JPS63199412A - Vapor growth device - Google Patents

Abstract

PURPOSE:To obtain a vapor phase reaction device effectively inhibiting wall deposition by a nonreactive gas flow by mounting a plurality of blow-off nozzles blowing off a nonreactive gas in the direction along the inner surface of the wall of a reaction vessel and a plurality of suction nozzles oppositely faced to the blow-off nozzles. CONSTITUTION:A plurality of blow off nozzles 5 blowing off a nonreactive gas in the direction along the inner surface of the wall of a reaction vessel 3 and a plurality of suction nozzles 6 being opposed to the blow-off nozzles 5 at fixed distances and sucking and discharging the nonreactive gas blown off from the blow-off nozzles 5 before the nonreactive gas is diffused in the direction of a substrate 1 are set up at predetermined positions in the inner surface of the wall of the reaction vessel in a device supplying a reaction gas into the reaction vessel 3 and shaping a vapor growth film onto the substrate 1 positioned into the vessel 3. The nonreactive gas flow flowing, separating from a reaction gas flow near the substrate 1 substantially is formed along the prescribed positions of the inner surface of the wall of the reaction vessel and covers the positions. On a horizontal type furnace, the nonreactive-gas blow-off nozzles 5 are fitted at four corners of a bell jar 3, and the nonreactive-gas suction nozzles 6 are installed at approximately the centers of each wall of the bell jar 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a vapor phase growth apparatus for vapor phase growth of a semiconductor or the like on a substrate. More specifically, the present invention relates to a vapor phase growth apparatus in which wall deposition in a reaction vessel is suppressed by a non-reactive gas flow.

(Prior Art) Horizontal furnaces, vertical furnaces, and the like are available as vapor phase growth apparatuses for epitaxial films and polycrystalline films on semiconductor substrates and the like.

In these devices, the quartz herbal jar is heated by radiant heat from the susceptor etc. in the case of high-frequency heating, and by radiant heat from the heater and susceptor in the case of resistance heating, resulting in a phenomenon in which reaction products adhere to the inner wall (wall decal). position) occurs. Once the reaction product has adhered, the adhered portion is likely to be heated, further accelerating the adhesion. If this deposit peels off and falls onto the substrate, it causes crystal defects such as protrusions.

As a method for suppressing this wall deposition, an attempt has been made to make the herjar in a vertical furnace a double structure and to lower the herjar temperature by flowing a cooling gas through the gap between them. However, this method does not cool the Pelger sufficiently, making it difficult to completely suppress wall deposition. It is particularly difficult to suppress wall deposition near the high temperature susceptor.

Also, JP-A-54-20971 and JP-A-54-2
Publication No. 0972 proposes flowing a non-reactive gas along the inner surface of the Herger to prevent the reactive gas from coming into contact with the inner wall of the Herger. However, in the devices proposed in these publications, the blown out non-reactive gas diffuses or mixes with the reactive gas as it flows along the Pelger inner wall. It is unavoidable that the reaction gas comes into contact with the reactor gas, and wall deposition at these locations is hardly suppressed. Moreover, the blown out non-reactive gas may disturb the gas flow on the surface of the susceptor or reduce the concentration of the reactant gas, which may lead to non-uniform film thickness.

On the other hand, in a horizontal furnace, for example, JP-A-53-126867
No. 54-21973, the reaction tube (Herger) has a double structure, the inner tube has many holes, and non-reactive gas is blown out from the holes so that the reaction gas does not come into contact with the Herger surface. We are proposing measures to do so. In order to suppress wall deposition in the devices proposed in these publications, it is necessary to blow out a sufficient amount of non-reactive gas. In this case, as in the case of the vertical furnace described above, it is inevitable that the gas flow on the surface of the susceptor will be disturbed by the blown out non-reactive gas, and that the concentration of the reactant gas will decrease. This results in non-uniform film thickness.

By the way, according to Japanese Patent Application Laid-Open No. 59-159980, in a horizontal gas phase reactor, a reactant gas flow flowing from one end of the container to the other end is surrounded by a non-reactive gas flow parallel to the reactant gas flow, and the inside of the container is I suggest running it. Although the purpose of the configuration proposed in this publication is to reduce gas consumption, this configuration also has the effect of suppressing wall deposition. However, in the device disclosed in this publication, the reactant gas is centered and the non-reactive gas is surrounded by non-reactive gas, and these gases are allowed to flow through the container almost as one, so it is difficult to apply it to anything other than a horizontal reactor. In addition, the distance over which the gas flows as one unit is long (reacting gas and non-reactive gas mix during the flow).Furthermore, the flow of non-reactive gas is concentrated in areas that are easily heated and prone to wall deposition. It is difficult to cover.

(Problems to be Solved by the Invention) Therefore, the present invention is characterized in that it provides a gas phase reactor that solves the above-mentioned problems of the prior art and effectively suppresses wall deposition using a non-reactive gas flow. In particular, a predetermined flow of non-reactive gas can be passed along a heated spot on the wall of the reaction vessel to cover the spot without disturbing the reactant gas flow, thereby adversely affecting the vapor phase growth rate or the grown film thickness. It is an object of the present invention to provide a vapor phase growth apparatus that suppresses wall deposition at the location without causing any damage.

(Means for Solving the Problems) Thus, the gist of the present invention is to provide an apparatus for forming a vapor phase growth film on a substrate placed in a reaction container by flowing a reaction gas into the reaction container. A plurality of blowout nozzles blowing out non-reactive gas in a direction along the inner surface of the reaction vessel wall, and a plurality of blowout nozzles provided opposite the blowout nozzles at a predetermined distance, and before the non-reactive gas blown out from the blowout nozzles is diffused toward the substrate. A plurality of suction nozzles for suctioning and discharging a non-reactive gas are provided at predetermined locations on the inner surface of the reaction vessel wall, and the non-reactive gas flow flowing substantially separately from the reaction gas flow near the substrate is provided on the reaction vessel wall. This is a vapor phase growth apparatus characterized in that it is formed along a predetermined location on the inner surface to cover the location.

(Function) In general, a non-reactive gas blowing nozzle and a suction nozzle are provided so as to form a non-reactive gas flow along a portion of the container wall that is particularly likely to be heated.

The non-reactive gas flow flowing between the opposing nozzles provided at a predetermined distance from each other is formed substantially separate from the reactant gas flow, so that the reactant gas flow is not disturbed by the non-reactant gas flow or the reaction occurs. The concentration of the gas hardly decreases due to mixing. Therefore, without reducing the speed of vapor phase growth on the substrate or causing non-uniformity in the thickness of the grown film,
Wall deposition can be effectively suppressed.

The non-reactive gas flow is determined by the location, direction, number, and location of the opposing nozzles.
Distance # (distance between opposing nozzles), and the blowout of each nozzle,
By selecting the amount of suction, it is possible to control the formation of an optimal gas flow.

(Example) Next, an example of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a sectional view taken along a plane perpendicular to the long axis of a first embodiment in which the present invention is applied to a horizontal furnace.

A semiconductor substrate 1 made of Si or the like is loaded on a susceptor 2 .

From the reaction gas supply port (not shown), for example, S i CQ
After the reaction gas containing 4 etc. is blown out and flows in the vicinity of the substrate 1 in the quartz Pelger 3 constituting the reaction vessel in a direction perpendicular to the plane of the paper in the figure, a reaction gas exhaust port (not shown)
is discharged from. At this time, the substrate 1 is heated by the high frequency coil 4 via the susceptor 2, and Si etc. are grown on the substrate 1 in a vapor phase.

There are non-reactive gas blowing nozzles 5 in the four corners of the Pelger 3.
is provided and supplies a non-reactive gas (for example, 1 (2) Consists of multiple supply ports opening in the direction, blowing out non-reactive gas in the direction of the arrow.Pelger 3
A non-reactive gas suction nozzle 6 is provided approximately at the center of each of the multiple folds, and the non-reactive gas blown out from the nozzle 5 is sucked and discharged. The suction nozzle 6 is composed of a plurality of suction ports provided in a non-reactive gas suction pipe extending in the longitudinal direction of the Pelger 3, facing the supply port forming the blow-off nozzle 5.

In this way, the non-reactive gas blowing nozzle 5 and the suction nozzle 6 open opposite each other in the direction along the inner surface of the wall of the Pelger 3, and the distance between the opposing nozzles is small.

Therefore, the non-reactive gas blown out from the nozzle 5 is mostly sucked and discharged by the suction nozzle 6 before it diffuses toward the substrate 1 or disturbs the flow of the reactive gas. In this way, the non-reactive gas forms a flow that is substantially separate from the reactive gas flow near the substrate 1 and covers the inner surface of the Pelger 3, which becomes hot, thereby preventing wall deposition.

Figure 2 is a longitudinal sectional view of an embodiment in which the present invention is applied to a vertical furnace.

The substrate 1 is placed on a rotating susceptor 2 and covered by a Pelger 3 constituting a reaction vessel.

The group Fi1 is heated by the high frequency coil 4 via the susceptor 2. The reaction gas is blown out from the blow-off nozzle 7, passes near the substrate 1, and then exhausted from the exhaust hole 8'.

The non-reactive gas blowing nozzle 5 and suction nozzle 6 are
Several sets are provided facing each other at approximately equal intervals in the circumferential direction along the inner surface of the side wall of the Pel jar 3, which is exposed to high temperatures. Therefore, the non-reactive gas covers the inner surface of the side wall of the Pelger 3 without disturbing the reactive gas flow in the vicinity of the groups vi, 1, thereby preventing wall deposition.

Implementation ±1 The present invention is not limited to the above-mentioned horizontal furnace and vertical furnace, but is applicable to all types of vapor phase growth apparatus. FIG. 3 shows an embodiment in which the present invention is applied to a vapor phase growth apparatus that is considered to be of the so-called hot wall type. With this type of device it is inevitable that the herger jar will heat up. Therefore, wall deposition is likely to occur (suppression of wall deposition is an important issue. Figure 3 (A) is a longitudinal cross-sectional view along the chain line A-A in Figure 3 (B), and Figure 3 (B) is
FIG. 2 is a cross-sectional view taken along the chain line BB in FIG.

The substrate 1 is placed on a rotating shelf-shaped susceptor 2 and heated by a heater 4' outside the quartz herbal jar 3. The reaction gas is blown out from the blow-off nozzle 7 , flows near the substrate 1 in the direction of the arrow, and then exhausted from the suction nozzle 8 .

The nozzle 7.8 is a pair of tubular bodies provided in the Pelger 3, and is composed of a plurality of blow-off ports and suction ports that open toward the substrate 1 and face each other.

The non-reactive gas blowing nozzle 5 and suction nozzle 6 are
It is composed of a plurality of blow-off ports and suction ports that open opposite to each other on the side surfaces of non-reactive gas supply pipes and exhaust pipes that are provided alternately in the circumferential direction along the side wall of the Pelger 3. Therefore, the non-reactive gas blown out from the blowing nozzle 5 flows along the inner surface of the side wall of the bell jar 3 without disturbing the flow of the reactive gas flowing near the substrate 1, and is sucked into the suction nozzle 6 and discharged.

In addition, in the vapor phase growth apparatus of the present invention, the flow rate and flow rate of non-reactive gas, and the amount of suction gas are important operating conditions for any of the apparatuses of the embodiments. The optimum values of these differ depending on the device shape, reaction gas flow rate, and flow rate.

Therefore, although it cannot be generalized, it is preferable that the amount of suction from the non-reactive gas suction nozzle is approximately equal to the amount of non-reactive gas blown out.

(Effects of the Invention) In the present invention, as described above, the inner surface of the wall of the reaction vessel is covered with a non-reactive gas flow that is substantially separated from the reactant gas flow near the substrate. Therefore, wall deposition can be effectively suppressed without adversely affecting the process of vapor phase growth of reactants such as Si onto the substrate. That is, it becomes possible to suppress wall deposition without causing nonuniform film thickness or crystal defects such as protrusions in the vapor-phase grown film.

In order to specifically confirm such effects of the present invention, the first
An experiment was conducted to compare the effects of the example apparatus shown in FIGS. 3 and 3 and the conventional horizontal vapor phase growth apparatus shown in FIGS. 4 and 5. (Both Figures 4 and 5 show longitudinal sections along the long axis of the horizontal device, and numerals 1, 2, 3, and 4 indicate the substrate, susceptor, Luger, and high-frequency coil, respectively. However, the device in Figure 5 Then Pelger goes inside Luger-3
It has a double structure with a and outer lugers 3b. In this device, a mixed gas (SiCQ42 vol.chi.) was used as the non-reactive gas introduced between the two, which was blown out from a plurality of holes provided in the inner Pelger 3a, and 112 was used as the non-reactive gas.

First, the temperature of the susceptor was set to 700° C., and S i'4° was detected at each position in the Herjar without placing the substrate, to check for interference between the reactive gas flow and the non-reactive gas flow. The Si concentration was detected by gas chromatogram analysis of the gas sampled at each point W in the Herjar. Note that the reason why the susceptor temperature was set to 700°C is to prevent S i CQ 4 from reacting and depositing on the susceptor or the like.

The following Table 1 shows the Si concentration (g/
7 for each device.

Table 1 The flow rates (β/m1n) of reactive gases and non-reactive gases used in each device in this experiment are as follows.

Table 2 As can be seen from Table 1, in the apparatus of the embodiment of the present invention shown in FIGS. 1 and 3, Si'lQ near the Pelger inner surface
5iNa on the surface of the susceptor where the substrate is placed, whereas the
The temperature hardly decreased from the vicinity of the reaction gas introduction part.

That is, it is recognized that the non-reactive gas flow covers the inner surface of the reaction vessel without substantially disturbing the reactant gas flow near the substrate.

On the other hand, in the conventional device shown in Fig. 4, which does not use non-reactive gas,
S i '174 degrees on the Herger surface is almost the same as the concentration on the susceptor surface, and it is recognized that the reactive gas reaches near the inner surface of the Herger.

In addition, in the conventional device shown in FIG. 5 using a non-reactive gas, although the Si concentration on the Pelger inner surface is low, the S i ta degree on the susceptor surface is also reduced to about 172 near the reactive gas introduction part. This is considered to be because the non-reactive gas flowing out from both herjars 3a and 3b reaches the vicinity of the substrate 1 and mixes with the reactive gas flow. Therefore, the non-reactive gas flow has an adverse effect on the vapor phase growth process on the substrate 1, and the S on the substrate is
It is expected that the growth rate of the i-grown film will be reduced or the film thickness will be made non-uniform.

Next, under the same gas amount conditions as in Table 2, the susceptor temperature was set to 12
00°C, the substrate was actually placed on the susceptor, and the presence or absence of wall deposition on the Pelger inner surface was detected, and the growth rate (μm/μm/
m1n) was measured. Table 3 below shows the results.

Table 3 The results in Table 3 support the gas flow conditions estimated from Table 1.

That is, in the apparatus of the embodiment of the present invention, the non-reactive gas flow does not disturb the reactive gas flow near the substrate, so wall deposition is suppressed without substantially reducing the growth rate.

In the conventional apparatus shown in FIG. 4, which does not use a non-reactive gas, wall deposition occurs. Fifth using non-reactive gas
Although wall deposition is suppressed in the conventional apparatus shown in the figure, the growth rate is reduced to 172 or less compared to the apparatus shown in FIG. This is thought to be because the reactive gas flow near the substrate mixed into the non-reactive gas flow.

As described above, the apparatus of the present invention covers the wall of the reaction vessel with a non-reactive gas flow that is substantially separated from the reactant gas flow near the substrate. Prevent position. In the present invention, the opposing nozzles that form the non-reactive gas flow can be installed at any location and with the opposing distance freely selected. Therefore, it is possible to intensively cover the region of the reaction vessel, which is at a high temperature and where wall deposition is likely to occur, with a flow of non-reactive gas, thereby effectively suppressing wall deposition.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view along a plane perpendicular to the longitudinal direction of an embodiment of the present invention when the present invention is applied to a horizontal furnace. Fig. 2 is a vertical cross-sectional view when the present invention is applied to a vertical furnace. Figures; Figures 3 (A) and (B) are vertical and horizontal cross-sectional views, respectively, when the present invention is applied to a Hosotowal Ayuko Furnace; Figure 4 is a conventional horizontal cross-sectional view that does not use non-reactive gas. A vertical sectional view along the long axis direction of a vapor phase growth apparatus; and FIG. 5 is a vertical sectional view along the long axis direction of a conventional horizontal vapor phase growth apparatus using a non-reactive gas. 1: Substrate 2: Sustainer 3: Bell jar 4: Heater 5: Non-reactive gas blowing nozzle 6: Non-reactive gas suction nozzle 7: Reactive gas blowing nozzle 8: Reactive gas suction nozzle

Claims (1)

[Claims] In an apparatus for forming a vapor phase growth film on a substrate placed in a reaction container by flowing a reaction gas into the reaction container, a plurality of blowing nozzles blowing out a non-reactive gas in a direction along the inner surface of the wall of the reaction container; a plurality of suction nozzles that are provided facing the blow-off nozzle at a predetermined distance and that suck and discharge the non-reactive gas blown out from the blow-off nozzle before the non-reactive gas is diffused toward the substrate; A gas flow is provided at a predetermined location on the inner surface, and a non-reactive gas flow is formed along the predetermined location on the inner surface of the reaction vessel wall and flows substantially separately from the reactive gas flow in the vicinity of the substrate to cover the location. Phase growth device.