JPS60195089A - Method for liquid-phase epitaxial growth and protecting substrate with use thereof - Google Patents

Abstract

PURPOSE:To produce a high-quality liquid-phase epitaxial growth layer, at a low cost, by covering the cavity for holding the growth substrate with a protection substrate having a frame-shaped thin film resistant to the etchant of the main body, and heating the growth substrate, etc. CONSTITUTION:The growth substrate 4 is placed in the cavity 3 of the substrate table 1, and the cavity 3 is covered with the protection substrate 5 composed of the protection substrate main body 13 made of a material containing an element dissipating from said growth substrate 4 by heating and the frame-shaped thin film 14 made of a material resistant to the etchant of the main body. The sliding member 6 having a hole 10 holding the molten liquid 12 of the raw material of the growing layer is placed on the protection substrate 5. The frowth substrate 4 is heated at a prescribed temperature, the sliding member 6 is transferred along the direction of the arrow, the protection substrate 5 is removed from the cavity 4, and the molten llquid 12 is made to contact with the growth substrate 4 to form a liquid-phase epitaxial growth layer. Since the protection substrate 5 has said thin film 14 on the surface contacting with the surface of the substrate table 1 in the etching and mending of the substrate, good flatness of the substrate can be maintained to prevent the damage of the growth substrate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid phase epitaxial growth method for forming a liquid phase epitaxial growth layer on a growth substrate, and to improvements in a protective substrate used therein.

Background of the Invention As a liquid phase epitaxial growth method for forming a liquid phase epitaxial growth layer on a growth substrate, the following method has been proposed.

That is, a flat surface 2 as shown in FIG.
A substrate arranging table 1 is used which has a substrate arranging recess 3 formed from the surface 2 side thereof and in which a growth substrate 4 on which a liquid phase epitaxial growth layer is to be formed is arranged.

Further, a protective substrate 5 is used, which is placed on the surface 2 of the substrate placement table 1, covering the substrate placement recess 3. In this case, the protective equipment plate 5 is made of a material containing an element that dissociates from the growth substrate 4 and evaporates to the outside when the growth substrate 4 is heated.

Further, a melt holding section 9 having a flat lower surface 8 that is in sliding contact with the surface 2 of the substrate placement table 1 and holding a melt 12 of the material that will become the liquid phase epitaxial growth layer is attached to the surface 2 of the substrate placement table 1. A recess 1 for arranging a protective substrate 5 in which a protective substrate 5 is disposed, having a hole 10 penetrating from the soil surface 7 to the lower surface 8 and formed from the lower surface 8 side.
1 is used.

The next step is then carried out using the above-mentioned substrate placement table 1, protective substrate 5, and sliding body 6.

That is, first, as shown in FIG.
A growth substrate 4 on which a liquid phase epitaxial growth layer is to be formed is placed in the substrate placement recess 3, and a protective substrate 5 is placed on the surface 2 of the substrate placement table 1.
The sliding body 6 is placed over the substrate placement recess 3 of the substrate placement table 1, and is placed in the protective substrate placement recess 11. The protective substrate 5 is placed on the melt holding portion 9 of the sliding body 6.
A material that will become a liquid phase epitaxial growth layer is housed in the 1c
In this state, a step is taken in which the growth substrate 3 is heated and the material that will become the liquid phase epitaxial growth layer housed in the melt holding section 9 is heated so that the melt 12 is obtained.

Next, by sliding the slider 6 as shown by the arrow, the substrate placement recess 3 in which the growth substrate 4 is placed is not covered by the protective substrate 5, Then, the melt 12 held in the melt holding part 9 is brought into contact with the growth substrate 4 placed in the substrate placement recess 3, so that the melt 12 is placed on the growth substrate 4 in the melt holding part. A step is taken to form a liquid phase epitaxial growth layer made of the material of the retained melt.

The above is a conventionally proposed liquid phase epitaxial growth method for forming a liquid phase epitaxial growth layer on a growth substrate.

According to such a liquid phase epitaxial growth method, the growth substrate 4 placed in the substrate placement recess 3 of the substrate placement table 1 and the liquid phase epitaxial growth layer accommodated in the melt holding part 9 are formed. In the step of heating the material, the growth substrate 4 and the material that will become the liquid phase epitaxial growth layer are heated in the substrate placement recess 3 where the growth substrate 4 is placed.
Since the process is performed while the growth substrate 4 is covered with the protective substrate 5, even if the elements constituting the growth substrate 4 dissociate and evaporate from the growth substrate 4 when it is heated, The evaporated vapor is confined within the substrate placement recess 3 and is not unnecessarily evaporated to the outside. Furthermore, when the protective substrate 5 is heated, the elements that dissociate and evaporate from the growth substrate 4 that constitutes the protective substrate 5 also dissociate and evaporate from the substrate placement recess 3 side, And it is also confined within the substrate placement recess.

For this reason, in the case of the conventional liquid phase epitaxial growth method described above, the growth substrate 4 placed in the recess 3 of the substrate placement table 1 and the liquid phase accommodated in the melt holding part 9 Even if the constituent elements dissociate and evaporate from the growth substrate 4 in the step of heating the material that will become the epitaxial growth layer, the amount thereof is extremely small. It has the characteristic of being virtually undamaged.

Furthermore, in the process of forming a liquid phase epitaxial growth layer on the growth substrate 4, it is possible to easily form a liquid phase epitaxial growth layer with desired characteristics. It has the following characteristics.

However, in the case of the conventional liquid phase epitaxial growth method described above, as described above, the growth substrate 4 placed in the substrate placement recess 3 of the substrate placement table 1 and the melt holding part 9
In the step of heating the material 1 which will become the liquid phase epitaxial growth layer housed in the liquid-phase epitaxial growth layer, the growth substrate 4 and the material 1 which will become the liquid-phase epitaxial cell growth layer housed in the liquid holding part 9 are heated. Heating is performed with the substrate placement recess 3 in which the growth substrate 4 is placed covered by the protective substrate 5, but there is no space between the substrate placement table 1 and the protective substrate 5. ,Up)! It is undeniable that there is a slight gap through which the evaporated vapor trapped in the depressed substrate placement recess 3 passes. Therefore, the evaporated vapor of the above-mentioned elements trapped in the substrate placement recess 3 passes through the slider 6 or the slight gap between the substrate placement table 1 and the slider 6. Since the element evaporates to the outside, the protective substrate 5 is damaged from its surface side, and therefore, the evaporation M of the above-mentioned elements from the protective substrate 5 into the recess 3 is reduced.

For this reason, the protective substrate 5 once used in the liquid phase epitaxial growth method described above is damaged from the surface side as described above, so the protective substrate 5 is heated. Also, the amount of evaporation of the above-mentioned elements from the protective substrate 5 is reduced. Therefore, the protective substrate 5 once used in the liquid phase epitaxial growth method described above can be used many times in the liquid phase bitaxial growth method described above. First, by repeating the liquid phase epitaxial growth method described above many times, it is not possible to inexpensively manufacture a large number of growth substrates 4 on which liquid phase epitaxial growth layers are formed.

Moreover, for this reason, conventionally, the protective substrate 5 once used by the above-mentioned liquid phase epitaxial growth method is
Liquid phase epitaxy mentioned above! In order to repeatedly use the epitaxial growth method many times, each time the protective substrate 5 is used once or a small number of times in the above-mentioned liquid phase epitaxial growth method, the protective substrate 5 is etched. It has been proposed to remove ii and I(u) from the surface of the substrate 5.

However, in this way, protective 1. When etching is performed on the I5 plate 5, the flatness of the lower surface of the protective substrate 5 is greatly degraded from the side surface side, as shown by the curve AN in FIG. In addition, in FIG. 2, the curve AO indicates the flatness of the lower surface of the protective substrate 5 when the lower surface of the protective substrate 5 remains surface-polished, and the curve AI
1 shows the flatness of the lower surface of the protective substrate 5 when the protective substrate 5 is used for the first time, in which the lower surface of the protective substrate 5 is polished and then lightly etched.

Therefore, the protective substrate 5 is etched and used in the liquid phase epitaxial growth method described above, and the protective substrate 5 is placed on the surface 2 of the substrate placement table 1 in the substrate placement groove of the substrate placement table 1. When disposed to cover the substrate 3, a relatively large gap is locally formed between the substrate placement table 1 and the protective substrate 5, so that the growth substrate 4 and the material that will become the liquid phase epitaxial growth layer are Even if a large amount of the above-mentioned elements are evaporated from the protective substrate 5 during the heating step, the growth substrate 4 is damaged because it evaporates outside the substrate placement recess 3.

Therefore, even if the protective substrate 5 is used after being etched, it has the disadvantage that the number of times it can be used is limited.

By the disclosure of the present invention, the present invention seeks to propose a novel liquid phase epitaxial growth method that does not have the above-mentioned drawbacks.

The present invention also aims to propose a new protective substrate for use in a new liquid phase epitaxial growth method that does not have the above-mentioned drawbacks.

According to the liquid phase epitaxial growth method according to the first invention of the present application, as in the case of the conventional liquid phase epitaxial growth method described above with reference to FIG. A process of heating the growth substrate and the material that will become the liquid-phase epitaxial growth layer using a base, a protective substrate, and a sliding body, and a step of heating the growth substrate and the material that will become the liquid phase epitaxial growth layer, and applying the liquid onto the growth substrate by sliding the sliding body. and a step of forming a phase epitaxial growth layer.

However, in the liquid phase epitaxial growth method according to the first invention of the present application, in the step of heating the growth substrate and the material that will become the liquid phase evictional growth layer, the substrate placement table on which the growth substrate is placed is heated. A control board covering the board placement recess has a flat bottom surface,
The protective substrate body is made of a material containing an element that dissociates from the growth substrate and evaporates to the outside when the growth substrate is heated, and has a flat surface and is resistant to etchants. A protective substrate having a thin film formed in a frame shape on the lower surface of a cold insulation substrate body made of a material having , the growth substrate and The material that will become the liquid phase epitaxial growth layer is heated.

Therefore, according to the liquid phase epitaxial growth method according to the invention of No. 1 of the present application, in order to repeatedly use the protective substrate that has been used in the liquid phase epitaxial growth method many times, the protective substrate is Even if the damage to the surface of the protective substrate main body of the protective substrate is removed by etching the protective substrate main body and used in the liquid phase epitaxial growth method according to the present invention, the protective substrate once used can be protected. When etching the main body of the protective substrate, the thin film of the protective substrate is not etched, or if it is etched, it is only slightly etched. Since there is no large gap locally between the substrate placement table and the protective substrate, and therefore good adhesion is maintained between the substrate placement table and the protective substrate, it is possible to use the conventional liquid phase epitaxial growth method described above. It has the characteristic that it does not have the disadvantages of

Further, according to the protective substrate according to the second invention of the present application,
It has a flat lower surface and contains an element that dissociates from the growth substrate and evaporates to the outside when the growth substrate on which the liquid phase epitaxial growth layer is to be formed is heated by the liquid phase epitaxial growth method. A protective substrate main body made of material, and a frame-shaped frame formed on the lower surface of the 1tVA substrate main body, which has a flat surface and is made of a material that is highly resistant to etchants on the protective substrate main body. It has a structure including a thin film.

Therefore, according to the protective substrate according to the second invention of the present application, by using it in the liquid phase epitaxial growth method according to the first invention of the present application, , it has the characteristic of being able to effectively exhibit the above-mentioned characteristics.

Other features and benefits of the liquid phase epitaxial growth method according to the present invention and the protective substrate used therein will become clear from the following description with reference to FIG. 3 and the subsequent drawings.

PREFERRED EXAMPLE OF THE INVENTION FIG. 3 shows an example of a liquid phase epitaxial growth method according to the invention and an example of a protective substrate according to the invention used therein.

In FIG. 3, parts corresponding to those in FIG. 1 are given the same reference numerals and detailed explanations are omitted.

In the example of the liquid phase epitaxial growth method according to the present invention shown in FIG. 3, as in the case of the conventional liquid phase epitaxial growth method described above in FIG. A substrate placement stand 1 having a flat surface 2 and a substrate placement recess 3 formed from the surface 2 side and in which a growth substrate 4 on which a liquid phase epitaxial growth layer is to be formed is placed. use

Further, as in the case of FIG. 1, a protective substrate 5 is used, which is placed on the surface 2 of the board placement if table 1, covering the substrate placement recess 3. However, the protective substrate 5 has a flat lower surface, which is clearly seen with reference to FIG. A protective substrate main body 13 made of a material containing an element that evaporates, and a protective substrate 71 having a flat surface. It has a structure including a thin film 14 formed in a frame shape on the lower surface of the protective substrate main body 13, which is made of a material that is resistant to edgeants on the body.

In this case, the growth group Fi4 placed in the substrate placement recess 3 of the substrate placement table 1 is a -v group compound semiconductor, e.g.
In the case of np, the element that dissociates from the growth substrate 4 and transpires to the outside when the growth substrate 4 is heated is P of the V1/A element, so that the protective substrate main body 13 is, for example, It is made of the same III-v group compound as the growth substrate 4, such as InP.

Further, when the protective substrate body 13 is made of InP, the protective substrate body 13 is made of, for example, sulfuric acid (H+ SO+ ).
Since the thin film 14 can be etched using a mixture of hydrogen oxide (H+O+) and water (H+O) as an etchant, the thin film 14 can be made of silicon oxide (e.g., 5iO
), silicon nitride (for example, 3!IN+), etc.

Furthermore, in an example of the liquid phase epitaxial growth method according to the present invention, which is not shown in FIG. 3, it has a flat lower surface 8 similar to that shown in FIG. In addition, a melt holding part 9 that holds a melt 12 of the material that will become the liquid phase epitaxial growth layer is placed on the surface 2 of the substrate placement table 1.
A recess 11 for arranging the protective substrate 5 in which the protective substrate 5 is placed α, which is formed in cooperation with the upper surface 7 and has a hole 10 penetrating from the upper surface 7 to the lower surface 8, and which is formed from the lower surface 8 side.
A sliding body 6 having the following is used.

Therefore, the board arrangement stand 1 and the protective board 5 described above are
and the sliding body 6 to perform the next step.

That is, first, as shown in FIG. 3, as in the case of the conventional liquid phase epitaxial growth method described above in FIG.
A growth substrate 4 on which a liquid phase epitaxial growth layer is to be formed is placed in a substrate placement recess 3 of a board placement table 1,
Then, the protective substrate 5 is placed on the surface 2 of the substrate placement table 1, covering the substrate placement recess 3 in which the growth substrate 4 is placed, and the substrate of the substrate placement table 1. The sliding body 6 is placed on the recess 3 for placement, and the recess 1 for placement of the protective substrate is placed on the recess 3 for placement.
The protective substrate 5 is placed inside the sliding body 6.
The growth substrate 3 is heated with the material that will become the liquid phase epitaxial growth layer accommodated in the JJJ section 9, and the liquid phase epitaxial V layer accommodated in the melt holding section 9 is heated. The process involves heating the material that will become the growth layer so that a melt 12 of the material is obtained.

However, during this process, the protective substrate 5 is placed on the surface of the substrate placement table 1 so that only the flat surface of the film 14 of the protective substrate 5 is in contact with the surface 2 of the substrate placement table 1. The above-described growth substrate 4 and the material that will become the liquid phase epitaxial growth layer are heated in the state in which they are placed in the substrate.

Next, as in the case of the conventional liquid phase epitaxial growth method described above in FIG. 3 is not covered by the protective substrate 5, and the melt 12 held in the melt holding part 9 is removed.
is brought into contact with the growth substrate 4 placed in the substrate placement recess 3, thereby forming a liquid phase epitaxial growth layer made of the material of the melt held in the melt holding part on the growth substrate 4. The process of doing this is taken.

The above is an example of a liquid phase epitaxial growth method for forming a liquid phase epitaxial growth layer on a growth substrate according to the present invention.

According to such a liquid phase epitaxial growth method, as in the case of the conventional liquid phase epitaxial growth method described in FIG. In the process of heating the substrate 4 and the material that will become the liquid phase epitaxial growth layer 1 that is housed in the melt holding part 9, the heating of the growth substrate 4 and the material that will become the liquid phase epitaxial growth layer is Since the substrate placement recess 3 in which the substrate 4 is placed is covered with the protective substrate 5, the growth substrate 4 is heated and the growth substrate 4 is exposed to the Bar. Even if the constituent elements dissociate and evaporate, the evaporated vapor is confined within the substrate placement recess 3 and does not unnecessarily evaporate to the outside.

Furthermore, as each of the protective substrate bodies 13 of the protective substrate 5 is heated, the growth substrate 4 forming the protective substrate body 13 of the protective substrate 5 is dissociated and evaporated. The elements also dissociate and evaporate toward the substrate placement recess 3, and are also confined within the substrate placement recess 3.

Therefore, in the case of the liquid phase 1 bitaxial growth method according to the present invention described above, as in the case of the conventional liquid phase epitaxial growth method, the substrate placement recess 3 of the substrate placement table 1 is
In the process of heating the growth substrate 4 placed in the growth substrate 4 and the material that will become the liquid phase epitaxial growth layer housed in the melt holding part 9, the elements constituting the growth substrate 4 are dissociated. Even if it evaporates, the amount thereof is extremely small, so that the growth substrate 4 is hardly damaged in this heating process.

Furthermore, as in the case of the conventional liquid phase epitaxial growth method described above in FIG. It has the characteristic that it can be easily formed.

Furthermore, in the case of the liquid phase epitaxial growth method according to the present invention described above, similarly to the case of the conventional liquid phase epitaxial growth method described above, the growth substrate 4 is placed in the substrate placement recess 3 of the substrate placement table 1. In the process of heating the material that will become the liquid phase epitaxial growth layer accommodated in the melt holding part 9, between the substrate placement table 1 and the protective substrate 5,
Since it is undeniable that there is a slight gap through which the evaporated vapor trapped in the above-mentioned substrate placement recess 3 is formed,
As described above, even if the protective substrate main body 13 of the protective substrate 5 is damaged from the surface side, the protective substrate 5 once used in the liquid phase epitaxial growth method according to the present invention described above cannot be protected. Protective board body 1 of board 5
By etching 3, damage to the surface of the protective substrate main body 13 of the protective substrate 5 can be removed.

Even if the protective substrate 13 of the protective substrate 5 is etched in this way, the thin film 14 of the protective substrate 5 is not etched, or if it is etched, it is only slightly etched. However, the flatness of the lower surface of the thin film 14 does not substantially deteriorate from its original flatness, as shown by the curve AN in FIG. In addition, in FIG. 5, the bend Δ0 indicates that the protective substrate 5 is
Showing the flatness of the lower surface of the protective substrate 5 when the lower surface of the protective substrate main body 13 remains flat-polished,
Further, the curve AI shows the protective substrate 5 when the protective substrate 5 is used for the first time, in which the lower surface of the protective substrate main body 13 has been flat-polished and then lightly etched. It shows the flatness of the lower surface of

Therefore, the protective substrate 5 is used in the liquid phase epitaxial growth method according to the present invention described above by etching the protective substrate main body 13, and the surface 2 of the substrate placement table 1 is etched.
When the protective substrate 5 is disposed on top of the substrate placement table 1 to cover the substrate placement recess 3 of the substrate placement table 1, the substrate placement table 1 and the protection substrate 5
Maintains good adhesion between the two. Therefore, even if a large amount of the above-mentioned elements are evaporated from the protective substrate 5 in the process of heating the growth substrate 4 and the material that will become the liquid phase epitaxial growth layer as described above, it will not be possible to remove the evaporation of the above-mentioned elements from the substrate placement recess. Therefore, the growth substrate 4 is not damaged.

Therefore, when the protective U-plate 5 is used after being etched, it has the characteristic that restrictions on the number of times it can be used can be significantly relaxed.

Further, according to the protective substrate 5 shown in FIG. 4 used in the liquid phase epitaxial growth method according to the present invention described above,
In the liquid phase epitaxial growth method according to the present invention described above, the above-mentioned characteristics can be effectively exhibited.
It has the following characteristics.

In the above description, the liquid phase epitaxial growth method according to the present invention and the protective substrate used therein have only been described as examples. For example, the growth substrate may be
It is clear that the present invention can be applied not only to cases where the compound is a group compound, but also to a case where the compound is a 1-VIM compound.

Various other modifications and changes may be made without departing from the spirit of the invention.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional liquid phase epitaxial growth method and a protective substrate used therein. FIG. 2 shows a growth substrate placed in a substrate placement recess of a substrate placement table in a conventional liquid phase epitaxial growth method using a conventional protective substrate, and a material that will become a liquid phase epitaxial growth layer. In the process of heating the protective substrate placed on the surface of the placement table, covering the substrate placement recess, the adhesion between the substrate placement table and the protection substrate is checked. It is a figure which shows the flatness of the lower surface of a protective board|substrate for explanation. FIG. 3 is a cross-sectional view showing an example of the liquid phase epitaxial growth method according to the present invention and an example of a protective substrate used therein. FIG. 4 is a perspective view showing an example of a protective substrate used in the liquid phase epitaxial growth method according to the present invention. Figure 915 shows the growth substrate placed in the substrate placement recess of the substrate placement table and the material 1' that will become the liquid phase epitaxial growth layer in the liquid phase epitaxial growth method of the present invention using the protective substrate of the present invention. ! In the step of heating 1 with the protective substrate placed on the surface of the substrate placement table covering the substrate placement recess, the adhesion between the substrate placement table and the protection substrate is improved. FIG. 4 is a diagram that does not show the flatness of the lower surface of the protective substrate for explaining the situation. 1...... Board placement stand 2... Surface of board placement stand 1 3...
. . . Substrate placement recess 4 formed in the substrate placement table 1 . . . Growth substrate 5 on which a liquid phase epitaxial growth layer is to be formed. ...Protection substrate 6...Sliding body 7...Top surface 8 of sliding body 6...Bottom surface 9 of sliding body 6... ...... Melt holding section 10 ... Hole 11 constituting melt holding section 9 ... Protective substrate 5 is arranged Recess for arranging the protective substrate 12... Melt liquid 13 of the material that will become the liquid phase epitaxial growth layer... Protective substrate main body 14 of the protective substrate 5... ... Thin film applicant of protective substrate 5
Nippon Telegraph and Telephone Public Corporation Figure 1 Figure 2 Figure I [17 direction foot rest - 1◆ Figure 3 Figure 4 Figure 5 mouth

Claims (1)

[Claims] 1. Liquid phase epitaxy having a flat surface and formed from the surface side 1? a substrate placement table having a substrate placement recess in which a growth substrate on which a growth layer is to be formed is placed; A protective substrate is placed on the right side of the substrate placement table, and a melt holding portion that holds the melt of the material that will become the liquid phase epitaxial growth layer is placed on the right side of the substrate placement table and has a flat bottom surface that is in sliding contact with the surface of the substrate placement table. The above-mentioned device has a hole penetrating from the upper surface to the lower surface that cooperates with the surface to form a °C, and is accompanied by the protective substrate and holds the melt in the melt storage section. A liquid phase epitaxial growth layer is to be formed in the substrate placement recess of the substrate placement table using a sliding member that slides over the substrate placement recess on the surface of the substrate placement table. the protective substrate is placed on the surface of the substrate placement table, covering the substrate placement recess in which the growth substrate is placed, and The above-mentioned sliding body is arranged on the surface of the table, and with the material to be a liquid phase epitaxial growth layer accommodated in the melt holding part of the above-mentioned sliding body, the growth substrate is heated, and the melt holding part is heated. a step of heating the material that will become the liquid phase epitaxial growth layer housed in the liquid phase epitaxial growth layer so as to obtain a melt of the material; A liquid phase forming a liquid phase epitaxial growth layer of the melt material on the growth substrate by sliding the growth substrate placed in the placement recess so as to touch the growth substrate. In the epitaxial growth method, the protective substrate is made of U II, which has a flat lower surface and contains an element that dissociates from the growth substrate and evaporates to the outside when the growth substrate is heated. A protective substrate having a substrate body, and a thin film formed in a frame shape on the lower surface of the protective substrate body, which is made of a material that has a flat surface and is resistant to the etchant applied to the protective substrate body. In the step of heating the growth substrate and the material that will become the liquid phase epitaxial growth layer using a substrate, the protective substrate having the protective substrate main body and the thin film is heated so that the thin film is on the surface of the substrate placement table. The growth substrate and the liquid phase epitaxial growth layer are placed on the surface of the substrate placement table so as to be in contact with the substrate placement recess in which the growth substrate is placed. A liquid phase epitaxial growth method characterized by heating. 2. A material having a flat lower surface and containing an element that dissociates from the growth substrate and evaporates to the outside when the growth substrate on which the liquid phase epitaxial growth layer is to be formed is heated by the liquid phase epitaxial growth method. a protective substrate body having a flat surface and made of a material that is resistant to etchants on the protective substrate body;
A protective substrate for use in a liquid phase epitaxial growth method, comprising a thin film formed in a frame shape on the lower surface of the protective substrate main body.