JPS6050919A - Vapor growth device - Google Patents

Abstract

PURPOSE:To prevent the deposit of product on a wall surface and increase the efficiency of reaction of reaction gas by a method wherein an exhaust nozzle is provided facing a mixed gas supply nozzle across a susceptor, and gas flows are formed only on the surface of an Si substrate. CONSTITUTION:A carrier gas released from a carrier gas supply port 18 flows toward an exhaust port 22. On the other hand, the mixed gas of the reaction gas released from a nozzle 24 with the carrier gas flows along the surfaces of the Si substrate 15 and the susceptor 23. In this case, the exhaust nozzle 27 is arranged in back of the susceptor 23 and made to act a compulsive exhaust force through an aperture 26, therefore the flow of the mixed gas on the surface of the susceptor 23 and the flow of carrier gas above it flow over the susceptor 23 while keeping parallel. Thereby, the amount of source gas or that of doping gas can be kept to a necessary minimum. Besides, the generation of unnecessary deposits on the wall surface of a reaction chamber 8 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vapor phase growth apparatus used in particular in the semiconductor industry.

Conventional Structure and Problems There is a process in the semiconductor industry in which a reactive gas is supplied onto a silicon substrate to form a film of a reactant on the surface of the substrate. In particular, by heating a silicon single crystal substrate to a temperature usually above 1000°C and supplying a mixed gas of silicon tetrachloride, dichlorosilane, or monorane with hydrogen, a silicon single crystal film is formed. can be formed and is called an epitaxial growth process. A reaction chamber portion of a conventional apparatus for forming such a film is shown in FIG. This device consists of a quartz tube 1 and a base 3 on which a silicon substrate 2 on which a film is to be formed is mounted. (hereinafter referred to as a sasefuri), a work coil 4 that heats the sasefuri 3, a gas supply nozzle 5, an exhaust port 6, and a door 7. By applying high frequency power to the work coil 4, the susceptor 3 and the silicon substrate 2 are heated to an appropriate temperature of 1000"C or more. On the other hand, a gas supply device (not shown) is used to heat the reaction of silicon tetrachloride, etc. A doping gas such as phosphine is mixed with hydrogen gas at a predetermined concentration, and this mixed gas is supplied from the gas supply nozzle 5 into the reaction chamber.

This mixed gas spreads throughout the reaction chamber and flows toward the exhaust port 6, and at this time, it contacts the susceptor 3 and the silicon substrate 2, absorbs heat, and the reaction gas molecules that reach a predetermined temperature or higher are separated and separated to form a film. Form. In such a device,
The temperature of the mixed gas shows a rapid temperature change along the gas flow direction on the susceptor 3, and therefore the thickness of the gas layer that contributes to the fractional separation also changes greatly, and the film thickness and resistivity change along the gas flow direction. It is easy to change. Therefore, in order to increase the uniformity of film thickness and resistivity, it is first necessary to increase the average flow velocity and suppress the gradient of temperature and concentration changes along the gas flow direction. A large amount of gas supply of about 1007 minutes is required. Furthermore, the reactant gas in the gas layer separated from the susceptor 3 and the silicon substrate 2 is discharged as unreacted 1-1, resulting in a disadvantage that the reaction efficiency is low. Furthermore, the high-temperature gas that comes into contact with the susceptor 3 and the silicon substrate 2, which are heated to a high temperature of 1000°C or more, becomes an upward air current due to convection, leaves the susceptor 3, and flows toward the top surface of the quartz tube 1. As a result, reaction products also adhere to the inner surface of the quartz tube 1, necessitating frequent maintenance work to clean the quartz tube 1.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and has a simple structure that increases the reaction efficiency of reaction gas, reduces the overall gas consumption, and further reduces the adhesion of reaction products to the wall surface of the reaction chamber. The purpose is to provide a vapor phase growth apparatus that is free of

Composition of the Invention The vapor phase growth apparatus of the present invention includes a gas supply apparatus having two supply pipes, a carrier gas supply pipe and a mixed gas supply pipe containing a reaction gas, a susceptor, and a susceptor mounted on the susceptor. a means for heating the silicon substrate, a carrier gas supply port, a gas discharge port, a mixed gas supply nozzle connected to the mixed gas supply pipe, and a position facing the mixed gas supply nozzle with the susceptor in between. A carrier gas flow containing no reactive gas is formed in the entire reaction chamber, and in this flow, a gas containing reactive gas is generated only on the surface of the silicon substrate. By forming a flow, the amount of gas consumed can be reduced and the generation of unnecessary deposits on the wall surface of the reaction chamber can be suppressed.

DESCRIPTION OF THE EMBODIMENTS The embodiments of the present invention will be explained below with reference to FIGS. 2 and 3. FIG. 2 is a cross-sectional view of a reaction chamber in an apparatus embodying an embodiment of the present invention, and the reaction chamber 8 has a wall member 1o made of a heat-resistant and corrosion-resistant metal such as stainless steel and provided with water cooling grooves 9 inside. and an upper opening/closing block 11. An infrared lamp heater unit 12 is installed inside the upper opening/closing block 11, and a transparent quartz plate 13 is installed near the infrared lamp heater unit 12 using known gas sealing means such as a ring. It is fixed by a fixture 14 via. As is clear from the perspective view of FIG. 3, this upper opening/closing block 11 can move up and down, and by lifting it upward, the upper part of the reaction chamber opens and silicon substrates 150 can be loaded and taken out. Further, by lowering this upper opening/closing block 11 and fixing it in a position where it is in contact with the wall member 1Q while sandwiching the +1417 ring 16, an airtight chamber is formed from outside air. Further, at one end of this reaction chamber 8, there is a carrier gas supply port 18 connected to a carrier gas supply pipe 17 extending from a gas supply device (not shown), and at the other end,
It has an exhaust port 22 to which an exhaust pipe 21 is connected to a vacuum pump 20 via a variable throttle valve 19. The wall member 10 near the carrier gas supply port 18 and the exhaust port 22 has a tapered internal shape, so that the gas introduced from the carrier gas supply port 18 gradually flows along the tapered shape. It spreads,
In the center of the reaction chamber, the flow fills the entire area, and on the exhaust side, the flow gradually becomes contracted due to the tapered throttle and flows without stagnation. Inside the reaction chamber 8, a susceptor 23 on which a silicon substrate 15 is placed is a transparent quartz plate 13.
It is installed at a position facing the infrared lamp heater unit 12 with the lamp in between. Further, a nozzle 24 connected to a mixed gas supply pipe of a gas supply device (not shown) penetrates the wall member 1o into the reaction chamber 8, and is adjacent to the carrier gas supply side of the susceptor 23. This nozzle 24 is made of transparent quartz and has a pipe shape with one end sealed, as shown in Fig. 3, and has a length approximately equal to the width of the susceptor 23 on the susceptor side. A gas blowing slit 25 is provided. Also, the susceptor 23
An exhaust nozzle 27 having an opening 26 is installed at a position facing the nozzle 24 across the exhaust nozzle 27 . This exhaust nozzle 27 is connected to an exhaust pipe 30 connected to a vacuum pump 29 via a variable throttle valve 28, as seen in FIG.

The reaction chamber in the apparatus of this embodiment has the above structure, and during epitaxial growth, a carrier gas such as hydrogen is supplied into the reaction chamber B through the carrier gas supply port 18, and at the same time, a carrier gas such as hydrogen is supplied through the nozzle 24. A hydrogen-based gas mixture containing a source gas such as chlorosilane and a doping gas such as phosphine at appropriate concentrations is supplied.

The carrier gas discharged from the carrier gas supply port 18 spreads along the tapered shape of the entrance of the reaction chamber 8 and flows toward the exhaust port 22 while filling the entire reaction chamber 8. On the other hand, the mixed gas coming out of the slit 25 of the nozzle 24 flows along the surface of the silicon substrate 16, which is located in the center of the reaction chamber 8 and is heated to a predetermined temperature, and the susceptor 23 on which it is placed. . During this time, heat is applied from the susceptor 23 and the gas gradually becomes high temperature. At this time, in the conventional example, since the temperature of the gas flow flowing in the upper layer is low, convection occurs between the surface high temperature gas layer of the susceptor 23, and therefore the surface gas flow in the rear half of the susceptor 23 becomes an extremely complicated flow. As a result, it becomes difficult to uniformly control the thickness of the grown film. Moreover, unnecessary reaction products will adhere to the upper wall surface of the reaction chamber.

However, in this embodiment, the exhaust nozzle 27 is arranged behind the susceptor 23 and a forced exhaust force is applied through the opening 26, so the thermal convection phenomenon is alleviated, and the flow of the mixed gas on the surface of the susceptor 23 is reduced. The flow of the carrier gas in the upper layer remains parallel to the susceptor 23. In this way, the pressure state within the reaction chamber 8 or the flow state of the entire reaction chamber 8 is controlled through the carrier gas supply port 18. This vapor phase growth reaction on the silicon/substrate 16 is controlled by the flow rate of the carrier gas to be sent, while being determined only by the gas layer on the surface of the silicon substrate 150. can be controlled by the exhaust capacity through the exhaust nozzle 27, which is determined by the adjustment of the exhaust nozzle 27. Therefore, the amount of source gas or doping gas can be kept to a small level. Furthermore, in order to obtain homogeneity of the grown film, an average flow rate in the reaction chamber of 10 cm per second or more is required in the conventional apparatus, but in this embodiment, the gas flow rate ejected through the nozzle 24 is set to a predetermined value or higher. The flow rate of the carrier gas supplied through the carrier gas supply port 18, which determines the flow rate of the entire reaction chamber 8, may also be the minimum necessary.

Furthermore, unnecessary deposition on the walls of the reaction chamber, which was a problem in conventional devices, is eliminated, and the inside of the reaction chamber 8 can be kept clean simply by replacing and cleaning the exhaust nozzle 27, greatly reducing maintenance work, etc. Ru.

In this example, an infrared heating method was used as the heating means, and a corresponding reaction chamber structure was adopted, but it is clear that the present invention can also be applied to devices using other heating methods. It is also possible to provide the nozzle 24 or the exhaust nozzle 27 so as to penetrate the wall member 10 from both sides. Furthermore, it is clear that the present invention is not limited to application to silicon single crystal growth, but can be applied to other film forming apparatuses.

Effects of the Invention As described above, the present invention provides a mixed gas supply nozzle and an exhaust nozzle, respectively, with a susceptor on which a silicon substrate is mounted, in addition to the supply port and exhaust port for the carrier gas flowing through the entire reaction chamber. With this structure, the gas layer on the surface of the silicon substrate that contributes to the vapor phase growth reaction can be controlled separately from the gas flow throughout the reaction chamber, increasing the reaction efficiency and reducing the overall gas consumption. There is no unnecessary deposition on the wall surface of the reaction chamber, and maintenance work can be significantly reduced, which is highly effective.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a reaction chamber of a conventional high-frequency heating type epitaxial growth apparatus, FIG. 2 is a sectional view of a reaction chamber of a vapor phase growth apparatus according to an embodiment of the present invention, and FIG. 08...reaction chamber, 12... which is a perspective view of a section broken away.
...Infrared lamp heater unit, 13...
Transparent quartz plate, 15...Silicon substrate, 18
... Carrier gas supply port, 22 ... Exhaust port, 23 ... Susceptor, 24 ... Nozzle, 27 ... Exhaust nozzle. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] A gas supply means having at least two systems of supply pipes, a carrier gas supply pipe for supplying a carrier gas and a mixed gas supply pipe for supplying a reaction gas or a mixed gas of a reaction gas and a carrier gas; A base on which a substrate to be formed is placed, a means for heating the substrate and the base, a reaction chamber in which the base is installed, and one end of the reaction chamber connected to the carrier gas supply pipe. a first exhaust port connected to a first exhaust pipe having a reed and a first forced exhaust means at the other end of the reaction chamber;
Connected to the mixed gas supply pipe and extending into the reaction chamber through the wall member forming the reaction chamber, a reaction gas or a mixture of reaction gas and carrier gas is applied to the surface of the substrate placed on the base. A second gas supply port having an opening through which gas is blown, and a second exhaust pipe having a second forced exhaust means, and extending into the reaction chamber through a wall member of the reaction chamber. and a second exhaust port having an opening at a position facing the second gas supply port across the base.