JPS5826099A - Liquid phase epitaxial growing method and boat for growth - Google Patents

Abstract

PURPOSE:To enhance the productivity of a growing method by forming the soln. sliding surface of a substrate supporting table with a detachable inserted plate and by carrying out liq. phase epitaxial growth while cleaning a contaminated inserted plate in a groove cut in a soln. holding table. CONSTITUTION:The surface of the substrate supporting table 1 of a carbon boat for growth contacting with a soln. is formed with a detachable inserted plate 11 made of carbon, and the upper surface of the plate 11 is allowed to coincide with the upper surface of the table 1. A groove 12 is cut in the soln. holding table 3 having a plurality of soln. reserving chambers 4, 4..., and a contaminated inserted plate 11 is put in the groove 12 and cleaned by contact with a soln. contg. the same components as a soln. for epitaxial growth, a soln. contg. one of the components, or a soln. exerting no influence on an epitaxially grown layer. The plate 11 is cleaned while carrying out liq. phase epitaxial growth using said boat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to liquid phase epitaxial growth methods and growth boats, and more particularly to improvements that increase the productivity of the growth methods.

In recent years, the liquid phase epitaxial growth method has been used especially for the layered growth of compound semiconductors, which involves bringing a solution into contact with the substrate surface,
This method involves growing several epitaxial layers through delicate temperature control, but adjusting the impurity concentration contained within the layers is an important and difficult problem. Since the impurity concentration is related to the number of electrons and holes, which is proportional to the electrical conductivity, it is also called the intermediate concentration, and there is a large difference in the intermediate concentration.
When growing epitaxial layers, the carbon growth boat is contaminated by many impurities (doping agents) contained in the solution used to grow the layer with high concentration, and then the boat is If you try to grow another layer with a low carrier concentration using a low carrier concentration solution, impurities will be dissolved from the contaminated boat and the grown layer will have a low carrier concentration. Without it, the concentration becomes high and the concentration cannot be adjusted.

Therefore, once used and contaminated growth boats,
The carbon boat is cleaned by high-temperature heat treatment in vacuum to evaporate impurities, or by contacting the solution with the contaminated surface at high temperature in high-purity hydrogen to dissolve impurities in the solution and remove them. A method has been adopted to do so. However, such cleaning JI&C requires time and man-hours similar to the geographical process of liquid phase epitaxial growth, which reduces productivity by half. That is, in order to constantly perform epitaxial growth, it is necessary to have a plurality of high-temperature heat treatment furnaces for growth processing and cleaning processing, and a plurality of carbon boats.

The present invention aims to solve such unproductive problems, and in a growth boat consisting of a substrate support stand and a solution holding stand, the solution sliding surface of the substrate support stand has a removable insertion plate. Using a growth boat with a recessed groove on the solution holding table surface into which another insertion plate is fitted,
At the same time as liquid phase epitaxial growth! ! This paper proposes an epitaxial growth method for cleaning an insertion plate by using a groove in one part, and a boat for the growth, which will be described in detail below with reference to the drawings.

FIG. 1 shows a cross-sectional view of a conventionally used carbon boat for growth, in which a growth substrate 2 is placed on a substrate support 1, solution components are poured into a reservoir chamber 4 of a solution holding table 3, and the The carbon boat thus prepared is placed in a high-temperature heat treatment furnace, and the solution components are dissolved in solutions 5 and 6. Then, slide the solution holding table 3 to the left on the solution sliding surface S of the substrate support table 1, align the growth target substrate 2 and the solution 5, grow an epitaxial layer from the solution 5, and then move the solution holding table 3 to the left again. The substrate 2 to be grown is brought into alignment with the solution 6, and another epitaxial layer is grown thereon from the solution 6. Figure 1 shows a boat with three liquid storage chambers 4, but normally there are seven to seven.
Many boats are equipped with 10 liquid reservoir chambers 4, and when an epitaxial layer is grown on the growth substrate 2 as described above, the impurities contained in each solution 5.6 are resistant to adhesion or dissolution on the slide wS. It gets stuck in and contaminates the slide INS.

Therefore, a contaminated boat is heated at <700~B, which is the same as the epitaxial growth temperature and time.
As mentioned above, this will reduce productivity.

No. 2 III shows a cross-sectional view of the carbon boat according to the present invention, and the slide surface that comes into contact with the melted solution 5 is removed to form an insert plate 11. The insertion plate 11 is made of carbon like the entire boat, and is a flat plate having a plate thickness of 5 mm, for example, and which, when fitted, corresponds to the upper surface of the substrate support. FIG. 3 shows a three-dimensional view of the substrate support 1,
Fit the insertion plate 11 as shown in the figure. In Figure 13, 7 is a holding hole for the growth substrate, and it is necessary to create a carbon boat with this structure, install a plurality of insertion plates 11, and change the insertion plates 11 for each growth process. Ba,
This carbon boat does not need to be cleaned and processed, and the same type of liquid phase epitaxial growth method can be used without restriction.

Furthermore, FIG. 4 shows a three-dimensional view of the entire carbon boat for growth according to the present invention, and the cross section shown at A in the same figure is the same as that shown in FIG. A recessed groove according to the present invention is provided on the upper surface of the solution holding table 3, and FIG. 5 is a view showing the recessed groove 12 in section BB'. The plane of the recess groove 12 has the same dimensions as the plane of the insertion plate 11, and in this recess 1llL2, the insertion plate 11 is fitted as shown by the dotted line in Fig. Impurities on the sliding surface of the plate 11 can be dissolved and removed.

Using the growth boat constructed as described above, one insertion plate is fitted onto the substrate support 1, and at the same time, the growth process in the liquid phase Evita is performed, and at the same time, the other insertion plates that have already been contaminated are removed. Insert it into the fourth part #I12 and add a solution with the same component as the solution being grown in Evita, or one of the solution components.
If the impurities adhere to or dissolve into the insert plate by contacting it with other mixed liquids (solutions that do not evaporate at heating temperatures) that have no effect on the growth of Evita shells, production will be doubled. can be done.

As an example to confirm the cleaning effect of the present invention, InPI
On the II plate, a low to medium concentration of In containing *(S) was applied.
The F3 layer is grown to a film thickness of 15 pieces, and then 1&
An In6 layer with a medium concentration was grown to a thickness of 2 μm, and the medium concentration of the epitaxially grown layer was measured. As a result, when a clean carbon boat is used, the concentration in the InF3 layer is 1 to 1.5 x 10''4 + InPt.
While the concentration in the layer is 4 x 101-,
In a contaminated carbon boat, the carrier concentration in the InPI layer was as high as 3 to 4 x 10'/, but when using the boat according to the present invention, the carrier concentration in the InF layer was stably reduced to 1 to 1.5. X 10', 2 r I!I P
, it was found that the inner layer concentration 4 x 10''4 can be obtained.Also, as another example, the inner layer concentration 5 × IA l rn P, the inner layer concentration 4 x 10
It was found that the growth layer with a large difference in concentration during the period of - is repeatedly modeled by growth. In this example, high-purity indium (In) was used as a solution for dissolving and removing impurities by contacting the contaminated insertion plate using a four-part groove.

As is clear from the above description, the present invention is an extremely effective method for mass production of liquid phase epitaxial growth, and is therefore useful for lowering the cost of semiconductor devices.

Note that when epitaxial layers of different types are grown in the same boat, it is necessary to also clean the liquid reservoir chamber, so it is natural that a conventional cleaning method must be used.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional growth boat, and FIG. 2 is a sectional view of a conventional growth boat. 3, 4, and 5 are sectional views and three-dimensional views 1 and 1 partial sectional views of the growth boat according to the present invention. In the figure, 1 is a substrate support stand, 2 is a growth substrate, 3 is a solution holding stand, 4 is a liquid reservoir chamber, 5 and 6 are solutions, 7 is a substrate holding hole, l
1 indicates an insertion plate, and 12 indicates a four-part groove. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) In the liquid phase epitaxial growth method, which is carried out by sliding a solution holding table on the substrate support of a growth boat, the solution sliding surface of the substrate support is a removable insertion plate, and there are multiple insertion plates. At the same time, the other insertion plate is fitted into the recess groove provided in the solution holding table, and the same component solution as the solution used for epitaxial growth, or its component solution, is fitted onto the sliding surface of one insertion plate to perform liquid phase epitaxial growth. Dissolving and contacting one of the solution components or another solution that does not affect the epitaxially grown layer,
A liquid phase epitaxial growth method comprising the step of cleaning the insertion plate. (No) A growth boat in which a solution holding table is slid on a substrate supporting table is fitted with a removable insertion plate on the solution sliding surface of the substrate supporting table, and a removable insertion plate is fitted on the solution holding table surface. A growth boat characterized by being provided with a recessed groove into which another identical insertion plate is fitted.