JPH04149100A - Method for joining synthetic single crystal body - Google Patents

Abstract

PURPOSE:To improve chemical, physical and optical properties by optically polishing the analogous faces formed by cutting respective mutual faces in such a manner that the physical properties are analogous with each other and optically joining these faces, and subjecting the entire part to heating and slow cooling. CONSTITUTION:The analogous faces formed by cutting the respective mutual faces, all of which allow the transmission of visible light or any of which allows the transmission of the visible light within the wavelength region possessed by the synthetic single crystals of the homogeneous crystal system or heterogeneous crystal system consisting of the same or different components in such a manner that their physical properties are analogous with each other are optically polished and are optically adhered. The entire part is then heated uniformly and slowly cooled or is slowly cooled after iterative heating to induce an interface reaction at the optically adhered surfaces.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to bonding homocrystalline or heterocrystalline synthetic single crystals in which the main components are the same or different, and which have a fixed arrangement of structural elements. The present invention relates to a method of joining synthetic single crystals, which involves integrated joining of laminated materials.

[Prior art]

Conventionally, the method of joining polycrystals or single crystals to each other has been indirect joining in which a binding agent of the same or different nature as the crystal is used as a mediator or catalyst at the interface between the crystals and sintered or welded by heating. This method was a direct method in which a synthetic single crystal was grown (epitaxy) by some method on a single crystal substrate grown from a gas phase or a liquid phase.

[Problem to be solved by the invention]

Therefore, the above-mentioned indirect bonding method involves using some kind of artificial medium, such as an adhesive, at the interface between the crystals, so that the chemical, physical, and optical properties of each crystal itself are It is impossible to take advantage of superior characteristics.

Further, the direct bonding methods described below are divided into those that grow polycrystals on a single crystal substrate and those that grow single crystals. In the case of polycrystals, it is relatively simple because there is no crystal system, but in the case of single crystals, there is a crystal system, and the main components are the same 5 in 2 and are hexagonal crystal systems, so for example, colorless and colored quartz single crystals. If it is a crystal, the lattice constant and linear expansion coefficient are similar, so it is thought that it can be easily grown. However, it is difficult to grow because the physical properties differ depending on the axial orientation. In addition, the main components are different between A1aO+ and Si, and the anomalous system is a hexagonal system and an equicrystalline system, so the growth of sapphire and silicon requires significant differences in lattice constant, coefficient of linear expansion, and axial orientation. Furthermore, it is impossible to stack and bond colorless and colored quartz single crystals whose main components are the same or different, which are homocrystalline or heterocrystalline, and synthetic single crystals of sapphire and silicon. It is.

It is an object of the present invention to solve the above-mentioned problems and easily perform stacking and bonding of desired synthetic single crystals.

[Means to solve the problem]

The present invention was made to solve the above problems,
Both homocrystalline or heterocrystalline synthetic single crystals with the same or different principal components transmit visible light within the wavelength range, or each mutual surface that transmits visible light is physically Similar surfaces cut to have similar physical properties are optically polished to form an optical bond, and the entire surface is uniformly heated and slowly cooled, or by repeated heating and slow cooling, an interfacial reaction is caused on the optically bonded surface. This is a method of joining homocrystalline or heterocrystalline synthetic single crystals having the same or different main components without damaging their original structural elements.

[For production]

A crystal has a different crystal structure between the inside and the surface.

The inside of a crystal consists of a three-dimensional framework in which atoms are arranged regularly, and three axes, including the "crystal axis C", are arranged in a regular manner.
The two angles are called "axial angles α, β, T", and the ratio of their lengths is [
The transport numbers a and b are called SCJ. Bonding forces act between the atoms and molecules that make up the crystal. Bonding forces can be divided into ionic bonds, covalent bonds, metallic bonds, van der Waals bonds, etc. according to their properties, but due to the existence of these bonding forces, atoms and molecules are arranged regularly in a lattice. Each crystal system has its own unique crystal structure. However, the surface of the crystal has a considerably different arrangement from the interior, and the surface layer has an atomic arrangement that is considerably distorted from the crystalline structure found inside. This situation is extremely unstable, so
When the temperature is raised, the structure changes in various ways, and chemical reactions are very likely to occur.

A property that clearly distinguishes crystals from other liquids and amorphous materials is their orientation, and they have anisotropy, which means that their physical properties differ in directions parallel to and perpendicular to the same axis. .

In order to enable and solve the problem of joining synthetic single crystals with such a crystal structure and anisotropy, as mentioned above, it is necessary to change the variability of the crystal surface layer and the cutting direction of the crystal body of the crystal system. By creating an artificially unstable state on the machined surface by selecting similar surfaces and by external influences such as cutting and polishing, we can overcome some of these inducing factors for the purpose of joining synthetic single crystals. can occur.

As mentioned above, a fairly unstable state can be created on the similar surfaces, and eventually, by gradual heating, an interfacial reaction occurs at the interface of each synthetic single crystal, and as it gradually cools, chemically bond.

Therefore, bonding which was impossible with conventional methods becomes impossible, and a new complex and precise bonding of homocrystalline or heterocrystalline synthetic single crystals having the same or different main components can be obtained.

〔Example〕

Before giving examples, optical adhesion will be explained.

Optical adhesion is already amorphous
This glass processing technology is well known.

Optical adhesion of synthetic single crystals in the present invention refers to, firstly, in order to bond synthetic single crystals of homocrystalline or heterocrystalline systems with the same or different main components, either or all of them must transmit visible light. to do.

Second, the mutual optically polished surfaces to be bonded have high precision (λ/10
<, λ=6328A).

Thirdly, do not allow fine particles such as dirt or dust to interfere with the mutual interface to be bonded.

Fourth, since both or any of the mutually bonded single crystals transmit visible light, the interference color at the mutual interface can be directly observed, and the interference color gradually disappears just by applying pressure from above. It is necessary that optical adhesion can be confirmed.

Example 1 An example will be given of a homocrystalline junction in which the main components of colorless and colored quartz single crystals are the same.

The main component (Sin2) and crystal system (hexagonal system) are the same,
A synthetic single crystal (colorless crystal single crystal) that transmits visible light (wavelength: 4000~7000A) (transmittance 90%);
A synthetic single crystal (colored crystal single crystal) that transmits only half of the visible light (transmittance <50%), whose surfaces are cut so that their physical properties are similar (coaxial, coaxial angles match). Optical polishing of the surface (coaxial surface) (surface accuracy λ/10<, λ=6
328A) to optically bond as described above, and uniformly and repeatedly heat the whole body (for example, gradually heat from room temperature to 480 °C below the transition point of 573 °C for 12 hours, and then leave it as it is for 6 hours.
The temperature is maintained for 12 hours, gradually cooled down to room temperature, heated again at 600° C. above the transition point, and then cooled down repeatedly in the same manner as described above.

The crystal structure layer of the optically polished similar planes of the optically bonded mutually synthesized single crystals was first significantly destroyed by cutting;
Next, due to polishing, the atomic arrangement is considerably distorted.

Such a state is extremely unstable, so when the temperature is gradually raised, the crystal structure changes in various ways, interfacial reactions occur at the interface, and as the temperature is gradually lowered, stable chemical bonds form.

Example 2 An example will be given of joining of different products whose main components are sapphire and silicon.

A synthetic single crystal (sapphire) whose main component is AhO3 and a hexagonal crystal system that transmits visible light; and a synthetic single crystal whose main component is Si and whose crystal system is equicrystalline that does not transmit visible light. A method of making mutual surfaces of (silicon) similar will be explained.

The physical properties of a sapphire single crystal differ depending on the axial direction, and the linear expansion coefficient is different in the direction parallel to the C-axis and in the direction perpendicular to the C-axis. Linear expansion coefficient (10-5/deg) 0.67 (50℃, //
c,) Linear expansion coefficient in the direction perpendicular to the C axis (10-'/deg)
0.50 (50°C, IC,). On the other hand, the physical properties of silicon crystal, which is an equicrystalline system, do not differ depending on the axis //= Hijikata inner direction, and its linear expansion coefficient is as follows: Linear expansion coefficient (10~'/deg) 0.50 ( 50℃
, //C,,=IC,).

Therefore, a similar plane that shares the physical properties of a sapphire single crystal and a silicon crystal is a plane that is perpendicular to the C axis of the sapphire single crystal. The similar surface cut perpendicular to the C-axis of this sapphire and the similar surface of silicon are optically polished (
λ/10 <, λ = 6328 people) and optically bonded as described above, and the whole was uniformly and repeatedly heated (e.g., gradually heated from room temperature to 400°C in 8 hours, maintained as it was for 8 hours, and gradually Cool slowly for 14 hours, return to room temperature, and return to 43
By repeating the heating and slow cooling at 0° C. (repeated heating in the same manner as above), an interfacial reaction occurs at the mutual interface, resulting in chemical bonding, as described in the previous example.

Example 3 An example will be given of an example in which homocrystalline or heterocrystalline systems having different main components are bonded and further laminated.

Colorless quartz single crystal and colored quartz single crystal (optically polished) already homocrystal-bonded in Example 1.

λ/10<, λ-6328 people) was anomalously joined in Example 2 to a sapphire single crystal (optically polished).

λ/1.0 <, λ-6328A) on top of the silicon crystal, optically bonded as described above, and uniformly heated the whole body repeatedly (for example, gradually heated to 400°C over 8 hours from room temperature).
℃, continued as it is for 8 hours, gradually cooled over 14 hours to return to room temperature, heated and slowly cooled again to 430℃ (the time course was repeated heating as above) as described above. Similarly, an interfacial reaction occurs at the interface between a colored quartz single crystal, which is an macrogonal system, and a sapphire single crystal, which is a hexagonal system.

Considering the joining, stacking, accumulation, etc. of homocrystalline or heterocrystalline synthetic single crystals with the same or different main components as described above,
Combinations thereof are possible within the scope of the invention.

〔Effect of the invention〕

The present invention makes it possible to join synthetic single crystals of homocrystalline or heterocrystalline systems in which the main components are the same or different, which was impossible with conventional methods, and to perform integrated bonding in which these are laminated.
A new synthetic single crystal with a complex and precise shape can be obtained.

Claims (5)

[Claims] (1) Synthetic single crystals of homocrystalline or heterocrystalline systems with the same or different principal components, both of which transmit visible light within the wavelength range, or whose mutual surfaces that transmit visible light are physically Similar surfaces cut to have similar physical properties are optically polished and optically bonded, and the whole is uniformly heated and slowly cooled, or
Alternatively, by repeatedly heating and slowly cooling, an interfacial reaction is caused on the optically bonded surface to produce a homocrystalline or heterocrystalline synthetic single crystal whose main components are the same or different, without damaging each other's original structural elements. A method for joining synthetic single crystals made by joining. (2) The method for joining synthetic single crystals according to claim 1, characterized in that homocrystalline or heterocrystalline synthetic single crystals having the same or different main components are stacked and integrally joined. (3) Synthesis of homocrystalline or heterocrystalline systems in which the main components are the same or different. Either each transmits visible light within the wavelength range of the single crystal, or one of them transmits visible light, thereby synthesizing each other. 3. The method of joining synthetic single crystal bodies according to claim 1, wherein the joining interface of the single crystal bodies is made visible. (4) A method for joining synthetic single crystals according to any one of claims 1 to 3, characterized in that the whole is uniformly heated and slowly cooled, or repeatedly heated and slowly cooled. (5) Uniformly heat the whole, and heat and slowly cool each of the synthetic single crystals with different main components or crystal systems below the transition point, whichever is lower, or heat and slowly cool above the transition point. 5. A method for joining synthetic single crystals according to claims 1 to 4, characterized in that: