JPS63159289A - Liquid phase epitaxial growth and device therefor - Google Patents

Abstract

PURPOSE:To obtain high-purity epitaxial growth layer continuously, by setting a given openable and closable ventilation channels to circulate a reducing gas in a storage part for a growing solution and removing impurities contained in the solution. CONSTITUTION:A storage part 9 for a solution 12 for liquid-phase epitaxial growth is set at the bottom of a substrate holder 8 having built-in substrates 11. The solution 12 is pushed up and withdrawn in the holder 8 by the operation of a piston 10 of the storage part 9. Reducing gas inlet and outlet ventilation channels 14 and 15 are openably and closably set between the holder 8 and the storage part 9. The solution is brought into contact with the reducing gas before the solution 12 is pushed up in the interior of the holder 8 to remove impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a liquid phase [bitaxial growth method and growth apparatus] for growing a semiconductor thin film on a substrate.

[Prior Art] Conventionally, a slide boat method has been used as a liquid phase epitaxial growth method, but it is not preferred in terms of mass productivity. In order to solve the problem of mass production, a plurality of liquid phase epitaxial growth substrates are arranged vertically in a substrate holder, and a liquid phase epitaxial growth solution is brought into contact with the substrates to grow a semiconductor thin film. There is a way.

6 and 7 respectively show conventional liquid phase epitaxial growth apparatuses, 1 is a solution for liquid phase epitaxial growth, 2 is a solution holder, 3 is an upper shutter, 4 is a part of a substrate holder, 5 is a lower shutter, 6 is a solution storage part, 7 is a substrate, 8 is a substrate holder, 9 is a solution storage part, 10 is a piston, 11
1 is a substrate, and 12 is a solution for forming a liquid phase epitaxial layer.

As shown in FIG. 6, the liquid phase epitaxial growth apparatus pulls the upper shutter 3 to drop the liquid phase epitaxial growth solution 1 to grow an epitaxial layer on the substrate 7, and after the growth, pulls the lower shutter 5 to grow the epitaxial layer. This method terminates liquid phase epitaxial growth by dropping the solution into the solution container 6, and although it is generally used, it is inconvenient for continuous operation.

The liquid phase epitaxial growth apparatus shown in FIG. 7 uses a piston 10 to push up a liquid phase epitaxial growth solution 12 and bring it into contact with a substrate 11 for growth. When the growth is finished, the piston 10 is pulled back and the growth solution falls into a solution storage section 9. With this device, the next liquid phase epitaxial growth can be performed simply by replacing the substrate holder 8.
It has the advantage of being easy to operate continuously and being suitable as an industrial FL device.

[Problems to be Solved by the Invention] However, the method using the apparatus shown in FIG. 7 has a drawback in obtaining a highly pure solution for liquid phase epitaxial growth.

That is, in the method using the apparatus shown in FIG. 6, the top view of the liquid-phase epitaxial growth solution 1 is generally in an atmosphere where high-purity reducing water and elementary gas are flowing. It can remove impurities such as oxygen and sulfur. However, in the apparatus shown in FIG. 7, the upper part of the liquid phase epitaxial growth solution 12 is a closed space, so five claws of reducing gas are required to purify the growth solution by bringing it into contact with reducing hydrogen gas. This is the point.

In other words, in order to take advantage of the advantages of the apparatus shown in Figure 7 and make it suitable for industrial production to obtain a high-purity epitaxial growth layer, it is necessary to change conditions such as dry cooking time and to use large amounts of hydrogen gas and electricity. There were problems with things like.

An object of the present invention is to provide a liquid phase epitaxial growth method suitable for industrial production that can easily and stably obtain a high-purity epitaxial growth layer by making it possible to easily contact a growth solution with a reducing gas to solve the above-mentioned problems. and to provide a growth device.

[Means for Solving the Problems] A growth method for achieving the above object includes a solution storage section having a piston mechanism at the bottom of a substrate boulder containing a substrate, and a solution for liquid phase epitaxial growth in the solution storage section. In the liquid phase epitaxial growth method of growing an epitaxial layer on the substrate by pushing it up inside the substrate holder, before pushing up the liquid phase epitaxial growth solution in the solution storage section into the substrate holder, the solution is brought into contact with a circulating reducing gas to grow the epitaxial layer. It is to remove impurities in the solution.

Further, in a growth apparatus that achieves the above object, a solution for liquid phase epitaxial growth is applied to the inside of the substrate holder by a piston operation at the bottom of a substrate holder in which a plurality of substrates for liquid phase epitaxial growth are arranged vertically. In a liquid phase epitaxial growth apparatus that is provided with a solution storage section that can be operated by pushing up or pulling down, an air passage through which a reducing gas flows is provided between the substrate holder and the solution storage section so as to be openable and closable. It is that you are.

[Function] In the present invention, an openable and closable ventilation path is provided in the solution storage section so that a reducing gas such as hydrogen can flow from the outside, and the reducing gas is brought into contact with the liquid phase epitaxial growth solution inside. Since impurities such as oxygen and sulfur contained in the growth solution are removed by this method, this growth device allows high-purity epitaxial growth while purifying the growth solution that starts liquid phase epitaxial growth. The layers can be obtained in succession.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. 1st
- Figure 3 is a sectional view of one embodiment of the present invention, and Figures 4 and 5 are sectional views of other embodiments, showing the same parts as Figures 6 and 7.
Also, the same reference numerals are given to parts that act the same, and 13 is a shutter that opens and closes the ventilation passage so that reducing gas such as hydrogen that has flowed in from the gas inlet passage 14 flows out from the gas outlet passage 15. It is.

The difference between this embodiment and the conventional liquid phase epitaxial growth apparatus is that before the liquid phase epitaxial growth solution 12 in the solution container 9 is pushed up into the substrate holder 8, the growth solution is brought into contact with a circulating reducing gas. The point is to remove impurities inside.

In the embodiment not shown in FIGS. 1 to 3, the reducing gas ventilation operation is performed by causing the reducing gas to flow into the space between the substrate holder 8 and the solution storage section 9 through the gas inflow path 14 and flow out through the gas outflow path 15. A ventilation passage and a shutter 13 are provided, and the ventilation passage is opened and closed by Fj movement operation of the shutter 13.

This apparatus is installed inside a reaction tube in a heating furnace in the state shown in FIG. Then, reducing hydrogen gas serving as an atmosphere is introduced, passes around the apparatus, flows in from the gas inflow path 14, passes over the liquid phase epitaxial growth solution 12, and flows out from the gas outflow path 15. During this time, the growth solution 12
The atmospheric gas above is efficiently replaced with hydrogen gas.

When the temperature is raised in this state, volatile impurities are released from the growth solution 12. Further, although oxygen and moisture come out from the inner wall of the apparatus, they are easily replaced by the flowing hydrogen gas, and the growth solution 12 is purified in a short time.

Once the growth solution 12 has been sufficiently purified in this way, the shutter 13 is pulled as shown in FIG. 2, and the gas inflow path 14 and outflow path 15 are closed.

In this state, the temperature of the heating furnace begins to decrease, and when the temperature has dropped several degrees Celsius, the piston 1o is pushed in as shown in FIG.
contact with. When the epitaxial growth layer has grown to a predetermined film layer, the piston 10 is pulled and the growth solution 1
2 is dropped into the solution storage section 9, and the substrate 11 and the growth solution 1 are
2 and separate.

In other embodiments shown in FIGS. 4 and 5, the ventilation path is arranged so that the substrate holder 8 or the solution storage section 9 slides sideways to form the gas inflow path 14.
It is formed so that the reducing gas flows in through the gas outlet passage 15 and flows out from the gas outlet passage 15, and the ventilation passage is opened and closed.

The operation of this device is as shown in FIG.
is slid horizontally to the left to allow hydrogen gas to flow in from the gas inflow path 14, pass through the upper part of the liquid phase epitaxial growth solution 12, and flow out through the gas outflow path 15. During this time, impurities are replaced with hydrogen gas in the same manner as in the previous embodiment, and then the λ1 plate 8 is returned to its original position as shown in FIG.
Thereafter, one bitaxial growth layer was grown to a predetermined thickness by the same operation as in the above example, and the substrate 11 and the growth solution 12 were grown.
and can be separated.

The apparatuses of these embodiments have a simple structure and can easily replace the atmospheric gas above the liquid phase epitaxial growth solution 12 in the solution storage section 9 with a reducing gas in a short time. In addition, volatile impurities emitted from the walls of the equipment and the growth solution during back-warming can be efficiently removed in a short time, and therefore only a small amount of hydrogen gas and electricity is needed, making it easy to grow high-purity epitaxial layers. And it can be obtained stably.

[Effects of the Invention] As explained above, according to the present invention, impurities can be removed from a solution for liquid phase epitaxial growth and other materials with easy operation, and a high-purity single-bitaxial growth layer can be stably produced, making it suitable for industrial use. It can have an excellent effect of being suitable for production.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views of a liquid-phase epitaxial growth apparatus according to one practical example of the present invention, FIGS. 4 and 5 are cross-sectional views of a liquid-phase epitaxial growth apparatus according to other embodiments, and FIGS. 6 and 7 are 1A and 1B are cross-sectional views showing examples of conventional liquid phase epitaxial growth apparatuses. 1: Solution for liquid phase epitaxial growth, 2: Solution holder, 3: Upper shutter, 4: Part of substrate holder, 5: T-shutter, 6: Solution storage section, 7: Substrate, 8: Substrate holder, 9: Solution accommodating part, 10: piston, 11: substrate, 12: epitaxial growth solution, 13: shutter, 14: gas inflow path, 15: gas outflow path. 40th 51st ■

Claims (4)

[Claims] (1) A solution storage part having a piston mechanism is provided at the bottom of a substrate holder containing a substrate, and a liquid phase epitaxial growth solution in the solution storage part is pushed up into the inside of the substrate holder to grow an epitaxial layer on the substrate. A liquid phase epitaxial growth method characterized in that, before the liquid phase epitaxial growth solution in the solution storage section is pushed up into the substrate holder, impurities in the growth solution are removed by bringing it into contact with a circulating reducing gas. . (2) A solution for liquid phase epitaxial growth is stored in the lower part of a substrate holder in which a plurality of substrates for liquid phase epitaxial growth are arranged in a vertical direction so that it can be moved up or down into the substrate holder by operating a piston. A liquid phase epitaxial growth apparatus provided with a solution storage section, characterized in that an air passage through which a reducing gas flows is provided between the substrate holder and the solution storage section so as to be openable and closable. Device. (3) A shutter is provided between the substrate holder and the solution storage section so that the ventilation path is formed, and the ventilation path is opened and closed by operating the shutter. 2. The liquid phase epitaxial growth apparatus according to item 2. (4) The liquid phase epitaxial growth apparatus according to claim 2, wherein the substrate holder or the solution storage section slides laterally to form the ventilation path and to open and close the ventilation path.