JP7396183B2 - Heat-resistant container used for single-segmentation treatment of oxide single crystal and method for single-segmentation treatment of oxide single crystal - Google Patents

Description

The present invention is used for single domain treatment of oxide single crystals such as lithium tantalate (LiTaO ₃ :hereinafter abbreviated as LT) single crystals and lithium niobate (LiNbO ₃ :hereinafter abbreviated as LN). This invention relates to a heat-resistant container and a method for dividing an oxide single crystal into a single domain.

Oxide single crystals (hereinafter sometimes abbreviated as "single crystals") are used in nonlinear optical materials, materials for surface acoustic wave devices, and the like. For growing single crystals, the Czochralski method (hereinafter sometimes abbreviated as Cz method) is used industrially. In the Cz method, a crucible containing a single crystal raw material is heated in a high-frequency induction heating furnace, a resistance heating furnace, etc. to turn the crystal raw material into a melt state, and a seed crystal with a desired orientation is brought into contact with the surface of the melt. After that, the seed crystal is pulled up in a furnace with a temperature gradient to grow a single crystal with the same orientation as the seed crystal.

In addition, the single crystal grown by the Cz method is in a multi-region state, and if it remains in the multi-region state, cracks are likely to occur during single crystal wafer processing, and the characteristics of nonlinear optical materials and surface acoustic wave devices may be affected. affect. Therefore, it is necessary to subject the grown single crystal to a single domain treatment.

As a method for single-domaining, for example, Patent Document 1 below describes a method for single-domaining an LN single crystal. Patent Document 1 discloses that an LN single crystal is embedded in the LN powder of a heat-resistant container containing the LN powder, the LN single crystal is sandwiched between a pair of electrodes via the LN powder, and the LN single crystal is heated to a temperature higher than the Curie point. A method is described in which the temperature is raised, maintained, and a voltage is applied between the electrodes to form a single region.

JP2019-127411A

By the way, the heat-resistant container used for the single-segmentation process is generally made of alumina and consists of a cylindrical container consisting of a bottom and a side wall, and a lid (see FIG. 8). In this single-area processing using a heat-resistant container, an electrode plate is placed on the bottom of the heat-resistant container, a single crystal powder similar to the single crystal is spread on it to a thickness of about 40 mm, the single crystal is placed, and the placed single crystal is placed on the electrode plate. Fill the single crystal powder until the area around the crystal is covered, place an electrode plate on top of it, and finally place the lid on the heat-resistant container to complete the process.

During this work, the distance between the single crystal and the pair of electrodes is set so that a predetermined voltage is applied, and is set, for example, to 15 mm to 25 mm. Furthermore, it is preferable that the single crystals are placed evenly on the top, bottom, left and right sides of the single crystal powder filled in the container so that the temperature of the single crystals processed in the heat resistant container is uniform. Therefore, the inner diameter of the heat-resistant container is, for example, 30 mm to 50 mm larger than the diameter of the single crystal to be treated. Traditionally, the mainstream size of single crystals was 4 inches in diameter, but now the diameter is increasing to 6 inches or larger than 6 inches. A single crystal with a diameter of 4 inches has a small weight, but a single crystal with a diameter of more than 6 inches weighs more than 10 kg. Furthermore, the difference in the inner diameter between the single crystal and the heat-resistant container (the distance between the single crystal C and the inner wall of the heat-resistant container 20) is approximately 20 mm per side. In such a situation, when placing a single crystal in a heat-resistant container for single-segmentation processing, or when taking out a single crystal from a heat-resistant container after single-segmentation processing, it is necessary to place the single crystal in a heat-resistant container. There were problems such as problems such as cracks occurring due to contact, and problems such as decreased workability because the work had to be carried out carefully so as not to allow the single crystal to come into contact with the heat-resistant container.

Therefore, the present invention has been made by focusing on the above-mentioned problems, and its problem is to place the oxide single crystal in a heat-resistant container in the single-zonal treatment of the oxide single crystal. The object of the present invention is to suppress defects such as cracks caused by the oxide single crystal coming into contact with the heat-resistant container and to improve workability when the oxide single crystal is removed from the heat-resistant container.

According to an aspect of the present invention, a single-domaining process is performed in which a voltage is applied at a predetermined temperature to an oxide single-crystal embedded in an oxide single-crystal powder to make the oxide single-crystal into a single domain. A heat-resistant container used for a heat-resistant container, comprising a saucer portion having a bottom and a wall portion, and a cylindrical portion having a cylindrical shape and installed above the saucer portion, the cylindrical portion being used for oxide single crystals and oxide single crystals. The powder can be stored inside, and the saucer part can hold the oxide single crystal powder and the cylindrical part holding the oxide single crystal and the oxide single crystal powder, and the outer diameter of the cylindrical part is Provided is a heat-resistant container whose inner diameter is smaller than the inner diameter of the saucer portion.

Further, the outer diameter of the cylindrical portion may be smaller than the inner diameter of the saucer portion by 30 mm or more and 50 mm or less. Alternatively, the saucer portion may be configured to be able to hold the entire amount of the oxide single crystal powder that is filled into the heat-resistant container during the single-segmentation process. Further, the inner diameter of the cylindrical portion may be 190 mm or more.

Further, according to an aspect of the present invention, a voltage is applied to the oxide single crystal embedded in the oxide single crystal powder at a predetermined temperature to form the oxide single crystal into a single domain. A method for single-segmenting a crystal, the method comprising performing a single-sectoring treatment on an oxide single crystal using the above-mentioned heat-resistant container. provided.

In addition, the single-segmentation process involves placing oxide single crystal powder in a saucer and embedding a part of the end of the oxide single crystal in the oxide single crystal powder installed in the saucer. , the oxide single crystal embedded in the oxide single crystal powder is covered with a cylindrical part, and the end of the cylindrical part is placed in the oxide single crystal powder placed in the saucer part, and the oxide single crystal is covered. Filling the inside of the cylindrical part with oxide single crystal powder, embedding the entire oxide single crystal in the oxide single crystal powder, and heating the oxide single crystal embedded in the oxide single crystal powder to a predetermined temperature. forming the oxide single crystal into a single domain by applying a voltage.

According to an aspect of the present invention, in the single-segmentation treatment of the oxide single crystal, when the oxide single crystal is placed in a heat-resistant container or when the oxide single crystal is taken out from the heat-resistant container, Problems such as cracks caused by contact with a heat-resistant container can be suppressed, and workability can be improved.

It is a perspective view showing an example of a heat-resistant container concerning this embodiment. It is a sectional view showing an example of a heat-resistant container concerning this embodiment. 2 is a flowchart illustrating an example of a single-domain processing method for an oxide single crystal according to the present embodiment. FIG. 2 is an explanatory diagram of a single-domain processing method for an oxide single crystal according to the present embodiment. FIG. 2 is an explanatory diagram of a single-domain processing method for an oxide single crystal according to the present embodiment. FIG. 2 is an explanatory diagram of a single-domain processing method for an oxide single crystal according to the present embodiment. FIG. 2 is an explanatory diagram of a single-domain processing method for an oxide single crystal according to the present embodiment. FIG. 1 is a schematic diagram showing an example of a heat-resistant container according to the prior art.

In the following description, reference will be made to the XYZ orthogonal coordinate system shown in FIG. 1 and the like as appropriate. In this XYZ orthogonal coordinate system, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction perpendicular to the X direction and the Y direction. Also, in each direction, the same side (direction) as the tip of the arrow is the + side (direction) (e.g., +Z side), and the side (direction) opposite to the tip of the arrow is the - side (direction) (e.g., -Z side). side). For example, in the vertical direction (Z direction), the upper side is the +Z side, and the lower side is the -Z side. In addition, in each drawing, a part or the whole is suitably described schematically, and the scale is changed and described. In addition, in the following description, the description "A to B" means "above A and below B".

[Embodiment]
Embodiments of the present invention will be described in detail below with reference to the drawings. In addition, FIG.1 and FIG.2 is a figure which shows an example of the heat-resistant container based on this embodiment. FIG. 1 is a perspective view. FIG. 2 is a cross-sectional view. Note that FIG. 2 is a diagram showing an example of a state in which a heat-resistant container is used, and shows a state in which a single crystal and a single-crystal powder are placed in the heat-resistant container. FIG. 8 is a schematic diagram showing an example of a heat-resistant container according to the prior art.

As mentioned above, single crystals grown by the Cz method etc. are in a multi-domain state, and if they remain in a multi-domain state, cracks are likely to occur during single crystal wafer processing, and they are also difficult to use for nonlinear optical materials and surface acoustic wave devices. It also affects other characteristics. For this reason, a single crystal in a multi-domain state grown by the Cz method or the like is subjected to a single-domain processing.

As a method for single-segmentation treatment, for example, a single crystal is embedded in the single-crystal powder in a heat-resistant container containing the single-crystal powder, and the single-crystal is sandwiched between a pair of electrodes via the single-crystal powder. The method used is to raise the temperature of the crystal to a temperature above the Curie point, maintain it, and apply a voltage between the electrodes to form a single domain.

As shown in FIG. 8, a conventional heat-resistant container 20 used for single-zone processing is composed of a cylindrical container 21 having a bottom portion 22 and a side wall 23, and a lid 24. When carrying out single-segmentation processing using this heat-resistant container 20, an electrode 25 (electrode plate) is placed on the bottom of the container 21, and a single-crystal powder P similar to the single-crystal C is spread on top of the electrode 25 (electrode plate). C is installed, single crystal powder P is filled around the installed single crystal C and until the single crystal C is covered, an electrode 26 (electrode plate) is installed on top of it, and finally a lid 24 is placed on the heat resistant container 20. The installation of the heat-resistant container 20, single crystal C, etc. to be used for single-segmentation processing is completed.

In the above work, the distance between the single crystal C and the pair of electrodes 25 and 26 is set so that a predetermined voltage is applied, and is set to, for example, 15 mm to 25 mm. Further, it is preferable that the single crystals C are placed evenly on the top, bottom, left and right in the single crystal powder P filled in the container 21 so that the single crystal C processed in the heat resistant container 20 has a uniform temperature. .

Therefore, the inner diameter of the heat-resistant container 20 is 30 mm to 50 mm larger than the diameter of the single crystal C to be treated. Conventionally, the main size of single crystal C was 4 inches in diameter, but now the diameter is increasing to 6 inches or larger than 6 inches. A single crystal C with a diameter of 4 inches has a relatively small weight, but a single crystal C with a diameter of more than 6 inches weighs more than 10 kg. Furthermore, the difference in the inner diameter of the single crystal C and the heat-resistant container 20 (distance between the single crystal C and the inner wall of the heat-resistant container 20) is approximately 20 mm per side, and under such circumstances, it is difficult to place the single crystal C in the heat-resistant container 20. When installing the single crystal C, or when taking out the single crystal C from the heat resistant container 20 after the single segmentation process, be careful not to let the single crystal C come into contact with the heat resistant container 20 and cause cracks, etc. Since the work must be carried out carefully, there have been problems such as reduced work efficiency and other problems.

Therefore, as shown in FIGS. 1 and 2, the heat-resistant container 1 of this embodiment includes a saucer portion 2 and a cylindrical portion 3, and is characterized in that the outer diameter of the cylindrical portion 3 is smaller than the inner diameter of the saucer portion 2. It is said that This will be explained in detail below.

The heat-resistant container 1 of this embodiment includes a saucer portion 2, a cylindrical portion 3, and a lid portion 4. The lid part 4 has an arbitrary configuration, and the heat-resistant container 1 may be provided with the lid part 4 as necessary. The saucer portion 2 has a bottom portion 6 and a wall portion 7. An electrode E1 is arranged on the inner bottom surface 8 of the saucer part 2, and the single crystal powder P is accommodated therein. The internal bottom surface 8 is the bottom surface inside the saucer section 2 (inside the wall section 7). The cylindrical portion 3 has a cylindrical shape. The cylindrical part 3 is installed above the saucer part 2. The cylindrical portion 3 is capable of accommodating (holding) the single crystal C and the single crystal powder P therein. The saucer part 2 can hold the single crystal powder P and the cylindrical part 3 holding the single crystal C and the single crystal powder P. The outer diameter L1 of the cylindrical portion 3 is set smaller than the inner diameter L2 of the saucer portion 2.

The material for each part of the heat-resistant container 1 may be any material that can withstand the single-zone treatment temperature, and for example, alumina or the like can be used as in the case of conventional heat-resistant containers.

As shown in FIG. 2, when the heat-resistant container 1 is used, the cylindrical part 3 is placed on top of the single crystal powder P housed in the saucer part 2, and the inside of the cylindrical part 3 includes the single crystal C and the surrounding area of the single crystal C. filled with single-crystal powder P covering the

The shape of the saucer part 2 is not limited as long as it has a bottom part 6 and a wall part 7. The shape of the saucer portion 2 of this embodiment is a cylindrical container with a bottom. That is, the wall portion 7 of this embodiment is provided on the outer peripheral portion of the saucer portion 2. The inner diameter L2 of the saucer portion 2 is set larger than the outer diameter L1 of the cylindrical portion 3. At this time, the size of the inner diameter L2 of the saucer portion 2 is determined in consideration of workability when installing the single crystal C. A single crystal C is installed above the central portion of the saucer portion 2. As described above, since the large-diameter single crystal C weighs more than 10 kg, sufficient space is required around the single crystal C as a working space. For example, the distance L3 between the wall portion 7 of the saucer portion 2 and the single crystal C is preferably 30 mm to 50 mm, and particularly preferably 40 mm.

Next, the height L4 of the wall portion 7 of the saucer portion 2 is not particularly limited, but it is preferable that the height L4 is lower because there is less trouble in installing and taking out the single crystal C. In addition, as will be described later, when taking out the single crystal C from the heat-resistant container 1 after the single-segmentation treatment, the cylindrical part 3 is removed and then the single crystal C is taken out. It is preferable to set the inner diameter L2 of the saucer part 2 and the height L4 of the wall part 7 so as not to overflow from the container part 2. In other words, it is preferable that the saucer portion 2 is able to hold the entire amount of the single crystal powder P filled into the heat-resistant container 1 during the single-segmentation process. The configuration in which the above-mentioned saucer portion 2 can hold the entire amount of single crystal powder P filled into the heat-resistant container during the single-segmentation process depends on the size of the target single crystal C, etc. It can be determined by calculation, preliminary experiment, etc. For example, if the outer diameter of the single crystal C is φ160 mm, the crystal length is 100 mm, and the inner diameter L5 of the cylindrical portion 3 is φ200 mm, the inner diameter L2 of the saucer portion 2 is set to φ275 mm, and the height L4 of the wall portion 7 is set to 100 mm. I can do it. With the above configuration, the single crystal powder P is not scattered, and the single crystal C can be easily taken out from the heat-resistant container 1.

The inner diameter L5 of the cylindrical portion 3 may be equal to the inner diameter of a conventional heat-resistant container, although it depends on the size of the single crystal C to be treated. The inner diameter L5 of the cylindrical portion 3 is preferably 30 mm to 50 mm larger than the outer diameter of the single crystal C. For example, when the outer diameter of the single crystal C is 160 mm, the inner diameter L5 of the cylindrical portion 3 is preferably 190 mm to 210 mm. That is, it is preferable to set the inner diameter L5 of the cylindrical portion 3 so that when the cylindrical portion 3 covers the single crystal C, the distance between the inner wall of the cylindrical portion 3 and the single crystal C is 15 mm to 25 mm. The heat-resistant container 1 of this embodiment has an inner diameter L5 of 190 mm or more of the cylindrical portion 3, and is therefore suitable for single-segmentation treatment of a large-diameter single crystal C of 6 inches (152.4 mm) or more than 6 inches. The effect of the heat-resistant container 1 of this embodiment is also significant.

Electrodes E1 and E2 are arranged above and below the single crystal C. The distance between the single crystal C and the electrodes E1 and E2 is set so that a predetermined voltage is applied, and is set to, for example, 15 mm to 25 mm. It is preferable that the single crystals C are placed evenly in the top, bottom, right and left in the single crystal powder P filled in the heat resistant container 1 so that the single crystal C processed in the heat resistant container 1 has a uniform temperature.

The length L7 of the cylindrical portion 3 is preferably set to be equal to or longer than the length of the single crystal plus the distance between the single crystal C and the electrodes E1 and E2. Note that since the single crystal length may vary depending on the conditions during growth, it is preferable to set the length L7 of the cylindrical portion 3 with a margin. For example, the length may be increased by about 40 mm to the length of the single crystal plus the distance between the single crystal C and the electrodes E1 and E2.

The lid part 4 is installed on the cylindrical part 3. The lid part 4 covers the opening of the cylindrical part 3. As mentioned above, the lid part 4 is not essential, but by installing the lid part 4 above the single crystal powder P, the vertical and horizontal conditions of the single crystal C can be made closer to each other during the single-domaining process. Therefore, stable single-domaining treatment can be performed on single crystal C.

Note that the thickness of each part of the heat-resistant container 1 is not particularly limited. For example, the thickness of each part of the heat-resistant container 1 can be 10 mm to 30 mm.

Next, an example of how to use the heat-resistant container according to the present embodiment described above will be explained, and a method for single-segmenting a single crystal oxide according to this embodiment (hereinafter referred to as a "single-segmenting processing method") will be explained. An example of (omitted) will be explained. FIG. 3 is a flowchart illustrating an example of the single domain processing method according to the present embodiment. 4 to 7 are explanatory diagrams of the single domain processing method according to this embodiment. Note that the single segmentation processing method according to this embodiment is not limited to the following description. For example, the single segmentation processing method according to the present embodiment may include the above-described matters.

The single-segmentation treatment method according to the present embodiment includes performing single-sectorization treatment on a single crystal using the heat-resistant container according to this embodiment.

(Step S1)
In the single segmentation processing method according to this embodiment, first, as shown in FIG. 4(A), an electrode E1 is installed on the internal bottom surface 8 of the saucer portion 2 (step S1 in FIG. 3). The electrode E1 is installed at the center of the saucer portion 2. The electrode E1 is not particularly limited, and for example, an electrode used in conventional single segmentation processing can be used.

(Step S2)
Next to step S1, as shown in FIG. 4(B), single crystal powder P is placed (filled) in the saucer portion 2 (step S2 in FIG. 3). In step S2, a predetermined amount of single crystal powder P is placed on the saucer portion 2 on which the electrode E1 is placed. At this time, the electrode E1 is covered with the single crystal powder P. Although the single crystal powder P is not particularly limited, it is preferably a single crystal powder having the same composition as the single crystal C to be subjected to the single-segmentation treatment. Further, the single crystal powder P may be a ground single crystal powder or a raw material powder. Moreover, it is preferable that the predetermined amount of the single crystal powder P in step S2 is an amount that can provide the distance between the lower end of the single crystal C and the electrode E1. Note that the single crystal C used in the heat-resistant container 1 and the single-segmentation treatment method of this embodiment is not particularly limited, and is arbitrary. For example, the component (composition), size, and shape of the single crystal C are arbitrary.

Furthermore, as shown in FIG. 4(B), the single crystal powder P filled in step S2 is placed at the center of the single crystal powder P when the lower surface of the single crystal C is conically convex downward. You can also liven up the club. As will be described later, by embedding the conical portion of the single crystal C in the raised single crystal powder P, the single crystal C can be stably installed. Note that the shape of the filled single crystal powder P is arbitrary and does not need to be raised.

In the heat-resistant container 1 and the single-segmentation processing method of the present embodiment, the distance L3 between the inner wall of the saucer portion 2 and the single crystal C can be made wider than when using the conventional heat-resistant container 20, and the saucer Since the height of the wall portion 7 of the portion 2 is also set lower than that of the conventional heat-resistant container 20, the workability when installing the single crystal C can be significantly improved compared to the conventional case, and the height of the wall portion 7 of the saucer portion 2 and Problems such as cracks caused by contact with single crystal C can be suppressed. This effect can be further improved by setting the distance L3 between the inner wall of the saucer portion 2 and the single crystal C within the above-mentioned preferable range, and/or by setting the height L4 of the wall portion 7 within the above-mentioned preferable range. Significantly expressed. Moreover, the above-mentioned effect becomes even more remarkable when the single crystal C having a large diameter and a large weight as described above is targeted.

(Step S3)
Next to step S2, as shown in FIG. 5(A), a part of the end of the single crystal C is embedded in the single crystal powder P placed in the saucer part 2. Thereby, the position of the single crystal C is fixed to the single crystal powder P. At this time, it is preferable to set the distance between the lower end of the single crystal C and the electrode E1 within the above-described preferable range. Further, it is preferable that the single crystal C be placed in the center of the saucer portion 2.

(Step S4)
Next to step S3, as shown in FIG. 5(B), the single crystal C embedded in the single crystal powder P is covered with the cylindrical part 3, and the cylindrical part 3 is covered with the single crystal powder P placed in the saucer part 2. The end portion is installed (step S4). In step S4, the cylindrical part 3 is placed over the single crystal C fixed to the single crystal powder P in step S2, and the end of the cylindrical part 3 is placed on the single crystal powder P in the saucer part 2. The position of 3 is fixed. In step S4, the cylindrical part 3 is placed on the single crystal powder P so that the single crystal C installed in the saucer part 2 is at the center of the cylindrical part 3 in plan view (when viewed from the +Z direction). preferable. This makes it possible to align the horizontal conditions for the single crystal C during the single-segmentation process, and to perform the stable single-segmentation process on the single crystal C.

According to the heat-resistant container 1 and the single-segmentation processing method of the present embodiment, since the single crystal C whose position is fixed is covered by the cylindrical portion 3, it is easier to cover the single crystal C than with conventional heat-resistant containers. The crystal C can be placed inside the heat-resistant container 1. The above effect becomes even more remarkable when the single crystal C having a large diameter and weight as described above is targeted.

(Step S5)
Next to step S4, as shown in FIG. 6(A), the inside of the cylindrical part 3 covering the single crystal C is filled with single crystal powder P, and the entire single crystal C is embedded in the single crystal powder P (step S5). At this time, the saucer portion 2 holds the oxide single crystal powder P, and the cylindrical portion 3 holding the oxide single crystal C and the oxide single crystal powder P. At this time, it is preferable to adjust the amount of single crystal powder P so that the distance between the upper end of single crystal C and electrode E2 is set within the above-described preferable range.

(Step S6)
Next to step S5, as shown in FIG. 6(B), an electrode E2 is installed on the single crystal powder P in which the entire single crystal C is embedded (step S6). At this time, it is preferable to set the distance between the upper end of the single crystal C and the electrode E2 within the above-described preferable range.

(Step S7)
Next to step S6, as shown in FIG. 7(A), the electrode E2 installed in step S6 is embedded with single crystal powder P (step S7). For example, the electrode E2 may be embedded by about 10 mm and fixed. The electrode E2 is not particularly limited, and for example, an electrode used in conventional single segmentation processing can be used. Note that step S7 is optional. After installing the electrode E2, if the electrode E2 is fixed by installing the lid in the next step, step S7 may not be performed.

(Step S8)
Next to step S7, as shown in FIG. 2, the lid part 4 is installed to cover the opening of the cylindrical part 3 (step S8). As mentioned above, by installing the lid part 4 above the single crystal powder P, the vertical conditions of the single crystal C can be made more similar during the single-segmentation process. A stable single domain processing can be applied to the data.

(Step S9)
Next to step S8, a voltage is applied at a predetermined temperature to the single crystal C embedded in the single crystal powder P to transform the single crystal C into a single domain (step S9). In step S9, the heat-resistant container 1 containing the single crystal C is placed in a heat treatment furnace (not shown). In this state, a voltage is applied between the electrodes E1 and E2 while the temperature in the furnace is raised and maintained at a temperature equal to or higher than the Curie temperature of the single crystal C, thereby carrying out a single segmentation process. As a result, the single crystal powder P is housed in the heat-resistant container 1, the single crystal C is embedded in the single crystal powder P, and the single crystal C is sandwiched between the pair of electrodes E1 and E2 via the single crystal powder P. A single domain of the single crystal C, in which the temperature of the single crystal C is raised to a temperature equal to or higher than the Curie temperature of the single crystal C, and a voltage is applied to a pair of electrodes E1 and E2 to form a single domain of the single crystal C. processing is performed. In addition, in the process of single segmentation in step S9, there are no particular restrictions on the conditions such as temperature, time, voltage, etc. of the heat treatment, and for example, known conditions can be used.

(Step S10)
After completing the process in step S9, the single crystal C is taken out from the heat-resistant container 1 (step S10). In step S10, after the process in step S9 is completed, the heat-resistant container 1 containing the single crystal C is cooled and taken out from the heat treatment furnace. Next, the single crystal C is taken out from the heat-resistant container 1. At this time, after removing the lid part 4 and the electrode E2 of the heat-resistant container 1, the cylindrical part 3 is pulled upward and removed. Thereby, the cylindrical portion 3 can be easily removed without coming into contact with the single crystal C. Further, at this time, the single crystal powder P spreads over the saucer portion 2, and the buried single crystal C is exposed from within the single crystal powder P, so that the single crystal C can be easily taken out. This effect becomes remarkable when the single crystal C, which has a large diameter and a large weight as described above, is targeted.

As described above, in the heat-resistant container 1 of the present embodiment, a voltage is applied to the oxide single crystal C embedded in the oxide single crystal powder P at a predetermined temperature to separate the oxide single crystal C into a single unit. This is a heat-resistant container used for single-zoning treatment, and includes a saucer part 2 having a bottom part 6 and a wall part 7, and a cylindrical part 3 that is cylindrical and installed above the saucer part 2. , the cylindrical part 3 can accommodate the oxide single crystal C and the oxide single crystal powder P, and the saucer part 2 can accommodate the oxide single crystal powder P, the oxide single crystal C, and the oxide single crystal powder. The outer diameter L1 of the cylindrical portion 3 is smaller than the inner diameter L2 of the saucer portion 2. The configuration other than the above is an arbitrary configuration in the heat-resistant container 1. According to the heat-resistant container 1 of the present embodiment, when the oxide single crystal C is placed in the heat-resistant container 1 or when the single crystal C is taken out from the heat-resistant container 1 in the single segmentation treatment of the oxide single crystal C, , it is possible to suppress problems caused by contact of the single crystal C with the heat-resistant container 1, and to improve workability.

In addition, in the method for single-segmenting an oxide single crystal of the present embodiment, a voltage is applied at a predetermined temperature to the oxide single crystal embedded in the oxide single crystal powder to separate the oxide single crystal. A method for single-segmenting an oxide single crystal, which involves performing a single-sectoring process on an oxide single crystal using the heat-resistant container 1 of the present embodiment described above. including. According to the method for single-segmenting an oxide single crystal of the present embodiment, in the single-segmenting treatment of the oxide single crystal C, when the oxide single crystal C is placed in the heat-resistant container 1 or the heat-resistant container When taking out the single crystal C from the heat-resistant container 1, problems caused by the single crystal C coming into contact with the heat-resistant container 1 can be suppressed, and workability can be improved. In addition, in the single-domain treatment method for an oxide single crystal of the present embodiment, the configurations other than those described above are arbitrary configurations. The single segmentation processing method of the present embodiment may include steps other than those described above. For example, the single-segmentation processing method of the present embodiment includes placing the oxide single crystal powder P in the saucer part 2, and adding the oxide single crystal powder P to the oxide single crystal powder P installed in the saucer part 2. In addition, the oxide single crystal C embedded in the oxide single crystal powder P is covered with the cylindrical part 3, and the oxide single crystal powder P placed in the saucer part 2 is covered with the cylindrical part 3. and filling the inside of the cylindrical part 3 covering the oxide single crystal C with oxide single crystal powder P, and embedding the entire oxide single crystal C in the oxide single crystal powder P. and applying a voltage at a predetermined temperature to the oxide single crystal C embedded in the oxide single crystal powder P to transform the oxide single crystal C into a single domain. Further, the single-zone processing method of this embodiment may include the matters described in the heat-resistant container 1 of this embodiment described above.

The present invention will be specifically explained below using examples, but the present invention is not limited to these examples in any way.

[Example 1]
In Example 1, LN single crystal was subjected to single-segmentation treatment using the heat-resistant container and single-segmentation treatment method according to the present embodiment described above. In Example 1, a single LN single crystal (Curie point: 1138°C) having a congruent composition (Li:Nb=48.4:51.6 (molar ratio)) and a diameter of 160 mm (6.3 inches) and a total length of 100 mm was used. Segmentation processing was performed.

First, a heat-resistant container similar to the heat-resistant container 1 shown in FIG. 2 described above, consisting of a saucer portion, a cylindrical portion, and a lid, was prepared. The saucer part was made of alumina and had an inner diameter of 270 mm, a wall height of 100 mm, and a thickness of 20 mm. The cylindrical part was made of alumina and had an inner diameter of 200 mm, a length of 170 mm, and a thickness of 15 mm. The lid was made of alumina and had an outer diameter of 310 mm and a thickness of 20 mm. Next, an electrode having a diameter of 180 mm and a thickness of 0.3 mm was placed on the inner bottom surface of the saucer part. Next, 25 mm of single crystal powder obtained by crushing LN crystal was spread. Moreover, the single crystal powder was raised into a mountain shape at the center. The cone-shaped lower part of the single crystal was embedded in the mountain-like part. Next, a cylindrical part was placed over the single crystal powder in the saucer part so that the single crystal was in the center of the cylindrical part. The inside of the cylindrical part was filled with single crystal powder around the single crystal, an electrode with a diameter of 180 mm and a thickness of 0.3 mm was placed at a position 25 mm from the top surface of the single crystal, and the single crystal powder was filled on top of the electrode to a thickness of 10 mm. A lid part was placed on top of the cylindrical part and closed.

After placing the heat-resistant container containing the single crystal on the hearth plate of an elevating electric furnace, use the platinum wire of the electrode facing the bottom of the single crystal as the positive electrode, and the platinum wire of the electrode facing the top of the single crystal. It was connected to a DC power source as a negative electrode. The temperature of the electric furnace was raised to 1150°C and held for 5.5 hours until the single crystal became stable at 1150°C. 5.5 hours after reaching 1150° C., a voltage is applied between the electrodes at a rate of 0.4 V/min, and about 45 minutes later, the voltage between the electrodes is set to 18 V. Seventy-five minutes after the voltage reached 18V, the temperature of the electric furnace was lowered while applying 18V between the electrodes, and when the temperature reached around 900°C, the voltage between the electrodes was set to 0V.

After the single-zone treatment, the heat-resistant container was taken out from the electric furnace. The lid and upper electrode of the heat-resistant container were removed. Thereafter, by lifting the cylindrical part upward and removing it, the single crystal powder spread in the saucer, and the exposed single crystal was taken out from within the single crystal powder.

When we examined the LN single crystal after the single domain treatment, there were no cracks, and when we evaluated the polarization state of the LN single crystal, there was no polarization in the opposite direction, and it was found that it was well formed into a single domain. . Furthermore, the work efficiency of placing the single crystal in the heat-resistant container and taking it out from the heat-resistant container was improved by 50% compared to the work of conventional heat-resistant containers.

From the results of the above examples, it is clear that according to the heat-resistant container and the single-segmentation processing method of the present embodiment, when the single crystal is placed in the heat-resistant container or from the heat-resistant container, It is confirmed that there is a remarkable effect of suppressing problems caused by contact of the single crystal with the heat-resistant container when taking out the crystal, and improving workability.

Note that the technical scope of the present invention is not limited to the aspects described in the above-mentioned embodiments. One or more of the requirements described in the above embodiments etc. may be omitted. Furthermore, the requirements described in the above embodiments and the like can be combined as appropriate. In addition, to the extent permitted by law, the disclosures of all documents cited in the above-mentioned embodiments, etc. are incorporated into the description of the main text.

1...Heat-resistant container 2...Saucer part 3...Cylindrical part 4...Lid part 6...Bottom part 7...Wall part 8...Inner bottom surface E1, E2...Electrode C・・・Oxide single crystal (single crystal)
P...Oxide single crystal powder (single crystal powder)

Claims (6)

A heat-resistant container used for a single-segmentation process in which a voltage is applied at a predetermined temperature to an oxide single-crystal embedded in an oxide single-crystal powder to form the oxide single-crystal into a single-segmentation process,
a saucer portion having a bottom portion and a wall portion;
a cylindrical part having a cylindrical shape and installed above the saucer part;
The cylindrical portion is capable of accommodating the oxide single crystal and the oxide single crystal powder therein,
The saucer portion is capable of holding the oxide single crystal powder, and the cylindrical portion holding the oxide single crystal and the oxide single crystal powder,
The outer diameter of the cylindrical portion is smaller than the inner diameter of the saucer portion. The heat-resistant container according to claim 1, wherein the outer diameter of the cylindrical portion is smaller than the inner diameter of the saucer portion by 30 mm or more and 50 mm or less. The heat-resistant container according to claim 1 or 2, wherein the saucer portion is capable of holding the entire amount of the oxide single crystal powder filled into the heat-resistant container during the single-segmentation treatment. The heat-resistant container according to any one of claims 1 to 3, wherein the cylindrical portion has an inner diameter of 190 mm or more. A single domain treatment method for oxide single crystals in which a voltage is applied at a predetermined temperature to the oxide single crystal embedded in oxide single crystal powder to make the oxide single crystal into a single domain. There it is,
A single-segmenting treatment for an oxide single crystal, comprising performing a single-sectoring process on the oxide single crystal using the heat-resistant container according to any one of claims 1 to 4. Method. The single segmentation process is
placing the oxide single crystal powder in the saucer portion;
embedding a part of the end of the oxide single crystal in the oxide single crystal powder placed in the saucer;
Covering the oxide single crystal embedded in the oxide single crystal powder with the cylindrical part, and placing an end of the cylindrical part on the oxide single crystal powder placed in the saucer part;
filling the inside of the cylindrical portion that covers the oxide single crystal with the oxide single crystal powder, and embedding the entire oxide single crystal in the oxide single crystal powder;
6. Applying a voltage at a predetermined temperature to the oxide single crystal embedded in the oxide single crystal powder to transform the oxide single crystal into a single domain. Single-domain processing method for oxide single crystals.

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