JP3214069B2 - Liquid phase epitaxial growth equipment - Google Patents

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 in magneto-optical devices such as optical isolators, circulators, and switches utilizing the Faraday rotation effect. Used. As a main production method of the magnetic garnet single crystal, a liquid phase epitaxial growth method (LPE method) is known.

[0003] In this liquid phase epitaxial growth method, PbO and B as an oxide and a solvent of elements constituting garnet are put in a platinum crucible kept in a vertical heating furnace under predetermined conditions.
It is charged with ₂ O ₃ and homogenized at about 1200 ° C. to form a solution. This solution is combined with liquidus (Liquidus) and solidus (Solidus).
After maintaining the temperature during s), that is, a constant temperature of about 900 ° C. to supersaturate the garnet, a Gd ₃ Ga ₅ O ₁₂ (GGG) substrate as a base substrate is immersed in this solution,
The 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 growth is completed by rotating the base substrate out of the solution at a high speed and pulling the solution off the single crystal film by centrifugal force. The base substrate is held horizontally by a noble metal substrate holder attached to the lower end of the support rod. Several legs provided on the substrate holder have inward and outward elasticity, 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.
There is a disadvantage that productivity is poor. Therefore, there is a liquid phase epitaxial growth apparatus in which the legs of the substrate holder are extended long downward and a plurality of base substrates are held in parallel between the legs to improve mass productivity.

However, in the case of this method, the biasing force inward of the leg is applied to the free end (lower end) and the base (upper end) of the leg.
However, there is a problem that the stress of the leg 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, and therefore the base substrate is liable to crack or chip, but 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, there is a disadvantage that the underlying substrate falls off from the substrate holder and the recovery rate of the grown substrate is reduced. Accordingly, 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 at a high recovery rate without giving an unreasonable stress to an underlying substrate.

[0006]

In order to achieve the above object, a substrate holder of the present invention is provided with a mounting frame fixed to a lower end of a support rod, and is detachably mounted on the mounting frame.
The bottom plate and the outer peripheral surface of the underlying substrate extending upward from the bottom plate
A holding frame having a side leg that regulates the position and prevents displacement during rotation. An outer peripheral portion is formed inside the holding frame by the side leg.
It housed in the support state, and a spacer disposed between each base substrate, in which a plurality of underlying substrates were possible horizontally held while keeping a distance in the vertical direction by the spacer.

When growing a single crystal film by immersing a plurality of base substrates in a solution, since each base substrate is horizontally held at intervals vertically by spacers, the components of the single crystal are formed. Spread all over the underlying substrate, and epitaxial growth is promoted. After the growth of the single crystal film is completed, when the underlying substrate is rotated from the solution at a high speed and pulled up, an outward force due to centrifugal force acts on the underlying substrate , but the outer peripheral surface of the underlying substrate is <br / > Since the position is regulated by the side legs of the holding frame, the base substrate does not shift or fall off. When removing the base substrate from the substrate holder, the base frame can be easily removed by removing the holding frame from the mounting frame and removing the spacer housed in the holding frame. In this manner, the base substrate can be easily removed without applying excessive stress.

[0008]

FIG. 1 shows an apparatus for growing a magnetic garnet film according to an embodiment of the present invention. A platinum crucible 3 having a bottom surface supported by a support 2 is disposed inside a vertical cylindrical core tube 1 made of alumina. The crucible 3 is filled with a raw material of a magnetic garnet film and a solvent. I have. Outside the furnace tube 1, upper, middle and lower three-stage heaters 4, 5 and 6 are provided, and the crucible 3 is arranged inside the middle heater 5. The crucible 3 in the furnace 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 furnace tube 1 is maintained at a predetermined temperature.

Disc-shaped base substrate 8 made of a GGG substrate
Is horizontally held by a substrate holder 9 made of platinum or a platinum alloy shown in FIGS. Substrate holder 9
Comprises a mounting frame 10, a holding frame 15, and a spacer 18. The mounting frame 10 includes a boss 10 a fixed to the lower end of the alumina support rod 20 and an annular support 12 connected to the boss 10 a via a radial connection 11.
And an annular plate-shaped holding plate 13 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 12 a into which screws 14 made of platinum or a platinum alloy are screwed are formed at three places on the outer peripheral portion.

The holding frame 15 is composed of three side legs 16 in contact with the outer peripheral surface of the support portion 12 and an annular bottom plate 17 connected to the lowermost end of the side legs 16. The portion 16 has a plurality of long holes 16a formed at regular intervals. The diameter of the inscribed circle of the side leg 16 is substantially equal to the diameter of the base substrate 8. The spacer 18 is formed in a substantially triangular shape with a wire made of platinum or a platinum alloy, and each apex is provided with a foot 18a extending vertically and an engaging pin 18b extending radially. 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 disposing the base substrate 8 between the spacers 18, the 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 taken
Is absorbed by. The slot 16a at the upper end is an insertion hole through which the screw 14 is inserted.

In order to hold the base substrate 8 on the substrate holder 9, the following is performed. That is, when the base substrate 8 is first stored in the holding frame 15 from above, 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, the holding frame 1 is bent while the spacer 18 is being bent.
5, the engaging pin 18b is engaged with the lowermost slot 16a, and three positions on the upper surface of the outer peripheral portion of the base substrate 8 placed on the bottom plate 17 are pressed by the feet 18a. Then, spacer 1
Next, the next base substrate 8 is placed on the base substrate 8, the next spacer 18 is placed on the base substrate 8,
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 placed on the holding frame 15.
To house. Then, after placing the base substrate 8 on the uppermost spacer 18, the side legs 16 of the holding frame 15 are fitted onto the support portions 12 of the mounting frame 10, and the side legs 16 are screwed from outside with the screws 14. The assembly is completed by connecting the support portion 12. Thus, the position of the outer peripheral surface of the base substrate 8 is regulated by the inner surface of the side leg 16 of the holding frame 15, and the upper and lower outer peripheral surfaces are between the bottom plate 17 of the holding frame 15 and the feet 18 a of the spacer 18, or It is sandwiched between the legs 18a of the upper and lower spacers 18 and is stably held. Therefore, the substrate holder 9 is
Even when the substrate 8 was rotated in the normal or reverse direction at 30 minutes at 00 rpm, no deviation in the rotation direction of the base substrate 8 occurred.

The upper end 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 connection between the support bar 20 and the driving means can adjust the eccentricity of the support bar 20. At the upper end of the furnace tube 1, a quartz glass shutter 21 for suppressing intrusion of cool air into the furnace is mounted, and the support bar 20 is inserted through the center of the shutter 21.

Next, an example of the operation of the liquid phase epitaxial growth apparatus having the above configuration will be described. First, the garnet raw material and the solvent are mixed in the crucible 3, heated and melted at 1200 ° C., kept 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 on the holding frame 15 while keeping the distance by the spacers 18, and the upper end of the holding frame 15 is fixed to the mounting frame 10 with screws 14. The support rod 20 holding the base substrate 8 at the lower end in this manner
Is lowered, and the base substrate 8 is immersed in the solution 7. Then, the support bar 20 is rotated in one direction or forward and reverse 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 rotating at a high speed, and the attached solution on the single crystal film is shaken off by centrifugal force. At this time, a rotational force is applied to the substrate holder 9 by high-speed rotation. However, the position of the base substrate 8 is regulated by the side legs 16 of the holding frame 15 so that the base substrate 8 There is no displacement or dropping out of the holder 9. After the shaking off of the adhesion solution is completed, the support bar 20 is further pulled up, the holding frame 15 is separated from the mounting frame 10 at a predetermined position, and is transported to another place, where the base substrate 8 is taken out from the holding frame 15. Also at this time, since no excessive force is applied to the base substrate 8, no cracking or chipping occurs.

FIGS. 4 and 5 show a substrate holder 3 according to the present invention.
0 shows another embodiment. 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 33 and an annular support 35 connected to the boss 33 via a radial connection 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 a platinum alloy are screwed are formed in three places on the outer peripheral portion.

The holding frame 40 has an annular rim 41 almost in contact with the outer peripheral surface of the support portion 35, three side legs 42 extending downward from the rim 41, and a side leg 42. And a bottom leg 43 of an annular plate connected to the lowermost end of the ring. Lip 41
And the diameter of the inscribed circle of the side leg 42 is substantially equal to the diameter of the underlying substrate 8, and the inner diameter of the bottom leg 43 is slightly smaller than the outer diameter of the underlying substrate 8. In addition, the above-mentioned screw 37 is
Are formed. The spacer 50 is formed of platinum or a platinum alloy wire, and includes 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 on 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 legs 42, and the lower surface of the outer peripheral portion is placed on the bottom leg 43. Next, the spacer 50 is housed in the holding frame 40,
Next, the next base substrate 8 is placed on the base substrate 8, and the next spacer 50 is placed on the base substrate 8. Hereinafter, similarly, the base substrate 8 and the spacer 50 are sequentially housed in the holding frame 40. After the base substrate 8 is placed on the uppermost spacer 50, the edge 41 of the holding frame 40 is connected to the support 35 of the mounting frame 32.
And the lip portion 41 and the support portion 35 are screwed from outside.
And concatenate. At this time, the uppermost base substrate 8 is sandwiched between the spacer 50 and the support portion 35. In the substrate holder 30 assembled in this manner, the position of 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. Because it is sandwiched, it is stably held.

In this embodiment, the spacer 50 is attached to the holding frame 4.
0, it is only necessary to insert it in the holding frame 4
There is a feature that the base substrate 8 and the spacer 50 can be easily stored and removed to zero.

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

[0019]

As is apparent from the above description, according to the present invention, the substrate holding method can be changed from the conventional sandwiching method from the outer peripheral direction to the vertical holding method using the holding frame and the spacer.
Since the housing structure has been changed, a plurality of base substrates can be reliably held without applying excessive stress. In particular, the holding frame has a bottom plate
Extends upward from this bottom plate and regulates the outer peripheral surface of the underlying substrate
And side legs for preventing displacement during rotation are provided.
Therefore, 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 at a distance in the vertical direction by the spacers, the solution easily enters the gaps between the base substrates and helps the growth of the single crystal. Therefore, high-quality single crystals can be efficiently mass-produced.

[Brief description of the drawings]

FIG. 1 is a longitudinal 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.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace tube 3 Crucible 7 Solution 8 Base substrate 9 Substrate holder 10 Mounting frame 15 Holding frame 18 Spacer 20 Support rod

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masato Kumagaya 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. No. 2 Murata Manufacturing Co., Ltd. (72) Inventor Hiroshi Takagi 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. (56) References JP-A-63-122110 (JP, A) Akira Mikai 49-18464 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00

Claims (1)

(57) [Claims] 1. A substrate holder is attached to a lower end of a support rod,
The base substrate held horizontally by the substrate holder is immersed in a crucible in which the single crystal raw material is dissolved, and grown for a predetermined time while rotating at a predetermined position, thereby forming a single crystal film on the surface of the base substrate. in the liquid phase epitaxial growth apparatus for growing, the substrate holder comprises a mounting frame fixed to the lower end of the support rod detachably attached to the attachment frame, a bottom plate
Extends upward from this bottom plate and regulates the outer peripheral surface of the underlying substrate
A supporting frame having side legs for preventing displacement during rotation, and an outer peripheral portion supported by the side legs inside the holding frame.
It is housed in a state, and a spacer disposed between each base substrate, the liquid phase epitaxial growth, characterized in that a plurality of underlying substrates were possible horizontally held while keeping a distance in the vertical direction by the spacer apparatus.