JP2003002792A - Method for producing magnetic garnet single crystal film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing magnetic garnet single crystal films by which a plurality of magnetic garnet single crystal films having a film thickness of >=30 μm can simultaneously be produced, and the cracking of substrates can be prevented in the process of working. SOLUTION: A plurality of YIG (yittrium-iron-garnet) single crystal films having a film thickness of >=30 ×m are simultaneously produced on a plurality of GGG (gadolinium-gallium-garnet) substrates arranged parallel at intervals in a thickness direction by an epitaxial process. In this case, provided that the diameter of the GGG substrates is defined as D (mm), the distance among the GGG substrates as d (mm), and the film thickness of the magnetic garnet single crystal films to be produced as t (μm), d>=(D/10)+0.025t-0.75 is satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a magnetic garnet single crystal film, and in particular, it simultaneously produces a plurality of magnetic garnet single crystal films having a thickness of 30 μm or more by a liquid phase epitaxial method (hereinafter referred to as “LPE method”). To do
The present invention relates to a method for manufacturing a magnetic garnet single crystal film.

[0002]

2. Description of the Related Art Currently, magnetic garnet single crystal films are
Manufactured by the E method, an optical isolator, a magnetostatic wave device,
It is used in microwave devices and magneto-optical devices.
In the production of a magnetic garnet single crystal film by the LPE method, the raw material melt obtained by melting the components of the magnetic garnet single crystal film is made into a supersaturated state, and a non-magnetic garnet substrate is brought into contact with it to form a magnetic garnet single crystal film on the non-magnetic garnet substrate. After the growth, the non-magnetic garnet substrate is separated from the raw material melt. The thickness of the magnetic garnet single crystal film to be produced is selected in the range of several μm to several hundreds μm depending on its application.
A magnetic garnet single crystal film with a thickness of 200 μm to 500 μm is used for optical isolators and magneto-optical elements. In the conventional technique, a magnetic garnet single crystal film is manufactured by mainly contacting non-magnetic garnet substrates one by one with a raw material melt, but a magnetic garnet single crystal film having a relatively thin film thickness of around 10 μm. In order to reduce the manufacturing cost,
It is also possible to simultaneously produce multiple magnetic garnet single crystal films by arranging multiple substrates in parallel in the vertical direction and contacting them with the raw material melt (Journal of Cryst).
al Growth 31 (1975) 358-365). Here, no consideration has been given to the distance between the substrates when simultaneously producing a plurality of magnetic garnet single crystal films.

[0003]

In the prior art, for example, when two magnetic garnet single crystal films are simultaneously manufactured, a magnetic garnet single crystal film is formed on the lower surface of the upper substrate and the upper surface of the lower substrate. There was in-plane variation in thickness. Such an in-plane variation of the film thickness is further increased when the thickness of the manufactured magnetic garnet single crystal film is 30 μm or more, because the variation in the concentration of the magnetic garnet single crystal component in the raw material melt is drastically increased. It became noticeable. Further, when the thickness of the magnetic garnet single crystal film is about 10 μm, which is relatively small, this is not a big problem, but the thickness 3 used for the microwave element, the optical isolator, and the magneto-optical element is 3
In the case of a magnetic garnet single crystal film having a thickness of 0 μm or more, the yield is deteriorated because the substrate is cracked or the quality of the magnetic garnet single crystal film is deteriorated due to the stress caused by the imbalance of the film thickness on the front and back surfaces during processing. There was a problem of doing. Here, the in-plane variation of the film thickness may be within a range in which cracks do not occur in the substrate during processing, but if the CV value (standard deviation / average value) is 2% or less, the adjustment process during device fabrication Is more preferable because it can be greatly simplified.

Therefore, the main object of the present invention is to provide a film thickness of 30 μm capable of preventing the cracking of the substrate during processing.
It is an object of the present invention to provide a method for producing a magnetic garnet single crystal film capable of producing a plurality of magnetic garnet single crystal films at the same time.

[0005]

A method of manufacturing a magnetic garnet single crystal film according to the present invention comprises a plurality of magnetic garnets having a film thickness of 30 μm or more formed by an epitaxial method on a plurality of substrates which are arranged in parallel at intervals in the thickness direction. A method of manufacturing a magnetic garnet single crystal film for simultaneously manufacturing a single crystal film, wherein a substrate diameter is D (mm) and a substrate interval is d.
(Mm) and the thickness of the magnetic garnet single crystal film produced is t (μm), d ≧ (D / 10) +0.0
A method for producing a magnetic garnet single crystal film satisfying 25t-0.75. In the method of manufacturing a magnetic garnet single crystal film according to the present invention, d ≧ (D / 10) + 0.5t +
It is more preferable to satisfy 26.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the invention with reference to the drawings.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION (Example 1) Iron yttrium garnet (Y ₃ Fe ₅ O ₁₂ ) by the LPE method:
G ”. ) A gadolinium gallium garnet (Gd ₃ ) having a diameter of 75.6 mm and a thickness of 0.5 mm is formed on the single crystal film.
Ga ₅ O ₁₂ : hereinafter referred to as “GGG”. ) Fabricated on a substrate. In this case, first, two GGG substrates were attached to and held by a holder at 10 mm intervals. While maintaining this holding state, the two GGG substrates were rotated at 100 rpm and were lowered at a lowering speed of 150 mm / min until the lower GGG substrate reached about 10 mm above the liquid surface of the raw material melt. 2 at this position
After preheating one GGG substrate sufficiently, while rotating the two GGG substrates at 50 rpm, lower it at a lowering speed of 50 mm / min until the upper GGG substrate reaches 40 mm below the liquid surface of the raw material melt, and supercool it. The melted raw material was brought into contact with the raw material melt. After that, in the same manner, the two GGG substrates are 50 rp.
Two YIG single crystal films were grown and manufactured for 240 minutes while rotating at m. The film thickness of the two produced YIG single crystal films was measured using an optical film thickness measuring device. The results are summarized in Table 1. In the first embodiment, the diameter of the GGG substrate is D (mm), and the gap between the GGG substrates is d (m).
m) and the thickness of the produced magnetic garnet single crystal film is t
(Μm), d ≧ (D / 10) + 0.025t
-0.75 is satisfied.

[0008]

[Table 1]

In Example 1, as shown in Table 1, in the two manufactured YIG single crystal films, the CV value of the film thickness was large between the lower surface of the upper GGG substrate and the upper surface of the lower GGG substrate. Was 0.5 m from these YIG single crystal films.
When a chip measuring m × 0.5 mm × 0.2 mm was produced, no crack was generated on the GGG substrate during processing.

Comparative Example 1 A YIG single crystal film was manufactured by the LPE method on a GGG substrate having a diameter of 75.6 mm and a thickness of 0.5 mm. In this case, first, two GGG substrates were attached to and held by a holder at 5 mm intervals. While maintaining this holding state, the two GGG substrates were rotated at 100 rpm and were lowered at a lowering speed of 150 mm / min until the lower GGG substrate reached about 10 mm above the liquid surface of the raw material melt. After sufficiently preheating the two GGG substrates at this position, the two GGG substrates are rotated at 50 rpm while the descending speed is 5
At 0 mm / min, the upper GGG substrate is 40 below the surface of the raw material melt.
It was lowered to mm and brought into contact with the raw material melt in the supercooled state. Then, in the same manner, while rotating the two GGG substrates at 50 rpm, 240 minutes, two YI
A G single crystal film was grown and manufactured. Two manufactured YIG
The measurement results of the thickness of the single crystal film are summarized in Table 2. In Comparative Example 1, the diameter of the GGG substrate is D (mm), and
When the gap between the G substrates is d (mm) and the film thickness of the manufactured magnetic garnet single crystal film is t (μm), d ≧ (D /
10) + 0.025t-0.75 is not satisfied.

[0011]

[Table 2]

In Comparative Example 1, as shown in Table 2, in the two manufactured YIG single crystal films, the CV value of the film thickness was extremely high between the lower surface of the upper GGG substrate and the upper surface of the lower GGG substrate. It is a large value, 0.5 than those of these YIG single crystal films.
An attempt was made to manufacture a chip having a size of mm × 0.5 mm × 0.2 mm, but the GGG substrate was cracked during processing, which made it difficult to manufacture.

(Example 2) A YIG single crystal film was produced by the LPE method on a GGG substrate having a diameter of 75.6 mm and a thickness of 0.5 mm. In this case, first, two GGG substrates were attached to and held by a holder at intervals of 60 mm. While maintaining this holding state, the two GGG substrates were rotated at 100 rpm and were lowered at a lowering speed of 150 mm / min until the lower GGG substrate reached about 10 mm above the liquid surface of the raw material melt.
After preheating the two GGG substrates sufficiently at this position, the two GGG substrates are rotated at 50 rpm, and the upper GGG substrate is at a descending speed of 50 mm / min, below the surface of the raw material melt.
It was lowered to 0 mm and brought into contact with the raw material melt in a supercooled state. Then, similarly, the two GGG substrates are rotated at 50 rpm for 240 minutes, and the two Y substrates are rotated.
An IG single crystal film was grown and manufactured. 2 YIs manufactured
Table 3 shows the measurement results of the film thickness of the G single crystal film. In addition,
In the second embodiment, the diameter of the GGG substrate is D (mm), and G
When the distance between the GG substrates is d (mm) and the thickness of the YIG single crystal film to be manufactured is t (μm), d ≧ (D / 1
0) + 0.5t + 26 is satisfied.

[0014]

[Table 3]

In Example 2, as shown in Table 3, a uniform YIG single crystal film having a film thickness of approximately 50 μm and a CV value of 2% or less was manufactured on both surfaces of the upper and lower GGG substrates. We were able to. Further, when chips of 0.5 mm × 0.5 mm × 0.2 mm were produced from these YIG single crystal films, no crack was generated on the GGG substrate during processing.

(Embodiment 3) First, YIG single crystal films of various thicknesses were formed on a GGG substrate by the same method as in Embodiments 1 and 2 using a GGG substrate having a diameter of 75.6 mm and a thickness of 0.5 mm. When the YIG single crystal film having a film thickness smaller than 30 μm was manufactured by changing the distance, cracks did not occur in the GGG substrate during processing even if the distance between the GGG substrates was narrowed. Therefore, the thickness of the YIG single crystal film to be manufactured is set to 30 μm,
When the diameter of the GGG substrate was changed and the relationship between the diameter of the GGG substrate and the gap between the GGG substrates in which cracks did not occur in the GGG substrate during processing (minimum substrate gap) was found.
The graph shown in was obtained. Similarly, when the thickness of the YIG single crystal film to be manufactured is set to 70 μm and the diameter of the GGG substrate is changed, the diameter of the GGG substrate and the gap between the GGG substrates in which no crack is generated in the GGG substrate during processing ( When the relationship with the minimum substrate spacing) was investigated, the graph shown in FIG. 2 was obtained. From the above, the diameter of the GGG substrate is D (mm)
When the gap between the GGG substrates is d (mm) and the thickness of the magnetic garnet single crystal film produced is t (μm), d ≧ (D / 10) + 0.025t−0.75 is satisfied. It has been found that the GGG substrate can be prevented from cracking during processing.

(Embodiment 4) Diameter 75.6 mm and thickness 0.
In the same manner as in Examples 1 and 2 using a 5 mm GGG substrate, Y with various film thicknesses was changed while changing the gap between the GGG substrates.
A graph of FIG. 3 shows the relationship between the gap between the GGG substrates and the CV value of the film thickness on the lower surface of the upper GGG substrate when the IG single crystal film is manufactured. In this case, the gap between the GGG substrates is 2.
When trying to manufacture a YIG single crystal film having a thickness of 5 mm and a film thickness of 50 μm or more, the GGG substrate was cracked during cooling due to the stress caused by the variation in the film thickness. Further, in this case, when the gap between the GGG substrates was set to be smaller than 10 mm, the GGG substrates were cracked during processing except for the YIG single crystal film having a film thickness of 10 μm. 4 is a graph showing the relationship between the film thickness and the gap between the GGG substrates, which is necessary for the CV value of the film thickness to be 2% or less from the graph shown in FIG.
It became a straight line as shown in the graph. Similarly, GG
When the diameter of the G substrate was changed to 52 mm and 100 mm, the relationship between the film thickness and the gap between the GGG substrates necessary for the CV value of the film thickness to be 2% or less was plotted. It became a straight line as shown in the graph of FIG. From the graphs shown in FIG. 4, FIG. 5 and FIG.
The diameter of the substrate is D (mm), and the gap between the GGG substrates is d.
(Mm) and the thickness of the YIG single crystal film produced is t
(Μm), d ≧ (D / 10) + 0.5t + 2
It was found that a YIG single crystal film having a uniform film thickness can be manufactured if 6 is satisfied.

In the above embodiment, two GGG substrates are used to manufacture the YIG single crystal film, but in the present invention, substrates other than the GGG substrate may be used, and three or more substrates may be used. Substrate may be used, and YIG
A magnetic garnet single crystal film other than the single crystal film may be manufactured.

[0019]

According to the method of manufacturing a magnetic garnet single crystal film according to the present invention, a plurality of magnetic garnet single crystal films having a film thickness of 30 μm or more capable of preventing the substrate from cracking during processing can be manufactured simultaneously. . In the method for producing a magnetic garnet single crystal film according to the present invention, the diameter of the substrate is D (mm), the distance between the substrates is d (mm),
The thickness of the magnetic garnet single crystal film produced is t (μm)
Then, if d ≧ (D / 10) + 0.5t + 26 is satisfied, a magnetic garnet single crystal film having a uniform film thickness can be manufactured.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the diameter of a GGG substrate and the minimum substrate spacing at which cracks do not occur when the thickness of a YIG single crystal film to be manufactured is 30 μm.

FIG. 2 is a graph showing the relationship between the diameter of a GGG substrate and the minimum substrate distance where cracks do not occur when the thickness of a YIG single crystal film to be manufactured is 70 μm.

FIG. 3 is a graph showing a relationship between a gap between GGG substrates and a CV value of a film thickness on a lower surface of an upper GGG substrate when YIG single crystal films having various thicknesses are manufactured.

FIG. 4 shows the film thickness and the CV of the film thickness on the lower surface of the upper GGG substrate when the diameter of the GGG substrate is 75.6 mm.
It is a graph which shows the relationship with the space | interval of the GGG board | substrate whose value becomes 2% or less.

FIG. 5 shows the film thickness and the CV value of the film thickness on the lower surface of the upper GGG substrate when the diameter of the GGG substrate is 52 mm.
It is a graph which shows the relationship with the space | interval of the GGG board which becomes below%.

FIG. 6 shows the case where the diameter of the GGG substrate is 100 mm,
It is a graph which shows the relationship between the film thickness on the lower surface of the upper GGG board | substrate, and the space | interval of the GGG board | substrate whose CV value of film thickness becomes 2% or less.

Claims (2)

[Claims] 1. A method for producing a magnetic garnet single crystal film, wherein a plurality of magnetic garnet single crystal films having a film thickness of 30 μm or more are simultaneously produced on a plurality of substrates arranged in parallel at intervals in the thickness direction by an epitaxial method. , The diameter of the substrate is D (mm), and the distance between the substrates is d.
(Mm) and the thickness of the magnetic garnet single crystal film produced is t (μm), d ≧ (D / 10) +0.0
A method for producing a magnetic garnet single crystal film, which satisfies 25t-0.75. 2. The method for producing a magnetic garnet single crystal film according to claim 1, wherein d ≧ (D / 10) + 0.5t + 26 is satisfied.