Patent Publication Number: US-2021180208-A1

Title: Vapor phase growth apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is continuation application of, and claims the benefit of priority from the International Application PCT/JP2019/28426, filed Jul. 19, 2019, which claims the benefit of priority from Japanese Patent Application No. 2018-157826, filed on Aug. 24, 2018, the entire contents of all of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a vapor phase growth apparatus that supplies gas to a substrate to form a film. 
     BACKGROUND OF THE INVENTION 
     As a method for forming a high-quality semiconductor film, there is an epitaxial growth technique for forming a single crystal film by vapor phase growth on a surface of a substrate. In a vapor phase growth apparatus using an epitaxial growth technique, a substrate is mounted on a holder in a reactor held at a normal pressure or a reduced pressure. 
     Then, while heating the substrate, the process gas containing a raw material of a film is supplied from a gas chamber at an upper portion of the reactor to the reactor through the gas flow path. A thermal reaction of the process gas occurs on the surface of the substrate, and thus, an epitaxial single crystal film is formed on the surface of the substrate. 
     If the growth of the film in the reactor is repeated, reaction products may be deposited at the end of the gas flow path on the reactor side. As the amount of deposited reaction products increases, the opening cross-sectional area of the gas flow path changes. When the opening cross-sectional area of the gas flow path changes, the supply of the process gas to the reactor becomes unstable, and thus, the reproducibility of the characteristics of the film deteriorates. Therefore, it is preferable to suppress destabilization of the supply of the process gas to the reactor and improve the reproducibility of the characteristics of the film. 
     Patent Document 1 discloses a vapor phase growth apparatus that suppresses gas wraparound at the end of the gas flow path on the reactor side and suppresses the occurrence of particles due to the adhesion of deposits. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, there is provided a vapor phase growth apparatus including: a reactor; a first gas chamber provided above the reactor, a first process gas being introduced into the first gas chamber; and a plurality of first gas flow paths supplying the first process gas from the first gas chamber to the reactor, in which at least one of the plurality of first gas flow paths has a first region and a second region located between the first region and the reactor, the first region has a first opening cross-sectional area in a plane perpendicular to a direction of a flow of the first process gas and a first length in the direction, the second region has a second opening cross-sectional area in the plane perpendicular to the direction and a second length in the direction, the first opening cross-sectional area is smaller than the second opening cross-sectional area, and the first length is equal to or less than the second length. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of a vapor phase growth apparatus according to the first embodiment; 
         FIG. 2  is a schematic cross-sectional view of a first gas flow path of the first embodiment; 
         FIG. 3  is a schematic cross-sectional view of a second gas flow path of the first embodiment; 
         FIG. 4  is an explanatory diagram of functions and effects of the vapor phase growth apparatus according to the first embodiment; 
         FIG. 5  is an explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment; 
         FIG. 6  is an explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment; 
         FIG. 7A  and  FIG. 7B  are explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment; 
         FIG. 8  is a schematic cross-sectional view of a first gas flow path of a second embodiment; and 
         FIG. 9  is a schematic cross-sectional view of a vapor phase growth apparatus according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, an embodiment of the invention will be described with reference to the drawings. 
     In this specification, in some cases, the same or similar members may be denoted by the same reference numerals. 
     In this specification, a direction of gravity in a state where a vapor phase growth apparatus is installed so that films can be formed is defined as “lower”, and the opposite direction is defined as “upper”. Therefore, “lower portion” denotes a position in the direction of gravity with respect to a reference, and “below” denotes the direction of gravity with respect to the reference. In addition, “upper portion” denotes a position opposite to the direction of gravity with respect to the reference, and “above” denotes a direction opposite to the direction of gravity with respect to the reference. In addition, a “vertical direction” is the direction of gravity. 
     In addition, in this specification, a “process gas” is a general term for gases used for forming a film and has a concept including, for example, a source gas, an assist gas, a dopant gas, a carrier gas, and a mixed gas thereof. 
     A conductance denotes easiness of flow of a fluid flowing through a flow path. For example, the conductance of a cylindrical flow path having a diameter of D and a length of L is proportional to D 4 /L. Hereinafter, D 4 /L will be referred to as a conductance coefficient. In addition, in this specification, it is assumed that there is no change in pressure between an inlet and an outlet of the flow path due to a change in shape of the flow path. In addition, in a viscous flow region, the conductance is proportional to an average pressure of the flow path, but in this specification, the conductance is omitted in calculation so as not to be complicated. By doing so, the conductance of the flow path can be treated as being proportional only to the conductance coefficient. 
     First Embodiment 
     A vapor phase growth apparatus according to a first embodiment includes: a reactor; a first gas chamber provided above the reactor, a first process gas being introduced into the first gas chamber; and a plurality of first gas flow paths supplying the first process gas from the first gas chamber to the reactor, in which at least one of the plurality of first gas flow paths has a first region and a second region located between the first region and the reactor, the first region has a first opening cross-sectional area in a plane perpendicular to a direction of a flow of the first process gas and a first length in the direction, the second region has a second opening cross-sectional area in the plane perpendicular to the direction and a second length in the direction, the first opening cross-sectional area is smaller than the second opening cross-sectional area, and the first length is equal to or less than the second length. 
     Since the vapor phase growth apparatus according to the first embodiment has the above configuration, even in a case where the reaction products are deposited at the end of the first gas flow path on the reactor side, destabilization of the supply of the first process gas to the reactor can be suppressed. Therefore, according to the vapor phase growth apparatus according to the first embodiment, it is possible to improve a reproducibility of characteristics of the film. 
       FIG. 1  is a schematic cross-sectional view of the vapor phase growth apparatus according to the first embodiment. The vapor phase growth apparatus  100  according to the first embodiment is, for example, a single wafer type epitaxial growth apparatus in which a single crystal SiC film is epitaxially grown on a single crystal SiC substrate. 
     The vapor phase growth apparatus  100  according to the first embodiment includes a reactor  10 , a first gas chamber  11  (gas chamber), a second gas chamber  12 , a plurality of first gas flow paths  51  (gas flow paths), a plurality of second gas flow paths  52 , a first gas supply port  81 , and a second gas supply port  82 . The reactor  10  includes a susceptor  14  (holder), a rotating body  16 , a rotating shaft  18 , a rotation drive mechanism  20 , a first heater  22 , a reflector  28 , support columns  30 , a fixing base  32 , a fixing shaft  34 , a hood  40 , a second heater  42 , and a gas discharge port  44 . 
     The reactor  10  is made of, for example, stainless steel. The reactor  10  has a cylindrical wall. A SiC film is formed on a wafer W in the reactor  10 . The wafer W is an example of a substrate. 
     The susceptor  14  is provided in the reactor  10 . The wafer W can be mounted on the susceptor  14 . The susceptor  14  may be provided with an opening at the center. The susceptor  14  is an example of the holder. 
     The susceptor  14  is made of, for example, a highly heat-resistant material such as SiC, carbon, or carbon coated with SiC or TaC. 
     The susceptor  14  is fixed to the upper portion of the rotating body  16 . The rotating body  16  is fixed to the rotating shaft  18 . The susceptor  14  is indirectly fixed to the rotating shaft  18 . 
     The rotating shaft  18  can be rotated by the rotation drive mechanism  20 . By the rotation drive mechanism  20 , the rotating shaft  18  is rotated, so that the susceptor  14  can be rotated. By rotating the susceptor  14 , the wafer W mounted on the susceptor  14  can be rotated. 
     By the rotation drive mechanism  20 , the wafer W can be rotated at a rotation speed of, for example, 300 rpm or more and 3000 rpm or less. The rotation drive mechanism  20  is configured with, for example, a motor and a bearing. 
     The first heater  22  is provided below the susceptor  14 . The first heater  22  is provided in the rotating body  16 . The first heater  22  heats the wafer W held by the susceptor  14  from below. The first heater  22  is, for example, a resistance heating heater. The first heater  22  has, for example, a disk shape with a comb-shaped pattern formed. 
     The reflector  28  is provided below the first heater  22 . The first heater  22  is provided between the reflector  28  and the susceptor  14 . 
     The reflector  28  reflects heat radiated downward from the first heater  22  to improve heating efficiency of the wafer W. In addition, the reflector  28  prevents members below the reflector  28  from being heated. The reflector  28  has, for example, a disk shape. The reflector  28  is made of, for example, a highly heat-resistant material such as carbon coated with SiC. 
     The reflector  28  is fixed to the fixing base  32  by, for example, the plurality of support columns  30 . The fixing base  32  is supported by, for example, the fixing shaft  34 . 
     A push up pin (not illustrated) is provided in the rotating body  16  in order to attach/detach the susceptor  14  to/from the rotating body  16 . The push up pin penetrates, for example, the reflector  28  and the first heater  22 . 
     The second heater  42  is provided between the hood  40  and the inner wall of the reactor  10 . The second heater  42  heats the wafer W held by the susceptor  14  from above. By heating the wafer W with the second heater  42  in addition to the first heater  22 , it is possible to heat the wafer W to the temperature required for the growth of the SiC film, for example, 1500° C. or more. The second heater  42  is, for example, a resistance heating heater. 
     The hood  40  has, for example, a cylindrical shape. The hood  40  has a function of preventing a first process gas G 1  and a second process gas G 2  from coming into contact with the second heater  42 . The hood  40  is made of, for example, a highly heat-resistant material such as carbon coated with SiC. 
     The gas discharge port  44  is provided at the bottom of the reactor  10 . The gas discharge port  44  discharges surplus reaction products after reaction of the source gas on the surface of the wafer W and surplus process gases to the outside of the reactor  10 . The gas discharge port  44  is connected to, for example, a vacuum pump (not illustrated). 
     In addition, the reactor  10  is provided with a wafer inlet/outlet and a gate valve (not illustrated). The wafer W can be loaded in reactor  10  and unloaded from the reactor  10  by the wafer inlet/outlet and the gate valve. 
     The first gas chamber  11  is provided above the reactor  10 . The first gas chamber  11  is provided with the first gas supply port  81  for introducing the first process gas G 1 . The first gas chamber  11  is filled with the first process gas G 1  introduced from the first gas supply port  81 . 
     The first process gas G 1  contains, for example, a source gas for silicon (Si). The first process gas G 1  is, for example, a mixed gas of the source gas for silicon, an assist gas that suppresses clustering of silicon, and a carrier gas. 
     The source gas for silicon is, for example, silane (SiH 4 ). The assist gas is, for example, hydrogen chloride (HCl). The carrier gas is, for example, argon gas or hydrogen gas. 
     The second gas chamber  12  is provided above the reactor  10 . The second gas chamber  12  is provided between the reactor  10  and the first gas chamber  11 . The second gas chamber  12  is provided with the second gas supply port  82  for introducing the second process gas G 2 . The second gas chamber  12  is filled with the second process gas G 2  introduced from the second gas supply port  82 . 
     The second process gas G 2  contains, for example, a source gas for carbon. The second process gas G 2  is, for example, a mixed gas of the source gas for carbon, a dopant gas for n-type impurity, and a carrier gas. The second process gas G 2  is different from the first process gas G 1 . 
     The source gas for carbon is, for example, propane (C 3 H 8 ). The dopant gas for n-type impurity is, for example, nitrogen gas. The carrier gas is, for example, argon gas or hydrogen gas. 
     The plurality of first gas flow paths  51  are provided between the first gas chamber  11  and the reactor  10 . The first gas flow paths  51  supply the first process gas G 1  from the first gas chamber  11  to the reactor  10 . 
     The plurality of second gas flow paths  52  are provided between the second gas chamber  12  and the reactor  10 . The second gas flow paths  52  supply the second process gas G 2  from the second gas chamber  12  to the reactor  10 . 
       FIG. 2  is a schematic cross-sectional view of the first gas flow path of the first embodiment. The first gas flow path  51  has an upper region  51   a  (first region) and a lower region  51   b  (second region). The lower region  51   b  is located between the upper region  51   a  and the reactor  10 . 
     The upper region  51   a  has a first opening cross-sectional area S 1  in a plane (P 1  in  FIG. 2 ) perpendicular to a direction in which the process gas flows (white arrow in  FIG. 2 : first direction). In addition, the upper region  51   a  has a first length L 1  in the direction in which the process gas flows (white arrow in  FIG. 2 ). 
     The upper region  51   a  has, for example, a cylindrical shape having a length of L 1 . The opening cross section of the upper region  51   a  on the plane P 1  has, for example, a circular shape having a diameter of D 1 . 
     The lower region  51   b  has a second opening cross-sectional area S 2  in a plane (P 2  in  FIG. 2 ) perpendicular to the direction in which the process gas flows (white arrow in  FIG. 2 ). In addition, the lower region  51   b  has a second length L 2  in the direction in which the process gas flows (white arrow in  FIG. 2 ). 
     The lower region  51   b  has, for example, a cylindrical shape having a length of L 2 . The open cross section of the lower region  51   b  on a plane P 2  has, for example, a circular shape having a diameter of D 2 . 
     An angle θ formed by an inner wall surface of the lower region  51   b  and the plane P 2  is, for example, 80 degrees or more. The second length L 2  is, for example, 5 mm or more. 
     The first opening cross-sectional area S 1  is smaller than the second opening cross-sectional area S 2 . In addition, the first length L 1  is equal to or less than the second length L 2 . That is, the second flow path area (opening cross-sectional area) at the lower end of the lower region  51   b  is larger than the first flow path area (opening cross-sectional area) at the upper end of the upper region  51   a , and a flow path area at the intermediate position (position of an intermediate height of the upper end and the lower end) of the gas flow path  51  is larger than the first flow path area at the upper end and is equal to or less than the second flow path area at the lower end. 
     The upper region  51   a  has a first conductance C 1 , and the lower region  51   b  has a second conductance C 2 . The first conductance C 1  is smaller than the second conductance C 2 . A ratio of the first conductance C 1  to the second conductance C 2  (hereinafter, also referred to as a conductance ratio) is, for example, 1° or more and 40° or less. 
     The magnitude relationship between the first conductance C 1  and the second conductance C 2  matches with the magnitude relationship between the conductance coefficient of the upper region  51   a  and the conductance coefficient of the lower region  51   b . In addition, the ratio of the first conductance C 1  to the second conductance C 2  (conductance ratio) matches with the ratio of the conductance coefficients, that is, ((D 1 ) 4 /L 1 )/((D 2 ) 4 /L 2 ). 
       FIG. 3  is a schematic cross-sectional view of the second gas flow path of the first embodiment. The second gas flow path  52  has an upper region  52   a  (third region) and a lower region  52   b  (fourth region). The lower region  52   b  is located between the upper region  52   a  and the reactor  10 . 
     The upper region  52   a  has a third opening cross-sectional area S 3  in a plane (P 3  in  FIG. 3 ) perpendicular to a direction in which the process gas flows (white arrow in  FIG. 3 : second direction). In addition, the upper region  52   a  has a third length L 3  in the direction in which the process gas flows (white arrow in  FIG. 3 ). 
     The upper region  52   a  has, for example, a cylindrical shape having a length of L 3 . The open cross section of the upper region  52   a  on the plane P 3  has, for example, a circular shape having a diameter of D 3 . 
     The lower region  52   b  has a fourth opening cross-sectional area S 4  in a plane (P 4  in  FIG. 3 ) perpendicular to the direction in which the process gas flows (white arrow in  FIG. 3 ). In addition, the lower region  52   b  has a fourth length L 4  in the direction in which the process gas flows (white arrow in  FIG. 3 ). 
     The lower region  52   b  has, for example, a cylindrical shape having a length of L 4 . The open cross section of the lower region  52   b  on the plane P 4  has, for example, a circular shape having a diameter of D 4 . 
     An angle θ formed by an inner wall surface of the lower region  52   b  and the plane P 4  is, for example, 80 degrees or more. The fourth length L 4  is, for example, 5 mm or more. 
     The third opening cross-sectional area S 3  is smaller than the fourth opening cross-sectional area S 4 . In addition, the third length L 3  is equal to or less than the fourth length L 4 . 
     The upper region  52   a  has a third conductance C 3 , and the lower region  52   b  has a fourth conductance C 4 . The third conductance C 3  is smaller than the fourth conductance C 4 . A ratio of the third conductance C 3  to the fourth conductance C 4  (conductance ratio) is, for example, 1% or more and 40% or less. 
     The magnitude relationship between the third conductance C 3  and the fourth conductance C 4  matches with the magnitude relationship between the conductance coefficient of the upper region  52   a  and the conductance coefficient of the lower region  52   b . In addition, the ratio of the third conductance C 3  to the fourth conductance C 4  (conductance ratio) matches with the ratio of the conductance coefficient, that is, ((D 3 ) 4 /L 3 )/((D 4 ) 4 /L 4 ). 
     Next, the functions and effects of the vapor phase growth apparatus according to the first embodiment will be described. 
       FIG. 4  is an explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment.  FIG. 4  is a schematic cross-sectional view of the gas flow path  59  of Comparative Example. The gas flow path  59  of Comparative Example has a cylindrical shape. The opening cross section of the gas flow path  59  of Comparative Example has a circular shape having a diameter of D 0 . 
     For example, in a case where an SiC film is formed on the wafer W, the temperature at the end of the gas flow path  59  on the reactor  10  side rises due to radiant heat. As the temperature rises, the reaction products  99  of the process gas may be deposited at the end of the gas flow path  59  on the reactor  10  side. The reaction product  99  is assumed to have a thickness of t and a length of Lx. By repeating the formation of the SiC film, the thickness t of the deposit becomes thicker, and the length Lx becomes longer. 
     Due to the deposition of the reaction products  99 , the effective diameter of the inner wall surface at the end of the gas flow path  59  on the reactor  10  side is reduced as small as (D 0 −2t). Due to the reduction of the effective diameter of the inner wall surface, the opening cross-sectional area is also reduced, and the conductance of the gas flow path  59  is reduced. Therefore, it becomes difficult for the process gas to flow through the gas flow path  59 . 
     Due to the change of the conductance of the gas flow path  59  with time, the flow velocity and flow rate of the process gas flowing through the gas flow path  59  change with time, and the reproducibility of the characteristics of the SiC film deteriorates. In particular, in a case where the deposition of the reaction products  99  on the plurality of gas flow paths  59  depends on the position of the gas flow paths  59 , the reproducibility of the wafer in-plane uniformity of the characteristics of the SiC film also deteriorates. That is, the amount of change in conductance differs between the plurality of gas flow paths  59 , so that the balance of the process gas supplied into the reactor  10  is lost, and the reproducibility of the wafer in-plane uniformity of the SiC film deteriorates. 
     Due to the deposition of the reaction products  99 , for example, the reproducibility of the average value of the film thickness or the carrier concentration of the SiC film deteriorates. In addition, for example, the reproducibility of the wafer in-plane uniformity of the film thickness or the carrier concentration of the SiC film deteriorates. 
       FIG. 5  is an explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment.  FIG. 5  is a schematic cross-sectional view of the first gas flow path  51 . 
     The first gas flow path  51  of the vapor phase growth apparatus according to the first embodiment has a two-stage structure of an upper region  51   a  having a small conductance and a lower region  51   b  having a large conductance. The lower region  51   b  having a large conductance is located on the reactor  10  side of the first gas flow path  51 . By allowing the first opening cross-sectional area S 1  to be smaller than the second opening cross-sectional area S 2 , the conductance of the first gas flow path  51  is allowed to be smaller than the conductance of the lower region  51   b.    
     Even if the reaction products  99  are deposited at the end of the lower region  51   b  on the reactor  10  side and the conductance of the lower region  51   b  is decreased, the decrease in conductance of whole of the first gas flow path  51  is suppressed as compared with the case of Comparative Example. Therefore, the deterioration of the reproducibility of the characteristics of the SiC film is suppressed. 
       FIG. 6  is an explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment.  FIG. 6  is a diagram illustrating calculation results of a conductance change rate in a case where the reaction products are deposited in the gas flow paths of Comparative Examples and Examples 1 to 5. 
     Examples 1 to 5 are premised on the shape of the first gas flow path  51  illustrated in  FIG. 2 . In addition, the deposited reaction products  99  were assumed to have a thickness of t=0.5 mm and a length of Lx=5 mm. 
     The conductance ratio is the ratio of the first conductance C 1  to the second conductance C 2 , that is, the ratio of the conductance coefficient. In addition, the conductance change rate is a ratio of the conductance coefficient after the deposition to the conductance coefficient of whole of the first gas flow path  51  before the deposition of the reaction products  99 . As the conductance change rate is closer to 100°, the decrease in conductance is smaller. 
     By adopting the structure of the example, the conductance change rate is closer to 100% than that of Comparative Example. Therefore, the change in conductance associated with the deposition of the reaction products  99  is suppressed. Accordingly, the deterioration of the reproducibility of the characteristics of the SiC film is suppressed. 
     The conductance ratio is preferably 1° or more and 40% or less, and more preferably 20% or more and 30% or less. If the conductance ratio falls below the above-mentioned range, there is a concern that the gas flow rate may be decreased. If the conductance ratio exceeds the above-mentioned range, there is a concern that the effect of suppressing the change in conductance associated with the deposition of the reaction products  99  may be insufficient. 
       FIG. 7A  and  FIG. 7B  are explanatory diagram of the functions and effects of the vapor phase growth apparatus according to the first embodiment.  FIG. 7  A and  FIG. 7B  are a diagram illustrating a change in the characteristics of the SiC film with time in cases where the gas flow paths of Comparative Example and Example are used.  FIG. 7A  corresponds to the case of Comparative Example, and  FIG. 7B  corresponds to the case of Example. In Example, the gas flow path corresponding to the fourth embodiment of  FIG. 6  is used. 
     The horizontal axis indicates the number of treatments for forming the SiC film by using the vapor phase growth apparatus. The vertical axis indicates the wafer in-plane uniformity of the carrier concentration of the SiC film (carrier concentration uniformity). In addition, the vertical axis indicates an atomic ratio (C/Si ratio) of carbon contained in the second process gas G 2  introduced into the second gas chamber  12  to silicon contained in the first process gas G 1  introduced into the first gas chamber  11 . During forming the SiC film, by adjusting the C/Si ratio, the wafer in-plane uniformity of the carrier concentration is controlled to be, for example, within 15%. 
     As illustrated in  FIG. 7A , in the case of Comparative Example, in order to maintain the wafer in-plane uniformity of the carrier concentration, it was necessary to change the C/Si ratio by 0.21 in the range. On the contrary, as illustrated in  FIG. 7B , in the case of the example, the wafer in-plane uniformity of the carrier concentration can be maintained only by changing the C/Si ratio by 0.03 in the range. From the above-described results, the reproducibility of the characteristics of the SiC film in the examples is clearly improved as compared with Comparative Example. 
     In the first gas flow path  51 , an angle formed by an inner wall surface of the lower region  51   b  and the plane P 2  is preferably 80 degrees or more, and more preferably 85 degrees or more. If the angle falls below the above-mentioned range, the inner wall surface of the lower region  51   b  is likely to be irradiated with radiant heat. Therefore, the temperature rise of the inner wall surface of the lower region  51   b  becomes large, and thus, there is a concern that the amount of the deposited reaction products  99  may increase. 
     In addition, by setting the first length L 1  to the second length L 2  or less, the occurrence of the deposition of the reaction products  99  on the inner wall surface of the upper region  51   a  is suppressed. 
     In the first gas flow path  51 , the second length L 2  is preferably 5 mm or more, and more preferably 10 mm or more. If the second length L 2  falls below the above-mentioned range, there is a concern that the deposition of the reaction products  99  on the inner wall surface of the upper region  51   a  may occur. 
     As described above, according to the vapor phase growth apparatus according to the first embodiment, even in a case where the reaction products are deposited at the end of the gas flow path on the reactor side, destabilization of the supply of the process gas to the reactor can be suppressed. Therefore, according to the vapor phase growth apparatus according to the first embodiment, it is possible to improve a reproducibility of characteristics of a film. 
     Second Embodiment 
     A vapor phase growth apparatus according to a second embodiment is different from the vapor phase growth apparatus according to the first embodiment in that the first region is a component that is separable from the second region. Hereinafter, a portion of the description of contents overlapping with the first embodiment will be omitted. 
       FIG. 8  is a schematic cross-sectional view of the first gas flow path of the second embodiment. The first gas flow path  51  has an upper region  51   a  and a lower region  51   b . The first gas flow path  51  includes a component  51   x.    
     The component  51   x  constitutes at least a portion of the upper region  51   a . The component  51   x  is separable from the lower region  51   b.    
     By forming the upper region  51   a  with the component  51   x  separable from the lower region  51   b , the first opening cross-sectional area S 1  and the first length L 1  can be easily adjusted. Therefore, it becomes easy to improve a reproducibility of characteristics of a film. 
     According to the vapor phase growth apparatus according to the second embodiment, similarly to the vapor phase growth apparatus according to the first embodiment, even in a case where the reaction products are deposited at the end of the gas flow path on the reactor side, destabilization of the supply of the process gas to the reactor can be suppressed. Therefore, it is possible to improve a reproducibility of characteristics of a film. In addition, by using the component  51   x , it becomes easy to improve the reproducibility of the characteristics of the film. 
     Third Embodiment 
     A vapor phase growth apparatus according to a third embodiment is different from the vapor phase growth apparatus according to the first embodiment in that the vapor phase growth apparatus has one gas chamber. Hereinafter, a portion of the description of contents overlapping with the first embodiment will be omitted. 
       FIG. 9  is a schematic cross-sectional view of the vapor phase growth apparatus according to the third embodiment. A vapor phase growth apparatus  300  according to the third embodiment is, for example, a single wafer type epitaxial growth apparatus in which a single crystal SiC film is epitaxially grown on a single crystal SiC substrate. 
     The vapor phase growth apparatus  300  according to the third embodiment includes a reactor  10 , a gas chamber (first gas chamber), a plurality of gas flow paths  55  (first gas flow paths), a first gas supply port  81 , and a second gas supply port  82 . The reactor  10  includes a susceptor  14  (holder), a rotating body  16 , a rotating shaft  18 , a rotation drive mechanism  20 , a first heater  22 , a reflector  28 , a support column  30 , a fixing base  32 , a fixing shaft  34 , a hood  40 , a second heater  42 , and a gas discharge port  44 . 
     The gas chamber  15  is provided above the reactor  10 . The gas chamber  15  is provided with a gas supply port  85  for introducing a process gas G 0  (first process gas). The gas chamber  15  is filled with the process gas G 0  introduced from the gas supply port  85 . 
     The process gas G 0  is, for example, a mixed gas containing a source gas for silicon (Si), a source gas for carbon (C), an dopant gas for n-type impurity, an assist gas that suppresses clustering of silicon, and a carrier gas. The source gas for silicon is, for example, silane (SiH 4 ). The source gas for carbon is, for example, propane (C 3 H 8 ). The dopant gas for n-type impurity is, for example, nitrogen gas. The assist gas is, for example, hydrogen chloride (HCl). The carrier gas is, for example, argon gas or hydrogen gas. 
     The plurality of gas flow paths  55  are provided between the gas chamber  15  and the reactor  10 . The gas flow paths  55  supply the process gas G 0  from the gas chamber  15  to the reactor  10 . The gas flow path  55  has, for example, the same configuration as the first gas flow path  51  of the first embodiment. 
     According to the vapor phase growth apparatus according to the third embodiment, similarly to the first vapor phase growth apparatus, even in a case where the reaction products are deposited at the end of the gas flow path on the reactor side, destabilization of the supply of the process gas to the reactor can be suppressed. Therefore, according to the vapor phase growth apparatus according to the third embodiment, it is possible to improve a reproducibility of characteristics of a film. 
     The embodiments of the invention have been described above with reference to specific examples. The above-described embodiments are merely given as examples and do not limit the invention. In addition, the components of the embodiments may be combined as appropriate. 
     In the embodiments, the case of forming a single crystal SiC film has been described as an example, but the invention can also be applied to formation of a polycrystalline or amorphous SiC film. In addition, the invention can also be applied to formation of films other than the SiC film. 
     In addition, in the embodiments, the wafer of single crystal SiC has been described as an example of the substrate, but the substrate is not limited to the wafer of single crystal SiC. 
     In addition, in the embodiments, nitrogen has been described as an example of the n-type impurity, but for example, phosphorus (P) can be applied as the n-type impurity. In addition, it is also possible to apply p-type impurities as impurities. 
     In addition, in the embodiments, a case where the gas flow path has a cylindrical shape has been described as an example, but the shape of the gas flow path is not limited to the cylindrical shape and may be other shapes such as a quadrangular prism. In addition, in the embodiments, a case where the opening cross section of the gas flow path has a circular shape has been described as an example, but the opening cross section of the gas flow path is not limited to a circle and may be other shapes such as an ellipse, a square, and a rectangle. 
     In the embodiments, the description of portions and the like that are not directly required for the description of the invention such as the apparatus configuration and the manufacturing method is omitted, but the required apparatus configuration, the manufacturing method, and the like can be appropriately selected and used. In addition, all vapor phase growth apparatuses, annular holders, and vapor phase growth methods that include the elements of the invention and can be appropriately changed in design by those skilled in the art are included in the scope of the invention. The scope of the invention is defined by the scope of the claims and the scope of the equivalents. 
     In addition, the gas flow path according to the invention has a remarkable effect in a case where the reaction products are deposited at the end of the gas flow path on the reactor side. In a case where the deposition of reaction products on a plurality of gas flow paths depends on the position of the gas flow path, the gas flow path of the invention may be used only for the gas flow path in which reaction products are likely to be deposited.