JP2641136B2 - Epitaxial growth apparatus and epitaxial growth method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial growth method and an epitaxial growth apparatus, and more particularly, to an epitaxial growth method and an epitaxial growth apparatus.
The present invention relates to an epitaxial growth method and an epitaxial growth apparatus using a so-called uneven reaction.

[0002]

2. Description of the Related Art Conventionally, a method of forming a thin film of the same or different kind of semiconductor single crystal on a single crystal semiconductor substrate such as silicon has been widely applied to a method of manufacturing a semiconductor device as an epitaxial growth method. In this technique, control of film formation conditions is extremely important from the viewpoint of formation of a single crystal, and is known as one of the difficult techniques in manufacturing a semiconductor device such as an LSI.

As an early method, Japanese Patent Publication No. 43-2136
As shown in FIG. 7, there is an epitaxial growth method using a non-uniform reaction. In this growth method, the temperature of the source substrate needs to be higher than the temperature of the substrate to be grown in order to perform mass transport. Therefore, as shown in FIG. 16, a silicon substrate is placed as a source substrate 3 on a source substrate holder 2 having a heater, and a silicon substrate is placed as a growth substrate 5 so as to face the substrate and at a predetermined interval. .

Then, by flowing a gas comprising bromine or its hydrogen compound into the gap between the silicon substrates 3 and 5, the source silicon substrate 3 is etched, and the reaction product generated by the etching is used as a substrate to be grown. It is deposited on a silicon substrate 5. At this time, the temperature of the growth target substrate 5 is set within a predetermined temperature range so as not to lower the growth rate. Therefore, the two substrates are brought as close as possible. However, if the distance is too close, precipitation occurs, so that it is necessary to maintain an appropriate distance. Therefore, an appropriate interval is maintained by interposing the spacer 4 between the two substrates 3 and 5.

However, after the growth is completed, it may be necessary to adjust the distance between the substrates again when performing the next growth. In this case, it is necessary to replace the spacer with a lower one or replace it with a new source substrate.
As described above, the above-described growth method was used for pursuing a basic mechanism of epitaxial growth, but was not suitable for mass production and was not practically used industrially.

Accordingly, a CVD method for depositing a reaction product generated only by a reaction gas has been developed and is becoming mainstream. As such a CVD method, a plasma CVD method or an optical CVD method has been proposed, and the use of disilane (Si ₂ H ₆ ) has been proposed, but none of them has reached a practical level. At present, thermal CV is the most practical CVD method.
Method D is used.

As a basic thermal CVD method, a silicon substrate or the like is heated in a hydrogen atmosphere at a high temperature of 1000 ° C. or more,
A reaction gas such as H ₄ , SiH ₂ Cl ₂ , SiHCl ₃ is supplied together with hydrogen onto the substrate to be grown, and SiH ₄ → Si + 2H ₂ (thermal decomposition) SiH ₂ Cl ₂ → Si + 2HCl (thermal decomposition) SiHCl ₃ + H ₂ → Si + 3HCl (Hydrogen reduction) A reaction such as SiCl ₄ + 2H ₂ → Si + 4HCl (hydrogen reduction) is caused on the surface of the growth target substrate to form a silicon film. At this time, as the film forming conditions, the reaction gas is heated to a reaction temperature or higher, there is no natural oxide film or contaminants on the surface of the substrate, and the substrate is decomposed so that a single crystal nucleus can be formed. Si adhered
It is required that the atoms have sufficient mobility. At present, high-temperature treatment in a hydrogen atmosphere is performed to remove a natural oxide film.

The epitaxial growth apparatuses applied to the above-mentioned growth methods are classified into vertical, horizontal, barrel, cluster, etc., depending on the shape of the reaction chamber. It is classified into a lamp heating method and the like, and further classified into a single-wafer method, a batch method and the like according to a wafer processing method.

[0009]

By the way, in order to cope with high density and high integration of a semiconductor device, a wafer has a diameter of 2 mm.
The one with a diameter of 00 mm is mainly used. It is considered that the era of a wafer having a diameter of 300 mmφ will come in the near future. Therefore, problems associated with the practical use of an epitaxial growth apparatus and an epitaxial growth method that can cope with an increase in the diameter of a wafer are being studied.

In the above-described CVD apparatus, the size of the apparatus must be increased in order to cope with the increase in the diameter of the wafer. If the apparatus becomes large, the gas flow pattern will be controlled, and the geometrical shape of the reactor will be optimized. Therefore, there is a risk that the uniformity of the film thickness and film quality within and between the wafers may be reduced, and a large amount of hydrogen gas is consumed to improve the uniformity of the film thickness and film quality. In particular, in the case of a batch type, the energy cost for heating rises and the temperature tends to fluctuate. For this reason, when a single wafer type is used, the throughput decreases, and the manufacturing cost per wafer And other problems arise.

Further, SiH ₄ , SiH ₂ Cl ₂ ,
Since gases such as SiHCl ₃ and SiCl ₄ are used, sufficient attention is required from the viewpoint of safety and prevention of corrosion of the growth apparatus. The present invention has been made in view of the problems of the conventional example, and improves mass productivity while responding to a large diameter wafer.
It is an object of the present invention to provide an epitaxial growth apparatus and an epitaxial growth method capable of improving the uniformity of the film thickness and film quality, saving energy, reducing costs and improving safety.

[0012]

The first object of the present invention is to provide a chamber for performing film formation, a source substrate holder provided in the chamber, and a first substrate provided in the source substrate holder.
Heating means, a substrate-to-be-grown holder provided in the chamber, facing the source substrate-holder, first moving means for vertically moving the substrate-to-be-grown, and a reactant gas in the chamber. And a gas introduction port for introducing a gas. The second invention is characterized in that the growth target substrate holder has a second heating means. Thirdly, the present invention is achieved by the epitaxial growth apparatus according to the first or second invention, characterized in that the epitaxial apparatus has second moving means for vertically moving the source substrate holder. Fourth, a chamber for forming a film, a source substrate holder provided in the chamber, and a third substrate provided in the source substrate holder. Heating means, third moving means for moving the source substrate holder up and down, a substrate to be grown provided in the chamber, facing the source substrate holder, and introducing a reaction gas into the chamber. Fifthly, the epitaxial growth apparatus according to the fourth aspect of the present invention is achieved by an epitaxial growth apparatus characterized by having a gas inlet that performs heating. Achieved by the sixth
A chamber for forming a film, a source substrate holder provided in the chamber, a fifth heating means provided in the source substrate holder, and a source substrate holder provided in the chamber. An epitaxial growth apparatus, comprising: a substrate holder to be grown, a sixth heating means provided on the substrate holder, and a gas inlet for introducing a reaction gas into the chamber. Seventh, the invention is achieved by the epitaxial growth apparatus according to any one of the first to sixth inventions, wherein the chamber has a gas inlet for introducing hydrogen gas. Is connected to the exhaust system,
This is achieved by the epitaxial growth apparatus according to any one of the first to seventh inventions, wherein the inside of the chamber can be decompressed. Ninthly, the epitaxial apparatus has at least the source substrate holder and An epitaxial growth apparatus according to any one of the first to eighth aspects of the present invention includes a fourth moving unit that moves any one of the holders for growing a substrate in a plane direction parallel to a growth surface. Tenth, at least one of the source substrate and the substrate to be grown is moved up and down, the source substrate and the substrate to be grown are brought close to each other, and the source substrate is heated. The temperature of the source substrate is made higher than the temperature of the growth substrate by adjusting the gap with the growth substrate, and the temperature of the source substrate is increased. The growth target substrate has a predetermined temperature difference, a reaction gas is introduced into the gap between the source substrate and the growth target substrate, and a reaction product of the source substrate and the reaction gas is grown. Eleventh is achieved by an epitaxial growth method characterized in that the source substrate and the growth substrate are moved up and down so that at least one of the source substrate and the growth substrate is moved up and down so that a gap is formed between the source substrate and the growth substrate. The source substrate and the growth substrate are separately heated so that the temperature of the source substrate is higher than the temperature of the growth substrate, and the growth substrate has a predetermined temperature with respect to the temperature of the source substrate. And a reaction gas is introduced into the gap between the source substrate and the growth substrate, and a reaction product between the source substrate and the reaction gas is formed on the growth substrate. The method is achieved by an epitaxial growth method characterized by being deposited on a substrate. Twelfth, before the source substrate and the growth substrate are brought close to each other and opposed to each other, the source substrate and the growth substrate are separated from the gap. The substrate to be grown is heated and surface-treated in a hydrogen atmosphere in a state where the substrate and the substrate are opposed to each other with a wide gap therebetween. This is achieved by the epitaxial growth method according to the tenth or eleventh aspect of the present invention, wherein the source substrate is opposed to the substrate to be grown with the gap provided therebetween. An eleventh aspect, wherein the growth target substrate is heated in a hydrogen atmosphere in a state where the temperature of the growth target substrate is substantially equal to the temperature of the growth target substrate to perform a surface treatment. Fourteenth, achieved by the epitaxial growth method according to any one of the tenth to thirteenth inventions, wherein the film formation is performed under reduced pressure, and fifteenth, Depositing the reaction product on the growth substrate while moving at least one of the source substrate and the growth substrate in a plane direction parallel to a growth surface.
Sixteenth aspect of the present invention is achieved by the epitaxial growth method according to any one of the tenth to fourteenth aspects, and sixteenth aspect, wherein the material of the source substrate is silicon, germanium, or a compound semiconductor. The first is achieved by the epitaxial growth method described in
A seventh aspect is achieved by the epitaxial growth method according to the sixteenth aspect, wherein the silicon, germanium, or compound semiconductor contains an impurity imparting a conductivity type. The material is achieved by the epitaxial growth method according to any one of the tenth to seventeenth aspects, wherein the reactive gas is a gas containing halogen. The invention is attained by the epitaxial growth method according to any one of the tenth to eighteenth aspects, wherein the halogen is chlorine (Cl), bromine (Br ₂ ), iodine (I ₂ ), hydrogen chloride.
(HCl), hydrogen bromide (HBr), hydrogen iodide (HI), silicon tetrachloride (SiCl ₄ ), trichlorosilane (SiHCl ₃ ), or dichlorosilane (SiH ₂ Cl ₂ ) Twenty-first is achieved by the epitaxial growth method according to the nineteenth aspect, wherein the gas containing halogen is at least hydrogen (H ₂ ), helium (He), nitrogen (N ₂ ), and argon.
A gas containing any of (Ar)
This is achieved by the epitaxial growth method according to the ninth or twentieth aspect.

[0013]

The present invention uses an epitaxial growth method based on a so-called non-uniform reaction. That is, as is well known, in a chamber, for example, a silicon substrate is placed as a source substrate on a high temperature side, and a silicon substrate is placed as a growth substrate on a low temperature side, for example, a halogen gas such as iodine is supplied. Introduce. Thus, in the high temperature side of the source substrate, SiI ₂ occurs _{Si + 2I 2 → SiI 4 SiI} 4 + Si → like reactions 2SiI ₂ is happening. The SiI ₂ is moved to the low temperature side of the growth substrate, reactions such as 2SiI ₂ → Si + SiI ₄ occurs. This Si is deposited on the growth substrate.

By the way, after the reaction product is generated from the source substrate and deposited on the growth substrate, the surface layer of the source substrate is etched, and the surface of the source substrate recedes almost by the deposited film thickness. doing. Therefore, when the substrate to be grown is set at the same position as the previous time when facing the source substrate to deposit on the next substrate to be grown,
The distance between the source substrate and the substrate to be grown becomes different from the previous time. In particular, when a thick film is deposited, the interval becomes too large to maintain a predetermined temperature difference.

The epitaxial growth apparatus of the present invention has a source substrate holder having first heating means and a first moving means for vertically moving a growth substrate holder opposed thereto. Or, a source substrate holder having a third heating means, and a growth substrate holder facing the source substrate holder,
And third moving means for vertically moving the source substrate holder.

Therefore, as in the epitaxial growth method of the present invention, the distance between the source substrate and the source substrate is adjusted by heating and keeping the temperature of the source substrate and vertically moving the source substrate or the growth target substrate. The temperature of the substrate to be grown can be lower than the temperature of the source substrate, and a predetermined temperature difference can be generated from the source substrate. Similar adjustment of the temperature difference can also be achieved by heating the growth target substrate separately from the source substrate without adjusting the interval.

As described above, since the facing distance between the source substrate and the substrate to be grown and the temperature difference between the source substrate and the substrate to be grown can be easily adjusted, it is possible to form a film continuously on different substrates to be grown. Can be. In addition, since a non-uniform reaction is used, high-speed film formation is possible. As a result, throughput can be improved, and mass productivity can be improved.

Further, by using the above-mentioned vertical moving means, the distance between the source substrate and the substrate to be grown is kept wide before deposition so as not to cause an uneven reaction, and then hydrogen is introduced from the gas inlet. Hydrogen treatment. Moreover, the film formation can be started immediately in the same chamber after the hydrogen treatment. Therefore, a film can be formed on a clean surface, and the film quality can be improved. Further, it is possible to perform the hydrogen treatment in a state where the temperature of the source substrate and the temperature of the growth substrate are almost equal. By making the temperatures of both substrates approximately equal, mass transfer can be suppressed.

Further, by providing a heating means on the substrate holder, the entire substrate to be grown can be directly heated, so that the temperature uniformity is increased. In addition, since it is a face-to-face type using a non-uniform reaction, it is not affected by the shape of the reactor, the gas flow rate, or the like. Thereby, the uniformity of the film thickness and the film quality can be improved, and it is possible to cope with an increase in the diameter of the wafer. Further, since the fourth moving means for moving at least one of the source substrate and the growth substrate in a plane direction parallel to the growth surface is provided, the growth substrate can be uniformly faced over the entire source substrate. Therefore, a non-uniform reaction can be caused uniformly over the entire source substrate surface. This makes it possible to maintain the flatness of the source substrate surface after the reaction.

Furthermore, high-speed film formation is possible, and a sufficient throughput can be obtained even in a single-wafer method, so that energy can be saved. Further, since it is not necessary to use a large amount of hydrogen gas, cost reduction can be achieved. In addition, halogen gas such as chlorine, bromine,
Since a gas containing iodine, hydrogen chloride, hydrogen bromide or hydrogen iodide is used, it is safe.

The heating means may be provided on the source substrate side, and then the heating means may be provided on the growth substrate side. in this case,
The moving means can be omitted to form a predetermined temperature difference between the source substrate and the growth substrate. Further, even when the heating means is provided on both the source substrate side and the growth substrate side, the moving means can be provided on at least one of the source substrate and the growth substrate. Thus, while maintaining a predetermined facing distance between the source substrate and the growth target substrate,
A predetermined temperature difference can be maintained.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. (1) Description of an epitaxial growth apparatus according to an embodiment of the present invention (a) First embodiment FIG. 1 is a side view showing a configuration of an epitaxial growth apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a chamber capable of reducing pressure, 12 denotes a source substrate holder provided in the chamber 11, and the source substrate holder 12 has a heater (first heating means). At the time of film formation, the source substrate 17 is placed on the source substrate holder 12. Reference numeral 13 denotes a substrate-to-be-grown which is provided in the chamber 11 so as to face the source substrate holder 12, and is fixed to a vertical moving shaft (first moving means). The growth substrate holder 13 is moved up and down by the vertical movement shaft 14. During film formation, the substrate to be grown 18 is placed.

Reference numeral 15 denotes a gas inlet for introducing a reaction gas or another gas into the chamber 11. As shown in FIG.
The gas inlet 15 is provided with a halogen gas (HCl, HBr).
), Hydrogen gas (H ₂ ), and helium gas (He). An exhaust port 16 reduces the pressure in the chamber 11 and exhausts unnecessary reaction gas.

An example of an epitaxial growth method using the above epitaxial growth apparatus will be described. Before film formation, the substrate to be grown 18 is pulled up, and pretreatment such as hydrogen treatment is performed. Further, the substrate to be grown 18 is moved downward during film formation, and is held at a predetermined distance from the source substrate 17.
As a result, heat from the source substrate 17 is conducted to the growth substrate 18 via the gap, and the temperature of the growth substrate 18 is maintained so as to have a predetermined temperature difference with respect to the source substrate 17. After the film formation, the substrate to be grown 18 is pulled up again,
After the post-processing is performed, the substrate to be processed 18 is taken out.

As described above, the epitaxial growth apparatus of the first embodiment has the source substrate holder 12 having a heater and the vertical movement shaft 14 for vertically moving the growth substrate holder 13 opposed thereto. . Therefore, by heating the source substrate 17 and moving the growth substrate 18 up and down to adjust the distance from the source substrate 17, the temperature of the growth substrate 18 facing the source substrate 17 is reduced. Lower than the source substrate 17
In this case, a predetermined temperature difference can be generated in the growth target substrate 18.

As described above, the facing distance between the source substrate 17 and the growth substrate 18 and the temperature difference between the growth substrate 18 and the source substrate 17 can be easily adjusted. Epitaxial growth can be performed. In addition, since a non-uniform reaction is used, high-speed film formation is possible. As a result, throughput can be improved, and mass productivity can be improved.

In the epitaxial growth apparatus according to the first embodiment, only the source substrate holder 12 has a heater. However, the growth substrate holder 13 is provided with a heater (second heating means). You may. This allows
Since the entire substrate to be grown 18 can be directly heated,
Increased temperature uniformity. In addition, since it is a face-to-face type using a non-uniform reaction, it is not affected by the shape of the reactor, the gas flow rate, or the like. Thereby, the uniformity of the film thickness and the film quality can be improved, and it is possible to cope with an increase in the diameter of the wafer.

Further, in the above embodiment, the growth substrate holder is provided on the upper side, and the source substrate holder is provided on the lower side.
The growth substrate holder may be provided on the lower side, and the source substrate holder may be provided on the upper side. Further, only the growth substrate holder 13 is connected to the vertical movement shaft 14 and only the growth substrate holder 13 moves up and down.
2 may also be connected to the vertical movement axis so that both can move up and down.

(B) Second Embodiment FIG. 2 is a side view showing a structure of an epitaxial growth apparatus according to a second embodiment of the present invention. The difference from the first embodiment is that only the source substrate holder 12 having a heater (third heating means) is connected to the vertical movement shaft (third movement means) 14a. In the figure, components denoted by the same reference numerals as those in FIG. 1 indicate the same components as those shown in FIG.

In the second embodiment, the source substrate holder 13 is moved up and down by the up and down movement shaft 14. At the time of film formation, the growth substrate 18 is placed on the growth substrate holder 13, and the source substrate 17 is mounted on the source substrate holder 12. Prior to the film formation, the source substrate 17 is pulled down, and a pretreatment such as a hydrogen treatment is performed with a wide space between the source substrate 17 and the growth substrate 18. In addition, the source substrate 17 is moved upward during film formation, and is held at a predetermined distance from the growth substrate 18. Accordingly, heat from the source substrate 17 is conducted to the growth substrate 18 via the gap, and the temperature of the growth substrate 18 is maintained such that a predetermined temperature difference occurs with respect to the source substrate 17. After film formation, the source substrate 17 is pulled down again,
After performing post-processing and the like, the substrate to be processed 18 is taken out.

As described above, in the epitaxial growth apparatus according to the second embodiment, the source substrate holder 12 having a heater, the growth substrate holder 13 opposed thereto,
Vertical movement shaft 14a for vertically moving source substrate holder 12
And Therefore, by heating the source substrate 17 and moving the source substrate 17 up and down, the source substrate 17
By adjusting the distance from the source substrate 17, the temperature of the growth substrate 18 facing the source substrate 17 can be lower than the temperature of the source substrate 17, and a predetermined temperature difference can be generated with respect to the source substrate 17. .

As described above, the facing distance between the source substrate 17 and the growth substrate 18 and the temperature difference of the growth substrate 18 with respect to the source substrate 17 can be easily adjusted. Epitaxial growth can be performed. In addition, since a non-uniform reaction is used, high-speed film formation is possible. As described above, throughput can be improved and mass productivity can be improved.

In the epitaxial growth apparatus according to the second embodiment, only the source substrate holder 12 has a heater. However, even if the growth target substrate holder 13 is provided with a heater (fourth heating means). Good. (C) Third Embodiment FIG. 3 is a side view showing a configuration of an epitaxial growth apparatus according to a third embodiment of the present invention.

What is different from the first and second embodiments is that
Both the source substrate holder 12 and the to-be-grown substrate holder 13a have a heater, and are fixed at predetermined intervals with spacers 19 interposed therebetween. In the figure, components denoted by the same reference numerals as those in FIG. 1 indicate the same components as those shown in FIG. In the third embodiment, before film formation, the growth substrate 18 is placed on the growth substrate holder 13a, and the source substrate 17 is mounted on the source substrate holder 12. Then, they are opposed to each other with a predetermined space therebetween with the spacer 19 interposed therebetween.

During film formation, the source substrate 17 is heated by the heater of the source substrate holder 12 and the heater of the growth substrate holder 13a.
Then, the growth substrate 18 is separately heated. Then, the temperature of the source substrate 17 is maintained higher than the temperature of the growth substrate 18, and the temperature of the growth substrate 18 is maintained at a predetermined temperature difference from the source substrate 17. Substrate 1 after film formation
Take out 8.

Next, when forming a film on a new substrate to be grown, the same spacer 19 is interposed. At this time, since the surface layer of the source substrate 17 is etched by the previous film formation, the distance between the source substrate 17 and the substrate to be grown is different, and a predetermined temperature difference may not be maintained between them. However, it can be adjusted so that the temperature condition is satisfied by each heater.

As described above, in the epitaxial growth apparatus of the third embodiment, the adjustment of the temperature difference similar to that of the first and second embodiments is performed separately from the source substrate 17.
8 can be achieved by heating. Therefore, the temperature difference between the growth substrate 18 and the source substrate 17 can be easily adjusted, so that film formation can be continuously performed on different growth substrates. In addition, since a non-uniform reaction is used, high-speed film formation is possible. From the above,
Throughput is improved, and mass productivity can be improved.

(D) Fourth Embodiment FIG. 4 is a side view showing the structure of an epitaxial growth apparatus according to a fourth embodiment of the present invention. The difference from the second embodiment is that the growth substrate holder 13b is connected to a plane direction moving means (fourth moving means) (not shown) so that it can be moved in a direction parallel to the film forming surface. It is that you are. In the figure, the components denoted by the same reference numerals as those in FIG. 2 indicate the same components as those in FIG.

The epitaxial growth using this epitaxial growth apparatus is performed as follows. As shown in FIG. 8A, during the film formation, the growth target substrate 18 is moved in a direction parallel to the film formation surface so as to uniformly face the surface of the source substrate 17 so that the entire surface of the source substrate 17 is formed. Etching is performed uniformly, and the flatness of the surface of the source substrate 17 is maintained.

According to the epitaxial growth apparatus of the second embodiment, both the source substrate 17 and the substrate to be grown 18 are fixed at fixed positions and are not moved in the plane direction. As shown in FIG. 8B, the surface facing the growth substrate 18 is mainly etched. According to the epitaxial growth apparatus of the fourth embodiment, since the plane direction moving means for moving the substrate to be grown 18 in the direction parallel to the growth surface is provided, the substrate to be grown 18 is uniformly faced over the entire surface of the source substrate 17. be able to. Therefore, a non-uniform reaction can be caused uniformly over the entire surface of the source substrate 17. Thereby, the source substrate 1 after the reaction
7 Surface flatness can be maintained.

In the epitaxial growth apparatus according to the fourth embodiment, the plane moving means is connected only to the source substrate holder 12, but the in-plane moving means is connected only to the growth substrate holder 13. Or an in-plane moving means may be connected to both. (2) Description of the epitaxial growth method according to the fifth embodiment of the present invention The fifth embodiment of the present invention will be described with reference to FIGS. 6 (a), 6 (b) and 7.
An epitaxial growth method according to the example will be described.

As an epitaxial growth apparatus, both the source substrate holder 12 and the growth substrate holder 13c have a heater, and the vertical movement shaft 14 is connected to the growth substrate holder 13c. The one to which the plane direction moving means 12 is connected is used. In the figure, components denoted by the same reference numerals as those in FIG. 1 indicate the same components as those in FIG. First, FIG.
As shown in (a), after the pressure in the chamber 11 is reduced, the growth substrate holder 13c is pulled up and held at a wide interval, and a silicon substrate is placed as the growth substrate 18 while the source substrate is mounted. A silicon substrate is placed on the holder 12 as the source substrate 17.

Next, the growth substrate 18 is heated by the heater of the growth substrate holder 13c, and is maintained at a temperature of about 1000.degree. Subsequently, hydrogen gas is supplied from the gas inlet 15 to the chamber 1.
1 and maintained so that the pressure in the chamber 11 becomes 1 Torr. This state is maintained for about one hour. As a result, foreign substances such as a natural oxide film react with the hydrogen gas and are removed from the surface of the growth target substrate 18.

Next, while the pressure in the chamber 11 is maintained, the source substrate 17 is heated by the heater of the source substrate holder 12 as shown in FIG. The source substrate 17 and the substrate to be grown 18 are brought closer to each other by pulling down 18 to maintain a predetermined gap. Then, the temperature of the source substrate 17 is maintained higher than the temperature of the growth substrate 18, and the temperature of the growth substrate 18 is maintained at a predetermined temperature difference from the source substrate 17. It should be noted that the gap should be carefully determined so that the temperature in the gap does not drop below the reaction temperature. When the inside of the gap is in a reduced pressure state, it is possible to set the gap to 10 mm or more. When a heater is provided only on the source substrate side, it is necessary to determine that the temperature of the growth target substrate 18 is within a predetermined range in addition to the above conditions.

Subsequently, hydrogen chloride (halogen gas) is introduced from the gas inlet 15 in addition to the hydrogen gas. In addition, the source substrate holder 12 is moved in the direction parallel to the film formation surface by the plane direction moving means so that the entire surface of the source substrate 17 uniformly faces the surface of the growth substrate 18. Thus, the etching mainly occurs on the source substrate 17 having a high temperature, and also occurs uniformly on the entire surface of the source substrate 17. Then, a reaction product generated by the etching is deposited on the substrate to be grown 18 having a low temperature.

FIG. 9 shows a state of the growth reaction. That is, a reaction such as Si + 2HCl → SiCl ₂ + H ₂ occurs on the source substrate 17 on the high temperature side, and SiCl ₂ is generated. This SiCl ₂ moves onto the growth substrate 18 on the low temperature side, and a reaction such as 2SiCl ₂ → Si + 2SiCl ₄ occurs. This Si is deposited on the growth substrate 18.

After maintaining this state for a predetermined time, a silicon film having a predetermined thickness is grown on the substrate 18 to be grown. Next, the introduction of the halogen gas is stopped, and only the hydrogen gas is introduced. Subsequently, as shown in FIG.
While the substrate 3 is pulled up, the substrate 18 is subjected to a heat treatment. Thereafter, the growth substrate 18 is taken out.

As described above, according to the epitaxial growth method of the fifth embodiment, the source substrate 17 and the substrate 1
8 and the growth substrate 1 with respect to the source substrate 17.
Since the temperature difference of 8 can be easily adjusted, it is possible to form films continuously on different substrates 18 to be grown. In addition, since a non-uniform reaction is used, high-speed film formation is possible. As described above, throughput can be improved and mass productivity can be improved.

Further, by moving the growth substrate 18 up and down, the distance between the source substrate 17 and the growth substrate 18 is kept wide before deposition so as not to cause a non-uniform reaction. For hydrogen treatment. Therefore, epitaxial growth can be performed on a clean surface, and the film quality can be improved. Furthermore,
By providing a heater on the growth substrate holder 13c, the entire growth substrate 18 can be directly heated, so that the temperature uniformity increases. In addition, since it is a face-to-face type using a non-uniform reaction, it is not affected by the shape of the reactor, the gas flow rate, or the like.
Thereby, the uniformity of the film thickness and the film quality can be improved, and it is possible to cope with an increase in the diameter of the wafer.

Since the source substrate 17 is moved in the direction parallel to the growth surface, the growth substrate 18 can face the entire surface of the source substrate 17 uniformly. Therefore, a non-uniform reaction can be caused uniformly over the entire surface of the source substrate 17. Thereby, the surface of the source substrate 17 after the reaction can be kept flat. Furthermore, since a non-uniform reaction is used, high-speed film formation is possible, and a sufficient throughput can be obtained even in a single-wafer method.
Energy saving can be achieved. Further, since it is not necessary to use a large amount of hydrogen gas, cost reduction can be achieved.

Further, since a gas containing hydrogen chloride is used as a reaction gas, it is safe. Note that, instead of hydrogen chloride, a gas containing another halogen gas such as chlorine, bromine, iodine, hydrogen bromide, or hydrogen iodide can be used as the reaction gas. In some cases, silicon tetrachloride (SiCl ₄ ), trichlorosilane (SiHCl ₃ ), or dichlorosilane (SiH ₂ Cl ₂ ) may be used. Various combinations such as the following, for _{example, H 2 / SiCl 4, H} 2 / SiHCl 4, H 2 / Br 2, H 2 / HC
l, He / SiCl ₄ , He / Br ₂ or He / HCl can be used.

Although a silicon substrate is used as the source substrate and the substrate to be grown, a germanium substrate or a compound semiconductor substrate may be used. Further, although hydrogen gas is mixed with halogen gas, helium, nitrogen or argon may be used instead of hydrogen, or 100% halogen gas or halogen hydrogen gas is used without dilution with these gases. It is also possible.

The halogen gas may be generated from a solid or a liquid. Furthermore, the pretreatment with hydrogen is performed with the gap between the source substrate and the growth substrate widened.However, the source substrate and the growth substrate are separately heated, and the hydrogen is maintained with the temperature of both substrates substantially equal. Processing may be performed. This suppresses substance transfer regardless of the size of the gap, so that it is not necessary to adjust the gap between the source substrate and the growth target substrate.

Although the hydrogen treatment and the film formation are performed under reduced pressure, both may be performed at normal pressure, or either one may be performed at normal pressure or reduced pressure. Further, the heat treatment is performed in a hydrogen atmosphere as a pretreatment, but a vapor treatment of hydrofluoric acid may be performed. Next, in the above method, the growth conditions are as follows: (a) the kind of gas; (b) the source substrate temperature; (c) the growth substrate temperature; and (d) the gap (gap). Regarding the film, (a) the growth rate and (b) the correspondence between the specific resistance of the source substrate and the specific resistance of the grown film were investigated. In the investigation described below, film formation was performed under normal pressure using the epitaxial growth apparatus shown in FIG. Further, the temperature difference between the source substrate and the growth substrate was maintained at 20 to 60 ° C. At this time, the gap was about 100 μm. The results of the survey are described below.

FIG. 10 shows hydrogen chloride (H) in hydrogen (H ₂ ).
FIG. 4 is a characteristic diagram illustrating a relationship between a growth rate and a Cl) concentration. The horizontal axis represents the concentration of hydrogen chloride (%) in hydrogen on a logarithmic scale, and the vertical axis represents the growth rate (μm) on a logarithmic scale.
/ Min). Using a mixed gas of HCl + H ₂ as a gas, changing the content of hydrogen chloride in the range 2-100%. This is compared with the temperatures of 1150 ° C and 1250
C was investigated.

According to the investigation results shown in FIG. 10, the growth rate increases as the temperature of the source substrate increases. 1150 ℃
In the case of, a growth rate of about 2 μm / min is obtained with a hydrogen chloride content of 2%, the growth rate increases as the hydrogen chloride content increases, and becomes about 6 μm / min at 50%.
Thereafter, it is almost constant up to 100%. In the case of 1250 ° C., a growth rate of about 4 μm / min is obtained at a hydrogen chloride content of 2%, and the growth rate increases as the hydrogen chloride content increases, and becomes about 25 μm / min at 50%. Thereafter, it is almost constant up to 100%.

FIG. 11 is a characteristic diagram showing the relationship between the growth temperature and the growth rate. The horizontal axis represents the reciprocal (× 10 ⁻⁴ / K) of the temperature of the source substrate shown on a linear scale, and the vertical axis represents the growth rate (μm / min) shown on a logarithmic scale. Using a mixed gas of HCl + H ₂ or HCl + the He as a gas, the temperature is changed in the source substrate in the range of 1050 ° C. to 1300 ° C.. This is achieved by adding three types of HCl (in H ₂ ) with a content of 10
0, 50, 3.3% and one HCl (in He) content of 3% were investigated. Here, in FIG.
l (in H ₂₎ shows what content 100%. The white circle is H
It shows a sample having a Cl (in H ₂ ) content of 50%. Open triangles indicate those with an HCl (in H ₂ ) content of 3.3%. Black triangles indicate those with an HCl (in He) content of 3%.

According to the investigation results shown in FIG. 11, the growth rate is inversely proportional to the reciprocal of the source substrate temperature. That is, the higher the temperature, the higher the growth rate. HCl (in H ₂₎
When the content is 100 and 50%, they change almost simultaneously, and 11
It shows a growth rate of about 7 μm / min at 50 ° C. and about 50 μm at 1300 ° C.
μm / min. When the content of HCl (in H ₂ ) is 3.3%, the growth rate is about 1.5 μm / min at 1100 ° C. and about 6 μm / min at 1250 ° C. When the content of HCl (in He) is 3%, the growth rate is 0.7 μm / min at 1080 ° C. and 7 μm / min at 1250 ° C.

FIG. 12 shows that bromine in hydrogen or helium (B
FIG. 9 is a characteristic diagram showing a relationship between a growth rate and r ₂ ) concentration. The horizontal axis represents the concentration of bromine in hydrogen or helium (%) on a logarithmic scale, and the vertical axis represents the growth rate (μm / min) on a logarithmic scale. Br ₂ + H ₂ or B as gas
Using a mixed gas of r ₂ + He, the bromine content was changed in a range of 0.15 to 20%. This was investigated for each mixed gas at temperatures of 1100 ° C. and 1200 ° C. for the two types of source substrates. Here, in the drawing, the solid line shows the case where Br ₂ + H ₂ is used. The dotted line shows the case where Br ₂ + He is used.

According to the investigation results shown in FIG. 12, Br ₂ +
When H ₂ is used, the growth rate is higher than when Br ₂ + He is used, and the dependence on the bromine content is greater. The higher the temperature of the source substrate, the higher the growth rate. In the case of Br ₂ + H ₂ at 1100 ° C., the growth rate increases as the bromine content increases, and the growth rate becomes about 8 μm / min at a bromine content of about 8%. After that, it becomes almost constant. In the case of 1200 ° C., the growth rate increases as the bromine content increases, and the growth rate becomes about 15 to 20 μm / min when the bromine content is about 8%. After that, it becomes almost constant.

On the other hand, in the case of Br ₂ + He, at 1100 ° C., the bromine content becomes almost constant in the range of about 1% or more,
The growth rate is about 1.5 μm / min. In the case of 1200 ° C., the bromine content becomes substantially constant in the range of about 1% or more, and the growth rate becomes about 3 μm / min. FIG. 13 is a characteristic diagram showing the relationship between the growth temperature and the growth rate. The horizontal axis represents the temperature (× 10 ⁻⁴ / K) of the source substrate shown on a linear scale, and the vertical axis represents the growth rate (μm / min) shown on a logarithmic scale.

As a gas, Br ₂ + H ₂ or Br ₂ + He
The temperature of the source substrate was changed in the range of 1080 ° C. to 1250 ° C. using the mixed gas of This is achieved with one hydrogen chloride / hydrogen content of 7% and one hydrogen chloride / helium content of 7%.
%. Here, in the figure, black circles indicate Br ₂ +
The case where H ₂ is used is shown. Black triangles indicate the case where Br ₂ + He is used.

According to the survey results shown in FIG. 13, Br ₂ +
In the case of H ₂ , the growth rate is 2 μm / min at 1120 ° C., and the growth rate increases as the temperature rises, and reaches 6 μm / min at 1250 ° C. In the case of Br ₂ + He, the growth rate is about 4 μm / min at 1080 ° C., and the growth rate increases as the temperature rises, and becomes 30 to 40 μm / min at 1250 ° C.

FIG. 14 is a characteristic diagram showing the relationship between the gap between the substrates and the growth rate. The horizontal axis represents the gap (μm) shown on a logarithmic scale, and the vertical axis represents the growth rate (μm / min) shown on a logarithmic scale. The gap was changed in the range of 10 to 1000 μm. This was investigated the type and the source substrate temperature of the mixed gas of HCl + H ₂ or Br ₂ + H ₂ as a parameter. In this investigation, only the source substrate is heated, and the temperature difference between the source substrate and the growth substrate may not always be maintained at 20 to 60 ° C.

Here, in the figure, white circles indicate HCl + H ₂ (H
This shows the case where a Cl content of 4%) and a source substrate temperature of 1260 ° C. are used. The white triangle marks HCl + H ₂ (HCl content 3.
8%) and a source substrate temperature of 1200 ° C. Black triangles indicate the case where Br ₂ + H ₂ (HCl content 3%) and the source substrate temperature is 1200 ° C. According to the investigation results shown in FIG. 14, when HCl + H ₂ (HCl content 4%) and the substrate temperature to be grown is 1260 ° C., the gap is almost constant in the range of 10 to 100 μm, and the growth rate is about 8 μm / min. Thereafter, it gradually decreases as the gap becomes wider, and the gap becomes 1000
In the case of μm, the growth rate is about 2 μm / min.

HCl + H ₂ (HCl content 3.8
%), And when the source substrate temperature is 1200 ° C., it gradually decreases as the gap becomes wider. The growth rate is about 4.5 μm / min when the gap is about 10 μm, and about 1-2 μm / min when the gap is about 150 μm. Further, Br ₂ + H
₂ (HCl content 3%) and a source substrate temperature of 1200 ° C., the value gradually decreases as the gap becomes wider. When the gap is about 10 μm, the growth rate is about 3 to 4 μm / min, and when the gap is about 80 μm, the growth rate is about 1 μm / min.

These data are obtained when the film is formed under normal pressure, and show that if the gap is widened, a reaction occurs during the movement of the gas and does not contribute to the film formation.
On the other hand, when the film is formed under reduced pressure, the mean free path of the gas particles is extended, so that it is possible to suppress the growth rate from decreasing to a wider portion of the gap. FIG. 15 is a characteristic diagram showing a correlation between the epitaxial layer resistivity and the source resistivity. The horizontal axis represents the specific resistance (Ωcm) of the source substrate shown on a logarithmic scale, and the vertical axis represents the specific resistance (Ωcm) of the epitaxial layer shown on a logarithmic scale.

The specific resistance of the source substrate was changed in the range of 0.001 to 100 Ωcm. This was investigated using the type of dopant as a parameter. Here, in the figure, white circles indicate antimony (Sb), black circles indicate boron (B),
White triangles indicate arsenic (As), black triangles indicate phosphorus (P)
Is shown. According to the investigation results shown in FIG. 15, the mutual specific resistances have almost a one-to-one correlation regardless of the type of the dopant. Therefore, if a source substrate having the same specific resistance as that of the epitaxial layer to be grown is used, an epitaxial layer having almost a desired specific resistance can be obtained.

[0070]

As described above, the epitaxial growth apparatus of the present invention has a source substrate holder having heating means and a substrate holder to be grown facing the source substrate holder. Moving means for vertically moving any of the growth substrate holders.

Therefore, as in the epitaxial growth method of the present invention, the distance between the source substrate and the source substrate is adjusted by heating and keeping the temperature of the source substrate and vertically moving the source substrate or the substrate to be grown. The temperature of the opposing substrate to be grown may be lower than the temperature of the source substrate, and a predetermined temperature difference may occur between the substrate and the source substrate. Similar adjustment of the temperature difference can also be achieved by heating the growth target substrate separately from the source substrate.

As described above, since the facing distance between the source substrate and the growth substrate and the temperature difference between the growth substrate and the source substrate can be easily adjusted, it is possible to form a film continuously on different growth substrates. Can be. In addition, since a non-uniform reaction is used, high-speed film formation is possible. As a result, throughput can be improved, and mass productivity can be improved.

Further, by using the above-mentioned vertical moving means, the distance between the source substrate and the substrate to be grown is kept wide before deposition so as not to cause an uneven reaction, and hydrogen is introduced from the hydrogen gas inlet. To perform a hydrogen treatment. Therefore, a film can be formed on a clean surface, and the film quality can be improved. Further, by providing the heating means on the growth substrate holder, the entire growth substrate can be directly heated, so that the temperature uniformity increases. In addition, since it is a face-to-face type using a non-uniform reaction, it is not affected by the shape of the reactor, the gas flow rate, or the like. Thereby, the uniformity of the film thickness and the film quality can be improved, and it is possible to cope with an increase in the diameter of the wafer.

Further, high-speed film formation is possible, and a sufficient throughput can be obtained even in a single-wafer method, so that energy can be saved. Further, since it is not necessary to use a large amount of hydrogen gas, cost reduction can be achieved. Further, since a gas containing chlorine, bromine, iodine, hydrogen chloride, hydrogen bromide or hydrogen iodide is used as a reaction gas, it is safe.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an epitaxial growth apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an epitaxial growth apparatus according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing an epitaxial growth apparatus according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing an epitaxial growth apparatus according to a fourth embodiment of the present invention.

FIG. 5 is an apparatus configuration diagram showing connection of a reaction gas to an epitaxial growth apparatus according to an example of the present invention.

FIG. 6 is a sectional view (part 1) illustrating an epitaxial growth method according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view (part 2) illustrating an epitaxial growth method according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing an epitaxial growth method using an epitaxial growth apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating a non-uniformity reaction, which is a growth principle of the epitaxial growth method according to the embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between a hydrogen chloride content in a reaction gas and a growth rate by an epitaxial growth method according to an example of the present invention.

FIG. 11 is a characteristic diagram showing a relationship between a growth substrate temperature and a growth rate according to the epitaxial growth method of the example of the present invention.

FIG. 12 is a characteristic diagram showing a relationship between a bromine content in a reaction gas and a growth rate by an epitaxial growth method according to an example of the present invention.

FIG. 13 is a characteristic diagram showing a relationship between a growth target substrate temperature and a growth rate by the epitaxial growth method according to the example of the present invention.

FIG. 14 is a characteristic diagram showing a relationship between a gap between a source substrate and a substrate to be grown and a growth rate by the epitaxial growth method according to the embodiment of the present invention.

FIG. 15 is a characteristic diagram showing a relationship between the specific resistance of the source substrate and the specific resistance of the growth layer formed on the growth target substrate by the epitaxial growth method according to the embodiment of the present invention.

FIG. 16 is a sectional view showing an epitaxial growth apparatus according to a conventional example.

[Explanation of symbols]

 Reference Signs List 11 chamber, 12 source substrate holder, 13, 13a, 13b, 13c substrate to be grown holder, 14 vertical movement axis (first movement means), 14a vertical movement axis (third movement means), 15 gas inlet , 16 exhaust port, 17 source substrate, 18 substrate to be grown, 19 piping.

Continued on the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location C30B 25/14 C30B 25/14

Claims (21)

(57) [Claims] A chamber for performing film formation; a source substrate holder provided in the chamber; a first heating unit provided in the source substrate holder; and a source substrate provided in the chamber. Epitaxial growth comprising: a substrate holder to be grown facing the holder; first moving means for vertically moving the substrate holder to be grown; and a gas inlet for introducing a reaction gas into the chamber. apparatus. 2. The epitaxial growth apparatus according to claim 1, wherein said substrate holder has second heating means. 3. The epitaxial growth apparatus according to claim 1, wherein said epitaxial apparatus has second moving means for vertically moving said source substrate holder. 4. A chamber for forming a film, a source substrate holder provided in the chamber, a third heating means provided on the source substrate holder, and the source substrate holder is moved up and down. Epitaxial growth comprising: a third moving unit; a substrate holder to be grown, provided in the chamber, facing the source substrate holder; and a gas inlet for introducing a reaction gas into the chamber. apparatus. 5. The epitaxial growth apparatus according to claim 4, wherein said substrate holder has fourth heating means. 6. A chamber for forming a film, a source substrate holder provided in the chamber, a fifth heating unit provided in the source substrate holder, and a source provided in the chamber. It has a substrate holder to be grown facing the substrate holder, sixth heating means provided on the substrate holder, and a gas inlet for introducing a reaction gas into the chamber. Epitaxial growth equipment. 7. The apparatus according to claim 1, wherein said chamber has a gas inlet for introducing hydrogen gas.
7. The epitaxial growth apparatus according to claim 3, claim 4, claim 5, or claim 6. 8. The apparatus according to claim 1, wherein said chamber is connected to an exhaust device to reduce the pressure inside said chamber. The epitaxial growth apparatus according to claim 6. 9. The apparatus according to claim 1, wherein said epitaxial apparatus has a fourth moving means for moving at least one of said source substrate holder and said growth target substrate holder in a plane direction parallel to a growth surface. The epitaxial growth apparatus according to claim 1, 2, 3, 4, 5, 5, 6, 7 or 8. 10. At least one of a source substrate and a substrate to be grown is moved up and down, the source substrate and the substrate to be grown are brought close to each other, and the source substrate is heated. Adjusting the gap with the growth substrate, the temperature of the source substrate is higher than the temperature of the growth substrate, and the growth substrate has a predetermined temperature difference with respect to the temperature of the source substrate, A reactive gas is introduced into the gap between the source substrate and the growth substrate, and a reaction product of the source substrate and the reaction gas is deposited on the growth substrate. 11. At least one of the source substrate and the growth substrate is moved up and down, and the source substrate and the growth substrate are brought close to each other with a gap therebetween, and the source substrate and the growth substrate are separated from each other. The temperature of the source substrate is higher than the temperature of the growth substrate, and the growth substrate has a predetermined temperature difference with respect to the temperature of the source substrate. A reactive gas is introduced into the gap of the substrate, and a reaction product of the source substrate and the reactive gas is deposited on the growth target substrate. 12. A hydrogen atmosphere in a state where the source substrate and the growth substrate are opposed to each other with a gap larger than the gap before the source substrate and the growth substrate are approached and opposed to each other. The growth target substrate is heated to perform a surface treatment, and thereafter, the source substrate and the growth target substrate are brought closer to each other by the vertical movement, and the source substrate and the growth target substrate are opposed to each other with the gap therebetween. The epitaxial growth method according to claim 10 or 11, wherein 13. The method according to claim 13, wherein, before depositing the reaction product, surface growth is performed by heating the growth target substrate in a hydrogen atmosphere with the temperature of the source substrate and the temperature of the growth target substrate being substantially equal. The epitaxial growth method according to claim 11, wherein: 14. The method according to claim 10, wherein the film is formed under reduced pressure.
3. The epitaxial growth method according to 3. 15. The reaction product is deposited on the growth substrate while at least one of the source substrate and the growth substrate is moved in a plane direction parallel to a growth surface. Claim 10, Claim 11, Claim 1
2. The epitaxial growth method according to claim 13 or claim 14. 16. The epitaxial growth according to claim 10, wherein the material of said source substrate is silicon, germanium, or a compound semiconductor. Method. 17. The epitaxial growth method according to claim 16, wherein said silicon, germanium or compound semiconductor contains an impurity imparting a conductivity type. 18. The method of claim 10, wherein the material of the substrate to be grown is silicon, germanium or a compound semiconductor. Item 18. The epitaxial growth method according to Item 16 or 17. 19. The method according to claim 10, wherein said reaction gas is a gas containing halogen.
An epitaxial growth method according to claim 17 or claim 18. 20. The halogen is chlorine (Cl), bromine (B
r ₂ ), iodine (I ₂ ), hydrogen chloride (HCl), hydrogen bromide (HBr),
Hydrogen iodide (HI), silicon tetrachloride (SiCl ₄₎ and trichlorosilane (SiHCl _3), dichlorosilane epitaxial growth method according to claim 19, wherein a is either (SiH ₂ Cl _2). 21. The gas containing halogen includes at least hydrogen (H ₂ ), helium (He), nitrogen (N ₂ ), and argon (Ar).
2. A gas containing any one of the following:
The epitaxial growth method according to claim 9 or 20.