JPH0415914A - Vapor growth film formation device - Google Patents

Abstract

PURPOSE:To obtain a film of uniform crystal thickness or uniform thickness by a method wherein material and a substrate are heated to different temperatures in an air-tight container with a transport agent enclosed in, a crystal is developed on the substrate and the temperature is equalized near the substrate at the time of formation of a film. CONSTITUTION:A semiconductor wafer for material supply 5 and a semiconductor wafer for a substrate 6 are secured on both ends of a grow chamber 4 in a quartz ampoule 10. With a transport agent enclosed in the grow room 4, the quartz ampoule 10 is so heated in a temperature gradient electric furnace 9 that the semiconductor wafer for material supply 5 is heated to high temperature and the semiconductor wafer for a substrate 6 is heated to low temperature. If a liner tube 8 is installed outside of the quartz ampoule 10 at this time, radiant heat emitted from the wall of the furnace 9 is first absorbed by the liner tube 8 to be made uniform and then is emitted again toward the quartz ampoule 10. Thus, the temperature is equalized near the semiconductor wafer for a substrate 6 and a semiconductor film of uniform thickness and uniform quality can be formed on the surface of the semiconductor wafer for a substrate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vapor phase deposition film forming apparatus for performing semiconductor epitaxial crystal growth and film formation by closed tube vapor phase growth.

[Prior art] Figure 4(a) is an analogy that has been used in the past.
FIG. 2 is a cross-sectional configuration diagram showing a vapor phase growth film forming apparatus that performs semiconductor epitaxial crystal growth and film formation by the closed tube vapor phase growth method described in the specification of Japanese Patent Application No. 2275. In this figure, (1) is a quartz outer tube for storing the contents, and (2) is a quartz inner tube for fixing the contents and vacuum welding, and the quartz outer tube (1) and quartz inner tube (2) are sealed together. A quartz ampoule (10), which is a container, is constructed. (3) is the quartz outer tube (1) and the quartz inner tube (2)
(4) is a quartz ampoule (L).
(5) a growth chamber in which film formation is performed by vapor phase growth in O);
is a semiconductor wafer for supplying raw materials for supplying epitaxial crystal constituent elements, which is disposed at one end of the growth chamber (4);
6) is a semiconductor wafer for raw material supply (
5) is a substrate semiconductor wafer which is a substrate on which crystals are grown, (7) is a transport agent, and (9) is a temperature gradient type for heating a quartz ampoule (10) with a temperature difference. The electric furnace is composed of a temperature gradient type electric furnace high temperature section heater (9a) and a temperature gradient type electric furnace low temperature section heater (9b).

Next, the operation will be explained.

A raw material supply semiconductor wafer (e.g. InP) (5) and a substrate semiconductor wafer (e.g. InP) (6) are fixed at both ends of the growth chamber (4) in a quartz ampoule (10), and a transport agent (e.g. InCh) (7) is sealed in the growth chamber (4).

This quartz ampoule (10) is transferred to a semiconductor wafer for raw material supply (
5) is high temperature (e.g. 750°C), semiconductor sea urchin A for substrate (
6) is placed in a temperature gradient electric furnace (9) and heated so that the temperature is low (for example, 650° C.). At that time, the temperature distribution on the wall surface of the quartz ampoule (10) in this conventional device was v!
This is shown in the graph of Figure I4 (b). By heating, the growth chamber (4
), the following phenomena occur. That is, generation of raw material gas is observed in the raw material supply semiconductor wafer (5) due to the etching action of the gasified transport agent (7), and this generated raw material gas is transferred to the raw material supply semiconductor wafer (5) and the semiconductor substrate. Due to the equilibrium partial pressure of the temperature difference provided between the wafers (6), it is transported by diffusion, convection, etc. to the surface of the substrate semiconductor wafer (6) located in the low temperature part. The transported raw material gas causes a crystal growth reaction to occur on the surface of the semiconductor wafer (6) for substrate, forming a film. However,
Gas convection occurs in the growth chamber (4) due to the presence of gravity and temperature difference, and a concentration difference of the source gas occurs on the surface of the semiconductor wafer for substrate (6). As a result, there is a problem in that the thickness or quality of the grown crystal becomes non-uniform. In addition, FIG. 5(a) shows a quartz ampoule (lO
) is an explanatory diagram schematically showing the velocity distribution of the raw material gas when horizontal, and FIG. 5(b) is an explanatory diagram showing the concentration distribution of the raw material gas using isoconcentration lines.

[Problems to be Solved by the Invention] Since semiconductor closed-tube vapor phase growth is performed in the conventional vapor phase deposition apparatus as described above, gas convection occurs in the growth chamber due to gravity and temperature differences. Therefore, there is a problem that a difference in the concentration of the raw material gas occurs on the substrate surface, resulting in non-uniformity in the thickness or quality of the grown crystal film.

This invention was made in order to solve the above-mentioned problems, and it is a film-forming H that can realize vapor phase growth that can obtain a film with a uniform crystalline thickness or film quality even under gravity.
The purpose is to provide a

[Means for Solving the Problems] The vapor phase growth film forming apparatus of the present invention produces raw materials generated from raw materials by heating the raw materials and a substrate by creating a temperature difference between the raw materials and the substrate in a closed container filled with a transport agent. This device transports gas to grow crystals on a substrate ball to form a film, and is equipped with a heating means to maintain a uniform temperature in the vicinity of the substrate.

[Function] The heat equalizing means in the vapor phase growth acid M apparatus of the present invention, for example, the heat equalizing tube provided on the outer periphery of the sealed container near the substrate, makes the temperature near the substrate of the sealed container uniform, and maintains a substantially constant temperature near the substrate. Form an isothermal region. Therefore, in vapor phase growth using this device, the temperature of the sealed container is almost constant near the substrate, so gas convection caused by gravity and temperature differences is suppressed in this area, and the source gas flows toward the substrate. The transport of is mainly due to diffusion, and the difference in the concentration of the raw material gas on the substrate surface becomes small, so the crystal film thickness and film quality become uniform even under gravity.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a cross-sectional configuration diagram showing a vapor phase growth film forming apparatus according to an embodiment of the present invention. In the figure, (8) is a heating means for keeping the vicinity of the substrate semiconductor wafer (6) at a uniform temperature. , conductor wafer for substrates (6)
This is a heat soaking pipe (for example, a steel pipe) installed in the vicinity. Note that the same reference numerals as in FIG. 3 indicate the same components.

Next, the operation will be explained.

A raw material supply semiconductor wafer (for example, 1nP) (5) and a substrate semiconductor wafer (6) (for example, I nP) are fixed at both ends of the growth chamber (4) in a quartz ampoule (10), and a transport agent (for example, I nCI+) is sealed in the growth chamber (4).

This quartz ampoule (10) is transferred to a semiconductor wafer for raw material supply (
5) When the temperature is high (e.g. 750°C), the semiconductor wafer for substrate (
6) is placed in a temperature gradient electric furnace (9) and heated so that the temperature is low (for example, 650° C.). At this time, since the soaking tube (8) is provided outside the quartz ampoule (10), the furnace (9)
) The radiant heat from the wall is absorbed by the heat soaking tube (8), made uniform, and re-radiated toward the quartz ampoule (lO), so that
A constant temperature region where the temperature of the quartz ampoule (lO) is approximately constant is created near the semiconductor wafer (6) for substrate (indicated by A in the figure). That is, the temperature near the semiconductor wafer (6) for substrate becomes uniform. The graph in FIG. 1(b) shows the temperature distribution on the wall surface of the quartz ampoule (10) at this time. Due to heating, the following phenomenon occurs in the growth chamber (4). That is,
On the semiconductor wafer for raw material supply (5), generation of raw material gas was observed due to the etching action of the gasified transport agent (7), and this generated gas was transferred to the semiconductor wafer for raw material supply (5).
) and the semiconductor wafer for substrate (6) due to the equilibrium partial pressure of the temperature difference, the semiconductor wafer for substrate (6) is transported to the surface of the semiconductor wafer for substrate (6) located at the low temperature part by diffusion, convection, etc. Semiconductor wafers for substrates (
6) A crystal growth reaction occurs on the surface and a film is formed. By the way, in this embodiment, the temperature distribution near the semiconductor wafer for substrate (6) is almost constant due to the soaking tube (8).
In this part, gas convection due to the presence of gravity and temperature difference is suppressed, and the transport of the raw material gas is mainly due to diffusion, so that the concentration difference on the surface of the semiconductor wafer (6) for substrate becomes small. Therefore, a semiconductor film with uniform thickness and quality can be obtained.

FIG. 2(a) is a cross-sectional configuration diagram showing a vapor phase growth film forming apparatus according to another embodiment of the present invention. In the above embodiment, the soaking tube (8) was provided only near the semiconductor wafer (6) for the substrate to form an equal temperature region, but in this embodiment, in order to uniformly supply the raw material gas, (5) Near (
A soaking tube (8) is provided both in the vicinity of the semiconductor wafer (6) (indicated by B in the figure) and the substrate semiconductor wafer (6) to form an equal temperature region. FIG. 2(b) is a graph showing the temperature distribution on the wall surface of the quartz ampoule (10) at this time.

Note that FIG. 3(a) is an explanatory diagram schematically showing the velocity distribution of the raw material gas in the example of FIG. 2(a), obtained by three-dimensional thermal-hydraulic analysis under the same conditions as the conventional example. Figure 3 (
b) is an explanatory diagram showing the concentration distribution of the raw material gas using isoconcentration lines. Large convection occurs in areas where there is a temperature gradient on the wall surface, and in areas where there is no temperature gradient, convection is small in areas of equal temperature. Diffusion becomes dominant. For this reason, semiconductor wafers for raw material supply (5)
The difference in the concentration of the raw material gas near the hill and the lower part of the substrate semiconductor wafer (6) is small. Therefore, highly uniform crystal film formation can be achieved.

In this way, by forming an isothermal region with a uniform temperature near the substrate, it is possible to form a crystalline film with a uniform thickness and quality even under gravity.

In addition, although the above embodiment shows the case where quartz is used as the material of the closed container, the same effect can be obtained even when other heat-resistant materials are used.

Further, although a steel pipe is used as an example of the heat-uniforming pipe, the same effect can be achieved even if other materials are used as long as they have heat resistance and good thermal conductivity.

[Effects of the Invention] As described above, the present invention transports the raw material gas generated from the raw material by heating the raw material and the substrate by creating a temperature difference between the raw material and the substrate in a closed container filled with a transport agent. The vapor phase growth film deposition system that grows crystals and forms films on the substrate is equipped with a soaking means to maintain a uniform temperature near the substrate.
The nearby temperature remains almost constant. As a result, gas convection caused by the presence of gravity and temperature differences is suppressed in this region, so diffusion is dominant in the transport of the source gas to the substrate in this region, and the source gas near the substrate surface is This has the effect of making the concentration distribution uniform and forming a film with uniform crystal film thickness and film quality even under gravity.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional configuration diagram showing a vapor phase growth film forming apparatus according to an embodiment of the present invention, FIG. 1(b) is a graph showing the temperature distribution of the closed container, and FIG. 2(a) is a graph showing the temperature distribution of the closed container. A cross-sectional configuration diagram showing a vapor phase growth film forming apparatus according to another embodiment of the present invention, FIG. 2(b)
is a graph showing the temperature distribution of the sealed container, Figure 3(a)
is an explanatory diagram showing the velocity distribution of the source gas in another embodiment of the present invention, FIG. 3(b) is an explanatory diagram showing the concentration distribution of the same, and FIG. 4(a) is a conventional vapor phase growth film forming apparatus. FIG. 4(b) is a graph showing the temperature distribution of the closed container, FIG. 5(a) is an explanatory diagram showing the velocity distribution of the raw material gas in the conventional example, and FIG. It is an explanatory diagram showing concentration distribution in the same case. In the figure, (lO) is a quartz ampoule that is a closed container, consisting of an outer quartz tube (1) and an inner quartz tube (2).
(4). (5) is a raw material supply semiconductor wafer that supplies epitaxial crystal constituent elements, which are raw materials; (6)
is a substrate semiconductor wafer on which crystals are grown, (
7) is a transport agent, (8) is a heat soaking tube which is a heat soaking means, (9)
is a temperature gradient type electric furnace with a temperature gradient type high temperature section heater (9
a) Consists of a temperature gradient type electric furnace low temperature section heater (9b). In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A raw material and a substrate are arranged facing each other in a sealed container, a transport agent is sealed, and a temperature difference is created between the raw material and the substrate to heat the whole, thereby transporting the raw material gas generated from the raw material to the substrate. What is claimed is: 1. A vapor phase growth film forming apparatus for forming a film by growing crystals thereon, characterized in that the apparatus is provided with a soaking means for maintaining a uniform temperature in the vicinity of the substrate.