrication Was a limiting factor. Accordingly, in this embodiment, Ri by the irradiation with ions to the rutile type crystal T io _2, denature the rutile crystal T i 0 _2, and soluble in acid, to etch the soluble portion In this way, the rutile crystal surface is processed.

First, they shot an accelerated ions to soluble rutile crystal T i O ₂ in a hydrofluoric acid irradiation. Rutile crystals T i 0 ₂ Ri by the irradiation with ions using a phenomenon ing and soluble in hydrofluoric acid, the desired path on the upper surface of the rutile crystal T i 0 ₂ plate 2 as shown in FIG. 2 The mask 3 is formed by irradiating accelerated ions with the mask 3 formed in the turn (Fig. 2 (a)), and then dissolving and removing the ion-irradiated portion 2a with hydrofluoric acid (Fig. 2 (b)). Etching that reflects the pattern can be performed.

Why rutile crystal T i O ₂ E Tsuchingu becomes possible by irradiating thus accelerated ions are as follows. Figure 3 shows the XRD spectrum of the rutile-type crystal T i O _2, the lower the upper after the copper ion 2. 0 X 1 0 ¹³ cm ² were irradiated with 8 4. 5ME V is before irradiation However, from this Figure 3, before ion irradiation Peak indicating crystallinity was observed rutile crystal T io ₂ it is clearly visible that significantly reduced by ion irradiation. Therefore, more crystalline structure of the rutile crystal T io ₂ to irradiation of ions is disturbed, amorphization (amorphous) was can be seen. In other words crystalline rutile crystal T io ₂ is lost by ion irradiation if, it can be said that the amorphization occurs. As a result, a portion where the amorphization occurs is become possible high processing the selection択性to by Ri rutile crystal T io ₂ surface to dissolved by hydrofluoric acid.

Then, irradiation conditions to that ions soluble in acid in microfabrication rutile crystal T i 0 ₂ as described above, and will be described. Etch depth, which in relation to the irradiation I O emissions and ESP Determined. When an ion is incident on a substance, the ion travels while losing energy due to interaction with electrons in the substance. In other words, electrons in the substance are given energy from ions. ESP is the value of the energy that an ion loses per unit length at this time, the electronic stopping power. This value depends on the incident ion, incident energy, and incident substance. Figure 4 is a graph showing the value of the ESP at the time of irradiation with the various ions in the rutile crystal T i 0 _2. According to this graph, when an ion is incident on the rutile crystal T i 0 ₂ , the ion proceeds while losing energy due to interaction with the electrons of the rutile crystal T i O ₂ , while the rutile crystal T i 0 2 The electrons in ₂ are energized by ions. And the ions reach the point (range) where ESP becomes zero.

In contrast, the depth at which etching actually occurred due to the irradiation of each ion is indicated by the “black” mark in Fig. 4. As is apparent from FIG. 4, the depth actually etched is smaller than the range shown in FIG. From this, it is understood that ESP of a certain value or more is necessary in order to make the crystal Ti 0 ₂ amorphous by the irradiated ions. Therefore, the result of calculation performed simulations of these experiments, the rutile-type crystal T i 0 ₂ to permit amorphized etching was found to be required 4 ke V / nm or more ESP It is.

As the atomic number of the irradiated ion decreases, the interaction between the ion and the electrons in the substance decreases. As a result, ESP becomes smaller and ESP of 4 ke VZ nm or more There are limits to getting it. As a result, a simulation was performed based on the experimental results shown in Fig. 4 described above, and a calculation was performed. As a result, in the case of an atom having an atomic number smaller than that of neon (Ne), no matter how much acceleration energy was applied, 4 keV / nm could not be obtained. Therefore, the ion to be used must be an ion of an atom having an atomic number of Ne or more. Furthermore, it can be seen from FIG. 4 that the etching depth can be adjusted by selecting the type of ion to be irradiated and by changing the acceleration energy of the ion.

Furthermore, in order to uniformly etch the ion irradiated portion 2a, the entire ion irradiated portion 2a must be substantially amorphous. Therefore, irradiation injection amount (dose) of ions was scrutinized the relationship between the etching surface, uniform by the ^{8 X l 0 1 3 c πΓ} 2 or more ion irradiation rutile crystal T i 〇 ₂ while it is etched ring, less, for example, 2. 2 X ¹ 0 1 ³ this unevenness of C u ions cm ² in the etched etching surface by irradiation shines afterwards hydrofluoric acid is formed Togawaka' Was. In other words, it was found that by adjusting the dose amount, the etched surface could be made uniform and irregularities could be formed. Therefore, a large dose is required for optical applications that require uniformity, and for applications such as solar cells and photocatalysts, it is advantageous to increase the surface area to increase power generation efficiency and catalyst efficiency. The ion irradiation conditions may be appropriately adjusted depending on the intended use, such as performing etching with a reduced dose amount.

As described in detail above, the micromachining method of the crystal T iO ₂ of the present embodiment includes the steps of: irradiating the crystal T i O ₂ with accelerated ions to make the irradiated portion soluble in a solution; Is a method of processing the crystal Ti 0 ₂ by removing a portion irradiated with the crystal. The rutile-type crystal Ti 0 ₂ is not originally etched by hydrofluoric acid, but after masking the desired portion and irradiating with accelerated ion, only the portion irradiated with ions becomes amorphous. Since the amorphized portion is dissolved in an acid or the like, fine processing can be performed by dissolving and removing (etching) the portion. In this case, the accelerated ions are capable of forming a deep pattern since entering deeply by setting a higher acceleration energy, and can be sharp and precise microfabrication crystal T i 0 ₂ . This 03 03499

Thus, it becomes possible to fabricate a fine structure with a large aspect ratio. In addition, the etching depth and the etched surface can be adjusted by changing the ion species, the acceleration energy of the ions, and the dose, and when a mask is used, the shape of the mask can be changed to a rutile crystal Tio. ₍₂ ) It can be transferred to the surface and is expected to have technical applications such as enabling the production of photonic crystals on insulators. The crystal T i 0 ₂ microfabricated of this embodiment obtained in this way is a deep pattern formation, and has a good accuracy that reproduces the shape of the mask sharp.

In the above embodiment, although the etching after the ion irradiation has Gyotsu by hydrofluoric acid, crystalline T i O ₂ is as long as amorphous T i 0 ₂ is soluble in insoluble, other such as sulfuric acid Acids can also be used. The crystal T io ₂ are all regardless of rutile, the same effect can anatase T i 0 ₂ can be expected. However, anatase Ze-type crystal T i 0 ₂ of, since it is a small amount but are etched in an acid, since the rutile-type crystal T i 0 can not be obtained ₂ as selectivity, it is necessary to consider that point . Next will be described the crystal T i 0 ₂ microfabrication method according to a second embodiment of the present invention. To amorphous crystals T i 0 ₂ is about being ESP requires a certain level of value, it is as described in the microfabrication method of the first embodiment. Here, the ESP usually accelerated ions highest in rutile crystal T i O ₂ of the surface as shown in FIG. 4, and decreases as ions progresses into the crystal T i 0 ₂ Go. This means that when ions enter the rutile crystal T i O ₂ , the surface has energy equivalent to the acceleration energy, but as the ions enter the rutile crystal T i 〇 ₂ , the crystal T i This is because energy is lost due to interaction with the electrons in O ₂ . However, the rate of acceleration energy further increased to take the ions of ions will increase summer, so that when the ion enters the rutile crystal T io _2, due to its large velocity, electrons and interact The ESP on the surface of the material is smaller than on the inside because of the shorter application time. Figure 5 shows an example of this phenomenon. Figure 5 is a graph showing the relationship between the depth and the ESP chlorine ions from 2 l M e V and 9 OM rutile accelerating respectively e V crystal T i 0 ₂ sample surface when irradiated in However, as is clear from this graph, when chlorine is accelerated at 21 MeV, ESP is the largest at the sample surface and then decreases rapidly. However, when the injection is accelerated at 9 OM eV, the ESP becomes maximum at a depth of about 9 μιη inside the sample.

Thus, by utilizing the characteristics of the good Una ion irradiation, which effects the amorphization from the surface of the rutile crystal T i 0 ₂ (first embodiment), the inside amorphization of crystalline T i 0 ₂ Two types of ion irradiation with the effect to be brought about are possible by adjusting conditions such as ESP. That is, the second embodiment utilizes the nature of such accelerated ions, and in order for the crystal T io ₂ to become amorphous by ion irradiation, ESP must be larger than a certain threshold value. The ESP of the irradiated ion does not exceed this threshold on the surface of the rutile crystal T i 0 ₂ , and the energy is set so that the ESP gradually increases inside the sample and exceeds the threshold. by irradiating a method of etching amorphized only the internal crystal T io _2.

Specifically, rutile crystal T i O ₂ to 1 0 OM e C accelerated with V a ion ^{3 X 1 0 1 4 c πι} - ^{where 2} is irradiated, and etching at the following 2 0% hydrofluoric acid, It was confirmed that the ion-irradiated surface was not etched, and that the portion approximately 5 μm 內 from the surface was etched. Then, it was examined Ri by the thinned upper of the focal-crystalline crystal T io ₂ in X-ray diffraction, it is observed that retain the rutile type, that the method of the second embodiment is effective confirmed.

Therefore, by using the method of the present embodiment, by this by forming the amorphous layer 12 on the inner side of the rutile crystal T i 0 ₂ plate 11 as shown in FIG. 6 and the hollow layer 12 a , processing of dividing the rutile crystal T i 0 ₂ plate into upper and lower layers becomes possible, it can be obtained by Ri rutile crystal T i 0 ₂ of the sheet thereto. At this time, the depth at which the amorphous layer 12 is formed on the inside can be adjusted by changing the energy and ion species of the ions to be irradiated, and the amorphous layer can be adjusted by changing the amount of ions to be irradiated. Since the thickness of 12 can also be adjusted, the thickness of this thin plate can be adjusted. In this way, in the present embodiment, the machine regardless of the processing can be processed rutile crystal T i 0 ₂ of the sheet, the degree 1 0 mu m or less was not possible with Ri machined by the this It is possible to obtain a rutile-type crystal T i 0 ₂ plate of Further, as an application of the fine processing method of the present embodiment, for example, under conditions that result in amorphization from first surface side is subjected to mask 22 in FIG. 7 urchin by shown in (a) rutile type crystal T i 0 ₂ plate 21 Irradiated with accelerated ions to form an amorphous portion 23a, and then irradiated with accelerated ions under the condition of causing amorphization inside, as shown in FIG. 7 (), to form an amorphous portion 23b, and By performing etching with an acid, a more complicated and finely processed crystal T i 0 having a three-layer structure of a first layer 31, a hollow layer 32, and a substrate 33 having a desired pattern as shown in FIG. _{The two} plates 21 can be manufactured.

Or as detailed, crystalline T i 0 ₂ microfabrication method according to the second embodiment of the present invention, allowed the ions by irradiating ions accelerated crystal T i 0 ₂ is irradiated portion soluble liquid and soluble by removing a portion of said ions are irradiated, the crystalline T i 0 a method of processing _2, crystalline than the electronic stopping power (ESP) crystal T i O ₂ of surface ions T higher becomes the inside portion enters the i 0 _2, the inner portion in the previous SL crystalline T io ₂ is because it is a method of irradiating set to be soluble in the solution, the middle air-like or thin plate-like The crystal TiO ₂ can be finely processed, and the thickness of the thin plate can be reduced to 10 μιη or less.

In the present embodiment, since the accelerated ions have rectilinearity, by irradiating the ions through a mask having a desired pattern as in the first embodiment described above, the rutile-type crystal Ti It is also possible to form a pattern equivalent to a mask inside O ₂ . Further, similarly to the first embodiment described above, the etching after ion implantation can be performed not with hydrofluoric acid but with an acid such as sulfuric acid. Further, the crystal TiO ₂ is not only a rutile type but also an anatase type. T i 0 ₂ even the same effect can for needless to say that you can expect.

Next, a description of a third crystal T i 0 ₂ microfabrication method according to an embodiment of the present invention. This embodiment is based on the method of the first and second embodiments described above, in which the rutile-type crystal TiO ₂ is irradiated with ions and then subjected to a heat treatment without etching.

Specifically, FIG. 9 is a rutile type crystal T i 0 ₂ to 1 2 OM 1 bromine I O emissions were accelerated at ^{e V X 1 0 1 4 c} Hi - 2 was irradiated, 3 0 0 at subsequent air 30 minutes heat treatment at ° C 03499

12 shows the XRD spectrum obtained when the heat treatment was performed.As is clear from the figure, a peak indicating an anatase type was not observed at all before the heat treatment, and an anatase type crystal Ti 0 ₂ was formed. It was confirmed that. At this time, since the peak indicating rutile type did not increase, it can be said that the amorphous part changed to anatase type by the heat treatment.

After the rutile crystal T i O ₂ was amorphous by O Ri ion irradiation above results, that young to be able to form an anatase type crystal T io ₂ by heat treatment. However, in the crystal T i 0 ₂ microfabrication method of the third embodiment of the UNA present invention by the above-described, when heat-treated at a temperature in excess of 9 0 0 ° C, anatase T i O ₂ rutile crystal since T i 0 ₂ in will change, the heat treatment it is necessary to perform the following 9 0 0 ° C.

By utilizing such properties, as shown in FIG. 10, a mask (not shown) having a desired pattern is applied, and then ions are irradiated to form an amorphous surface on the rutile crystal Tio ₂ plate A. section 42 is formed, then Ri by the heat treatment is performed, when re-crystallized moieties § amorphous reduction, since amorphous portion 42 is anatase T i 0 ₂ 43, rutile crystal T i Crystal T i 0 _{2 in} which O ₂ 41 and anatase crystal T i O ₂ 43 are mixed can be formed. In addition, the pattern of the anatase crystal TiO ₂ 43 can be made into a desired pattern by using a mask, and it can be formed on the surface side or inside by the energy of the ions to be irradiated. Both crystals can be mixed in the embodiment described above. Further, as a modified example of the method of forming a crystalline T io ₂ with mixed rutile and anatase, Ri FOR A FULL irradiation a small amount of ions to the extent that the entire ion irradiation unit is not completely amorphous, rutile crystals by T i 0 ₂ and the amorphous T i O ₂ is heat treated at 9 0 0 ° C or less after forming a situation you mixed crystal T i 0 ₂ in which the rutile type and anatase peptidase type mixed can be formed . After further forming an uneven surface by etching after the minor irradiated with ions, if Hodokose heat Aniri ring again ion irradiation, a large anatase T i O ₂ or anatase one peptidase type and rutile-type surface area It is also possible to produce a crystal Ti 0 _{2 in} which is mixed, and high efficiency of an optical element, a photocatalyst, and the like can be expected. Or as detailed, crystalline T i 0 ₂ microfabrication method of the third embodiment, after irradiation with ions accelerated to the rutile type crystal T i 0 _2, child heated 9 0 0 ° C below the temperature Thus, the portion irradiated with ions is converted into an anatase crystal T i 0 ₂ , so that a microstructure in which rutile crystal T i O ₂ and anatase crystal T i 0 ₂ are mixed is used. Can be. With such a mixed crystal of rutile type and anatase type T i 0 ₂ , improvement in functions such as photocatalyst can be expected. Furthermore, it is possible to improve the function of the anatase T i O ₂ or rutile crystalline T io ₂ you mix anatase becomes possible made work optical element of crystalline T io ₂ large area.

Claims

The scope of the claims

1. By irradiating ions accelerated crystal T io ₂ and soluble portions in which the ions are irradiated to the solvent liquid, by removing a portion of said ions are irradiated, processing the crystalline T i 0 ₂ A microfabrication method for crystal T i 0 ₂ , wherein

2. Crystal T io ₂ fine processing method according to claim 1, wherein the irradiation by setting the ion so soluble in the solution from the surface side of the crystal T i O _2.

3. The electronic stopping power of the ion increases in the inner part enters the crystal T i 0 in ₂ than the surface of the crystal T i O _2, and soluble in the crystal T io ₂ is solution in the inner part _2. The method according to claim 1, wherein the irradiation is performed under the following conditions.

4. Crystal T i O ₂ of the micro-machining method of claim 2, wherein said ion is an ion of atomic number 1 0 or more atoms.

5. Crystal T i 0 ₂ fine processing method according to claim 3, wherein said ion is an ion of atomic number 1 0 or more atoms.

6. The crystalline T i 0 ₂ crystal T io ₂ microfabrication method according to claim 2, characterized by having a rutile crystal structure.

7. The crystalline T i 0 ₂ crystals T i 0 ₂ microfabrication method according to claim 3, characterized by having a rutile crystal structure.

8. By the child irradiating the crystal T i O ₂ through the ion mask having a desired shape,請Motomeko 2, wherein the forming a shape of the mask on the crystal T io ₂ surface The microfabrication method of the crystal Ti 0 ₂

9. By the child irradiating the crystal T i O ₂ through the ion mask having a desired shape, according to claim 3 the shape of the mask you and forming a crystalline T io ₂ inner part crystal T i 0 ₂ microfabrication methods described.

1 0. Crystal T i 0 ₂ microfabrication methods請Motomeko 2, wherein a solution dissolving a portion in which the ions are irradiated is an acid.

1 1.請Motomeko 3 crystal T i 0 ₂ microfabrication method, wherein said ion is a solution acid to dissolve the portion irradiated.

1 2. Irradiate the accelerated ions on the rutile crystal T i 0 ₂ and then heat it at 900 ° C or less to convert the ion-irradiated portion to an anatase crystal T io ₂ A micromachining method for a crystal T i 0 ₂ , characterized by the following.

1 3. crystals T i 0 ₂ fine processing method according to claim 1 2, wherein said ion is an atomic number 1 0 or more ions.

1 4. Irradiating the ions to the rutile-type crystal T i 0 ₂ through a mask having a desired shape, thereby forming an anatase-type crystal T i 0 ₂ only in a portion other than the mask. crystal T i O ₂ of the micro-machining method of claim 1 2 wherein.

1 5. The crystalline T i 0 ₂ crystals T i 0 ₂ fine processing method according to claim 2, wherein it is a single crystal or polycrystalline.

1 6. The crystalline T i 0 ₂ crystals T i 0 ₂ fine processing method according to claim 3, wherein it is a single crystal or polycrystalline.

1 7. The crystalline T i 0 ₂ crystals T i 0 ₂ fine processing method according to claim 1 2, wherein it is a single crystal or polycrystalline.

1 8. A micro-processed crystal T io _2o characterized by irradiating accelerated ions to make the irradiated portion soluble in a solution and removing the irradiated portion.

1 9. irradiated by setting the ion so soluble in the solution from the crystalline T i O ₂ of the surface, a microfabricated according to claim 1 8, wherein the removal from the surface side crystal T i O ₂ .

2 0. the electronic stopping power of the ion increases in the inner part enters into the crystal T i O ₂ than the surface of the crystal T i O _2, soluble in the crystal T i 0 ₂ a solution in the inner part by irradiating set to be a solvent, characterized in that the inner part has been removed from the surface請Motomeko 1 8 microfabricated crystal T i 0 ₂ according.

2 1. By irradiating the ion in the crystal T i 0 ₂ through a mask having a desired shape, according to claim 1 9, characterized in that the shape of the mask is formed on the crystal T i 0 ₂ surface The described micromachined crystal T i 0 ₂ .

2 2. By irradiating the ions to the crystal Ti 0 ₂ through a mask having a desired shape, the shape of the mask is formed inside the crystal Ti 0 _2. 22. The micromachined crystal T i 02 according to claim ₂₀ .

2 3. After irradiation with accelerated ions in the rutile crystal T i 0 _2, 9 0 by heating in the following temperature CTC, characterized in that the portion of ions is irradiated with the anatase T io ₂ The micromachined crystal T i 0 ₂ .

2 4. By irradiating the rutile crystal T i 0 ₂ through a mask the ions having a desired shape, and characterized in that the formation of the anatase T i 0 ₂ only in a portion other than the mask The micro-processed crystal T i 0 according to claim _19, wherein the crystal T i 0 ₂ is a single crystal or a polycrystal. i O ₂₀ '

2 6. The crystalline T i O ₂ is claim 2 0 microfabricated crystal T i 0 ₂ according which is a single crystal or polycrystalline.

27. The micro-processed crystal T i O _{20 according} to claim _23, wherein the crystal T i O ₂ is a single crystal or a polycrystal.