JP2002184709A - Method and device for manufacturing thin semiconductor film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the forming rate of a thin semiconductor film and the uniformity of the grown thickness of the film. SOLUTION: In a method of manufacturing thin semiconductor film, thin semiconductor films are respectively grown on a plurality of substrates by dipping the substrates in a crucible filled up with a solution containing a semiconductor as a solute and moving the substrates in the solution. In the method, a flow of the solution is formed by moving the substrates in the directions which are deflected from the directions of normal lines to the central parts of the growing surfaces of the substrates by 5-87 deg.. Alternatively, the flow of the solution is formed without generating any substantial eddy current in the vicinities of the growing surfaces of the substrates by moving the substrates in the directions which are deflected from the normal lines by 93-175 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor thin film and an apparatus for manufacturing the same, and more particularly, to a semiconductor device,
The present invention relates to a liquid phase growth method or a liquid phase growth apparatus for producing a substrate that can be used for manufacturing a solar cell, an optical sensor, and the like.

[0002]

2. Description of the Related Art With global warming, there is a movement to regulate CO ₂ emissions worldwide. Therefore, when generating electricity, CO ₂
There is an interest in solar cell power generation that does not emit carbon dioxide.

[0003] A crystalline silicon solar cell using single crystal or polycrystalline Si has higher conversion efficiency and lower deterioration than an amorphous Si solar cell, but has a disadvantage of high manufacturing cost. In recent years, attempts have been made to reduce the thickness of a silicon crystal part to be a power generation layer in order to reduce costs.

[0004] Further, a crystalline Si solar cell thinned is
In order to withstand a certain amount of bending, it is possible to freely select the form of the product to some extent, such as by pasting it on a curved surface.

There is a liquid phase growth method as a method for forming single crystal Si or polycrystal Si to be a power generation layer of a solar cell. In this liquid phase growth method, compared to the vapor phase growth method, there is no waste of the raw material, and it is possible to obtain the thickness required for the power generation layer at low cost. Therefore, in order to improve mass productivity, there is a demand for a method and apparatus capable of processing a plurality of substrates at once in a liquid phase growth method.

As a specific example of a method for processing a plurality of substrates at once, Japanese Patent Laid-Open No. 1-72988 discloses a liquid phase growth method capable of processing a plurality of substrates. FIG. 32 shows a situation when this liquid phase growth method is performed. here,
101 is a substrate holder, 102 is a graphite container, 10
3 is a solution, 104 is a substrate.

FIG. 32A shows a situation in which the substrate 104 is disposed horizontally with respect to the solution surface.
FIG. 2 (b) shows a situation where the substrate 104 is arranged perpendicular to the solution surface. In this processing apparatus, a semiconductor layer is formed on a substrate by immersing a growth substrate 104 in a solution 103 stored in a graphite container 102.

Similarly, as a method for holding a plurality of substrates horizontally, Japanese Patent Application Laid-Open No. 5-330984 discloses a liquid phase growth method and a holder by a dipping method in which a plurality of substrates are arranged horizontally with respect to the solution surface. ing.

The configuration of this liquid phase growth apparatus is shown in FIGS. Here, 201 is a vertical cylindrical core tube, 20
Reference numeral 3 denotes a crucible, 204 denotes a heater, 103 denotes a solution, 104 denotes a growth substrate, 209 denotes a substrate holder, and 220 denotes a support rod. FIG. 34 shows a substrate holder. 210 is a mounting frame,
215 is a holding frame, 216 is a side leg, 216a is a long hole, 2
18b is an engagement pin, 217 is a bottom plate, and 218 is a spacer.

The growth substrate 10 supported by each spacer
4 can be stored in the holder. As is clear from FIG. 33, the growth substrate 104 is held horizontally with respect to the level of the solution 103.

As a method for vertically holding a plurality of substrates, Japanese Patent Application Laid-Open No. Hei 5-330979 discloses a liquid phase growth method using a dipping method and a holder. The configuration of this liquid phase growth apparatus is shown in FIG. Here, 310 is an electric furnace, 203 is a crucible, 103 is a solution, 3
Reference numeral 12 denotes a growth substrate that can be attached to a support rod, 315 denotes a support rod, 317 denotes a driving unit, 318 denotes a support base, and 319 denotes a lifter.

The growth substrate 312 is supported vertically with respect to the solution surface, and when the support rod 315 descends,
It is immersed in the solution 103 to start crystal growth.

[0013]

Problems to be Solved by the Invention
In the growth method disclosed in Japanese Unexamined Patent Application Publication No. Hei 5-330984, when the substrate is held horizontally with respect to the solution surface, the depth of the solution into which each substrate is immersed is different. There is a problem that the growth conditions between the substrates are not constant, and the thickness of the crystal film becomes uneven between the substrates.

On the other hand, in the method disclosed in Japanese Patent Application Laid-Open No. 5-330979, when the substrate is held perpendicular to the solution surface and rotated in the plane of the substrate, the film thickness variation between the substrates is changed. However, since the substrate itself is inserted into and fixed to the support rod, a hole must be formed, and that portion cannot be used. Further, since the substrate is rotated at a predetermined position about the center thereof, the supply of the solution to the substrate surface is also limited,
There was a problem that the film forming speed did not increase. In addition, with the conventional substrate arrangement, it is difficult to process many substrates in one process.

The present invention has been made based on the above circumstances, and the object is to improve the mass productivity by processing a plurality of substrates at a time by utilizing the features of the liquid phase growth method. Another object of the present invention is to provide a method and an apparatus capable of forming a high-quality semiconductor thin film having a uniform thickness of a crystal film.

[0016]

In order to achieve the above object, the present invention provides a method of immersing a plurality of substrates in a crucible filled with a solution containing a semiconductor as a solute and moving the substrates in the solution. In the method of manufacturing a semiconductor thin film, the semiconductor thin film is grown while being rotated. An angle between a normal direction at a center portion of a growth surface of the substrate and a moving direction of the substrate is 5 degrees or more and 87 degrees or less, and A method for manufacturing a semiconductor thin film, wherein the flow of the solution is formed by moving.

Further, the present invention relates to a method of manufacturing a semiconductor thin film, wherein a plurality of substrates are immersed in a crucible filled with a solution containing a semiconductor as a solute, and the semiconductor thin film is grown while moving the substrates in the solution. The angle between the normal direction at the center of the growth surface of the substrate and the direction of movement of the substrate is not less than 93 degrees and not more than 175 degrees, and the movement of the substrate substantially causes an eddy current near the growth surface. A method for producing a semiconductor thin film, characterized in that the flow of the solution is formed without generation.

Further, the present invention provides at least a crucible filled with a solution containing a semiconductor as a solute, a means for controlling the temperature of the crucible, and a substrate moving means for integrally moving a plurality of substrates in the solution. The angle between the normal direction at the center of each substrate and the moving direction of each substrate is 5 degrees or more.
And a substrate support means for supporting the semiconductor thin film at a temperature of 93 degrees or less or 175 degrees or less.

In the present invention, "the normal direction at the center of the growth surface of the substrate" means "a vector set in a direction away from the substrate along the normal of the growth surface of the substrate starting from the surface of the substrate." And the "movement direction of the substrate" means "the direction of a vector representing the motion of the center of gravity of the substrate".

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thickness or quality of a semiconductor film grown on a substrate varies between the substrates or exhibits a large distribution in the plane because a solute (such as silicon) is present in each part of the solution in the crucible. This is due to the difference in the concentration of the semiconductor) and the temperature in each part. As a countermeasure, it is conceivable to provide a stirring mechanism for the solution in the crucible and forcibly circulate the solution. However, it is not preferable because the apparatus becomes complicated and a space in the crucible is required. Therefore, the present invention provides a means for efficiently stirring a solution without providing a complicated mechanism and improving the uniformity of the solution.

That is, as shown in FIG. 24, a plurality of substrates are immersed in a crucible filled with a solution containing a semiconductor, and the respective substrates are integrally moved in a predetermined direction while a predetermined surface of the substrate (growth). When the semiconductor film is grown on the surface, the normal lines set at the center of the growth surface of each substrate are arranged so as to have a predetermined angle θ with respect to the moving direction of the substrate. Therefore, the solution flows along the surface of the substrate, and the solution moves from one area A of the substrate row including a plurality of substrates to the other area B of the substrate row. The flow of the solution circulating in the crucible can be formed by the flow from the region A to the region B across the substrate row, so that the solute concentration and the temperature in the solution become uniform.

However, if the angle θ is too small, as shown in FIG. 25, the flow of the solution is interrupted at the edge of the substrate, and does not cross the space between the substrates, so that a flow from the region A to the region B cannot be formed. In addition, the solution stays between the substrates, and the concentration of the solute tends to locally decrease at the center of the substrate. If the angle θ is smaller than 5 degrees, such a situation is likely to occur.

If the angle θ is too large, a smooth solute flow is formed along the substrate surface as shown in FIG. 26, but the force for forming the flow across the substrate is weak. A flow to the region B cannot be formed. Angle θ
Is larger than 87 degrees, such a situation is likely to occur.

Further, the angle θ can be made larger than 90 degrees. In this case, the growth surface faces the downstream side of the flow, but the flow is formed along the substrate, so that the semiconductor film can be grown. The condition for forming the flow from the region A to the region B can be basically considered in the same manner as when the angle θ is smaller than 90 degrees. Specifically, the range of the appropriate angle θ is 93 degrees or more and 175 degrees or less. However, since the growth surface faces the downstream side of the flow,
As shown in FIG. 27, a vortex may be generated on the downstream side of the substrate. The solution circulates in the vortex and the mixing of the solution inside and outside the vortex is restricted, so that the concentration of the solute decreases in the vortex and the thickness of the semiconductor film on the growth surface where the vortex was in contact Decrease. Therefore, in this case, the conditions such as the size and shape of the substrate and the flow speed are carefully selected.

In the present invention, the size and shape of the substrate
The condition such as the flow speed is a condition under which the movement of the substrate does not substantially generate a vortex near the growth surface. Here, “substantially no eddy current” does not mean that there is no eddy current but means that there is no eddy current that adversely affects semiconductor film growth.

Examples of the form of the movement of the substrate include linear reciprocating movement and rotational movement. The reciprocating movement of the substrate support table as shown in FIG. 1 and the reciprocating movement of the substrate as shown in FIG. It can be easily realized by a simple rotation of the substrate support.

Similarly, as a form of the movement of the substrate, an example of a spiral movement can be cited, and the movement can be realized by rotating and vertically moving a support for supporting the substrate.

Even when the angle θ is the same, the plane extending between the normal line set at the center of the growth surface and the moving direction of the substrate can be oriented in various directions. Typical examples include a case where the plane stands substantially vertically and a case where the plane lays substantially horizontal. Here, "almost" means
Error is tolerated, and the error is specifically ±
About once.

As described above, the direction of movement of the substrate is "the direction of the vector representing the movement of the center of gravity of the substrate". (It can also be called a vector of a trajectory in a very short time). As shown in FIG. 24, when the plane is substantially vertical and the angle θ is not less than 5 degrees and not more than 87 degrees, the solution forms a flow rising from the bottom of the crucible toward the surface of the solution.
As shown in FIG. 27, when the angle θ is 93 degrees or more and 175 degrees or less, a flow descending from the surface of the solution toward the bottom of the crucible is formed.

In order to arrange a plurality of substrates, the flow of the solution formed by each substrate is coordinated by moving the substrate integrally along a predetermined straight line or curve at the center of the growth surface of each substrate. Thus, the circulation of the solution in the crucible is effectively formed. In particular, when the substrate is in a circular motion, the substrate is arranged so as to be rotationally symmetric at predetermined intervals along a circumference around a predetermined straight line as a center axis, and the angle θ is set to an appropriate value, and the substrate is integrated. Rotating as circulates the solution more effectively. In FIG. 28, the four substrates are angled θ.
Is 45 degrees and the plane with the angle θ stands vertically,
This shows a case where the device is placed in a solution in a cylindrical crucible. Here, the distance between the outer peripheral end of the substrate and the inner side surface of the crucible is reduced within a range that does not hinder the movement of the substrate. The solution is scooped from the bottom to the surface by the rotating substrate, but the solution moves to the center of the crucible and descends near the center axis. The solution thus circulates throughout the crucible. FIG.
FIG. 9 shows a case where four substrates are placed in a solution placed in a cylindrical crucible with an angle θ of 45 degrees and a plane extending at an angle θ lying horizontally. Here, the distance between the lower end of the substrate and the bottom of the crucible is narrowed as long as the movement of the substrate is not hindered. In this case, the solution is extruded from the vicinity of the central axis of the crucible to the outer periphery, and the solution rises to the surface of the solution and then descends again near the central axis to circulate throughout the entire crucible.

When a large crucible capable of processing a large number of substrates in one batch is used, the substrates may be arranged so as to form a plurality of substrate rows along a plurality of circumferences sharing a central axis. For example, when a crucible having a diameter larger than the size of the substrate is used, the substrates may be arranged along a plurality of circumferences having different radii on the same plane with different sizes as shown in FIG. FIG. 9 is a plan view of the same device, and FIG. 10 is a side view of the same device. When a crucible deeper than the size of the substrate is used, as shown in FIG. 11, the substrates may be arranged along a plurality of circles having the same radius that are vertically shifted and not on the same plane. FIG. 12 is a plan view of the same apparatus, and FIG. 13 is a side view of the same apparatus.

However, in actual design, it may be difficult to arrange a large number of substrates so as to be rotationally symmetric with respect to the central axis. Further, in such a configuration, it may be difficult to mount the substrate on the support base or to remove the substrate from the support base. In such a case, it is preferable to first form a substrate group in which a plurality of substrates are arranged in parallel with each other, and to arrange the substrate group so as to be rotationally symmetric with respect to the central axis. With such a configuration, almost the same effect can be obtained with respect to the formation of the circulation of the solution. In this case as well, it is possible to arrange the substrate group along a plurality of circumferences. Specifically, FIG. 14 to FIG.
7 to 19 and FIGS. 20 to 22. 1 shows a perspective view, a side view, and a plan view of the same device.

In the method of manufacturing a semiconductor thin film according to the present invention, the solvent for forming the semiconductor-containing solution is I
Metals such as n, Sn, Al, Cu, and Ga can be used. The types of semiconductor thin films that can be manufactured include:
In addition to Si, GaAlAs, InGaAsP, GaP,
Compound semiconductors such as GaAsP and HgCdTe can be used.

In the method of manufacturing a semiconductor thin film of the present invention, the substrate material on which the semiconductor thin film is epitaxially grown may be a semiconductor substrate of Si, InP, GaP, CdTe, etc., a metal-grade Si substrate, a ceramic substrate or a SU.
A metal substrate such as an S substrate and a different material such as glass may be used. The substrate may have a rectangular shape in addition to a circular wafer.

Products manufactured by the method for manufacturing a semiconductor thin film of the present invention include a solar cell, an SOI substrate, an epitaxial wafer, and a light emitting diode.

[0036]

EXAMPLES Examples of the present invention will be specifically described.
Example 1 is an example of manufacturing a solar cell characterized in that a single-crystal silicon film is grown on a substrate while reciprocating a plurality of substrates in a solution in a straight line. Example 2 is an example of manufacturing an epitaxial wafer characterized by growing a single crystal silicon film while rotating a plurality of substrates in a solution. Example 3 is also an example of manufacturing an epitaxial wafer. Example 4 is an example of manufacturing a light emitting diode characterized in that a plurality of substrates are rotated in a solution and a compound semiconductor film is grown on the substrates. The present invention,
Not only the embodiments described below but also embodiments in any combination using these are included.

In the description of each embodiment of the present invention, the same or corresponding parts are denoted by the same reference numerals.

Example 1 In this example, a plurality of substrates supported so that the angle between the normal to the center of the substrate growth surface and the direction of movement was a predetermined value were linearly moved in the solution.
This is an example of manufacturing a solar cell characterized by growing a single crystal silicon film on a substrate, and FIG. 1 is a sectional view of a liquid phase growth apparatus according to an embodiment of the present invention. This liquid phase growth equipment
A mechanism for reciprocating the substrate in the horizontal direction is mounted to form a flow of the solution.

The liquid phase growth apparatus has a quartz reaction tube 7, in which a crucible 6 containing a metal solution 5 is provided. The crucible 6 is a quartz glass container. On the crucible 6, a substrate support bar introducing rod 4 equipped with a vertical mechanism for immersing the substrate in the metal solution 5 and a mechanism for moving the substrate left and right in the solution is arranged. A substrate support 1 capable of supporting five substrates is connected to the substrate support introduction rod 4 and supports the substrate such that a normal line on the growth surface forms an angle of 45 degrees from horizontal. Reference numeral 8 indicates a heater. In addition, the dissolution substrate as a means for dissolving the solute of the semiconductor can be mounted on the same support base as the growth substrate,
The solute is replenished by immersion in a metal solution prior to the growth of the semiconductor film.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the single crystal solar cell of Example 1. First, as shown in FIG. 2A, by anodizing the single-crystal Si substrate 11,
The porous Si layer 12 is formed. The method of forming a porous Si layer by this anodization method is well known (for example,
T. Unagami and M. Seki J. Electrochem. Soc 125, 8 (197
8)), concentrated hydrofluoric acid (4
9% HF). In addition, during anodization, hydrogen bubbles are generated from the Si wafer.
Add alcohol. In addition, a method of applying ultrasonic waves is also used for removing bubbles.

The thickness of the porous Si layer 12 was 10 μm. Through the steps described above, the porous Si layer 12 as shown in FIG. 2B was formed on the surface of the single crystal Si substrate 11. Then, the substrate was put into a liquid phase growth apparatus.

FIG. 3 shows the procedure of liquid phase growth on the substrate. First, the Si substrate for melting 20 is held on the substrate support 1, and the substrate support 1 is lowered using the up-down mechanism.
It is immersed for 20 minutes in a solution 5 (hereinafter, In + Ga solution) in which Ga is mixed at 10% by weight of In at 900 ° C.
Was dissolved to form a saturated state (see FIG. 3A).

Thereafter, the melting Si substrate 20 is set.
The substrate support 1 is lifted, and then a porous
The substrate 12 on which Si is formed is set on the substrate support 1, and I
Before immersion in the n + Ga solution 5, the atmosphere gas inlet (see FIG.
) And hydrogen annealing at 1020 ° C.
(See FIG. 3B). Then to 890 ° C
Then, the metal solution 5 and the substrate are cooled and the In + Ga solution 5
When Si becomes supersaturated, use the up / down mechanism
To lower the substrate support 1, and put the substrate in the In + Ga solution 5.
Immerse and reciprocate the substrate left and right at a rate of 10 times per minute.
The temperature of the metal solution is further reduced, and the
Approximately 2 μm thick p in 5 minutes⁺ The Si layer 13 was grown (see FIG.
3 (c)). During the growth, the In of the solution is replaced by the Si layer 13.
Is hardly incorporated into Ga, but Ga is incorporated in large amounts and p
Functions as a type dopant. p ⁺ Sheet of Si layer 13
The distribution of resistance was 100 ± 15Ω / □.

Next, after replacing the In + Ga solution 5 in the crucible with the In solution 22, the dissolving substrate was dissolved in the metal solution in the same manner as described above (see FIG. 3 (d)). ). At that time, the Si was melted at 1000 ° C., and when the Si was cooled to 990 ° C., the substrate was immersed in the In solution, and the substrate was reciprocated right and left at a rate of 10 times per minute.
The p ^- Si layer 14 was grown in 15 minutes (see FIG. 3E). The thickness distribution of the p ^- Si layer 14 is 30 ± 2 μm in the plane.
m.

Thereafter, the In solution 22 in the crucible is replaced with n ⁺ S
After exchanging with the Sn solution 23 for i-growth, the substrate for dissolution was dissolved in the Sn solution at 800 ° C. instead of n ⁺ Si24 (see (f) in FIG. 3), and in 5 minutes A single crystal n ⁺ Si layer 15 having a thickness of about 0.2 μm was grown in a liquid phase (see FIG. 3 (g)).

As described above, the single-crystal p ⁺ Si layer 13 and the p ^- S
An i layer 14 and an n ⁺ Si layer 15 were grown (see FIG. 2E).

At this time, a wedge was inserted into the porous Si layer 12 to separate the Si layer to be a solar cell from the Si substrate 19 (see FIG. 2 (f)). The porous Si layer has a large amount of voids inside it compared to the Si wafer or the Si layer grown by liquid phase, so the mechanical strength such as pulling, compression, shearing, etc. is weak, and when a wedge is inserted It is broken and the Si layer can be peeled from this portion. Porous Si
The layer 12 has a dramatically increased surface area compared to the volume, and the chemical etching is performed on a non-porous single-crystal Si.
The speed is significantly increased as compared with. Therefore, the tape can be stuck to the surface of the single crystal layer to mechanically separate it, or immersed in an etching solution to form the S from the porous Si layer 12.
The i-substrate 19 and the single crystal layer can be separated.

After the separation, a stainless steel sheet is adhered to the lower surface of the p ⁺ Si layer 13 as the conductive substrate 18, and the grid electrode 16 is printed on the surface of the n ⁺ Si layer 15 as shown in FIG. After that, the antireflection layer 17 is formed on the surface of the n ⁺ Si layer 15 (see FIG. 2H), and the unit cell of the solar cell is completed. AM-
When evaluated with a 1.5 solar simulator, the conversion efficiency showed an average characteristic of 15%, showing good characteristics.

On the other hand, the lower limit of the angle θ at which the effects of the present invention can be obtained.
Prepare board supports with different angles θ to compare
Was done. Other conditions are common, and the angle during liquid phase growth is
When the substrate support 1 at θ = 4 degrees is used, p⁺Si layer 13
Sheet resistance distribution is 250 ± 150Ω / □, p^-Si
The thickness distribution of the layer 14 is 14 ± 6 μm, and p⁺Si layer
13 has extremely high resistance, p^-Si layer 14 is extremely thin
Was. Thin film, especially at the center of the substrate, tends to have high resistance
It was observed. The conversion efficiency of the created solar cell is 8 on average.
%. Using the substrate support 1 with an angle θ = 6 degrees
If you use ⁺The sheet resistance distribution of the Si layer 13 is 13
5 ± 35Ω / □, p^-The distribution of the thickness of the Si layer 14 is 25 ±
At 5 μm, the average conversion efficiency was remarkably improved to 13%.
This is because when θ = 4 degrees, the In solution flows between the substrates as shown in FIG.
On the other hand, when θ = 6 degrees,
It is considered that the liquid flowed between the substrates. In this embodiment,
Is reciprocating, so when the substrate returns,
In general, θ = 5 degrees corresponds to θ = 175 degrees.

[Embodiment 2] In this embodiment, a plurality of substrates supported so that an angle θ between a normal line at the center of the substrate growth surface and a moving direction has a predetermined value is rotated in a solution. This is an example of manufacturing an epitaxial wafer characterized in that a semiconductor film is grown on a substrate, and a p ⁺ Cz silicon wafer having a plane orientation (100) of 6 inches φ is used as the substrate. FIG. 11 is a perspective view of a substrate support used in this embodiment. FIG. 12 is a plan view of the same device, and FIG. 13 is a side view of the same device. Here, an example in which the angle θ is 45 degrees is shown, but for comparison, θ = 0 degrees, 5 degrees, 30 degrees, 45 degrees, and 6 degrees.
0 degree, 87 degree, 90 degree, 93 degree, 135 degree, 175 degree,
A 180-degree substrate support was also prepared.

First, B-doped p ^- Si for melting is used.
The substrate was held on the substrate support, and the substrate support 1 was lowered using the up-and-down mechanism, immersed in an In solution 5 at 950 ° C. for 20 minutes, and Si as a raw material was dissolved to obtain a saturated state.

Thereafter, the substrate support 1 on which the p ^- Si substrate for melting is set is raised, and eight (100) p ⁺ Cz silicon wafers are set on the substrate support 1 as growth substrates 2. Before immersion in the In solution, hydrogen was introduced from an atmosphere gas inlet (not shown), and hydrogen annealing was performed at 1000 ° C. to remove a natural oxide film on the surface of the substrate 2. Then, the In solution was cooled to 940 ° C., and when the Si in the In solution became supersaturated, the substrate support 1 was lowered using the up / down mechanism, and the substrate was immersed in the In solution, and the rate was increased 10 times per minute. While rotating the substrate counterclockwise (as viewed from above), the temperature of the In solution was further lowered, and a Si layer was grown on the substrate 2. After growing for 20 minutes, the substrate support 1 was lifted, and the substrate was removed. Grown Si
Almost no In deposition was observed on the surface of the layer, but it was immersed in hydrochloric acid for 30 minutes to make sure that the metal content was completely removed. Also, while the In of the solution is hardly taken into the Si layer during the growth, the B dissolved out of the substrate is
Since the Si layer was taken into the i-layer, the specific resistance of the Si layer was approximately 1 to 2
It became about Ωcm. In this way on the p ⁺ wafer p ^- S
An epitaxial wafer having an i-layer was formed.

Table 1 shows the results of measuring the thickness of the grown p ^- Si layer. Here, of the eight substrates, the upper four
^- average thickness and distribution of the Si layer, and the four lower p ^- S
The average of the thickness of the i-layer and the distribution width are shown.

[0054]

[Table 1] In the range of the angle θ = 5 degrees to 87 degrees and 93 degrees to 175 degrees,
Both the upper and lower Si layers have substantially the same average thickness and a narrow distribution. However, the angle θ = 0 degree, 90 degrees, 18
At 0 degrees, the thickness of the lower Si layer is significantly reduced. Further, at θ = 0 degrees and 180 degrees, the distribution was widened because the thickness was significantly reduced at the center of the substrate. Angle θ = 0 degree, 90
At 180 degrees, the circulation of the In solution in the crucible becomes insufficient, and the solution containing low-density Si at a high concentration stays on the surface of the solution, while the portion near the bottom of the crucible lacks Si and the growth rate decreases. It is thought that it was done. At θ = 0 ° and 180 °, it is considered that the supply of the melt containing Si at a high concentration to the central portion of the substrate was further insufficient, and the thickness distribution became remarkable.

[Embodiment 3] In this embodiment, an epitaxial wafer was manufactured using the same liquid phase growth apparatus as that of Embodiment 2, and further, the dependence on the preparation conditions and the jig used was examined in detail. . That is, the rotation speed was changed to 10, 20, and 30 rotations per minute. The angle θ is 45 degrees, 13
A comparison was made using a 5 degree substrate support. In addition, in the epitaxial wafer, it is preferable that the epitaxial wafer be grown on the inside of a predetermined width from the edge of the front surface with high accuracy, as well as on the back surface of the substrate. Therefore, in order not to grow outside the desired portion, a substrate support plate and a peripheral ring whose sectional structures are shown in FIGS. 30 and 31 were used in combination.

After the p ^- Si layer was grown in the same manner as in Example 2, the thickness and distribution of the p ^- Si layer of eight substrates were examined in each case. In the present embodiment, since the angle θ is set to an ideal value, there is no difference in thickness between the upper and lower tiers, so the upper and lower tiers are not distinguished.

Table 2 shows the case where the peripheral ring shown in FIG. 30 is used, and Table 3 shows the case where the peripheral ring shown in FIG. 31 is used.

[0058]

[Table 2]

[0059]

[Table 3] When the angle θ is 45 degrees in Table 2, the Si layer tends to be slightly thicker as the number of rotations increases, but the distribution does not spread. In the case where the angle θ was 135 degrees, at 20 rotations per minute or more, the thickness was remarkably reduced in almost a half area on the tip side in the moving direction of the substrate, and the thickness distribution was expanded. Although a similar tendency is seen in Table 3, even at an angle θ of 135 degrees, the distribution did not expand up to 20 rotations per minute.

At the angle θ = 135 ° (the growth surface of the substrate is on the downstream side), a vortex is likely to be formed on the downstream side as shown in FIG. 27 as the rotational speed increases. It is considered that the thickness distribution was expanded. When a peripheral ring is used, the flow of the solution is turbulent at the corner where the ring and the substrate are in contact with each other, and a vortex is easily formed. In particular, when the growth surface is directed to the downstream side at θ = 135 degrees, the tendency seems to increase. However, in the case of Table 3 using the peripheral ring of FIG. 31, the peripheral ring was thinner and the cross-sectional shape of the ring was devised so that the flow was less likely to stagnate due to the peripheral ring. it is conceivable that.

[Embodiment 4] Here, a plurality of substrates supported so that an angle θ between a normal direction of a substrate growth surface and a moving direction becomes a predetermined value is rotated in a solution to form a semiconductor on a substrate. 3 is an example of a method for manufacturing a light emitting diode, which comprises growing a film.

FIG. 4 is a sectional view of a liquid phase growth apparatus used in this embodiment. This liquid phase growth apparatus is equipped with a mechanism for rotating a substrate support as a substrate moving mechanism. The angle θ between the normal direction 50 of the substrate and the moving direction 51 is 45 degrees, and four rectangular substrates can be mounted. 5 is a perspective view of the substrate support, FIG. 6 is a plan view of the same, and FIG. 7 is a side view of the same.

FIG. 23 is a sectional view showing a manufacturing process of the light emitting diode in the fourth embodiment. Here, as shown in FIG. 23A, an n-type InP substrate 40 was prepared.
Thereafter, an InP solution containing an n-type dopant was charged into the crucible using a liquid phase growth apparatus, and then an n-type InP layer 41 serving as a buffer layer was formed as shown in FIG.

After that, the solution in the crucible was replaced with an InGaAsP solution containing no dopant, and the solution was replaced with an InGaAsP solution containing no dopant as shown in FIG.
As shown in FIG. 7, an active layer InGaAsP layer 42 was formed. Hereinafter, similarly, the solution in the crucible is replaced with an InP solution containing a P-type dopant, and the P-type clad layer In
A P layer 43 was formed (see FIG. 23D). next,
A P-type InGaAsP layer 44 serving as a cap layer was formed (see FIG. 23E).

When the substrate is rotated in the solution during the growth of each layer, a new solution comes into contact with the surface of the substrate one after another, so that the film formation rate is improved and at the same time, the solution in contact with the substrate surface is removed. It circulates efficiently in the crucible, and stirring is performed efficiently.

As a result, it was possible to efficiently grow on many substrates. In addition, a vertical movement may be added at the time of this rotation, and a spiral movement may be performed as a whole.

Thereafter, the substrate was taken out of the liquid phase growth apparatus, and electrodes 45 were formed on the back surface of the n-type InP substrate 40 and the surface of the p-type InGaAsP layer 44 (see FIG. 23 (f)). Then, the light transmitting portion of the electrode on the surface of the P-type InGaAsP layer 44 was removed by etching.

Thereafter, as shown in FIG.
Half dicing was performed to the inside of the mold InP substrate 40, cut out into each diode chip, and assembled as shown in FIG. 23 (h) to complete a light emitting diode.

[0069]

According to the method of the present invention, when a substrate containing a semiconductor as a solute is immersed and liquid phase growth is performed while moving in a solution, the direction of the normal to the center of the substrate growth surface and the direction of movement can be reduced. By setting the angle to a predetermined range, the solution comes into contact with the growth surface one after another, so that the relative speed with respect to the solution is increased and the film formation rate is improved. At the same time, the substrate itself forms a flow that suitably agitates the solution, and does not form a swirl of the solution near the growth surface, thereby improving the uniformity of the grown film thickness. Further, according to the method of the present invention, a large number of substrates can be collectively processed by a simple mechanism, which leads to an improvement in mass productivity.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a liquid phase growth apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the solar cell according to the first embodiment of the present invention.

FIG. 3 is a sectional view illustrating an apparatus state in a manufacturing process according to the first embodiment of the present invention.

FIG. 4 is a schematic side view of a liquid phase growth apparatus according to a second embodiment of the present invention.

FIG. 5 is a perspective view of a substrate support according to the present invention.

FIG. 6 is a top view of a substrate support according to the present invention.

FIG. 7 is a side view of the substrate support according to the present invention.

FIG. 8 is a perspective view of a substrate support as another example of the present invention.

FIG. 9 is a top view of a substrate support as another example of the present invention.

FIG. 10 is a side view of a substrate support as another example of the present invention.

FIG. 11 is a perspective view of a substrate support as another example of the present invention.

FIG. 12 is a top view of a substrate support as another example of the present invention.

FIG. 13 is a side view of a substrate support as another example of the present invention.

FIG. 14 is a perspective view of a substrate support as yet another example of the present invention.

FIG. 15 is a side view of a substrate support as still another example of the present invention.

FIG. 16 is a top view of a substrate support as still another example of the present invention.

FIG. 17 is a perspective view of a substrate support as still another example of the present invention.

FIG. 18 is a side view of a substrate support according to still another example of the present invention.

FIG. 19 is a top view of a substrate support as still another example of the present invention.

FIG. 20 is a perspective view of a substrate support, showing another example of the substrate support in the present invention.

FIG. 21 is a side view of the substrate support, showing another example of the substrate support in the present invention.

FIG. 22 is a top view of the substrate support, showing another example of the substrate support in the present invention.

FIG. 23 is a cross-sectional view illustrating a step of manufacturing the light-emitting diode according to the second embodiment of the present invention.

FIG. 24 is an explanatory diagram showing the arrangement of substrates and the flow of a solution.

FIG. 25 is an explanatory diagram showing the arrangement of substrates and the flow of a solution.

FIG. 26 is an explanatory diagram showing the arrangement of substrates and the flow of a solution.

FIG. 27 is an explanatory diagram showing the arrangement of substrates and the flow of a solution.

FIG. 28 is an explanatory view showing a case where four substrates are placed in a solution placed in a cylindrical crucible with an angle θ of 45 degrees and a plane extending at an angle θ standing vertically;

FIG. 29 is an explanatory diagram showing a case where four substrates are placed in a solution placed in a cylindrical crucible such that a plane at an angle θ of 45 degrees and an angle θ extends horizontally lie horizontally.

FIG. 30 is a cross-sectional view showing a case where a substrate support plate and a peripheral ring are used in combination with each other.

FIG. 31 is a cross-sectional view showing a case where a substrate support plate and a peripheral ring are used in combination with each other.

FIG. 32 is a cross-sectional view of a conventional dipping type Si liquid phase growth apparatus.

FIG. 33 is a cross-sectional view of a conventional dipping type Si liquid phase growth apparatus.

FIG. 34 is a perspective view of a main part of a conventional dipping type liquid crystal growth apparatus for Si.

FIG. 35 is a cross-sectional view of a conventional dipping type liquid phase Si growth apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate support 2 Growth substrate 4 Substrate support rod 5 Metal solution 6 Crucible 7 Quartz reaction tube 8 Heater 9 Crucible base 11 Single-crystal Si substrate 12 Porous Si layer 13 P ⁺ Si layer 14 Single-crystal P ⁻ Si layer 15 N ⁺ Si layer 16 Grid electrode 17 Anti-reflection layer 18 Conductive substrate 19 Si substrate 20 P ⁺ Si substrate for dissolution 21 P ^- Si substrate for dissolution 22 Metal solution for P ^- Si growth 23 N ⁺ Si Metal solution for growth 24 N ⁺ Si substrate for dissolution 40 n-type InP substrate 41 n-type InP layer 42 InGaAsP layer 43 P-type InP layer 44 P-type InGaAsP layer 45 electrode 46 Electrode removal part 47 Cut by dicing 50 Substrate growth Surface normal direction 51 Substrate moving direction 101 Substrate holder 102 Graphite container 103 Solution 104 Growth base Reference Signs List 201 vertical cylindrical furnace tube 203 crucible 204 heater 209 substrate holder 210 mounting frame 215 holding frame 216 side leg 216a long hole 217 bottom plate 218b engaging pin 218 spacer 220 support rod 310 electric furnace 312 For growth that can be mounted on support rod Substrate 315 Support rod 317 Driving means 318 Support base 319 Lifter

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Yoshino 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Masaki Mizutani 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Non Co., Ltd. (72) Inventor Akishi Nishida 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Makoto Iwami 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Tetsuro Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tatsumi Shoji 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo F-term (reference) 5F041 CA04 CA39 CA63 5F051 AA02 CB02 CB29 CB30 5F053 AA03 AA47 BB04 BB52 BB54 BB60 DD01 DD04 DD05 DD07 DD12 DD15 GG01 HH01 HH05 LL02 LL05 RR01

Claims (31)

[Claims] In a method of manufacturing a semiconductor thin film, a plurality of substrates are immersed in a crucible filled with a solution containing a semiconductor as a solute, and the semiconductor thin films are grown while moving the substrates in the solution. Manufacturing a semiconductor thin film, wherein an angle formed between a normal direction at a center portion of a growth surface and a moving direction of the substrate is 5 degrees or more and 87 degrees or less, and the flow of the solution is formed by moving the substrate. Method. 2. A method of manufacturing a semiconductor thin film, comprising: immersing a plurality of substrates in a crucible filled with a solution containing a semiconductor as a solute, and growing the semiconductor thin film while moving the substrates in the solution. The angle between the normal direction at the center of the growth surface and the direction of movement of the substrate is 93 ° or more and 175 ° or less, and the solution is substantially free from eddy near the growth surface due to the movement of the substrate. Forming a flow of a semiconductor thin film. 3. A method of manufacturing a semiconductor thin film, comprising: immersing a plurality of substrates in a crucible filled with a solution containing a semiconductor as a solute, and growing the semiconductor thin film while moving the substrates in the solution. The substrate integrally reciprocates on a straight line. On the outward path, the angle between the normal direction at the center of the growth surface of the substrate and the direction of movement of the substrate is set to 5 degrees or more and 87 degrees or less, and Forming a flow of the solution by movement, and in the return path, immersing a plurality of substrates in a crucible filled with a solution containing a semiconductor as a solute, and growing the semiconductor thin film while moving the substrates in the solution; In the manufacturing method of (1), the angle between the normal direction at the center portion of the growth surface of the substrate and the moving direction of the substrate is not less than 93 degrees and not more than 175 degrees. A method for producing a semiconductor thin film, wherein a flow of the solution is formed without qualitatively generating a vortex. 4. The method according to claim 1, wherein the plurality of substrates rotate integrally as a unit. 5. The method according to claim 4, wherein the plurality of substrates are rotated by rotation of a support that supports the substrates. 6. The method according to claim 1, wherein the plurality of substrates move along a spiral as a unit. 7. The method according to claim 6, wherein the plurality of substrates perform a spiral motion by rotating and vertically moving a support that supports the substrates. 8. The method according to claim 1, wherein the plurality of substrates are oriented such that a normal line formed at the center of each growth surface and a plane extending in the direction of movement of the substrates stand substantially perpendicularly.
4. The method for producing a semiconductor thin film according to any one of items 1 to 3. 9. The method according to claim 1, wherein the plurality of substrates are oriented such that a normal line formed at the center of each growth surface and a plane extending in the direction of movement of the substrates lie substantially horizontally.
4. The method for producing a semiconductor thin film according to any one of items 1 to 3. 10. The plurality of substrates are arranged so as to be rotationally symmetric at predetermined intervals along a circumference around a predetermined straight line as a central axis, and the substrates move along the circumference. 3. The method for producing a semiconductor thin film according to claim 1, wherein: 11. The method according to claim 10, wherein the circumference is a plurality of circumferences sharing a central axis. 12. The plurality of circumferences having different radii on the same plane.
3. The method for producing a semiconductor thin film according to item 1. 13. The method according to claim 11, wherein the plurality of circles are circles having the same radius that are not on the same plane. 14. The plurality of substrates are arranged in parallel with each other to form a substrate group, and the substrate group is rotationally symmetric at predetermined intervals along a circumference around a predetermined straight line as a central axis. The method according to claim 1, wherein the semiconductor thin film is disposed. 15. The method according to claim 14, wherein the predetermined circumference is a plurality of circumferences sharing a central axis. 16. The system according to claim 15, wherein the plurality of circumferences are circumferences having different radii on the same plane.
3. The method for producing a semiconductor thin film according to item 1. 17. The method according to claim 15, wherein the plurality of circumferences are circumferences having the same radius that are not on the same plane. 18. A crucible filled with a solution containing a semiconductor as a solute, a means for controlling the temperature of the crucible, a substrate moving means for integrally moving a plurality of substrates in the solution, Substrate support means for supporting an angle between the normal direction at the center of the growth surface and the direction of movement of each substrate to be 5 to 87 degrees or 93 to 175 degrees. Equipment for manufacturing semiconductor thin films. 19. The apparatus for manufacturing a semiconductor thin film according to claim 18, wherein said substrate moving means integrally reciprocates the plurality of substrates on a straight line. 20. The apparatus according to claim 1, wherein the substrate moving means rotates the plurality of substrates integrally.
9. The apparatus for manufacturing a semiconductor thin film according to item 8. 21. The semiconductor thin film manufacturing apparatus according to claim 18, wherein the substrate moving means makes the substrate integrally spiral by rotating and vertically moving the substrate supporting means. 22. The substrate supporting means, comprising:
22. The semiconductor thin film according to claim 18, wherein a normal line formed at the center of the growth surface and a plane extending the moving direction are oriented substantially perpendicularly. apparatus. 23. The substrate supporting means, comprising:
22. The semiconductor thin film according to claim 18, wherein a normal line formed at the center of the growth surface and a plane extending in the moving direction are oriented so as to lie substantially horizontally. apparatus. 24. The substrate supporting means according to claim 20, wherein the plurality of substrates are arranged so as to be rotationally symmetric at predetermined intervals along a circumference centered on a predetermined straight line. 5. The apparatus for producing a semiconductor thin film according to claim 1. 25. The apparatus according to claim 24, wherein the predetermined circumference is a plurality of circumferences sharing the central axis. 26. The method according to claim 25, wherein the plurality of circumferences are circumferences having different radii on the same plane.
3. The apparatus for producing a semiconductor thin film according to claim 1. 27. The apparatus according to claim 25, wherein the plurality of circles are circles having the same radius that are not on the same plane. 28. The substrate supporting means, wherein a substrate group formed by arranging the plurality of substrates in parallel with each other is rotationally symmetric at predetermined intervals along a circumference having a predetermined straight line as a central axis. 18. An arrangement according to claim 18, wherein
2. The apparatus for manufacturing a semiconductor thin film according to claim 1. 29. The apparatus according to claim 28, wherein the predetermined circumference is a plurality of circumferences sharing a central axis. 30. The plurality of circumferences having different radii on the same plane.
3. The apparatus for producing a semiconductor thin film according to claim 1. 31. The apparatus according to claim 29, wherein the plurality of circles are circles having the same radius that are not on the same plane.