JPS6291487A - Method for manufacturing dielectric single crystal - Google Patents

Abstract

PURPOSE:To obtain the titled single crystal of regular shapes with a high crystal growth velocity and good productivity by pulling up a molten dielectric through a specified heating frame provided to a pulling outlet to enhance the stability at the solid-liq. interface. CONSTITUTION:A dielectric 3 such as sapphire (Al2O3), quartz (SiO2), and LN (LiNbO3) is charged in a crucible 1 made of a material selected from Pt, Rh, Ir, etc., or their alloy, heated by a heater 2, and melted. A frame 4 of regular shapes (e.g., a plate having 30mm width and 2mm thickness) made of the same material as the crucible and which is heated to a temp. higher than the solidifying point of the melt 3 (e.g., 1-20 deg.C higher than the temp. of the melt 3) is provided to the melt pulling outlet at the upper part. Then the molten dielectric 3 is pulled up, for example, at a velocity of about >=50cm/min through the outlet of the frame 4 by using a pulling jig 5, and the single crystal of regular shapes is continuously obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field 1 This invention is applicable to
This invention relates to a method for producing a single crystal of a dielectric material such as SfOz)'.

[Conventional lk technique 1 The dielectric 111 crystal has a high melting point C, and contamination is disliked during its production.Therefore, when producing a single crystal of the M electric material, platinum, platinum, etc. are used as the crucible monthly rate.・!1 dium,
First,: Iridium was used and a pulling method was used to grow a single crystal.

In addition, when overlapping to define the cross-sectional shape of the single crystal to be manufactured, E F G (F doe -define
If methods such as the d Film-fed (3rowt+) method were employed.

[Problems to be Solved by the Invention] However, there are several problems with the method described above. First, the pulling method [・ is - (J which defines the shape of the single crystal to be pulled up, -) Iishino is <,
stomach.

Therefore, if the final shape is subjected to various processing, the yield will be low.

In addition, in this case v2, the less popular eddy electric gradient is 4=J
[) The stability M of the solid-liquid interface tends to decrease. Ishino (due to this 1), the speed of crystallization is slow, and the production speed is slow.
'l becomes inferior. Well, the degree of perfection of the crystal is not -1.
Minute and 4 [ru.

On the other hand, E F G '1k 'C1,L,! , 41'l
) A1! Due to these characteristics, there are restrictions on the materials that can be used for the ladle and die.

In other words, this horn method can only be applied to a limited number of cases, such as Δa, 03 linonofi'+7&<r.

Therefore, the object of the present invention is to develop a dielectric single crystal that can define the shape of the obtained 111 crystal and also improve the stability of the liquid boundary 1al. The method for producing horns is to provide Ha.

[F stage for solving the problem] and [Operation and effect 1 of the invention] The method for manufacturing a dielectric single crystal according to the present invention involves pulling out a dielectric from a molten state and growing the dielectric into a single crystal solid. When drawing the molten material, a frame heated to 6 degrees higher than the freezing point of the molten material is installed, and the single crystal is pulled out from the method frame.

Melt drawing 1.11 By appropriately selecting the shape of the frame used for one stage, the shape of the obtained single crystal can be defined by 61 possibilities. ,(]Taga-)(,It is possible to produce 1!I crystals with a shape close to the final I1 shape, and to increase the yield.
Wear.

Since a frame heated to a temperature higher than the freezing point of the molten material is used, it is possible to prevent the generation of unnecessary crystal nuclei, making it easier to obtain a perfect single crystal. Furthermore, sudden i%
l <> It is also possible to create a temperature gradient, which can increase the stability of the solid-liquid interface. However, it is possible to increase the crystal growth rate and, in turn, increase the 41:R efficiency.

In this invention, from the beginning, the shape is defined 1) In other words, for example, the conventional
As seen in the law, support for 41 people is no longer necessary. In addition to this, -1-mentioned/-2, J: Since the solid-liquid interface in sea urchin is likely to be stable, the dielectric material 1 [!
The crystals are getting bigger and bigger. Furthermore, since a crucible as seen in the Bridgman method (k) is not used, it is possible to produce single crystals in a better and continuous manner.

The frame installed at the melt outlet is preferably heated to a temperature of 1-20°C higher than the temperature of the melt. If the frame is heated to a temperature higher than the molten temperature, the solid-liquid interface becomes more stable, as the 1-scale gradient at the time of withdrawal is reduced. Therefore, the withdrawal speed can be increased by 1jl b. It is conceivable to increase the temperature 1η of the entire molten body, but doing so may promote the reaction between the molten body and other objects. From the point of view (a), it is desirable to raise the temperature of the frame. However, the temperature difference between the frame and the melting body is 20
If the temperature is set higher than ℃, the reaction between the molten material and the frame will be slow, and it will not be very effective. The optimum temperature difference between the melt and the frame is 5°C.

The dielectric is pulled out from the molten state by pulling it upwards, pulling it downwards, or pulling it laterally. There are some cases.

tJ Oh, when pulling out the dielectric from the frame to avoid crystal growth into a single crystal solid, it is better to avoid rapid cooling.

This is because rapid cooling rJI (-(for example, internal defects are more likely to occur in the resulting single crystal, and the internal defects of the single crystal t'
This is because it has a negative effect on l.

As an example of a dielectric material, for example,
uzO3), RGO (BI4G8aO+z), 1-N(
L, t Nb Os ), LT (l I Ta Os
), GGG (Gd a (3a b () + z
), YAG (Yz△fu.

012), quartz (SiO2), alkali halide (Na
C-fu, etc.).

Considering that the dielectric material) 11 crystal has a high melting point and that contamination is disliked during its production, the frame is preferably platinum, []dium, iridium,
Platinum alloy, L] Radium gold, Iridium alloy carefully selected from 2i 1llj! It is best to make it from recycled materials.

[Example 1] Figure 1 shows an example of the apparatus used to carry out the present invention. l-, i Nb O8 is contained in the melt]-1, as shown in the figure.
The crucible 1 and the heating frame 1 are heated to b t64 from the freezing point of the molten material.
It is made from platinum. The melting point of IrO, 1iNb (1°C is 12!-i('3°C).

Then, using the drawing jig F5 (!), continuously form a single crystal into a flat plate with a width of 30 + nm and a thickness of 2I1 m.
3' /, =, 3 The current pulling speed 1σ is about 50
cil/ +n in, J:su I) I can spell it quickly.

Furthermore, using an iridium crucible and heating frame,
Gd s Qa h O+ 2 (GGG) ノ) A round rod single crystal with a diameter of 5 Q mm is

[Brief explanation of drawings]

FIG. 1 shows this invention in practice! FIG. In the figure, J3, 3 is 1-iNbO8 kept in a molten state.
, 4 indicates the heating frame.

Claims (5)

[Claims] (1) When pulling the dielectric out of the molten state and growing it into a single-crystal solid, a frame heated to a temperature higher than the freezing point of the molten material is installed at the outlet of the molten material, and the single crystal is grown from the frame. A method for producing a dielectric single crystal, characterized by bringing out the following. (2) The method for manufacturing a dielectric single crystal according to claim 1, wherein the frame is heated to a temperature 1 to 20° C. higher than the temperature of the melt. (3) Claim 2, characterized in that the frame is heated to a temperature 5° C. higher than the temperature of the melt.
A method for producing a dielectric single crystal as described in . (4) Claims 1 to 3, wherein the frame is made of a material arbitrarily selected from the group consisting of platinum, rhodium, iridium, platinum alloy, rhodium alloy, and iridium alloy. A method for producing a dielectric single crystal according to any one of the above. (5) The method for manufacturing a dielectric single crystal according to any one of claims 1 to 4, wherein the single crystal is pulled upward from the frame.