JP2612921B2 - Method for producing oxide garnet single crystal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an oxide garnet single crystal, and more particularly to an oxide garnet single crystal epitaxy useful as a bubble memory, a magneto-optical element, or a microwave element. The present invention relates to a method for producing a film.

(Prior Art) The production of oxide garnet single crystals has been conventionally performed by a liquid phase epitaxy method. This is performed using a vertical growth reactor for growing garnet epitaxy film,
The vertical growth furnace 3, as shown in FIG. 1 for example Y ₂ O _3, F
PbO and e ₂ O ₃ as a flux, a built-in barnardia japonica 1 containing melt dissolved with B ₂ O _3, it is sufficient to that to heat the heating unit 2 to a predetermined temperature, the operation For example, a holder 5 is attached to the tip of a rod-like gripper 4 made of alumina or the like, and a substrate 6 on which a garnet is to be grown is arranged in a shelf on the holder 5 and has a composition of Y ₂ O ₃ and Fe ₂ O _3. Is inserted into the crucible 1 containing the melt 7 and then pulled up after a predetermined time.

(Problems to be Solved) However, in this conventional method, after an epitaxial film is formed on the substrate 6, cracks often occur in the substrate 6 in the step of taking out the substrate 6 from the crucible 1. There is a problem that it is difficult to take out the crystal growth film.

(Means for Solving the Problems) The present invention relates to a method for producing an oxide garnet single crystal that has solved such disadvantages, and this method uses a liquid phase epitaxy method to convert a substrate held in a holder into a melt. A method for producing an oxide garnet single crystal, which comprises inserting and growing an oxide garnet single crystal on a substrate, wherein a heat shield plate is provided below the substrate.

That is, the present inventors have conducted various studies on a method for preventing the occurrence of cracks in a substrate during the production of an oxide garnet single crystal by a conventionally known method. As a result, the occurrence of this clutch was fixed to a holder for epitaxial growth. It is presumed that a difference in temperature occurs between the upper and lower surfaces of the substrate that has been heated by radiant heat from the melt in the crucible that exists below the substrate, which is presumed to cause cracks, and to prevent this, The present inventors have found that a heat shield plate for blocking radiant heat from the melt may be provided below the substrate. When the heat shield plate is attached, it has been confirmed that the occurrence of cracks in the substrate can be prevented, and the present invention has been completed.

(Function) In the present invention, an oxide garnet single crystal film is formed on a substrate by a liquid phase epitaxy method. The production of an oxide garnet single crystal by the epitaxy method may be performed by a known method. Therefore, this is the first
The vertical growth furnace 3 may be made of, for example, a tantalum wire heater, and the crucible 1 may be made of platinum or the like. Since the melt contained in this crucible forms oxide garnet, rare earth metal oxides such as Y ₂ O ₃ , Sm ₂ O ₃ , Lu ₂
O ₃ , Tb ₂ O ₃ etc. and iron oxides such as Fe ₂ O ₃ or CaO, GeO
₂ , a non-magnetic metal oxide such as Ga ₂ O _{3, which} may be melted at 1,000 to 1,100 ° C. together with PbO and B ₂ O ₃ as fluxes. Also,
Since the substrate 6 used here is epitaxially grown, gadolinium gallium garnet (GGG), samarium gallium garnet (SGG), neodymium, etc. having the same crystal structure as the oxide garnet single crystal film.
It may be a wafer of 2 to 4 inches made of gallium garnet (NGG) or the like. To manufacture this oxide garnet single crystal, the substrate 6 is placed on a holder 5 made of platinum, for example, in a shelf shape, and a bar-shaped holding tool 4 is attached thereto. Then, the substrate is immersed in 1 and rotated or inverted for 1 to 10 minutes, and then pulled up.

In the method of the present invention, when growing an oxide garnet single crystal using the vertical growth furnace 3 shown in FIG. 1, as shown in FIG. 2 below the substrate 7 placed on the holder 5. The heat shield plate 8 is disposed on the substrate 7 so that the substrate 7 is not heated by the radiant heat from the melt 6. This shield plate 8 has a high radiant heat from the melt 6 of about 1,000 ° C. In addition, since PbO having high corrosiveness is used as a flux, it is necessary to be made of a heat-resistant and corrosion-resistant material such as platinum, a platinum-gold alloy, or the like.

The method of the present invention is characterized in that this heat shield plate is attached, but according to this, since the substrate 6 is not exposed to the radiant heat from the melt 7, the temperature difference between the upper and lower surfaces of the substrate 6 is increased. Therefore, even if an oxide garnet single crystal is grown on the substrate 6 by the epitaxial method and then taken out of the holder 5, no crack is generated in the oxide garnet single crystal. The advantage is that crystals can be easily obtained with good yield.

(Example) Next, an example of the present invention will be described.

Example 4 Four 4 inch Φ gadolinium gallium garnet (GGG) wafers were placed in a 4 inch Φ platinum holder as shown in FIG. A platinum disk was installed.

Next, the platinum 150mm
Y ₂ O ₃ 3,451g during crucible _{Φ × 300mmH, Fe 2 O 3} 1,880.5g
Was charged together with 2,030.6 g of PbO as a flux and 270.6 g of B ₂ O ₃ , and was heated to 1,100 ° C. to be melted. Then, the holder was inserted into the holder while rotating it at 45 rpm using an alumina rod, and then 8 minutes. Pull up afterwards, cool from holder
When the GGG wafer was taken out, Y ₃ Fe ₅ O ₁₂
A wafer on which an epitaxial film was formed was obtained, and this was repeated 75 times to produce 300 epitaxial film GGG wafers. The crack generation rate was 2.0%.

However, for comparison, the platinum disk shown in FIG. 2 was not used, and only four GGG wafers were installed in a shelf as shown in FIG. In this case, a crack generation rate was as high as 16.2% when an epitaxy film GGG wafer was prepared.

(Effects of the Invention) In the present invention, when a single crystal oxide garnet film is formed on a substrate by a known epitaxy method, a heat shield plate is provided below the substrate. Since the radiant heat from the melt is blocked by this heat shield plate, there is no temperature difference between the upper and lower surfaces of the substrate, so that cracks on the substrate hardly occur. For example, up to 16.2% in the conventional method Since the crack occurrence rate that has been reached is reduced to 2% or less, the production yield is improved, and the advantage that the productivity can be improved by as much as 30% is provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a vertical growth furnace by an epitaxial method used in the method of the present invention, FIG. 2 is a longitudinal sectional view showing the installation of a substrate on a holder by the method of the present invention, and FIG. It is a longitudinal section showing installation of a substrate in a holder by a conventional method. DESCRIPTION OF SYMBOLS 1 ... Crucible, 2 ... Heater, 3 ... Vertical growth furnace, 4 ... Bar-shaped holding tool, 5 ... Holder, 6 ... Melt, 7 ... Substrate, 8 ... Heat shield plate.

Claims (1)

(57) [Claims] 1. A method for producing an oxide garnet single crystal, comprising: inserting a substrate held in a holder into a melt by liquid phase epitaxy to grow an oxide garnet single crystal on the substrate. A method for producing an oxide garnet single crystal, comprising providing a heat shield plate below.