JPH0638402B2 - Gas phase reaction vessel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vapor phase growth apparatus, and more particularly to a vapor phase reaction vessel used in a vapor phase epitaxial growth apparatus used in the semiconductor industry.

Configuration of Conventional Example and Problems Thereof In the semiconductor industry, there is a step of supplying a reaction gas 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 an appropriate temperature of usually 1000 ° C. or higher and supplying a mixed gas of dichlorosilane or monosilane and hydrogen,
A silicon single crystal film can be formed, which is called epitaxial growth. As the characteristics of the film obtained in this way, reduction of autodoping and reduction of crystal defects such as slip have been strongly demanded in recent years, and as an epitaxial growth method for responding to this, there are an infrared lamp heating and a reduced pressure growth method. A conventional apparatus adopting these methods is shown in FIG. This apparatus includes a transparent quartz chamber 1, a base 3 on which a silicon substrate 2 is placed, an infrared lamp unit 4 which is located outside the transparent quartz chamber 1 and faces the base 3, and a gas. It is composed of a supply nozzle 5 and an exhaust port 6. The exhaust port 6 is connected to a vacuum exhaust device (not shown). The infrared light emitted from the infrared lamp unit 4 passes through the transparent quartz chamber 1 and irradiates the silicon substrate 2 mounted on the base 3 to heat it to a temperature of 1000 ° C. or higher. At this time, a reaction gas such as dichlorosilane mixed in hydrogen at a predetermined concentration is supplied from the gas supply nozzle 5, and while the reaction gas flows toward the exhaust port 6, the reaction gas is decomposed and deposited, and the silicon substrate A film is formed on 2. The apparatus adopting such infrared lamp heating means is characterized in that low pressure epitaxial growth is possible and further that the surface of the silicon substrate can be directly heated. However, the transparent quartz chamber 1 itself transmits infrared rays. In order to absorb a part, the chamber 1 itself gradually rises in temperature, while the mixed gas containing the reaction gas flowing in the reaction chamber is heated to 1000 ° C. or higher. As a result, the temperature rises and the upper layer remains at an inflow temperature equal to room temperature, so a very large natural convection is caused by these temperature differences, and it is considered that the reaction gas concentration is almost uniform throughout the reaction chamber. Similar to the above, silicon crystals are deposited on the inner wall of the chamber which has reached a certain temperature. Once the silicon crystals start to adhere to the wall surface of the chamber 1, the light transmittance is impaired, the absorbed light increases, the temperature rises quickly, and the adhesion to the chamber 1 increases at an accelerated rate. Further, the chan 1 itself is further heated and its strength is lowered, which is extremely dangerous as a container in which a gas mainly containing hydrogen flows. Therefore, in actual work, it is necessary to frequently perform maintenance work such as removing the transparent quartz chamber 1, cleaning it, and reassembling and checking the leak.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide an infrared lamp heating system and to provide a gas-phase reaction container in which reaction products do not adhere to the wall surface of the reaction chamber. .

The gas phase reaction container of the present invention comprises a base on which a silicon substrate is placed, light radiation heating means for heating the silicon substrate and the base, and a mixture of hydrogen and a reaction gas such as dichlorosilane. The reaction chamber is composed of a reaction chamber having a gas supply port and a gas discharge port and in which the base is installed. The wall member forming the reaction chamber is sandwiched between at least the light radiation heating means and the base. Is composed of a transparent plate that transmits radiant light, and further preheats by flowing a carrier gas such as hydrogen along this transparent plate, which has a high temperature to some extent to partially absorb the radiant light, By pre-flowing the preheated carrier gas into the upper layer of the reaction chamber, the natural convection phenomenon with the mixed gas is suppressed, and the carrier gas film is formed in the vicinity of the transparent plate. Therefore, the reaction gas does not come into contact with the transparent plate, the reaction products do not adhere, and the maintenance work is reduced and the safety is greatly improved.

Description of Embodiments Embodiments of the present invention will be described below with reference to the drawings. Second
FIG. 1 is a cross-sectional view of a reaction chamber in an apparatus embodying an embodiment of the present invention. The reaction chamber 7 has a wall member 9 made of heat-resistant and corrosion-resistant metal such as stainless steel having a water cooling groove 8 formed therein.
And an upper heater block 10. An infrared lamp heater unit 11 is installed inside the upper heater block 10, and a transparent quartz plate 12 is fixed at a position close to the infrared lamp heater unit 11 via a known gas sealing means such as an O-ring. It is fixed by the tool 13. These upper heater blocks 10 are fastened to the upper surface of the wall surface member 9 via known gas sealing means such as an O-ring. Inside the reaction chamber 7, a base (hereinafter referred to as a susceptor) 15 made of graphite coated with SiC on which a silicon substrate 14 is mounted is located at a position facing the infrared lamp heater unit 11 with a transparent quartz plate 12 interposed therebetween. is set up.
FIG. 3 shows an external view of this reaction chamber. As is clear from the drawing, an opening 17 having an opening / closing door 16 is provided in the front wall member, and the silicon substrate 14 is taken in and out through the opening 17. Further, in the reaction chamber 17, the second
As is apparent from the drawing, a gas supply port 19 having a gas supply pipe 18 extending from a gas supply device (not shown) connected to one end thereof, and an exhaust port 21 having an exhaust pipe 20 connected to the other end thereof.
Is provided. On the exhaust port side of the upper heater block 10, a carrier gas supply port 23 is formed which is connected to the carrier gas supply pipe 22 and has an opening near the lower surface of the transparent quartz plate 12. Further, as shown in FIG. 2, the outer periphery is supported by the lower end projecting portion 24 of the upper heater block 10, and the carrier gas supplied from the carrier gas supply port 23 between the lower surface of the transparent quartz plate 12 and the lower surface of the transparent quartz plate 12 is moved by the arrow. As shown in the figure, it first flows along the lower surface of the transparent plate 12 and then turns back on the gas supply port 19 side to turn the reaction chamber 7
A partition plate 25 that forms a flow path is arranged so as to eject inside. The partition plate 25 is made of a material such as transparent quartz that transmits radiant light.

The reaction container in the apparatus of the present embodiment has the above-described structure, and during the epitaxial growth, the radiation heat rays from the infrared lamp heater unit 11 are transparent quartz plate 1.
2. The susceptor 15 and the silicon substrate placed on the susceptor 15 are irradiated with light passing through the partition plate 25 and the partition plate 25, and these are heated to a predetermined temperature of 1000 ° C. or higher. At this time, by supplying a hydrogen-based mixed gas containing a reaction gas such as dichlorosilane at an appropriate concentration through the gas supply port 19, the mixed gas flows toward the exhaust port 21,
During this period, the silicon substrate 14 heated to a predetermined temperature,
The reaction gas is decomposed and precipitated from the gas phase in contact with the susceptor 15, and an epitaxially grown film is formed on the silicon substrate 14.

At this time, only hydrogen gas as a non-reacting gas is simultaneously supplied through the carrier gas supply port 23. This gas is preheated to a similar temperature while absorbing a part of the transmitted radiant light and flowing along the transparent quartz plate 12 which is usually at a temperature of about 350 to 400 ° C., and thus preheated hydrogen. Gas is jetted into the reaction chamber 7 along the lower surface of the partition plate 25 in the same direction as the mixed gas.

By supplying hydrogen gas along the transparent quartz plate 12 and the partition plate 25 in this way, a non-reactive gas film is formed in the upper layer, and it is interrupted that the mixed gas containing the reactive gas contacts the solid wall surface. It will be. Furthermore, conventionally, the horizontal flow of the mixed gas and the susceptor 1 in the mixed gas phase are performed at the same time.
It is inevitable that the gas temperature near the surface of No. 5 and the gas temperature near the surface of No. 5 have an extremely large temperature difference, so that a large natural convection phenomenon appears and the mixed gas easily contacts the upper solid wall. Since the hydrogen gas flowing along the partition plate 25 has been sufficiently preheated, natural convection is significantly mitigated, and a more effective non-reactive gas film is formed. Therefore, the reaction gas does not come into contact with these transparent quartz parts and the reaction products do not adhere,
The transparency of the radiant light is not impaired forever, safety is maintained, and maintenance work is greatly reduced.

In addition, although the application to the epitaxial growth apparatus is shown in this embodiment, the present invention can be applied to various apparatuses that require film formation.

Effects of the Invention As described above, in the present invention, a partition plate is provided on the inner surface of the transparent quartz plate forming a part of the reaction chamber, and between the transparent quartz plate and the partition plate, a mixed gas containing a reaction gas and Does not allow only another carrier gas to flow in, but first, this carrier gas is made to flow along the lower surface of the transparent quartz plate to preheat the gas, and this preheated carrier gas is ejected to the lower surface of the partition plate. It was done,
The effect of suppressing natural convection of the mixed gas and the formation of a non-reactive gas film along the lower surface of the partition plate are realized, and since the reaction gas does not come into contact with the transparent quartz plate, no reaction product is generated and radiation is generated. Since the light transmittance is unchanged, it has a great effect on maintaining strength and safety. In addition, maintenance work is greatly reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a reaction chamber of a conventional epitaxial growth apparatus, FIG. 2 is a sectional view showing a reaction chamber of a vapor phase growth apparatus according to the present invention, and FIG. 3 is an external view of the apparatus. 7 ... Reaction chamber, 11 ... Infrared lamp heater unit,
12 ... Transparent quartz plate, 14 ... Silicon substrate, 1
5 ... Susceptor, 25 ... Partition plate.

Claims (1)

[Claims] 1. A first gas supply port for supplying a mixed gas of a reaction gas such as dichlorosilane and a carrier gas such as hydrogen to one end and a gas discharge port at the other end to shut off outside air. Then, a reaction chamber including a wall member for forming a gas atmosphere supplied from the first gas supply port, and a substrate installed inside the reaction chamber and forming a vapor phase growth film are placed. A base, a light radiation heating means arranged outside the reaction chamber for heating the substrate and the base and facing the base, and a wall surface between the light radiation heating means and the base. A transparent plate that forms a part of the member and is made of a material that transmits radiant light; a second gas supply port that is adjacent to the transparent plate and that supplies only a carrier gas such as hydrogen from the gas discharge port side; The carrier gas supplied from the second gas supply port is transparent Along the inner surface of the rate initially flows toward the first gas supply port side from the gas discharge port side, further first
A gas-phase reaction container comprising a partition plate made of a material that transmits radiant light and forms a carrier gas path that returns to the gas supply port side and flows into the reaction chamber in the same direction as the mixed gas.