JPWO2018042876A1 - Vapor growth equipment - Google Patents

Abstract

  The vapor phase growth apparatus 1 includes a reaction furnace 2, an introduction passage 8, a plurality of flow passages 15a, a branch passage 14a, and a division passage 16b. The reactor 2 vapor-phases an epitaxial layer on the substrate W with a source gas. The introduction passage 8 includes an inlet 8 a communicating with the reaction furnace 2, an outlet 8 b located above the inlet 8 a and on the reaction furnace 2 side from the inlet 8 a and reaching the reaction furnace 2, and a step portion located in the introduction passage 8. 8c. The plurality of flow paths 15a are 32 or more, and extend from the inlet 8a to the outside of the inlet 8a. The branch path 14a joins the plurality of flow paths 15a in a tournament shape from the inlet 8a side toward the upstream side of the raw material gas. The divided passage 16b is a passage in which the introduction passage 8 is divided corresponding to the plurality of flow paths 15a, and communicates with the plurality of flow paths 15a. This provides a vapor phase growth apparatus that can improve the uniformity of the film thickness of the epitaxial layer grown on the substrate.

Description

  The present invention relates to a vapor phase growth apparatus and an epitaxial wafer manufacturing method.

  With the miniaturization of semiconductor integrated circuits, the pattern formed on the semiconductor substrate that is the basis of the semiconductor integrated circuit is miniaturized, and the quality required for the semiconductor substrate is becoming stricter. Among the qualities required for semiconductor substrates, the demand for flatness is particularly high. And in the epitaxial wafer used for various uses among semiconductor substrates, it is a subject to make the flatness of a substrate and the flatness of an epitaxial layer compatible. The flatness of the epitaxial layer greatly depends on the film thickness distribution of the epitaxial layer. Therefore, in order to satisfy the required flatness of the epitaxial layer, it is necessary to improve the uniformity of the film thickness distribution of the epitaxial layer.

  Currently, when manufacturing an epitaxial wafer having a diameter of 300 mm, a single wafer type vapor phase growth apparatus is used. In such a vapor phase growth apparatus, a mechanism for supplying a source gas for growing an epitaxial layer on the substrate, a reactor for growing an epitaxial layer on the substrate by the supplied source gas, and a mechanism for discharging the gas in the reactor It is roughly composed of The mechanism for supplying the raw material gas includes an injection cap (hereinafter referred to as “cap”), a baffle, and an injection insert (hereinafter referred to as “insert”) in order from the upstream side of the raw material gas. The cap has a space through which the source gas passes when the source gas is introduced into the reaction furnace. The baffle is a plate-like member positioned between the cap and the insert, and has a plurality of through holes that guide the raw material gas in the cap to the insert. The flow of the raw material gas toward the insert is adjusted by this through hole. The insert has a plurality of flow paths that guide the raw material gas that has passed through the through holes of the baffle to the inlet to the reaction furnace. The raw material gas is guided to the reaction furnace through these members. The reactor to which the source gas is guided has an inlet through which the source gas flowing from the upstream through the reactor enters, an outlet located above the inlet and on the side of the reactor from the inlet to the reactor, and an inlet and an outlet. And a step portion located in the passage. The raw material gas introduced from the insert to the inlet of the reactor is guided into the reactor through the step in the passage leading to the reactor. An epitaxial layer is grown on the substrate by reacting the introduced source gas on the substrate. The gas generated by the reaction of the source gas in the reaction furnace and the unreacted source gas are discharged out of the reaction furnace by a mechanism for discharging the gas.

  When an epitaxial layer having a more uniform film thickness distribution is grown using such a single wafer type vapor phase growth apparatus, a uniform flow of source gas is introduced onto the surface of the substrate in the reaction furnace. Is the most important. In the current single wafer type vapor phase growth apparatus, the flow of the raw material gas once introduced into the cap is changed to an arbitrary flow by the baffle and flows into a plurality of (for example, 10) flow paths in the insert. However, since the flow of the raw material gas formed via the baffle itself is governed by the pressure balance in the cap, it cannot obtain a speed corresponding to the diameter of the through hole of the baffle. Furthermore, since the flow of the material gas subdivided via the baffle passes through the insert and is guided onto the substrate, the flow of the material gas depends on the number of flow paths of the insert. Therefore, for example, 10 speed irregularities corresponding to the number of flow paths of the insert are formed in the raw material gas flowing in the in-plane direction of the substrate, and the velocity distribution of the raw material gas introduced onto the substrate is determined by the eventuality. ing. Further, the raw material gas introduced into the inlet of the reaction furnace is guided to the reaction furnace over the stepped part in the passage leading to the inside of the reaction furnace, thereby being influenced by the shape of the stepped part. Specifically, the step portion positioned in the passage is curved from the first surface facing the inlet of the passage by being curved in an arc around the axis extending in the vertical direction on the reactor side, and from the upper end of the first surface. A second surface extends to the exit of the passage. For this reason, the flow of the raw material gas guided to this passage is drawn to the outside in the width direction of the passage by the first surface when trying to get over the stepped portion. Therefore, the velocity distribution of the source gas controlled outside the reactor is changed before being introduced into the reactor, and it becomes difficult to finely control the velocity distribution of the source gas introduced onto the substrate. Because of the structural limitations and difficulty in controlling the velocity distribution of the source gas in such a vapor phase growth system, the uniformity of the film thickness distribution of the epitaxial layer required for the epitaxial wafer used for advanced components must be satisfied. Has become difficult.

  Therefore, in order to satisfy the uniformity of the film thickness distribution, it has been performed to optimize the shape of the top dome that is a component constituting the ceiling of the reactor. This optimization resulted in an overall improvement in the film thickness distribution in the epitaxial layer grown on the substrate. However, a plurality of unevenness corresponding to the flow path of the insert is still formed in the velocity of the raw material gas introduced in the in-plane direction of the substrate by the insert. For example, when the epitaxial layer is grown on the substrate that rotates about the axis extending in the vertical direction by the source gas in which the unevenness of the speed is generated, the film thickness of the epitaxial layer is concentrically formed corresponding to the uneven speed of the source gas. Unevenness occurs. An epitaxial wafer in which such unevenness has occurred cannot satisfy the required flatness, and therefore it is necessary to make the variation in the speed of the source gas supplied onto the substrate uniform.

  In view of this, it has been attempted to make the speed of the raw material gas introduced onto the substrate uniform by improving the flow path formed in the cap. For example, a flow path in which the flow paths in the cap leading to a plurality of outlets located on the downstream side (reactor side) of the cap are joined in a tournament shape toward the upstream side of the cap as in Patent Document 1 is adopted. As a result, the raw material gas is distributed in the cap as the raw material gas moves from the upstream side to the downstream side, and unevenness in velocity distribution is improved between the raw material gases supplied from the outlets of the cap. However, since a step is located in the passage connecting the inlet of the reactor and the outlet leading to the reactor through the inlet, the velocity distribution of the raw material gas adjusted by the cap is disturbed by the step, and the reactor It cannot be maintained to the inside. In order to maintain the velocity distribution of the source gas up to the inside of the reactor, it is necessary to significantly modify the reactor itself so as to eliminate the stepped portion.

  Further, for example, in Patent Document 2, a passage (a passage having a step portion) for introducing the raw material gas into the reaction furnace corresponding to a plurality of flow paths in the insert is divided, and the flow of the raw material gas is a step portion of the passage. An apparatus that suppresses disturbance by the above is disclosed. Patent Document 3 discloses an apparatus for suppressing unevenness in the flow of the source gas by dividing the flow path in the insert into 64 or more.

JP 2009-277730 A JP 2007-324286 A JP 2011-86887 A

  However, in Patent Documents 2 and 3, the flow path of the source gas guided from the upstream side is not formed in a tournament shape. Therefore, the speed of the raw material gas cannot be sufficiently uniformed between the raw material gases passing through the respective flow paths in the insert. Therefore, the flow of the raw material gas introduced from the insert onto the substrate of the reaction furnace has unevenness corresponding to the number of flow paths in the insert, and the uniformity of the thickness of the epitaxial layer grown on the substrate should be improved. I can't.

  An object of the present invention is to provide a vapor phase growth apparatus and an epitaxial wafer manufacturing method capable of improving the uniformity of the film thickness of an epitaxial layer grown on a substrate.

Means for Solving the Problems and Effects of the Invention

The vapor phase growth apparatus of the present invention is
A reactor for vapor-phase growth of an epitaxial layer on a substrate with a source gas;
A passage having an inlet communicating with the reactor and an outlet located above the inlet and on the reactor side from the inlet and reaching the reactor, and connecting the inlet and the outlet to introduce the raw material gas into the reactor When,
A step portion having a first surface located in the passage and facing the inlet, and a second surface extending from the upper end of the first surface to the outlet;
A plurality of flow paths that extend from the inlet to the outside of the inlet and lead to the raw material gas to the inlet and having 32 or more;
A plurality of flow paths joined in a tournament form from the inlet side toward the upstream side of the raw material gas and connected to the upstream side of the raw material gas; and
A plurality of divided passages that are divided in correspondence with the plurality of flow paths along the direction in which the source gas flows, and that are respectively connected to the plurality of flow paths,
It is characterized by providing.

  According to the vapor phase growth apparatus of the present invention, the source gas flowing in each flow path is formed by branching the flow path from the upstream side to the downstream side by the tournament-shaped joint flow path to form a plurality of 32 or more flow paths. The speed can be effectively uniformed between the two. Then, the uniform flow of the source gas is guided to a passage leading to the inside of the reaction furnace. Here, this passage is divided into divided passages that communicate with each of a plurality of 32 or more passages. Therefore, the raw material gas can be introduced into the reaction furnace so as to maintain the flow of the raw material gas that is uniformized in the combined flow path and flows through the plurality of flow paths. Therefore, it becomes possible to improve the uniformity of the film thickness of the epitaxial layer grown on the substrate. In this specification, “tournament shape” means, for example, each point located at the lowest point from the top to the bottom of a complete bifurcated tournament table (an equivalent single-ignition tournament table). This means the overall shape of the line that branches off.

  In an embodiment of the present invention, the dividing passage extends from the inlet to the outlet via the step.

  According to this, even if the flow of the raw material gas introduced into a certain divided passage collides with a step portion in the divided passage, it is effective to affect the flow of the raw material gas introduced into another divided passage. Can be suppressed.

  In the embodiment of the present invention, the total number of the plurality of flow paths is 64 or more.

  According to this, the uniformity of the film thickness of the epitaxial layer grown on the substrate can be made better.

  In the embodiment of the present invention, the plurality of flow paths are arranged in parallel along the horizontal plane.

  Specifically, the plurality of flow paths are located adjacent to each other along the horizontal plane.

  According to this, the uniformity of the film thickness of the epitaxial layer grown on the substrate can be effectively improved.

  Moreover, in another embodiment of the present invention different from the above, a column portion extending from the reaction furnace toward the pair of flow paths is provided.

  According to this, even if the column portion is present, the uniformity of the film thickness of the epitaxial layer grown on the substrate can be improved.

In addition, the manufacturing method of the epitaxial wafer of the present invention,
A step of diverting the flow of the raw material gas to 32 or more in a tournament form in a reaction furnace for growing an epitaxial layer on the substrate with the raw material gas;
Maintaining the number of diverted source gases diverted to 32 or more in the diverting step and introducing the source gas into the reaction furnace;
A step of growing an epitaxial layer on the substrate by the source gas introduced by the step of introducing;
It is characterized by providing.

  In the epitaxial wafer manufacturing method of the present invention, the number of source gases that have been shunted to 32 or more in the tournament by the step of shunting is maintained, and the source gas is introduced into the reactor. Therefore, it is possible to effectively equalize the speed between the raw material gases separated in the step of dividing. Then, the source gas is introduced into the reaction furnace while maintaining the number of the uniformed source gas diversions, so that an epitaxial layer having a uniform film thickness can be grown on the substrate. Therefore, it is possible to manufacture an epitaxial wafer in which the uniformity of the film thickness of the epitaxial layer is good.

  In the embodiment of the present invention, the diverting step diverts the flow of the source gas to 64 or more.

  According to this, an epitaxial wafer in which the uniformity of the film thickness of the epitaxial layer becomes better can be manufactured.

1 is a schematic cross-sectional view showing a part of a vapor phase growth apparatus as an example of the present invention. The plane schematic diagram explaining the member through which the gas which goes to the board | substrate of the vapor phase growth apparatus of FIG. 1A passes. The schematic front view which shows the injection insert of FIG. 1B. IIB-IIB schematic cross section of FIG. 2A. FIG. 1B is a schematic cross-sectional view corresponding to FIG. 1A showing a dividing portion disposed in the introduction passage of FIG. The planar schematic diagram which shows the division part of FIG. 3A. FIG. 3B is a schematic right side view of the dividing unit in FIG. 3B. The schematic cross section corresponding to FIG. 1B which shows an example of the vapor phase growth apparatus in Example 2. FIG. The schematic cross section corresponding to FIG. 1B which shows an example of the vapor phase growth apparatus in the comparative example 1. FIG. 3 is a graph showing the film thickness distribution of an epitaxial wafer measured in Example 1. FIG. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Example 2. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Comparative Example 1. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Comparative Example 2. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Comparative Example 3. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Example 3. 3 is a graph showing the film thickness distribution of an epitaxial wafer measured in Example 1. FIG. 6 is a graph showing the film thickness distribution of an epitaxial wafer measured in Example 4.

  FIG. 1A shows a single wafer type vapor phase growth apparatus 1 which is an example of the present invention. The epitaxial layer is vapor-phase grown on the substrate W by the vapor phase growth apparatus 1, and an epitaxial wafer is manufactured.

  The vapor phase growth apparatus 1 includes a reaction furnace 2 that accommodates a substrate W. The reaction furnace 2 is formed in a container shape. The reactor 2 has a cylindrical or annular base ring 3, an upper dome 4 that covers the base ring 3 from the upper side and forms the ceiling of the reactor 2, and a base ring 3 that is covered from the lower side. Rowardome 5 constituting the bottom side of the furnace 2.

  The base ring 3 is a member serving as a base constituting the reaction furnace 2. The base ring 3 includes an introduction port 3 a for introducing gas into the base ring 3 and a discharge port 3 b for discharging the gas inside the base ring 3 to the outside of the base ring 3. The introduction port 3a and the discharge port 3b are formed as a center line of the base ring 3, for example, an opening having a curved surface with an axis O extending in the vertical direction as an axis, that is, an opening formed in an arch shape. . It is to be noted that the introduction port 3a and the introduction passage 8 described later are perpendicular to both the gas flow direction on the surface of the substrate W (the left-right direction on the paper surface in FIG. 1A) and the axis O (the vertical direction on the paper surface in FIG. The width in one direction (direction perpendicular to the paper surface of FIG. 1A) is not less than the diameter of the substrate W and not more than the outer diameter of the preheat ring 12 described later.

  An upper liner 6 and a lower liner 7 are located inside the base ring 3. The upper liner 6 and the lower liner 7 include an introduction passage 8 for introducing the gas introduced from the introduction port 3a into the reaction furnace 2 and a discharge passage 9 for guiding the gas in the reaction furnace 2 to the discharge port 3b for discharging the gas inside the reaction furnace 2 to the outside. And a member for forming.

  The upper liner 6 is formed in an annular shape that can be fitted into the inner periphery of the base ring 3. The upper liner 6 is positioned on the upper dome 4 side in a state of being fitted inside the base ring 3.

  The lower liner 7 is formed in an annular shape that can be fitted inside the base ring 3. The lower liner 7 is placed on the lower ward 5 while being fitted inside the base ring 3.

  The introduction passage 8 formed by the upper liner 6 and the lower liner 7 includes an inlet 8a that communicates with the reactor 2, and an outlet 8b that is located above the inlet 8a and closer to the reactor 2 than the inlet 8a and reaches the reactor 2. And a step portion 8c located in a passage connecting the inlet 8a and the outlet 8b. The inlet 8 a is formed in an arcuate curved opening with the axis O as an axis so as to correspond to the inlet 3 a of the base ring 3. The step portion 8c includes a first surface 8c1 facing the inlet 8a and a second surface 8c2 extending from the upper end of the first surface 8c1 to the outlet 8b. The first surface 8c1 is an arcuate curved surface with the axis O as an axis, and the second surface 8c2 is a horizontal plane. The introduction passage 8 corresponds to the “passage” of the present invention. The discharge passage 9 formed by the upper liner 6 and the lower liner 7 is the same as the introduction passage 8 and will not be described.

  Inside the reaction furnace 2, a susceptor 10 on which the substrate W is placed, a support part 11 that supports the susceptor 10, and a preheat ring 12 that is surrounded by the susceptor 10 are provided. The support portion 11 can be rotated around the axis O by driving means (not shown).

  Lamps 13 serving as heating sources are arranged above and below the reaction furnace 2 in FIG. 1A, and a mechanism for supplying gas into the reaction furnace 2 and gas inside the reaction furnace 2 are arranged on the left and right sides outside the reaction furnace 2. A discharging mechanism is located. In FIG. 1A, a part of a mechanism for supplying gas and a part for discharging gas are omitted.

  FIG. 1B is a schematic diagram for explaining a mechanism for supplying various gases for growing an epitaxial layer on the substrate W. FIG. FIG. 1B is a schematic plan view showing each member through which gas toward the substrate W passes. The gas to be supplied includes an injection cap 14 (hereinafter referred to as “cap 14”), an injection insert 15 (hereinafter referred to as “insert 15”), a dividing portion 16, a lower liner 7, The preheat ring 12 and the susceptor 10 pass through each member in this order to reach the substrate W. In FIG. 1B, the substrate W, the susceptor 10, the preheat ring 12, and the lower liner 7 are shown in a semicircular shape.

  The cap 14 is a member into which a gas to be supplied to the substrate W through a mass flow controller (not shown) is introduced. The cap 14 has a branch path 14a that distributes the introduced gas. The branch path 14a is configured as a tournament-shaped flow path 14a1 divided into a plurality of groups (three groups in FIG. 1B). A branch flow path B communicating with the insert 15 is located at the lowest point of the lowermost stage of each tournament-shaped flow path 14a1. The number of the branch flow paths B is 32 or more (64 in FIG. 1B) in the entire branch path 14a. Further, although not shown in the drawing, the uppermost stage of each tournament-shaped flow path 14a1 is connected to a flow path connected to the upstream side of the gas. The branch path 14a corresponds to the “joint channel” of the present invention.

  2A and 2B are schematic views of the insert 15. As shown in FIG. 2B, the insert 15 is formed in a flat plate shape having an arcuate side S1 and an opposite side S2 facing the side S1. The insert 15 includes a plurality of flow paths 15a penetrating linearly from the opposite side S2 toward the side S1. The plurality of flow paths 15a are formed in a number corresponding to the branch flow paths B as shown in FIG. 1B. Each flow path 15a communicates with one end of the corresponding branch flow path B, and the other end communicates with the inlet 8a of the introduction passage 8 as shown in FIG. 1A. Each flow path 15a extends in the horizontal direction from the inlet 8a of the introduction passage 8 toward the outside of the inlet 8a (outside of the reaction furnace 2). At least a part of the insert 15 is inserted into the introduction port 3 a and attached to the reaction furnace 2. As shown in FIG. 1B, the plurality of flow paths 15a are arranged in parallel along the horizontal plane, and the plurality of flow paths 15a are positioned adjacent to each other along the horizontal plane.

  As shown in FIG. 3A, the dividing portion 16 is a member that is attached in the introduction passage 8 and divides the introduction passage 8 into a plurality of passages. As shown in FIGS. 3B and 3C, the dividing portion 16 is formed corresponding to the shape of the introduction passage 8 shown in FIG. 1A. As shown in FIG. 1B, the dividing portion 16 includes a dividing wall 16a that divides the introduction passage 8 (FIG. 1A), and a dividing passage 16b that is divided by the dividing wall 16a. As shown in FIG. 3A, the dividing wall 16a extends from the inlet 8a of the introduction passage 8 toward the outlet 8b via the step portion 8c, and includes a plurality of introduction passages 8 along the direction in which the gas flows in the introduction passage 8. To divide. Specifically, as shown in FIG. 1B, the dividing wall 16a divides the introduction passage 8 (FIG. 1A) so as to correspond to the plurality of flow paths 15a. The plurality of division passages 16b formed by the division walls 16a are formed in a number corresponding to the plurality of flow paths 15a. Each divided passage 16b communicates with the corresponding flow passage 15a.

  After passing through the cap 14, the insert 15, and the dividing portion 16, gas is supplied to the substrate W through the lower liner 7, the preheat ring 12, and the susceptor 10. For example, vapor phase growth gas is supplied into the reaction furnace 2 during vapor phase growth. As the vapor phase growth gas, for example, a raw material gas that is a raw material of the silicon single crystal film, a carrier gas that dilutes the raw material gas, and a dopant gas that imparts conductivity to the single crystal film are provided.

  The main parts of the vapor phase growth apparatus 1 have been described above. In the case of manufacturing an epitaxial wafer by growing an epitaxial layer on the substrate W by the vapor phase growth apparatus 1, first, the substrate W is placed on the susceptor 10 of the reaction furnace 2. Then, a vapor growth gas whose flow rate is controlled by a mass flow controller (not shown) is supplied toward the reaction furnace 2. Then, the vapor phase growth gas is guided to the uppermost stage of each of the tournament-shaped flow paths 14a1 (FIG. 1B) divided into three groups, and is distributed from the uppermost stage toward the branch flow paths B. Eventually, the vapor phase growth gas is divided into 64 flows (branch flow path B) and guided (divided) into 64 flow paths 15a in the insert 15. The vapor growth gas that has passed through the flow path 15a reaches the introduction passage 8 shown in FIG. 3A. The vapor growth gas that has reached the introduction passage 8 flows through the divided passage 16b that communicates with the flow path 15a, and the flow of the vapor growth gas divided into 64 by each tournament-shaped flow path 14a1 (see FIG. 1B). (Diverted number) is maintained and introduced into the reactor 2 (introducing step). A silicon single crystal thin film is vapor-grown on the substrate W by the introduced vapor growth gas, and a silicon epitaxial wafer is manufactured.

  In the embodiment of the present invention, as shown in FIG. 1B, the branch path 14a through which the vapor growth gas flows from the upstream side of the vapor growth gas to the reaction furnace 2 (downstream side) has 32 or more branch flows in a tournament form. It branches to the path B and is connected to a plurality of flow paths 15 a of the insert 15. Therefore, it is possible to effectively equalize the speed between the vapor growth gases flowing through the plurality of flow paths 15a. The homogenized vapor phase growth gas flow is directly introduced into the reaction furnace 2 through the divided passages 16b communicating with the flow paths 15a. Therefore, the vapor growth gas can be introduced into the reaction furnace 2 so as to maintain the flow of the vapor growth gas that is made uniform by the branch passage 14a and flows through the plurality of flow paths 15a. Therefore, it is possible to improve the uniformity of the film thickness of the epitaxial layer grown on the substrate W. In particular, as shown in the following examples, it is preferable to apply the present invention to vapor phase growth on a substrate W having a diameter of 200 mm or more.

  In order to confirm the effect of the present invention, the following experiment was conducted. EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, these do not limit this invention.

(Example)
In Example 1, an epitaxial wafer was produced by the vapor phase growth apparatus 1 using a silicon single crystal substrate having a diameter of 300 mm and a crystal plane orientation (100), and the film thickness distribution of the produced epitaxial wafer was measured. In measuring the film thickness distribution, the film thickness at 33 measurement points was measured along the diameter direction of the wafer, excluding an area of 5 mm from the edge of the produced wafer. Then, the film thickness uniformity (%) and film thickness variation (%) shown below were calculated from each measured film thickness, and the film thickness distribution of the epitaxial wafer was obtained. The film thickness uniformity (%) is obtained by subtracting the minimum film thickness from the maximum film thickness based on the maximum film thickness and minimum film thickness obtained by measurement. A value obtained by dividing 100 by the value obtained by dividing by the value obtained by adding is used as a value indicating the uniformity (%) of the film thickness. The film thickness variation (%) was set to the following value. Specifically, a value obtained by multiplying 100 by a value obtained by subtracting 1 from the value obtained by dividing the film thickness at one measured measurement point by the average value of the film thickness at 33 measurement points was calculated. And the value which further subtracted 100 from the calculated value was made into the value which shows the dispersion | variation (%) of a film thickness.

  In Example 2, an epitaxial wafer was produced in the same manner as in Example 1 except that the vapor phase growth apparatus 101 shown in FIG. 4 was used, and the film thickness distribution of the epitaxial wafer was measured. Next, the vapor phase growth apparatus 101 will be specifically described. The same components as those in the vapor phase growth apparatus 1 are denoted by the same reference numerals and description thereof is omitted. The vapor phase growth apparatus 101 includes a column P for increasing the strength of the reaction furnace 2, and an injection cap 114 (hereinafter referred to as “cap 114”) corresponding to the column P, and an injection insert 115 (hereinafter referred to as “ An insert 115 ”) and a dividing portion 116. For convenience of explanation, the insert 115 will be described. The insert 115 is formed as two flat plates P1 and P2 each having an arcuate side S1 and an opposing side S2 facing the side S1. The insert 115 includes a plurality of flow paths 115a penetrating linearly from the opposite side S2 toward the side S1. Thirty-two flow paths 115a are formed in each of the flat plates P1 and P2. The flat plates P1 and P2 are arranged with a gap therebetween, and the support column P is positioned so as to extend from the reaction furnace 2 toward the flat plate gap and be sandwiched between the pair of flow paths 115a. The cap 114 and the dividing portion 116 include a branch path 114a, a dividing wall 116a, and a dividing path 116b corresponding to the flow path 115a. In Example 2, a vapor phase growth apparatus 101 similar to the vapor phase growth apparatus 1 was used except for the above configuration.

  In Example 3, the number of the branch flow paths B, the flow paths 15a, and the division paths 16b of the vapor phase growth apparatus 1 is changed from 64 to 32, and an epitaxial wafer is produced in the same manner as in Example 1, and the thickness of the epitaxial wafer is increased. Distribution was measured. Note that the branching of the tournament-shaped branching path 14a was changed in correspondence with the change in the number of branching paths B.

  In Example 4, an epitaxial wafer was produced in the same manner as in Example 3 except that the number of branch flow paths B, flow paths 15a, and division paths 16b in the vapor phase growth apparatus 1 was 96, and the film thickness of the epitaxial wafer was Distribution was measured.

(Comparative example)
In Comparative Example 1, an epitaxial wafer was prepared in the same manner as in Example 1 except that the conventional vapor phase growth apparatus 201 shown in FIG. 5 was used, and the film thickness distribution of the epitaxial wafer was measured. Next, the vapor phase growth apparatus 201 will be specifically described. The same components as those in the vapor phase growth apparatus 1 are denoted by the same reference numerals and description thereof is omitted. The vapor phase growth apparatus 201 uses an injection cap 214 (hereinafter referred to as “cap 214”), a baffle BA, and an injection insert 215 (hereinafter referred to as “insert 215”) instead of the cap 14, the insert 15 and the dividing portion 16. ) And a partition plate 216. Further, the vapor phase growth apparatus 201 includes a column part P. The cap 214 has a space (not shown) through which the vapor growth gas passes when the vapor growth gas is introduced into the reaction furnace 2. The baffle BA is a plate-like member that is positioned between the cap 214 and the insert 215 and has a plurality of through holes H that guide the vapor growth gas in the cap 214 to the insert 215. The flow of the vapor growth gas toward the insert 215 is adjusted by the through hole H. The insert 215 is formed as two flat plates P11 and P12 having an arcuate side S1 and an opposing side S2 facing the side S1. The insert 215 includes a plurality of flow paths 215a penetrating from the opposite side S2 toward the side S1. Five flow paths 215a are formed in each of the flat plates P11 and P12. The flat plates P11 and P12 are arranged with a gap therebetween. The support column P extends from the reaction furnace 2 toward the gap between the flat plates P11 and P12 so as to be sandwiched between the pair of flow paths 215a. The partition plate 216 is a plate-like member that sorts the gas flow from the insert 215 toward the reaction furnace 2, and four partition plates are arranged. In Comparative Example 1, a vapor phase growth apparatus 201 similar to the vapor phase growth apparatus 1 was used except for the above configuration.

  In Comparative Example 2, an epitaxial wafer was prepared in the same manner as in Example 3 except that the number of the branch flow paths B, flow paths 15a, and division paths 16b in the vapor phase growth apparatus 1 was 8, and the film thickness of the epitaxial wafer was Distribution was measured.

  In Comparative Example 3, an epitaxial wafer was prepared in the same manner as in Example 3 except that the number of branch flow paths B, flow paths 15a, and division paths 16b in the vapor phase growth apparatus 1 was 16, and the film thickness of the epitaxial wafer was Distribution was measured.

  When the vapor phase growth gas supplied to the substrate W is branched into 64 tournaments and led to the substrate W as in the first and second embodiments, the film thickness is uniform as shown in FIGS. 6A and 6B. In addition, the film thickness variation was good. Specifically, the uniformity (%) of the film thickness was 0.29 in Example 1 and 0.39 in Example 2. Further, the variation (%) in film thickness was smoothed in both Examples 1 and 2. On the other hand, when the conventional vapor phase growth apparatus 201 that branches the vapor phase growth gas supplied to the substrate W into a tournament shape and does not lead to the substrate W as in Comparative Example 1, as shown in FIG. 6C. The film thickness uniformity and film thickness variation were not good. Specifically, the film thickness uniformity (%) was 1.21, and the film thickness variation (%) was not sufficiently smoothed.

  When the vapor phase growth gas supplied to the substrate W is led to the substrate W branched into 8 or 16 tournaments as in Comparative Examples 2 and 3, the film thickness is as shown in FIGS. 7A and 7B. The uniformity and film thickness variation did not become good. Specifically, the uniformity (%) of the film thickness was 1.26 in Comparative Example 2 and 1.13 in Comparative Example 3. Further, the variation (%) in film thickness was not sufficiently smoothed in both Comparative Examples 2 and 3. On the other hand, when the vapor phase growth gas supplied to the substrate W is led to the substrate W branched into 32, 64, and 96 in the tournament as in Examples 3, 1, and 4, FIG. As shown in FIG. 7E, film thickness uniformity and film thickness variation were improved. Specifically, the uniformity (%) of the film thickness was 0.41 in Example 3, 0.29 in Example 1, and 0.41 in Example 4. Further, the variation (%) in film thickness was sufficiently smoothed in any of Examples 3, 1, and 4.

  Therefore, when the vapor phase growth gas supplied to the substrate W is branched into 32 or more tournaments and led to the substrate W, the film thickness distribution of the epitaxial wafer can be improved. In particular, when the vapor phase growth gas is branched into 64 tournaments and led to the substrate W, and the support P is eliminated (in the case of Example 1), the film thickness distribution of the epitaxial layer is most effectively smoothed. I was able to.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the specific description, and the illustrated configurations and the like can be appropriately combined within a technically consistent range. In addition, certain elements and processes may be replaced with known forms.

DESCRIPTION OF SYMBOLS 1 Vapor growth apparatus 2 Reactor 3 Base ring 6 Upper liner 7 Lower liner 8 Introduction passage (passage)
8a Inlet 8b Outlet 8c Step 8c1 First surface 8c2 Second surface 10 Susceptor 14 Injection cap 14a Branch (joint flow path)
15 Injection insert 15a Flow path 16 Dividing part 16a Dividing wall 16b Dividing path W Substrate

  The present invention relates to a vapor phase growth apparatus.

  An object of the present invention is to provide a vapor phase growth apparatus that can improve the uniformity of the film thickness of an epitaxial layer grown on a substrate.

Claims (8)

A reactor for vapor-phase growth of an epitaxial layer on a substrate with a source gas;
The reactor having an inlet communicating with the reactor, and an outlet located above the inlet and on the reactor side from the inlet and reaching the reactor, and connecting the inlet and the outlet to the reactor A passage for introducing the raw material gas therein,
A step portion having a first surface located in the passage and facing the inlet, and a second surface extending from an upper end of the first surface to the outlet;
A plurality of flow passages extending from the inlet to the outside of the inlet and leading to the source gas to the inlet, the number of which is 32 or more;
A plurality of flow paths that join together in a tournament shape from the inlet side toward the upstream side of the raw material gas and are connected to the upstream side of the raw material gas; and
A plurality of divided passages that are divided in correspondence with the plurality of flow paths along the direction in which the source gas flows, and that are respectively connected to the plurality of flow paths;
A vapor phase growth apparatus comprising:   The vapor phase growth apparatus according to claim 1, wherein the division passage extends from the inlet to the outlet via the stepped portion.   3. The vapor phase growth apparatus according to claim 1, wherein the total number of the plurality of flow paths is 64 or more.   The vapor phase growth apparatus according to any one of claims 1 to 3, wherein the plurality of flow paths are arranged in parallel along a horizontal plane.   The vapor phase growth apparatus according to claim 4, wherein the plurality of flow paths are located adjacent to each other along the horizontal plane.   The vapor phase growth apparatus of Claim 4 provided with the support | pillar part extended toward between a pair of said flow paths from the said reaction furnace. A step of diverting the flow of the source gas into a tournament to 32 or more into a reaction furnace for growing an epitaxial layer on the substrate with the source gas;
Maintaining the number of diverted source gases diverted to 32 or more in the diverting step and introducing the source gas into the reactor;
Growing the epitaxial layer on the substrate by the source gas guided by the guiding step;
An epitaxial wafer manufacturing method characterized by comprising:   The epitaxial wafer manufacturing method according to claim 7, wherein the diverting step diverts the flow of the source gas into 64 or more.

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