JPH05330984A - Device for liquid-phase epitaxial growth - Google Patents

Abstract

PURPOSE:To provide a device for liquid-phase epitaxial growth capable of producing a high-quality single crystal film in high recovery ratio without applying unnatural stress to substrate bases. CONSTITUTION:A substrate fixture is equipped with a fitting frame 10 fixed to the lower end part of a holding bar, a retaining frame 15 which is detachably attached to the fitting frame and supports the bottom and the outer peripheral face of substrate bases and spacers 18 which are kept in the interior of the retaining frame and arranged between the substrate bases. The fitting frame, the retaining frame and the spacers are made of a heat-resistant noble metal such as platinum. Plural sheets of the substrate bases are horizontally supported while maintaining intervals by the spacers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid phase epitaxial growth apparatus for growing a single crystal film on the surface of a base substrate.

[0002]

2. Description of the Related Art Conventionally, magnetic garnet single crystals have been widely used in magnetostatic wave (MSW) devices such as delay line filters, oscillators and nonlinear devices, and magneto-optical elements such as optical isolators, circulators and switches utilizing the Faraday rotation effect. It is used. A liquid phase epitaxial growth method (LPE method) is known as a main method for producing the magnetic garnet single crystal.

According to this liquid phase epitaxial growth method, a platinum crucible held in a vertical heating furnace under predetermined conditions contains an oxide of elements constituting garnet and PbO and B as a solvent.
Fill with ₂ O ₃ and homogenize at about 1200 ° C. to form a solution. This solution is applied to the liquidus (Liquidus) and solidus (Solidus)
s), that is, after maintaining the garnet in a supersaturated state by maintaining it at a constant temperature of about 900 ° C., immersing the Gd ₃ Ga ₅ O ₁₂ (GGG) substrate as the base substrate in this solution,
A magnetic garnet single crystal film is grown on the surface of the base substrate by performing growth for a predetermined time while rotating at a fixed position. After the growth of the magnetic garnet single crystal film is completed, the underlying substrate is rotated and pulled up from the solution at a high speed, and the solution deposited on the single crystal film is shaken off by the centrifugal force to complete the growth. The base substrate is held in a horizontal state by a noble metal substrate holder attached to the lower end of the support rod. Several legs provided on the substrate holder have elasticity in the inward and outward directions, and the elasticity of the legs sandwiches and holds the outer peripheral portion of the base substrate.

[0004]

However, according to the above method, only one single crystal plate can be manufactured by one growth,
It has the drawback of poor productivity. Therefore, there is also a liquid phase epitaxial growth apparatus in which the leg portion of the substrate holder is extended downward and a plurality of base substrates are held in parallel between the leg portions to improve mass productivity.

However, in the case of this method, the urging force to the inside of the leg portion causes the free end portion (lower end portion) and the base portion (upper end portion) of the leg portion.
However, there is a problem that the stress of the leg portion applied to the outer peripheral portion of the base substrate also differs depending on the base substrate. For example, the stress on the base substrate held near the base of the leg is large, so that the base substrate is likely to crack or chip, while the stress on the base substrate held near the free end of the leg is small and the solution When the substrate is rotated at a high speed for shaking off, the underlying substrate comes off from the substrate holder, and the recovery rate of the grown substrate is reduced. Therefore, an object of the present invention is to provide a liquid phase epitaxial growth apparatus capable of mass-producing a high quality single crystal film with a high recovery rate without giving an excessive stress to the underlying substrate.

[0006]

In order to achieve the above object, a substrate holder of the present invention is attached to a mounting frame fixed to a lower end portion of a support rod and detachably mounted to the mounting frame.
A holding frame that supports the bottom surface and outer peripheral surface of the base substrate, and spacers that are housed inside the holding frame and arranged between the base substrates are provided, and a plurality of base substrates are held horizontally by the spacers while maintaining a distance. It was possible.

[0007]

[Function] When a plurality of base substrates are soaked in a solution to grow a single crystal film, each base substrate is held horizontally by spacers, so that single crystal components are spread over the entire base substrate. , Epitaxial growth is promoted. After the growth of the single crystal film is completed, when the base substrate is rotated and pulled up from the solution at a high speed, an outward force due to centrifugal force acts on the base substrate, but the base substrate is housed inside the holding frame. Therefore, the base substrate does not fall off. When taking out the base substrate from the substrate holder, the base frame can be easily taken out by removing the holding frame from the mounting frame and taking out the spacers accommodated in the holding frame. In this way, it is possible to easily remove the base substrate without applying undue stress.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an apparatus for growing a magnetic garnet film which is an example of the present invention. Inside a vertical cylindrical core tube 1 made of alumina, a platinum crucible 3 whose bottom surface is supported by a support 2 is arranged, and the crucible 3 is filled with a raw material for a magnetic garnet film and a solvent. There is. Outside the core tube 1, upper, middle and lower heaters 4, 5 and 6 are provided, and the crucible 3 is arranged inside the middle heater 5. The crucible 3 in the core tube 1 is heated by the radiant heat of the heaters 4 to 6, the garnet raw material and the solvent are dissolved to form a solution 7, and the atmosphere in the core tube 1 is maintained at a predetermined temperature.

A disk-shaped base substrate 8 made of a GGG substrate
Are horizontally held by a substrate holder 9 made of platinum or platinum alloy shown in FIGS. Substrate holder 9
Is composed of a mounting frame 10, a holding frame 15, and a spacer 18. The mounting frame 10 includes a boss portion 10a fixed to a lower end portion of an alumina support rod 20, and an annular support portion 12 connected to the boss portion 10a via a radial connecting portion 11.
And a pressing plate 13 having an annular plate shape on the lower surface of the support portion 12. The outer diameter of the support portion 12 is substantially equal to the outer diameter of the base substrate 8, and screw holes 12a into which screws 14 made of platinum or platinum alloy are screwed are formed at three locations on the outer peripheral portion thereof.

The holding frame 15 comprises three side leg portions 16 contacting the outer peripheral surface of the support portion 12 and an annular plate-shaped bottom plate 17 connected to the lowermost end of the side leg portion 16. A plurality of long holes 16a are formed in the portion 16 at regular intervals. The diameter of the inscribed circle of the side leg portion 16 is substantially equal to the diameter of the base substrate 8. The spacer 18 is formed of a wire made of platinum or a platinum alloy in a substantially triangular shape, and each vertex has a leg 18a extending in the vertical direction and an engagement pin 18b extending in the radial direction. When the engaging pin 18b is engaged with the elongated hole 16a of the holding frame 15, the spacer 18 is horizontally attached to the holding frame 15. By arranging the base substrate 8 between the spacers 18, a plurality of base substrates 8 can be held at a distance. Since the height of the upper spacer 18 changes depending on the thickness of the base substrate 8, this change is caused by the long hole 16a.
Is absorbed by. The long hole 16a at the upper end is an insertion hole for inserting the screw 14.

The base substrate 8 is held by the substrate holder 9 as follows. That is, when the base substrate 8 is first stored from above in the holding frame 15, the outer peripheral surface of the base substrate 8 is guided by the side leg portions 16, and the lower surface of the outer peripheral portion is placed on the bottom plate 17. Next, while bending the spacer 18, the holding frame 1
5, the engaging pin 18b is engaged with the lowermost elongated hole 16a, and the foot 18a presses three places on the upper surface of the outer peripheral portion of the base substrate 8 placed on the bottom plate 17. Then, spacer 1
The next base substrate 8 is placed on the base substrate 8, the next spacer 18 is placed on the base substrate 8, and the engaging pin 1 of the spacer 18 is placed.
8b is engaged with the second long hole 16a from the bottom. Less than,
Similarly, the base substrate 8 and the spacer 18 are sequentially attached to the holding frame 15
To house. Then, after placing the base substrate 8 on the uppermost spacer 18, the side leg portions 16 of the holding frame 15 are externally fitted to the support portions 12 of the mounting frame 10, and the side leg portions 16 are screwed from outside to the side leg portions 16. The assembly is completed by connecting the support portion 12. In this way, the outer peripheral surface of the base substrate 8 is position-regulated by the inner surface of the side leg portion 16 of the holding frame 15, and the outer peripheral upper and lower surfaces are between the bottom plate 17 of the holding frame 15 and the legs 18a of the spacers 18, or It is sandwiched between the legs 18a of the upper and lower spacers 18 and stably held. Therefore, the substrate holder 9
Even when the base substrate 8 was rotated in the reverse direction every 30 seconds at 00 rpm, the base substrate 8 was not displaced in the rotation direction.

An upper end portion of the support rod 20 is detachably attached to a driving means (not shown) and is driven in a rotating direction and a vertical direction. The eccentricity of the support rod 20 can be adjusted at the connecting portion between the support rod 20 and the driving means. At the upper end of the furnace core tube 1, a shutter 21 made of quartz glass for suppressing invasion of cold air into the furnace is placed, and the support rod 20 is inserted at the center of the shutter 21.

Next, an example of the operation of the liquid phase epitaxial growth apparatus having the above structure will be described. First, a garnet raw material and a solvent are mixed in a crucible 3, heated and melted at 1200 ° C. and held for 2 hours, and then cooled to 890 ° C. to be in a supercooled state. Next, the plurality of base substrates 8 are horizontally held in the holding frame 15 by the spacers 18 while keeping the distance, and the upper end of the holding frame 15 is fixed to the mounting frame 10 with the screw 14. In this way, the support rod 20 holding the base substrate 8 at the lower end portion
And the base substrate 8 is dipped in the solution 7. Then, the support bar 20 is rotated in one direction or in the reverse direction to grow a magnetic garnet single crystal film. After the growth of the single crystal film is completed, the base substrate 8 is pulled up from the solution 7 while being rotated at a high speed, and the adhering solution on the single crystal film is shaken off by the centrifugal force. At this time, a force in the rotational direction acts on the substrate holder 9 due to high-speed rotation, but since the outer peripheral portion of the base substrate 8 is regulated by the side leg portions 16 of the holding frame 15, the base substrate 8 is the substrate. It does not slip off or fall off the holder 9. After the shaking off of the attached solution is completed, the support rod 20 is further pulled up, the holding frame 15 is separated from the mounting frame 10 at a predetermined position, and this is carried to another place, where the base substrate 8 is taken out from the holding frame 15. At this time as well, since no unreasonable force is applied to the base substrate 8, no cracking or chipping occurs.

4 and 5 show a substrate holder 3 according to the present invention.
Another embodiment of 0 is shown. The substrate holder 30 of this embodiment
A mounting frame 32 fixed to an alumina support rod 31,
It is composed of a holding frame 40 and a spacer 50. The mounting frame 32 includes a boss portion 33 and an annular support portion 35 connected to the boss portion 33 via a radial connecting portion 34. The outer diameter of the support portion 35 is substantially equal to the outer diameter of the base substrate 8, and screw holes 36 into which screws 37 made of platinum or platinum alloy are screwed are formed at three locations on the outer peripheral portion thereof.

The holding frame 40 has a ring-shaped lip 41 which is substantially in contact with the outer peripheral surface of the support 35, three side legs 42 which extend downward from the lip 41, and side legs 42. And the bottom leg portion 43 of the annular plate connected to the lowermost end of the. Rim 41
And the diameter of the inscribed circle of the side leg portion 42 are substantially equal to the diameter of the base substrate 8, and the inner diameter of the bottom leg portion 43 is slightly smaller than the outer diameter of the base substrate 8. The screw 37 is attached to the lip 41.
A long hole 44 for insertion is formed. The spacer 50 is formed of a wire made of platinum or a platinum alloy, and is composed of upper and lower ring portions 51 and a vertical connecting portion 52 connecting the ring portions 51. The outer diameter of the ring portion 51 is substantially equal to the outer diameter of the base substrate 8.

In order to hold the base substrate 8 in the substrate holder 30, the base substrate 8 is first stored from the edge 41 of the holding frame 40. The outer peripheral surface of the base substrate 8 is guided by the side leg portions 42, and the lower surface of the outer peripheral portion is placed on the bottom leg portions 43. Next, the spacer 50 is housed in the holding frame 40, and then the spacer 5
The next base substrate 8 is placed on the base substrate 0, and the next spacer 50 is placed on the base substrate 8. Thereafter, similarly, the base substrate 8 and the spacer 50 are sequentially housed in the holding frame 40. Then, after placing the base substrate 8 on the uppermost spacer 50, the rim portion 41 of the holding frame 40 is attached to the support portion 35 of the mounting frame 32.
To the rim portion 41 and the support portion 35 with screws 37 from the outside.
And are connected. At this time, the uppermost base substrate 8 is sandwiched between the spacer 50 and the supporting portion 35. In the substrate holder 30 assembled in this way, the outer peripheral surface of the base substrate 8 is regulated by the inner surface of the side leg portion 42 of the holding frame 40, and the outer peripheral upper and lower surfaces are formed by the ring portions 51 of the upper and lower spacers 50. Since it is sandwiched, it is stably held.

In this embodiment, the spacer 50 is attached to the holding frame 4.
Since it only has to be inserted into 0, the holding frame 4
There is a feature that it is easy to store and take out the base substrate 8 and the spacer 50 in 0.

Although the magnetic garnet single crystal has been described above, the present invention is not limited to this. For example, the present invention is also applicable to liquid phase epitaxial growth of lithium niobate, which is a single crystal for optical devices. Can be applied.

[0019]

As is apparent from the above description, according to the present invention, the substrate holding method is changed from the conventional sandwiching method using the legs to the detachable structure using the holding frame and the spacer. It is possible to securely hold the underlying substrate without applying excessive stress. As a result, problems such as detachment of the base substrate due to high-speed rotation after growth and chipping or cracking of the outer peripheral portion of the base substrate can be solved. In addition, since the base substrates are arranged with a distance from each other by the spacer, the solution easily enters the gaps between the base substrates to help the growth of the single crystal. Therefore, a good quality single crystal can be efficiently mass-produced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a liquid phase epitaxial growth apparatus according to the present invention before immersion.

FIG. 2 is a perspective view of a first embodiment of the substrate holder.

FIG. 3 is an exploded perspective view of the substrate holder shown in FIG.

FIG. 4 is a perspective view of a second embodiment of the substrate holder.

5 is an exploded perspective view of the substrate holder shown in FIG.

[Explanation of symbols]

 1 core tube 3 crucible 7 solution 8 base substrate 9 substrate holder 10 mounting frame 15 holding frame 18 spacer 20 support rod

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masato Kumagorani 2-26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Yutoku Sekijima 2-26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Hiroshi Takagi 2-26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A substrate holder is attached to a lower end portion of a support rod,
The base substrate horizontally held by this substrate holder is immersed in the crucible in which the single crystal raw material is dissolved, and the single crystal film is formed on the surface of the base substrate by growing for a predetermined time while rotating at a fixed position. In the liquid phase epitaxial growth apparatus for growing, the substrate holder includes a mounting frame fixed to a lower end portion of a support rod, and a holding frame detachably attached to the mounting frame and supporting a bottom surface and an outer peripheral surface of a base substrate. A liquid phase epitaxial growth apparatus comprising: a spacer housed inside a holding frame and arranged between the base substrates, and a plurality of base substrates can be held horizontally by the spacer while keeping a distance. ..