JPS6230692A - Liquid-phase epitaxial growth apparatus - Google Patents

Abstract

PURPOSE:To efficiently grow a multilayer crystal layer on a substrate, by providing plural melt reservoirs and melt housing baths in the upper and lower parts of a holding device for holding vertically plural semiconductor substrates through a slidable partition plate. CONSTITUTION:Plural melt reservoirs 24 are formed on a fixed substrate holding device 27 for vertically holding semiconductor substrates 25 through a slidable partition plate 21 having a perforated hole 29. Melt housing baths 28 in the same number as the melt reservoirs 24 are formed below the substrate holding device 27 through a slidable partition plate 22 having a perforated hole 29. A melt 23 is contained in the plural melt reservoirs 23, and the melt 23 is dropped by the operation of the partition plate 21 one after another and brought into contact with the substrates 25 to grow a crystal. The partition plate 22 is operated to drop the melt 23 in the substrate holding device 27 into the melt housing baths 28 and the operation is repeatedly carried out as much as the number of the melt reservoirs 24.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid phase epitaxial growth apparatus, and more particularly to a growth apparatus for simultaneously growing multilayer epitaxial layers on a large number of semiconductor substrates.

[Prior Art] In general, a liquid phase epitaxial growth method using a slide boat method is employed as an epitaxial layer growth method for semiconductor devices such as ■-V group compound semiconductor laser diodes and light emitting diodes.

By the way, forming a multilayer epitaxial layer using this sliding epitaxial growth method is very simple and effective for research and experiments, but since the melt is brought into contact with a horizontally tilted substrate, it is difficult to form a multilayer epitaxial layer in one step. The epitaxial growth process could only process one or two semiconductor substrates, making it unsuitable for mass production.

Therefore, as a method for processing a large number of substrates at the same time, as shown in FIGS. 3 and 4, a method was devised in which the substrates 2 in the substrate holding device 1 are stood up and the melt 3 is allowed to fall by gravity. In the one shown in FIG. 3, one partition plate 4 is pulled to allow the melt 3 to fall, and after a predetermined period of time, the melt 3 is taken out of the apparatus. The number shown in Figure 4 is an improved version of the one shown in Figure 3.
The upper partition plate 5 is pushed to cause the melt 3 to fall, and after a predetermined time, the lower partition plate 6 is pushed this time to separate the melt 3 from the substrate 2.

[Problems to be Solved by the Invention] However, although it is certainly possible to epitaxially grow a large number of layers at the same time in the cases shown in FIGS. 3 and 4 above,
There is a drawback that only a single phase can be grown in one epitaxial growth process.

A device which solves this drawback is a so-called push-up type disclosed in Japanese Patent Application Laid-Open No. 59-189621, and the one shown in FIGS. 3 and 4 is called a gravity fall type. The push-up method is as shown in Figures 5A and 5B.
An upper boat 1 in which a piston 7 is provided with a plurality of melt reservoirs 8 whose volumes change in the longitudinal direction of a lower boat 9, and a substrate holding device 10 and a dummy cavity 11 are formed.
2 is slidably provided on the lower boat 9, and the substrate holding device 10 is sequentially positioned on each melt reservoir 8 by sliding the upper boat 12. Each time the substrate holding device 10 is positioned, the piston 7
By operation, the melt 13 is pushed up and then lowered, and is collected in the original melt reservoir to grow multiple layers on the substrate 14.

However, although this push-up method has the great advantage that the number of epitaxy cell growth layers or the number of substrates held can be changed arbitrarily by increasing the melt reservoir and devising the position and shape of the substrate holding device in the upper boat. According to experimental results by the present inventors, the positioning of the substrate holding device may not be determined accurately, and the piston may move due to the weight of the melt during growth, which requires considerable skill to operate. Understood.

Note that even in the case of the one shown in Fig. 4, if a plurality of melt storage tanks 15 are provided in the longitudinal direction of the boat as shown in Fig. 5A and multilayer growth is attempted, the substrate holding device is still moved. .

[Objective of the Invention] The object of the first invention is to provide a liquid phase epitaxial growth apparatus that can simultaneously grow multilayer epitaxial layers on a large number of substrates without moving the substrate holder if.

Another object of the first invention is to provide a liquid phase epitaxy forming apparatus capable of growing a multilayer epitaxial layer using a gravity drop method.

As with the first object of the first invention, the second object of the invention is to provide a liquid phase epitaxial growth apparatus capable of simultaneously growing multilayer epitaxial layers on a large number of substrates without moving the substrate holding device. It is to be.

Another object of the second invention is to provide a liquid phase epitaxial growth apparatus that employs a push-down method and has good operability.

[Summary of the Invention] The liquid phase epitaxial growth apparatus of the first invention is characterized in that two or more melt reservoirs are communicated with each other on a common substrate holding device, and the communication is opened and closed by a partition plate.

That is, the liquid phase epitaxial growth apparatus of the first invention, as shown in FIGS. 1A to 1B corresponding to the embodiment, is on a substrate holding device 27 that is not a sliding type but a fixed type, and is commonly connected to the substrate holding device 27. Two or more melt reservoirs 24 are formed, and partition plates (218 to 21C) are slidably provided between each melt reservoir (24a to 24C) and a common substrate holding device.

On the other hand, the same number of melt storage tanks 28 as the melt reservoirs 24 are formed below the substrate holding device 27 and communicated therewith, and slide between each melt storage tank (28a to 28C) and the substrate holding device 27. Partition plates (22a to 22C) are freely provided.

By operating each partition plate, the melt is dropped and supplied from each melt reservoir to the substrate holding device without moving it,
In addition, each partition plate is operated independently so that different kinds of melts can be exchanged effectively without mixing when switching melts.

Also, the second defense liquid phase epitaxy 1? Le growth equipment is
The feature is that two or more melt reservoirs are communicated with each other under a common substrate holding device, and the communication is opened by a partition plate.

That is, in the liquid phase epitaxial growth apparatus of the second invention, as shown in FIGS. 2A and 2B corresponding to the embodiment, a melt reservoir 44 is provided below a fixed substrate holding device 47 and communicated therewith in common. 2 or more are formed, and each melt reservoir (44a to 44
c) Install the pistons 39 in each.

Furthermore, partition plates (418 to 41C) are provided between each melt reservoir 44 and the substrate holding device 47 so as to be slidable.

By operating each piston, melt is pushed up and supplied from each melt reservoir to the substrate holding device without moving it, and by independent operation of each partition plate, the piston is moved by the weight of the pushed up melt. , to prevent different types of melts from mixing when switching melts.

[Embodiment 1] An embodiment of the present invention will be described below based on FIGS. 1A to 2B.

FIGS. 1A and 1B show a liquid phase epitaxial growth apparatus using a gravity drop method. As shown in the front cross-sectional view of Figure 1A,
The hollow chamber of the device main body 2o is partitioned into three stages, upper, middle, and lower, by two partition plates 21 and 22. Melt liquid 2 is in the upper row
A U-plate holding device 2 that vertically supports a plurality of substrates 25 with spacers 26 in a back-to-back V is placed in the middle stage.
Melt liquid storage tanks 28 are provided below 7 and at the lower stage, respectively.

The two partition plates 21 and 22 are both slidably provided in both directions of the main body, and have a through hole 29 in the center and an operating rod 30 in the end pulled out from the main body side so that they can be operated from outside the growth furnace. In the upper partition plate 21, communication between the melt reservoir 24 and the substrate holding device 27 is cut off in the illustrated state, and when the operation bar 30 is pushed in, the two are communicated with each other. It is supposed to be done. In addition, in the lower partition plate 22, a substrate holding device 27 and a melt storage [2] are provided in the illustrated state.
By cutting off the communication with 8 and pushing in the operating rod 30, the two will communicate with each other.

Such melt reservoir 24, melt storage tank 28, partition plate 21
．． As shown in the side view of FIG. 1B, there are two or more operating rods 22 and 30 instead of one. That is, the substrate holding device 27
There are three melt reservoirs 24 (248 to 24c) communicating with the substrate holding device 27 in the width direction of the main body above, and correspondingly there are melt storage tanks communicating with this in the width direction of the main body below the plate holding device 27. 28 (288 to 28c) are arranged in parallel, and each melt reservoir 2
There are a total of six partition plates (21a to 21c) with operating rods 30 engaged in each communication path 32 connecting the substrate holding device 4 and the substrate holding device @27, and in each communication path connecting the substrate holding device 27 and each melt storage tank 28.
, 22a to 22c) are provided.

These partition plates 21 and 22 can be slid independently by operating rods 30, and the substrate holding device 27 located between the melt reservoir 24 and the melt storage tank 28 is fixed to the main body 20.

Next, we will specifically describe the effects of groove formation as described above.

The crystal growth apparatus main body 20 shown in FIG.
CII11 width 12c+n, height 12cm, 30111+11X 30 on the board holding device 27 stored in the middle shelf.
Set 20 substrates 25 of mm x O, 5 mm back to back through graphite spacers 26, and put IC6 in the first melt reservoir 24a with Ga A of 550 g, Qa.
600 (1, 20 mg, second melt reservoir 24a contains 550 g of Ga A, 300 g of Ga, zinc eo
omg, 40 g of QaAs in the third melt reservoir 24c,
QalliOOg, 8 g of aluminum, and 5 g of zinc were each weighed out.

After that, the main body 20 was placed in a liquid phase crystal growth furnace, and the temperature was raised to 800°C while flowing hydrogen, and after being left at 800°C for 3 hours, the temperature of the furnace was started to decrease at a constant rate of 0.5°C/min. did.

When the temperature starts to drop by 5℃, first the first
The partition plate 21a was pushed in using the operating rod 30 to fill the substrate holding device 27 with the first melt 23. Here the operating rod 30
is returned to its original position, the melt 23 is brought into contact with the substrate 25, and then 10
After a few minutes, the partition plate 22a was pushed in using the operating rod 30 located outside of the upper part @2, causing the melt in the plate holding device 27 to fall into the first melt storage tank 28a.

Next, in the same manner, the melt 23 is brought into contact with the substrate 25 for 5 minutes using the third operation rod 30 located at the upper center, and then the melt 23 is transferred to the second melt storage tank using the fourth operation rod 30 located at the lower center. 28b, and then the remaining fifth and sixth operating rods 30, 30.
Growth was performed for 2 minutes using the melt 23 by the operation of P
-GaAJ! △S/P-Ga As /n-Ga A
A three-layer epitaxial cell crystal of s/n-GaAsW plate was grown.

After cooling the furnace, the board 25 was taken out and evaluated.
Although the thickness of the peripheral 2 mm of the substrate was non-uniform, a substantially uniform growth layer was obtained in other parts.

When a solar cell was prototyped using this crystal, an electromotive force of 0.9V was obtained per cell.

FIGS. 2A and 2B show a push-up type liquid phase epitaxial growth apparatus. Compared to the gravity drop method, this method has better stability because the center of gravity can be lowered by installing the melt reservoir below the substrate holding device. As shown in the front sectional view of FIG. 2A, the hollow chamber of the device main body 40 is partitioned into an upper part and a lower part by a single partition plate 41. A fixed substrate holding device 47 that vertically supports a plurality of substrates 45 back to back is provided at the top, and a lid plate 36 with air vent holes 35 formed on its top surface and melt transfer holes 37 formed on its bottom surface. The bottom plates 38 are respectively attached.

Further, a melt reservoir 44 whose volume is changed by a piston 39 is provided at the bottom, and when the operating rod 50 engaged with the piston rod 42 is pushed in, the melt 43 in the melt reservoir 44 is pushed up into the substrate holding device 147. - It is now possible to do so.

The partition plate 41 is provided so as to be slidable in both directions of the main body, and when the operating rod 50 engaged with the partition plate 41 is pushed, the substrate holding device 4
7 and the melt reservoir 44, and conversely, when the operating rod 50 is pulled, the communication is restored.

The melt reservoir 44, the piston 39, the piston operating rod 42, the partition plate 41, and the partition plate operating rod 50 are the second B.
As shown in the side view of the figure, there are not one but two or more. That is, the substrate holding device 4 is placed below the substrate holding device 47 in the width direction of the main body.
There are three melt reservoirs 44 (44a to 44c) communicating with
) The pistons 39 which are arranged in parallel and operated by the piston operating rods 50 are respectively fitted, and furthermore, the partition plate operating rods 50 are installed in each communication path 42 connecting the substrate holding bag @ 47 and each melt reservoir 44. Partition plates 41a to 41c are provided, respectively.

Now, in the structure employing the above-mentioned push-up method, when growth of many types of compositions was performed, good results similar to those of the above-mentioned gravity fall method were obtained. In this case, the partition plate 41 is pulled before the melt 43 is pushed up by the piston 39 to allow the melt 43 to move upward, but after being pushed up, the partition plate is pushed back to its original position to prevent the melt 43 from falling. regulate. That is, the melt 43 is held in the substrate holding device 47 by the partition plate 41 rather than by the piston 39. Therefore, during growth, the piston is pushed back and the melt does not return to the melt reservoir 44. Therefore, it is possible to form a good multilayer epitaxial crystal (η) over the entire surface of the substrate.

In addition, in each of the embodiments of the above-mentioned growth apparatus, the case where the operating rod is operated by hand is described, but it is also possible to install an autoloader and automatically operate the operating rod to regulate the movement of the melt. You can also do it.

Furthermore, the number of melt reservoirs is not limited to 3, but can easily be increased to 4 or 5 within that limit by designing the main body of the device according to the capacity of the melt. This is made easier because the solution reservoir is provided in the width direction of the main body instead of in the length direction. This is because mutual interference between the partition plates or the pistons can be prevented by providing them in the width direction of the main body.

Furthermore, the present invention applies not only to the Qa As /Ga AβΔS semiconductor crystal system but also to the In Ga As P/In
P-based crystals and other crystals that can be grown by liquid phase growth can be widely applied.

[Effects of the Invention] To summarize, the present invention exhibits the following excellent effects.

(1) Melt liquid can be separately dropped into the substrate holding device from two or more solution reservoirs by simply operating the partition plate, so even though it is a gravity drop method, a large number of semiconductors can be processed without moving the substrate holding device. Multilayer epitaxial growth can be performed simultaneously on a substrate, making it highly suitable for mass production.

(2) In addition, an unprecedented sliding partition plate is provided between two or more melt reservoirs equipped with pistons and a substrate holding device that communicates with the top of these reservoirs, making it possible to use a push-up method. However, while it is possible to simultaneously perform multilayer epitaxial growth on a large number of semiconductor substrates without moving the substrate holding device, it is possible to reliably hold the melt inside the substrate holding device during growth using a partition plate rather than a piston. As a result, the piston does not move due to the weight of the melt during growth and the melt level does not change. Therefore, a multilayer epitaxial crystal of high quality can be obtained, which requires no skill and is easy to operate compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1A is a front sectional view showing an embodiment in which the present invention is applied to a liquid phase epitaxial growth apparatus using a gravity drop method, and FIG.
The drawings are a side view of Fig. 1A, Fig. 2A is a front sectional view showing another embodiment in which the present invention is applied to a push-up type liquid phase epitaxial growth apparatus, Fig. 2B is a side view of Fig. 2Δ, and Fig. 3 is a side view of Fig. 1A.
4 to 4 are front sectional views showing examples of conventional liquid phase epitaxial growth apparatuses using a gravity drop method, FIG. 5A are front sectional views showing examples of conventional liquid phase epitaxial growth apparatuses using a push-up method, and FIG. 5B. 5A is a sectional view taken along the line VB-48 in FIG. 5A. In the figure, 21.21a ~ 210.22.22a ~ 22
C is a partition plate, 23 is a melt, 24.24a to 24G are melt reservoirs, 25 is a substrate, 27 is a substrate holding device, 28.28
a to 28c are melt storage tanks, 39 is a piston, 41.4
1a to 41c are partition plates, 43 is a melt, 44.44a-
44c +, a tm liquid reservoir, 45 a substrate, and 47 a substrate holding device.

Claims (2)

[Claims] (1) On a fixed substrate holding device that vertically holds multiple semiconductor substrates, two or more melt reservoirs are formed in communication with the fixed substrate holding device, and the gap between each melt reservoir and the substrate holding device is adjusted according to the sliding direction. While the melt is held in the melt reservoir, partition plates are slidably provided to allow the melt to fall into the substrate holding device, and a melt storage tank is connected to the melt reservoir under the substrate holding device. The same number of melts are formed, and the melt that falls and moves between each melt storage tank and the substrate holder according to the sliding direction is held in the substrate holder, while being discharged to the outside of the substrate holder to serve as a melt reservoir. A liquid phase epitaxial growth apparatus characterized in that partition plates are slidably provided to accommodate the melt in the melt storage tank. (2) Two or more melt reservoirs are formed under a fixed substrate holding device that vertically holds multiple semiconductor substrates, and the melt is fed into each melt reservoir according to the sliding direction. At the same time, a piston is installed to lower and store the melt in the same melt reservoir, and between each melt reservoir and the substrate holding device, the melt pushed up by the piston according to the sliding direction is held in the substrate holding device. On the other hand, a liquid phase epitaxial growth apparatus is characterized in that partition plates that allow the melt to move up and down by pistons are provided in a slidable manner.