JP2011071490A - Vapor-phase growth device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor-phase growth device forming a high-quality laminate structure with a plurality of types of thin films laminated therein by accurately controlling temporal change of a flow rate. <P>SOLUTION: This vapor-phase growth device includes a reaction chamber 50 for holding substrates 15 being processing objects, and a gas introduction part 21 for supplying a reaction gas to the reaction chamber 50. The gas introduction part 21 includes a gas supply tube 20, and a gas passage expansion part for connecting the gas supply tube 20 to the reaction chamber 50 to run the reaction gas. The gas passage expansion part is structured to expand width in a plane direction being a direction extending along a main surface of the substrate 15 from the gas supply tube 20 to the reaction chamber 50 and intersecting the flow direction of the reaction gas toward the reaction chamber 50 side from the gas supply tube 20 side, wherein, on a sidewall defining the width in the plane direction of the gas passage expansion part, an inclination angle of a part located on the gas supply tube 20 side out of the inclination angle of the sidewall with respect to the discharge direction of the reaction gas introduced into the gas passage expansion part from the gas supply tube 20 is set smaller than an inclination angle with respect to the discharge direction of a part located on the reaction chamber 50 side out of the sidewall. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus, and more particularly to a vapor phase growth apparatus for vapor phase growing a thin film on a surface of a semiconductor substrate or the like.

  In general, a vapor phase growth apparatus is used when a thin film is grown to form a semiconductor element on one main surface such as a semiconductor substrate. Here, the main surface means a main surface having the largest area among the surfaces. Such a vapor phase growth apparatus includes a reaction chamber that holds, for example, a substrate that is a processing target, and a gas introduction unit that supplies a reaction gas to the reaction chamber. That is, with the substrate placed in the reaction chamber, a predetermined gas for film formation is introduced into the reaction chamber.

  Here, when the area of the main surface of the substrate is large, that is, when it has a large diameter, a region facing the main surface of the substrate (usually on the substrate) in order to uniformly supply the gas onto the main surface of the substrate. A reaction chamber in which a plurality of holes for injecting a gas are provided at regular intervals on the opposing ceiling portion of the reaction chamber. Such a structure having a large number of holes is called a showerhead structure, and a desired gas is uniformly sprayed over almost the entire area on the main surface of the substrate from the majority of the area facing the main surface of the substrate. It is possible to do. The shower head structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-323560 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-66413 (Patent Document 2).

Japanese Patent Laid-Open No. 11-323560 JP 2008-66413 A

  Patent Document 1 discloses a structure in which the amount of a gas for forming a film containing a metal element having a high activation energy is gradually reduced from the central portion of the shower head portion toward the peripheral portion. A film forming apparatus for forming a ferroelectric composite material thin film is disclosed. Further, Patent Document 2 includes a shower head structure configured to prevent a part of the raw material gas injected from the gas injection holes from flowing in the reverse direction and forming an unnecessary adhesion film on the gas injection surface. A film forming apparatus is disclosed.

  In any of the above-described film forming apparatuses, film formation is performed by continuously flowing a constant amount of a composite material thin film such as a BST thin film or a PZT thin film without changing time. For this reason, the same kind of gas is always supplied into the so-called buffer chamber in which the supplied source gas is diffused to be uniformly injected from the plurality of gas injection holes. That is, in the film forming method using the film forming apparatus described in each of the above patent documents, it is not necessary to switch the type of gas supplied into the buffer chamber. However, for example, when forming a laminated structure in which a plurality of thin films having different compositions constituting a semiconductor element is formed, it is necessary to switch the type of source gas supplied in the film forming apparatus in a short time. For example, when supplying a gas made of a Group III material and a gas made of a Group V material while alternately injecting them at an early timing of 1 second or less, the film forming apparatus in each of the above patent documents was used. In some cases, the following problems may occur.

  FIG. 6 shows the result of simulating the time change of the flow rate of the source gas when the supply amount of the source gas is controlled to change with time in a rectangular pulse using a conventional film forming apparatus. This shows, as an example, the flow rate of the gas in a pipe through which the source gas to be supplied circulates and the flow rate of the gas injected from the injection hole through the pipe. That is, in the graph of FIG. 6, the horizontal axis represents the elapsed time (seconds), and the vertical axis represents the flow rate of TMG (trimethylgallium: organometallic compound of gallium) used as the source gas in mole fraction. The solid line 100 in FIG. 6 indicates the molar fraction of the gas flowing through the pipe that supplies TMG as the source gas, and the dotted line 200 in FIG. 6 flows through the pipe and is injected from the injection hole. The mole fraction of TMG gas is shown.

As shown in FIG. 6, when a cycle in which TMG having a mole fraction of about 1.1 × 10 ⁻⁴ is supplied from a pipe for about 0.3 seconds and stopped for about 0.3 seconds is repeated, The flow rate of the TMG gas injected from the injection hole is slower to follow the rise and fall compared to the flow rate of the supplied gas. In other words, in order to form a thin film laminated structure, it is necessary to cause a steep flow rate change in a short time, but even if the flow rate is controlled to be a steep rectangular pulse on the upstream side of supplying the source gas, It becomes difficult to control the change in flow rate so as to form a pulsed pattern on the downstream side where the raw material gas is injected. This is because, for example, when the flow rate of the gas introduced into the buffer chamber of the film forming apparatus disclosed in each of the above-mentioned patent documents is changed over time in a rectangular pulse shape, a part of the gas is stored in the buffer chamber. to cause. Therefore, for example, when a plurality of types of source gases are alternately supplied over time in order to form a thin film laminated structure using the film forming apparatus, the gas introduced first into the buffer chamber and the buffer chamber afterwards If the gas introduced into is stored in the buffer chamber, there is a possibility that both will mix in the buffer chamber. If both are mixed in the buffer chamber, the gas injected from the injection hole is also a gas in which the materials constituting the plural types of thin films constituting the laminated structure to be formed are mixed. For this reason, it may be difficult to form a high-quality laminated structure in which a plurality of types of desired thin films are laminated.

  The present invention has been made in view of the above problems. An object of the present invention is to provide a vapor phase growth apparatus capable of accurately changing the flow rate (molar fraction) of each gas that alternately supplies a plurality of types of gases over time.

  The vapor phase growth apparatus according to the present invention includes a reaction chamber that holds an object to be processed and a gas introduction unit for supplying a reaction gas to the reaction chamber. The gas introduction part includes a gas supply pipe, and a gas flow path expansion part that connects the gas supply pipe and the reaction chamber to flow the reaction gas. The gas flow channel expanding portion has a width in a plane direction that is along the main surface of the object to be processed and intersects the flow direction of the reaction gas from the gas supply pipe to the reaction chamber. It is configured to spread from the tube side toward the reaction chamber side. In the side wall defining the width in the planar direction of the gas flow path expanding portion, the gas supply is included in the inclination angle of the side wall with respect to the discharge direction of the reaction gas introduced from the gas supply pipe to the gas flow path expanded portion. The first inclination angle of the portion located on the tube side is smaller than the second inclination angle of the portion located on the reaction chamber side of the side wall with respect to the discharge direction.

  The spread in the plane direction of the gas flow path enlarged portion is stepwise (the first spread angle is smaller and the latter spread angle is larger), so that the generation of vortices in the gas flow path expanded portion is suppressed. (Because the divergence angle is small in the first half, the gas supplied from the gas supply pipe flows along the side wall surface in the vicinity of the side wall (suppresses the flow from the side wall and the generation of vortices). Thereafter, the gas is expanded to the width of the reaction chamber by increasing the divergence angle in the latter half (preventing the length of the line in the gas flow direction from becoming longer than necessary). As a result, the gas is spread in the plane direction while suppressing the enlargement of the apparatus and the generation of vortices, and as a result, uniform film formation is realized. In addition, since the initial expansion of the gas flow path expansion portion is smaller, the boundary between the gas supply pipe and the gas flow path expansion portion, the portion where the gas flow channel expansion portion has a small expansion angle, and the expansion angle The flowing reaction gas flows smoothly at the boundary with the large portion. For this reason, the type of reaction gas supplied from the gas supply pipe to the reaction chamber can be rapidly switched, and a laminated structure of a plurality of types of thin films formed in the reaction chamber can be formed with high quality. it can.

  In the vapor phase growth apparatus according to the present invention described above, the length of the gas flow path expansion section in the gas flow path expansion section with respect to the length (L) of the gas flow path expansion section in the flow direction of the reaction gas in the gas flow path expansion section. The ratio (H / L) of the height (H) of the portion through which the reaction gas flows is preferably 0.0013 or more and 0.013 or less. In this way, the gas flow velocity distribution in the plane direction can be made more uniform. In order to suppress a decrease in gas flow rate, it is more preferably 0.01 or more and 0.013 or less.

  In the above-described vapor phase growth apparatus according to the present invention, it is preferable that a first inclination angle of a portion of the side wall located on the gas supply pipe side is 5 ° or more and 16 ° or less. In this way, it is possible to reliably suppress the generation of vortices on the inlet side of the gas flow path enlarged portion.

  In the above-described vapor phase growth apparatus according to the present invention, a plurality of gas introduction units are provided, and among the plurality of gas introduction units, a gas flow channel expansion unit of one gas introduction unit and a gas flow channel expansion of another gas introduction unit. A partition part that divides the part, and at least a downstream region in the flow direction of the reaction gas in the partition part is smaller in thickness than an upstream region in the reaction gas flow direction, It is preferable that the uppermost straight line and the lowermost straight line in the thickness direction (thickness direction) of the partition portion have an outer peripheral shape inclined with respect to the flow direction.

  Thus, in the downstream of the partition part, by having a tapered shape whose thickness is smaller than the thickness on the upstream side, it flows in the vicinity of the end of the partition part (the most downstream part of the partition part). The possibility of the reaction gas forming vortices is reduced. Therefore, the reaction gas flows smoothly in the most downstream area of the partition, that is, in the boundary between the gas introduction part (gas flow channel expansion part) and the reaction chamber (reaction gas relay path). For this reason, the type of reaction gas supplied from the gas supply pipe to the reaction chamber can be rapidly switched, and a laminated structure of a plurality of types of thin films formed in the reaction chamber can be formed with high quality. it can.

  In the vapor phase growth apparatus according to the present invention described above, the thickness direction of the outer peripheral shape in the cross section formed by the flow direction and the thickness direction of the outer peripheral shape in the region of the partition portion having a thickness of 0.05 mm or more. It is preferable to have a region where the angle formed by the uppermost straight line and the lowermost straight line is 50 ° or less. If it does in this way, the taper shape in the edge part of a partition part turns into a shape sharp enough. For this reason, at the end of the partition, that is, at the boundary between the gas introduction part and the reaction chamber (reaction gas relay path), the type of the reaction gas supplied to the reaction chamber can be sharply switched, A stacked structure of a plurality of types of thin films can be formed on the held substrate so as to have high quality. In addition, in order to make said effect more reliable, it is preferable that the thickness at the end portion on the most downstream side in the flow direction of the reaction gas among the partition portions is less than 0.05 mm.

  In the vapor phase growth apparatus of the present invention described above, the flow rate of the reaction gas is preferably 40 SLM or more and 60 SLM or less. In this way, it is possible to increase the value of the maximum switching frequency indicating the switching speed at which the gas in the reaction chamber can follow when the type of the reaction gas flowing from the gas supply chamber to the reaction chamber is switched.

  In the vapor phase growth apparatus of the present invention, since the width of the gas flow channel expanding portion in the planar direction is stepwise, the generation of vortices is suppressed and the type of gas supplied to the reaction chamber is steep. Can change over time. For this reason, when forming a laminated structure in which a plurality of types of thin films are laminated to form a laminated structure of thin films, a uniform and high quality film is formed on the main surface of the substrate that is the object to be processed. Can do.

It is a schematic sectional drawing which shows the aspect of the vapor phase growth apparatus which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing in line segment II-II of FIG. It is the schematic which shows the relationship of the dimension and inclination | tilt angle in each area | region which comprises the gas introduction part of FIG. Using the vapor phase growth apparatus according to the present invention, when the raw material gas is supplied so that the supply amount becomes a rectangular pulse pattern, the result of simulating the time change of the molar fraction of the raw material gas on the output side It is a graph to show. It is a schematic sectional drawing in the line segment VV of FIG. The result of simulating the time change of the molar fraction of the source gas on the output side when the source gas is supplied so that the supply amount becomes a rectangular pulse pattern using a conventional vapor phase growth apparatus is shown. It is a graph. It is a schematic sectional drawing which shows the aspect of the vapor phase growth apparatus which concerns on Embodiment 2 of this invention. It is a schematic sectional drawing which expands and shows the structure of the downstream part regarding the distribution direction of a reactive gas among the 2nd gas flow path expansion parts of FIG. It is a schematic sectional drawing which expands further and shows the 1st example of the edge part of the partition part of the 2nd gas flow path expansion part of FIG. FIG. 9 is a schematic cross-sectional view showing a second example of the end portion of the partition portion of the second gas flow path enlarged portion of FIG. 8 further enlarged than FIG. FIG. 9 is a schematic cross-sectional view showing a third example of the end of the partition portion of the second gas flow path enlarged portion in FIG. 8 further enlarged than in FIG. 8. FIG. 9 is a schematic cross-sectional view showing a fourth example of the end portion of the partition portion of the second gas flow path enlarged portion in FIG. 8 further enlarged than in FIG. 8. FIG. 9 is a schematic cross-sectional view showing a fifth example of the end of the partition portion of the second gas flow path enlarged portion in FIG. 8 further enlarged than in FIG. 8. It is a schematic sectional drawing which expands further from FIG. 8 and shows the 1st comparative example of the edge part of the partition part of the 2nd gas flow path expansion part of FIG. FIG. 9 is a schematic cross-sectional view showing a second comparative example of the end portion of the partition portion of the second gas flow path enlarged portion of FIG. 8 further enlarged than FIG. 8. It is a graph which shows the relationship between the angle which the front-end | tip of a partition part makes, and the maximum switching frequency of the reactive gas which distribute | circulates a 2nd gas flow path expansion part. When the reaction gas flowing through the second gas flow path expansion section is switched, the time required for the reaction gas flow rate to become 1/100 on the upstream side of the reaction chamber is determined for each angle formed by the tip of the partition section. It is a graph which shows the result investigated. When the reaction gas flowing through the second gas flow path expansion portion is switched, the time required for the reaction gas flow rate to become 1/100 on the downstream side of the reaction chamber is determined for each angle formed by the tip of the partition portion. It is a graph which shows the result investigated. It is a graph which shows the time change of the molar fraction of the said reaction gas on the board | substrate mounted in the reaction chamber at the time of switching the reaction gas which distribute | circulates a 2nd gas flow path expansion part by the flow volume of 20 SLM. It is a graph which shows the time change of the molar fraction of the said reaction gas on the board | substrate mounted in the reaction chamber at the time of switching the reaction gas which distribute | circulates a 2nd gas flow path expansion part with the flow volume of 40 SLM. It is a graph which shows the time change of the molar fraction of the said reactive gas on the board | substrate mounted in the reaction chamber at the time of switching the reactive gas which distribute | circulates a 2nd gas flow path expansion part with the flow volume of 60 SLM. It is the graph which expanded the data of the area | region of elapsed time from 1620 milliseconds to 1700 milliseconds of FIG. It is a graph which shows the relationship between the thickness of the front-end | tip of the said partition part, and the highest vortex-free flow velocity when not having the outer peripheral shape which inclines at the front-end | tip of a partition part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
As shown in FIG. 1, the vapor phase growth apparatus according to Embodiment 1 of the present invention includes a reaction chamber 50 and a gas introduction unit. The reaction chamber 50 is a region that holds, for example, a substrate 15 that is a processing target for forming a thin film to form a semiconductor element. The gas introduction part is an area for supplying a source gas (reaction gas) for film formation into the reaction chamber 50. For example, in the vapor phase growth apparatus of FIG. 1, there are three gas introduction portions (three routes) in order to supply three kinds of different reaction gases into the reaction chamber 50 during film formation. Specifically, in order from the upper side in FIG. 1, a gas introduction pipe 11, a gas supply pipe 20, and a first gas flow path including a gas supply pipe 10, a first gas flow path expansion section 12, and a second gas flow path expansion section 13. 3 of the gas introduction part 31 which consists of the expansion part 22, the gas introduction part 21 which consists of the 2nd gas flow path expansion part 23, and the gas supply pipe 30, the 1st gas flow path expansion part 32, and the 2nd gas flow path expansion part 33 It is a stand.

  Inside the reaction chamber 50, a susceptor 51 for holding the substrate 15, a rotating shaft 53 for rotatably supporting the susceptor 51, and one main surface of the susceptor 51 and the susceptor 51 were placed. A heater 55 for heating the reaction gas supplied in the vicinity of the surface of the substrate 15 is disposed.

  The gas supply pipes 10, 20, and 30 are buried behind the wall surface 3 (right side in FIG. 1) of the facility where the gas phase growth apparatus is installed, for example. A reaction gas relay path 7 for guiding the reaction gas from the gas introduction part to the inside of the reaction chamber 50 is arranged further downstream of the second gas flow path expanding part of each gas introduction part. Further, an exhaust gas passage 9 for exhausting excess gas existing in the reaction chamber 50 is disposed on the opposite side (left side in FIG. 1) to the reaction gas relay path 7 when viewed from the inside of the reaction chamber 50. ing. The gas introduction parts 11, 21, and 31 are preferably made of, for example, quartz or a metal such as chromium, iron, nickel, stainless steel, manganese, molybdenum, tungsten, or aluminum. If it does in this way, the said gas can be distribute | circulated smoothly, without receiving damage, such as each gas introduction part reacting with the gas which is going to distribute | circulate, for example. However, when a corrosive gas is used as the gas flowing through the gas introduction part, it is preferable to use a material other than aluminum among the above-described materials.

  In FIG. 1, partial regions of the gas supply pipes 10, 20, 30, the first gas flow channel expansion units 12, 22, 32 and the second gas flow channel expansion units 13, 23, 33 of each gas introduction unit. Is covered by the gas introduction case 1. The gas introduction part case 1 is fixed to the wall surface 3 by a fixing member 2 such as a bolt. In this way, each gas introduction part is fixed. However, the method of fixing each gas introduction part to the wall surface 3 is not limited to the method described above, and any generally known method can be used. In FIG. 1, each first gas flow path expanding portion is covered with a first gas flow path expanding portion case 4, and each second gas flow path expanding portion is covered with a second gas flow path expanding portion case 5. It has been broken. Also about these, it is not restricted to the structure mentioned above, Each member can be accommodated by a generally well-known arbitrary method. Further, in FIG. 1, the reaction gas relay path 7 is configured so as to cover and connect a part of the second gas flow path enlarged portion case 5, and the reaction gas relay path 7 and the exhaust gas flow path 9 are integrated. It is depicted as being unitary in the area of the part. However, both may be discontinuous.

  In FIG. 1, there are three gas introduction portions. In the cross-sectional view of FIG. 2, as an example, the gas introduction portion 21 has a plane direction that intersects the flow direction of the reaction gas (the left-right direction in FIG. 1). FIG. The gas introduction part extends in the horizontal direction in FIG. 1, that is, in the direction along the main surface of the substrate 15 in the reaction chamber 50, together with the gas supply pipe, the first gas flow path expansion part, and the second gas flow path expansion part. Yes. In FIG. 1, the gas introducing portions 11 and 31 are bent in the vertical direction of FIG. 1, that is, the direction in which the first gas flow path expanding portions 12 and 32 intersect the main surface of the substrate 15 in the reaction chamber 50. This is because the three gas supply pipes are arranged in parallel in the vertical direction of FIG. Therefore, for example, if the three gas supply pipes are arranged so as to be parallel to the direction along the main surface of the substrate 15 in FIG. 1, the first gas flow path expanding portions 12 and 32 are not bent in the vertical direction in FIG. It can be configured. In this case, it is preferable to arrange the first gas flow path expanding portions 12 and 32 in parallel in the depth direction perpendicular to the paper surface of FIG.

  Next, the operation of each part constituting the vapor phase growth apparatus will be described. It is made of, for example, a group III material supplied to the gas supply pipes 10, 20, and 30 from a gas supply source (not shown in FIG. 1) connected to the upstream side of the gas supply pipes 10, 20, and 30. The reaction gas or the reaction gas composed of the Group V raw material flows from the right side to the left side in FIG. 1, that is, in the order of the first gas flow path expansion part and the second gas flow path expansion part, and further passes through the reaction gas relay path 7. It reaches the inside of the reaction chamber 50. In addition, surplus gas after being used for film formation in the reaction chamber 50 and surplus gas generated by the reaction in the reaction chamber 50 are circulated through the exhaust gas passage 9 and discharged to the outside. . As shown in FIG. 2, the gas supply pipe 20 on the most upstream side of the gas introduction part has an inner wall surface (gas supply pipe side wall 24) with respect to a cross section that intersects the extending direction (the direction in which the reaction gas flows). The width indicated by the diameter (the vertical interval in FIG. 2) is substantially constant in each region. In other words, there is no change such that the width is increased or decreased.

  However, as shown in FIG. 2, the gas introduction unit 21 includes an inner wall surface (first gas) with respect to a cross section that intersects the extending direction in the first gas flow path expanding unit 22 located on the downstream side of the gas supply pipe 20. The width of the flow channel enlarged portion side wall 25) is configured to expand from the gas supply pipe 20 side toward the reaction chamber 50 side. In other words, the width of the first gas flow path enlarged portion side wall 25 means a width in a plane direction that is a direction intersecting with the flow direction of the reaction gas. Similarly, the width of the inner wall surface (second gas flow passage enlarged portion side wall 26) with respect to the cross section intersecting the extending direction is the same from the gas supply pipe 20 side to the reaction chamber 50 side. Configured to spread towards.

  Thus, if the width of the side wall is made wider on the downstream side of the gas introduction part 21 than the upstream side, the reaction gas flowing through the gas introduction part 21 tends to flow along the side wall. On the other hand, the region where the reaction gas flows can be gradually widened.

  Here, the susceptor 51 inside the reaction chamber 50 has a circular main surface as shown in the cross-sectional view of FIG. 2, and has a size capable of mounting, for example, three substrates 15. . The susceptor 51 is fixed to a rotating shaft 53 disposed inside the reaction chamber 50 at the center of the main surface opposite to the main surface on which the substrate 15 is placed (the lower side in FIG. 1). Yes. For this reason, the susceptor 51 is rotatable in a plane along the main surface with the rotation shaft 53 as an axis. In such a state where the susceptor 51 on which the plurality of substrates 15 are placed is heated using the heater 55, the reaction gas discharged from each gas introduction unit is supplied to the vicinity of the surface of the susceptor 51 (substrate 15). . Then, if the width of the region where the reaction gas is discharged is equal to or larger than the diameter of the main surface of the susceptor 51, the reaction gas can be supplied to the vicinity of the entire main surface of the susceptor 51 at a time. For this reason, as shown in FIG. 2, it is preferable that the width | variety of the gas introduction part 21 becomes wide toward the downstream from the upstream. The width of the second gas flow path expanding portion side wall 26 on the most downstream side of the second gas flow path expanding portion 23 is preferably equal to or larger than the diameter of the main surface of the susceptor 51.

  The width of the gas supply pipe 20 that guides the reaction gas from the gas supply source to the flow path (the width of the gas supply pipe side wall 24) is generally very narrow compared to the diameter of the main surface of the susceptor 51. For this reason, it is preferable that the gas introduction part 21 includes a gas flow path expanding part for expanding the width of the region through which the reaction gas flows than the gas supply pipe 20.

  Here, in the gas introduction part, the side wall of the gas flow path enlarged part has a large inclination angle with respect to the direction along the discharge direction of the reaction gas in the gas supply pipe 20 (the direction in which the gas supply pipe 20 extends). In this case, there is a possibility that a vortex may be generated in the flowing reaction gas in the vicinity of the boundary between the gas supply pipe 20 and the gas flow path expanding portion having the side wall with the large inclination angle. This is because, as described above, the reactive gas flows in the gas introduction part 21 along the side wall substantially. However, if there is a region in which the flowing direction is greatly changed (bent) as in the boundary part, Since the reaction gas cannot follow the change in the flow direction, it becomes difficult to flow in a desired direction (that is, a direction along the side wall of the gas flow path expanding portion). For this reason, in the vicinity of the boundary portion, a circulation vortex is likely to occur.

For this reason, as shown in the schematic diagram showing the relationship of the inclination angle between the sidewalls in each region of the gas introduction part 21 in FIG. 3, the gas flow path expanding part of the gas introduction part 21 has two regions with different inclination angles. It is preferable to include. Specifically, the first gas flow path expanding portion 22 and the second gas flow path expanding portion 23 described above. As shown in FIG. 3, the inclination angle θ ₁ of the first gas flow path enlarged portion side wall 25 with respect to the extending direction of the gas supply pipe side wall 24 (the extending direction of the dotted line in FIG. 3) depends on the extension of the gas supply pipe side wall 24. The inclination angle θ ₂ of the second gas flow path enlarged portion side wall 26 with respect to the current direction is smaller.

Thus, if the inclination angle θ ₁ formed between the gas supply pipe side wall 24 and the first gas flow path enlarged portion side wall 25 is made relatively small, the reaction gas that has circulated along the extending direction of the gas supply pipe side wall 24. Can easily follow the change in the angle at which the side wall extends in the vicinity of the boundary between the gas supply pipe side wall 24 and the first gas flow path enlarged portion side wall 25. That is, it is possible to suppress the reaction gas from generating a turbulent flow such as a vortex in the vicinity of the boundary between the gas supply pipe side wall 24 and the first gas flow path enlarged portion side wall 25. For this reason, it is impossible to control the flow rate and flow velocity of the reaction gas in the vicinity of the boundary, or a part of the reaction gas that should flow smoothly toward the downstream side is stored in the vicinity of the boundary. Can be prevented from occurring. Therefore, the reaction gas can be supplied from the reaction gas relay path 7 to the inside of the reaction chamber 50 (near the main surface of the substrate 15) at a desired flow rate and flow rate. In addition, for example, even when the type of reaction gas supplied into the reaction chamber 50 is changed over time to form a structure in which a plurality of different types of thin films are stacked, the type and amount of gas to be circulated are switched smoothly. be able to.

However the inclination angle when theta ₁ is small, for example, the main surface having a width W than the diameter by forming the gas flow channel expanding side walls so that (see FIG. 3), the gas flow path enlarged part side walls of the susceptor 51 The length L (see FIG. 3) in the extending direction of the gas supply pipe 20 becomes very large. For this reason, malfunctions, such as the manufacturing cost of the gas introduction part provided with the said gas flow path expansion part side wall becoming high generate | occur | produce and it becomes difficult to use for practical use. In view of this, it is preferable that the gas flow path expanding portion has an inclination angle that changes in two stages with respect to the extending direction of the gas supply pipe 20 (gas supply pipe side wall 24). That is, with reference to FIG. 2 and FIG. 3, the gas flow path expanding section preferably includes the second gas flow path expanding section 23 on the downstream side of the first gas flow path expanding section 22. Here, the inclination angle θ ₂ formed by the second gas flow path enlarged portion side wall 26 with respect to the extending direction of the gas supply pipe side wall 24 is larger than the above θ ₁ .

In this way, the length L of the side wall of the gas flow dew expansion portion necessary for setting the side wall width of the gas flow path to W in FIG. 3 can be shortened, and the manufacturing cost of the equipment can be reduced. This is achieved by shortening the length L ₂ (see FIG. 3) of the second gas flow path expanding portion 23 in the extending direction of the gas supply pipe 20, thereby reducing L ₁ (the first gas flow path expanding portion 22. This is because it is possible to shorten the L is the sum of the length in the direction of extension of the gas supply pipe 20. Referring to FIG. 3) and L _2.

It should be noted that the first gas flow path expanding portion 22 having the tilt angle θ ₁ (θ ₁ <θ ₂ ) is not provided, and the gas flow path expanding portion having the tilt angle θ ₂ is connected to the gas supply pipe 20. Since the inclination angle θ ₂ formed between the gas supply pipe side wall 24 and the side wall of the gas flow path expanding portion is large as described above, the vicinity of the boundary between the gas supply pipe 20 and the gas flow path expanded portion is large. Vortex may occur in As shown in FIG. 2 and FIG. 3, the side wall tilt angle is changed stepwise to reduce the angle formed between adjacent side walls with different tilt angles, thereby suppressing the generation of vortices in the supplied reaction gas. In addition, the manufacturing cost of the gas introduction part can be reduced.

That is, in order to enhance the above-described effect of improving the rectification property, the value of the inclination angle θ ₁ is preferably 16 ° or less. When the value of theta ₁ is greater than 16 °, more likely eddy described above occurs. However, if the value of theta ₁ is less than 5 °, L1 becomes very long in FIG. 3, there is a possibility that the manufacturing cost of the equipment is high. Therefore the value of the inclination angle theta ₁ is more preferably 5 ° or more 16 ° or less.

  4, the horizontal axis represents elapsed time (seconds), and the vertical axis represents the flow rate of TMG (trimethylgallium: organometallic compound of gallium) used as a raw material gas, in the same manner as the graph of FIG. 6 described above. Is shown. The solid line 100 in FIG. 4 indicates the flow rate of the gas flowing through the pipe supplying TMG as the raw material gas, and the dotted line 200 in FIG. The flow rate of the TMG gas injected toward the reaction gas relay path 7 from the location shown in the cross-sectional view of FIG. Furthermore, a one-dot chain line 300 in FIG. 4 indicates the same TMG gas flow rate as that of the dotted line 200 at a location 30 mm downstream from the location where the data of the dotted line 200 is calculated in the direction in which the reaction gas relay path 7 extends. Shown in mole fraction. The dotted line 200 and the alternate long and short dash line 300 in FIG. 4 have a shape close to the solid line 100 having a rectangular pulse shape indicating the input value of the gas flow rate as compared with the dotted line 200 in FIG. That is, it can be seen that the time change of the gas flow rate (molar fraction) in each region follows the time change of the gas supply amount from the gas supply source. As described above, since the reaction gas flows smoothly without being stored even in the vicinity of the region where the side wall is bent, the time change of the flow rate of the gas input on the upstream side also on the downstream side. By showing the waveform of the time change of the gas flow rate close to. For this reason, the time change of the supply amount of the reaction gas supplied to the vicinity of the region where the substrate 15 is placed inside the reaction chamber 50 also shows a mode closer to the time change of the supply amount of the reaction gas. Therefore, when the vapor phase growth apparatus according to the present embodiment is used, for example, when the group III gas is suddenly stopped after the group III gas is supplied for a certain period of time and the group V gas is supplied, the group V gas is supplied. When the gas is supplied, the Group III gas stored inside the gas introduction part is discharged and mixed into the Group V gas, thereby suppressing the occurrence of problems such as deterioration of the quality of the formed thin film. be able to. That is, by using the vapor phase growth apparatus according to the present embodiment, a process of forming a laminated structure of a plurality of thin films made of different materials can be performed with higher accuracy while switching the flow rates of various gases at short intervals. be able to.

In addition, in the gas flow path expanding portion of the present embodiment, the height (H) of the portion where the reaction gas flows in the gas flow path expanding portion with respect to the overall length L (see FIG. 3) of the gas flow path expanded portion. The ratio (H / L) is preferably 0.013 or less. Specifically, the second gas related to the height direction intersecting both the direction in which the reaction gas flows and the width W (W1) direction shown in the cross-sectional view in the most downstream portion of the gas introduction portion 21 shown in FIG. It is preferable that the ratio H / L of the height H of the flow path expanding portion 23 to the length L shown in FIG. 3 is 0.013 or less. However, if the value of H is very small, there is a possibility that the flow rate (flow velocity) of the gas flowing through the region will decrease. Therefore, the ratio H / L is more preferably 0.0013 or more and 0.013 or less. If all of the second gas flow path expanding portions 13, 23, and 33 have the same height H, the height H ₁ in FIG. Further, the width W ₁ in FIG. 5 is obtained by adding the thicknesses of the second gas flow path expanding portion case 5 and the reactive gas relay path 7 to the width W at the most downstream portion of the second gas flow path expanding portions 13, 23, 33. It is a thing.

  If the value of H is made as small as possible so that H / L is within the above-mentioned numerical range, the reaction gas supplied from the gas supply source to the gas introduction pipe can circulate more uniformly in the gas introduction section. it can. This is because if the value of H is small, the reaction gas is prevented from diffusing in the direction of H (vertical direction) in FIG. Further, if the value of H is small, for example, a part of the reaction gas that circulates excessively in the vicinity of the center in the W direction (left-right direction) in FIG. 5 interferes with the side wall in the H direction of the gas introduction part, This is because it diffuses to both end sides in the W direction. In this way, it is possible to reduce the deviation in the flow rate of the reaction gas flowing through each region in the direction W in FIG.

  In the above description, the gas introduction part 21 has been described as an example particularly in the description of the gas flow path expanding part using FIGS. However, since the gas introduction parts 11 and 31 have the same mode as the gas introduction part 21, they have the same operations and effects as the gas introduction part 21.

  Note that, for example, when a purge gas such as argon or nitrogen whose flow rate does not change with time is flowed through any of the second gas flow path expansion units 13, 23, 33, the gas introduction unit shown in the cross-sectional view of FIG. It is necessary to consider that problems such as difficulty in controlling the flow rate of the reaction gas occur because the flow rate is mixed with the reaction gas whose flow rate changes with time at the most downstream portion of the (second gas flow path expansion portion). Absent. This is because the purge gas has a function of circulating the reaction gas to a desired region. That is, even if the purge gas is mixed with the reaction gas, the reaction gas is stored in a part of the region, so that the flow direction and flow rate are affected and vortices are not generated.

(Embodiment 2)
As shown in FIG. 7, the vapor phase growth apparatus according to the second embodiment of the present invention has roughly the same aspect as the vapor phase growth apparatus (see FIG. 1) according to the first embodiment. However, the vapor phase growth apparatus according to the present embodiment differs in the configuration of the second gas flow path expanding portions 13, 23, and 33. Hereinafter, this embodiment will be described.

  In the vapor phase growth apparatus according to the present embodiment, partition portions 60 and 70 that are portions that divide each of a plurality (three) of second gas flow path expanding portions 13, 23, and 33 are arranged in a plate shape. Yes. That is, the second gas flow path expanding part 13 and the second gas flow path expanding part 23 are separated from each other with the partition part 60 as a boundary, and the second gas flow path expanding part 23 and the second gas flow are separated from each other with the partition part 70 as a boundary. The road enlargement portion 33 is separated. 7 is the same as FIG. 5, and the schematic cross-sectional view taken along line II-II in FIG. 7 is the same as FIG. 2.

  For example, the second gas flow path expanding part is integrally formed inside the second gas flow path expanding part case 5, and the boundary between the first gas flow path expanding parts 12, 22, 32 and the second gas flow path expanding part. The partition portions 60 and 70 may be formed so as to extend from the portion to the inside of the second gas flow path enlarged portion. Alternatively, each of the gas introduction parts 11, 21, 31 is composed of the gas supply pipes 10, 20, 30, the first gas flow path expansion parts 12, 22, 32 and the second gas flow path expansion parts 13, 23, 33. The part (outer peripheral part) where the second gas flow path expanding part 13 and the second gas flow path expanding part 23 come into contact is combined to form a partition 60, and the second gas flow path expanding part 23 and the second gas flow path expanding. The part which contacts the part 33 (outer peripheral part) may be combined, and the structure used as the partition part 70 may be sufficient.

  That is, even if the partition parts 60 and 70 have any of the above-described aspects, the partition parts 60 and 70 are made of the same material as the gas introduction parts 11, 21, and 31, that is, for example, quartz or chromium, iron, nickel, stainless steel, manganese, It is preferably formed of a metal such as molybdenum, tungsten, or aluminum.

  Referring to FIG. 8, partition 60 and partition 70 are straight lines that form the outermost periphery in the cross-sectional view of FIG. 8 in the downstream region in the reaction gas flow direction (the direction from the right side to the left side in FIG. 8). Is inclined. Specifically, as shown in FIG. 9, the outermost periphery of the end portion 61 on the downstream side of the reaction gas in the partition portion 60 is the outermost portion in the thickness direction of the end portion 61 (the vertical thickness in FIG. 8). The upper straight line 63 and the lowermost straight line 63 have a configuration inclined at a constant angle with respect to the flow direction of the reaction gas (the left-right direction in FIG. 8). That is, the outermost periphery of the partition 60 extends substantially parallel to the flow direction of the reaction gas on the upstream side from the inflection point 62 in FIG. 9, but bends at the inflection point 62 and is downstream from the inflection point 62. On the side, the distance between the uppermost straight line 63 and the lowermost straight line 63 (that is, the thickness of the partition 60) extends so as to decrease. The angle formed by the uppermost straight line 63 and the lowermost straight line 63 in the cross-sectional view of FIG. 9 is θ, and the uppermost straight line 63 and the lowermost straight line 63 intersect each other so as to have sharp points. ing.

  In the first example of FIG. 9, the uppermost straight line 63 and the lowermost straight line 63 of the end 61 intersect at an angle θ, and the tip in the sectional view of FIG. 9 has a sharp shape. However, as shown in the second example of FIG. 10, the cross-sectional view of the tip of the end portion 61 may have an arc shape. The end portion 61 of the partition 60 in FIG. 10 differs from the end 61 of the partition 60 in FIG. 9 only in that the tip has a circular cross-section at the tip. That is, on the downstream side (tip side) from the inflection point 64, the cross-sectional view of FIG.

  In this way, the reaction gas flowing through the second gas flow path expanding section 13 and the second gas flow path expanding section 23 partitioned by the partition section 60 forms a vortex by the straight line 63 having a tapered shape, thereby smoothly Can be prevented from disturbing distribution. That is, the vapor phase growth apparatus according to the present embodiment has a shape in which the gas flow path expands in two stages in a plan view, and has a shape in which the gas flow path at the distal end expands with an inclination in the thickness direction. This makes it possible to more reliably provide a smooth flow of the reaction gas, sharply change the type of the flow of the reaction gas, and form a stacked structure in which a plurality of thin films of different materials are stacked with higher quality. be able to.

Here, in order to further enhance the effect of the present vapor phase growth apparatus, the uppermost straight line is formed in the region where the thickness t is 0.05 mm or more in the end portion 61 of the partition portion 60 of FIGS. It is preferable to have a region in which an angle θ formed by 63 and the lowermost straight line 63 is 50 ° or less. Specifically, referring to the third example of FIG. 11, for example, the uppermost straight line 63 and the lowermost straight line 63 are formed on the end 61 side (front end side) with respect to the inflection point 62 of the partition 60. It is preferable that the angle θ is 50 ° or less. However, the angle formed by the uppermost straight line and the lowermost straight line on the tip side of the inflection point 65 where the thickness t, which is the distance between the uppermost straight line 63 and the lowermost straight line 63, is 0.05 mm. Is θ ₃ (> θ), and θ ₃ may be an angle exceeding 50 °. That is, the straight line formed by the outermost periphery may have two inflection points.

  In addition, in order to process the partition part 60 at industrially reasonable cost, it is preferable that the value of angle (theta) is 0.1 degree or more. Therefore, the value of θ is preferably 0.1 ° or more and 50 ° or less.

  Further, as shown in the fourth example of FIG. 12, the cross-sectional view of the tip of the end portion 61 may have an arc shape. Specifically, the end 61 of the partition 60 in FIG. 12 differs from the end 61 of the partition 60 in FIG. 11 only in that the cross section of the tip is circular so as to form an arc shape. Yes. That is, on the downstream side (front end side) from the inflection point 66, the cross-sectional view of FIG.

  However, as shown in FIG. 13, the thickness t of the most downstream region of the end portion 61 of the partition portion 60 where the uppermost (lowermost) straight line 63 is inclined and intersects at an angle θ is less than 0.05 mm. Preferably there is. In this way, it is possible to increase the maximum flow rate at which the reaction gas flowing through the second gas flow path expanding portions 13 and 23 can flow without forming vortices.

Therefore, for example, referring to the first comparative example of FIG. 14, the partition portion 60 in which the region of the thickness t ₁ exceeding the thickness t (0.05 mm) shown in FIGS. Even if the uppermost straight line 63 and the lowermost straight line 63 form an angle θ of 50 ° or less at the end 61 on the downstream side of the inflection point 62, the reaction gas is present in the vicinity of the most advanced region. The flow vortex 67 may occur. For this reason, it is necessary to precisely control the flow rate, for example, by reducing the flow rate of the reaction gas flowing through the second gas flow path expanding portions 13 and 23.

  Referring to the second comparative example of FIG. 15, the partition 60 in the conventional vapor phase growth apparatus is not formed with an inclination at the end. Therefore, it can be considered that the angle θ formed by the most advanced portion (most downstream side) is 180 °. In this case, the thickness t of the partition part 60 becomes a substantially constant value, and vortices are generated in the reaction gas flowing through the second gas flow path expanding parts 13 and 23, making it difficult to switch the gas steeply. there is a possibility. However, if the value of the thickness t is, for example, less than 0.05 mm, the possibility that vortices are generated in the reaction gas in the vicinity of the most distal end of the partition portion 60 can be reduced. Therefore, for example, similar to the partition portion 60 having an inclined shape shown in FIGS. 9 to 13, it is possible to easily switch a steep gas and easily form a high-quality thin film laminated structure.

  In addition, in order to process the partition part 60 with industrially reasonable cost and appropriate intensity | strength, it is preferable that the value of the thickness of the partition part of the said FIG. 15 is 0.01 mm or more. Therefore, when θ is 180 °, the thickness of the partition portion is preferably 0.01 mm or more and less than 0.05 mm.

  9 to 15, only the end portion 61 of the partition portion 60 has been described. However, the end portion 71 of the partition portion 70 of FIG. Thirteen aspects can be taken.

  In the following, data (simulation results) explaining the above contents will be described. The horizontal axis of the graph of FIG. 16 is an angle formed by the uppermost straight line 63 and the lowermost straight line 63 at the end 61 of the partitioning portions 60 and 70 of the vapor phase growth apparatus (see FIG. 7) of the present embodiment. θ (see FIG. 9) is shown. In addition, the vertical axis of the graph of FIG. 16 indicates the maximum switching frequency of the reaction gas flowing through the second gas flow path expanding portions 13 and 23 (the type of reaction gas flowing through the second gas flow path expanding portions 13 and 23 is 1 second). The number of times that can be switched to follow.

  In the simulation shown in the graph of FIG. 16, the thickness is 1 mm except for the end portions 61 and 71 of the partition portions 60 and 70 (a region having a substantially constant thickness upstream from the end portions 61 and 71). The height H (refer FIG. 5) of the 2nd gas flow path expansion parts 13 and 23 assumes the vapor phase growth apparatus which is 1 mm. Further, the length of the second gas flow path expanding portion 13 extending in the direction along the flow path of the reaction gas is 140 mm, and the partition portions 60 and 70 have sharp end portions 61 as shown in FIG. It is supposed to be.

  Here, when the angle θ at the end portion 61 of the partition portions 60 and 70 and the flow rate per unit time of the reaction gas flowing through the second gas flow path expansion portions 13 and 23 are changed, the type of the reaction gas is switched. The number of times that the type of reaction gas flowing in the upstream portion of the reaction chamber 50 can follow in one second was calculated. Specifically, first, in the upstream part of the reaction chamber 50, the time until the concentration of the reaction gas flowing before switching is reduced to 1/100 or less before switching is changed to the minimum of switching. It was time. In addition, the maximum number of times of switching per unit time when the switching of the reaction gas type is repeated for each minimum switching time is defined as the maximum switching frequency. And the change of the maximum switching frequency with respect to angle (theta) of the edge part 61 was investigated for every flow volume of the reactive gas. Specifically, the case where the angle θ of the end 61 is 180 °, 90 °, 50 °, 25 °, 12 ° and 6 ° was investigated. When the gas is switched at a frequency higher than the maximum switching frequency, the two gases are mixed in the reaction chamber, and the switching effect is lost. The higher the maximum switching frequency is, the more rapidly the gas can be switched at various switching speeds, thereby enabling more effective switching.

  As a result, as shown in FIG. 16, the maximum switching frequency is obtained when the flow rate of the reaction gas flowing through the second gas flow path expanding portions 13 and 23 is 20 SLM, regardless of the angle θ of the tip of the end portion 61. Is the lowest. When the flow rate of the reaction gas was 40 SLM, the maximum switching frequency was higher than that of 20 SLM, and the maximum switching frequency was highest when the tip angle θ was 25 ° or more. However, when the tip angle θ is 12 ° and 6 °, the maximum switching frequency is larger when the flow rate of the reaction gas is 60 SLM than when the flow rate is 40 SLM. Regardless of the flow rate of the reaction gas, when the tip angle θ is 50 ° or less, the maximum switching frequency is higher than when the tip angle θ is 90 ° or more.

  From this, it can be seen that the maximum switching frequency can be increased by setting the flow rate of the reaction gas to 40 SLM or more and 60 SLM or less and the tip angle θ of the end 61 of the partition 60 to 50 ° or less. The large maximum switching frequency means that the inside of the reaction chamber 50 can easily follow the rapid change in the type of reaction gas, and a high-quality thin film laminated structure can be formed. This reduces the tip angle θ and sharpens the tip of the end portion 61, thereby suppressing the generation of vortex of the reaction gas in the vicinity of the end portion 61 and controlling the time change of the flow rate of the reaction gas with higher accuracy. It is considered possible.

  The horizontal axis of the graphs of FIGS. 17 and 18 is the same as that of FIG. 16 and the uppermost straight line 63 at the end portion 61 of the partition portions 60 and 70 of the vapor phase growth apparatus (see FIG. 7) of the present embodiment. An angle θ (see FIG. 9) formed by the lowermost straight line 63 is shown. Also, the vertical axis of the graphs of FIGS. 17 and 18 indicates the upstream of the reaction chamber 50 when the type of the reactive gas flowing through the second gas flow path expanding portions 13 and 23 is changed or when the flow of the reactive gas is stopped. The time (arrival time (milliseconds)) until the concentration of the reaction gas becomes 1/100 in the part (downstream part) is shown. That is, the shorter the arrival time, the faster the reaction chamber 50 follows the reaction gas change. The other conditions relating to FIGS. 17 and 18 are the same as the conditions for extracting the data of FIG.

  17 and 18, the arrival time is longer when the flow rate is 20 SLM, regardless of the tip angle θ. On the other hand, in the case of the flow rates of 40 SLM and 60 SLM, it can be seen that the arrival time is shortened particularly when the tip angle θ is 50 ° or less. As described above, similarly to FIG. 16, the flow rate of the reaction gas is set to 40 SLM or more and 60 SLM or less, and the tip angle θ of the end portion 61 of the partition portion 60 is set to 50 ° or less. It can be seen that it is more preferable to control the above.

  Next, the type of reaction gas supplied to the reaction chamber 50 from the gas supply pipes 10, 20, 30 of the vapor phase growth apparatus described above is switched, or the flow of the reaction gas flowing through the gas supply pipes 10, 20, 30 19 to 22 show the results of investigating the change over time of the concentration of the reaction gas on the substrate 15 placed inside the reaction chamber 50 when the process is stopped. The data shown in the graphs of FIGS. 19 to 22 are derived using the same vapor phase growth apparatus as the vapor phase growth apparatus from which the data of FIGS. 16 to 18 are derived. Moreover, the shape of the front-end | tip part of the partition parts 60 and 70 which divides between the gas supply pipes 10, 20, and 30 of a vapor phase growth apparatus is the same as that of FIG.

  The horizontal axis of the graphs of FIGS. 19 to 22 shows the elapsed time from the time when the reactive gas (for example, TMG) supplied from the gas supply pipes 10, 20, 30 is stopped or the type of gas is switched, for example. ing. The vertical axis of the graphs of FIGS. 19 to 22 represents the reaction gas flowing through the gas supply pipes 10, 20, and 30 until time 0 of the horizontal axis on the surface of the substrate 15 placed on the susceptor 51 of the reaction chamber 50. Concentration (molar fraction).

  19 to 22, the angle θ formed by the uppermost straight line 63 and the lowermost straight line 63 (see FIG. 9) at the end portion 61 of the partitioning portions 60 and 70 is shown as the tip angle. For example, in FIGS. 19 and 20, even if the tip angle of the partition 60 changes from 180 ° to 25 °, the time change of the gas concentration on the substrate 15 hardly changes. However, as shown in FIG. 21, when the flow rate of the reaction gas is 60 SLM, the time change of the gas concentration on the substrate 15 in particular between 1500 milliseconds and 1700 milliseconds depends on the tip angles of the partitions 60 and 70. Change.

  More specifically, referring to FIG. 22, the tip angle is 25 °, 12 °, 6 °, especially when the tip angle is 180 ° or 90 ° between 1650 milliseconds and 1670 milliseconds. In this case, it can be seen that the decrease in density is faster. As shown in FIG. 22, in about 1650 milliseconds to 1670 milliseconds, the molar fraction of the reactive gas on the substrate 15 becomes about 1/100 of the molar fraction of the reactive gas on the substrate 15 at time 0 (steady state). ing.

  From this, by reducing the tip angle and sharpening the tip of the end portion 61, the generation of the vortex of the reaction gas in the vicinity of the end portion 61 is suppressed, and the time change of the flow rate of the reaction gas is more accurately ( It is considered that the control can be performed so that the time changes more rapidly.

  On the other hand, FIG. 23 does not have an inclined outer peripheral shape at the end portions 61 of the partition portions 60 and 70. For example, assuming that the partition portion 60 has θ of 180 ° as in FIG. The result of simulating the maximum flow velocity at which the reaction gas flowing through the second gas flow path expanding portions 13, 23, 33 can flow out toward the reaction chamber 50 without forming a vortex when the thickness changes Is shown. That is, the horizontal axis of the graph of FIG. 23 shows the thickness at the extreme end of the partition portions 60 and 70 having θ of 180 ° (having no inclined outer peripheral shape in the sectional view) as the most advanced thickness. Yes. Further, the vertical axis of the graph of FIG. 23 is directed toward the downstream side (reaction chamber 50 side) without causing the reaction gas to generate vortices in the vicinity of the tips of the partition portions 60 and 70 and to cause gas mixing. The maximum flow rate that can be circulated is shown as the maximum flow rate without vortex. Here, the calculation was performed assuming that the most advanced thicknesses were 2 mm, 0.5 mm, 0.1 mm, and 0.05 mm.

  From the results of FIG. 23, it can be said that when the partition portions 60 and 70 do not have an inclined outer peripheral shape, the thickness of the partition portions 60 and 70 is preferably 0.05 mm (50 μm) or less. This is because the reaction gas can have a flow velocity close to 10 m / s without generating vortices or mixing gases. Specifically, the maximum vortex-free flow velocity at the most advanced thickness of 2 mm is 0.073 m / s, the maximum vortex-free flow velocity at the most advanced thickness of 0.5 mm is 0.205 m / s, the highest The maximum flow speed without vortex when the tip thickness was 0.1 mm was 3.031 m / s, and the maximum flow speed without vortex when the tip thickness was 0.05 mm was 8.3 m / s.

  As described above, the embodiments of the present invention have been described. However, it should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. For example, as shown in FIGS. 2 and 3, the gas flow path expanding portion in the vapor phase growth apparatus of the present embodiment has two regions (first gas flow path expanding portion and second gas flow path expanding portion) having different inclination angles. ) Is included. However, for example, a gas flow path expanding portion including three or more regions having different inclination angles may be formed. Alternatively, a gas phase provided with a gas introduction part on the downstream side of the gas supply pipe, in which an inclination angle is gradually increased so that the width is gradually increased, and a gas channel expansion part having a curved gas channel expansion part side wall is formed. A growth apparatus may be used.

  The present invention is particularly excellent as a technique for forming a high-quality laminated structure in which a plurality of types of thin films are laminated by controlling the time change of the flow rate with high accuracy.

  DESCRIPTION OF SYMBOLS 1 Gas introduction part case, 2 Fixing member, 3 Wall surface, 1st gas flow path expansion part case, 5 2nd gas flow path expansion part case, 7 Reactive gas relay path, 9 Exhaust gas flow path 10, 20, 30 gas supply pipe, 11, 21, 31 gas introduction part, 12, 22, 32 first gas flow path expansion part, 13, 23, 33 second gas flow path expansion part, 15 substrate, 24 gas supply pipe side wall, 25 Side wall of first gas flow path expansion part, 26 Side wall of second gas flow path expansion part, 50 reaction chamber, 51 susceptor, 53 rotating shaft, 55 heater, 60, 70 partition part, 61, 71 end part, 62, 64, 65 , 66 Inflection point, 63 straight line, 67 vortex, 100 solid line, 200 dotted line, 300 dashed line.

Claims (7)

A reaction chamber for holding an object to be treated;
A gas introduction part for supplying a reaction gas to the reaction chamber,
The gas introduction part is
A gas supply pipe;
A gas flow path expansion section for connecting the gas supply pipe and the reaction chamber to distribute the reaction gas;
The gas flow path expanding section has a width in a plane direction that is along the main surface of the object to be processed and intersects the flow direction of the reaction gas from the gas supply pipe to the reaction chamber. It is configured to spread from the tube side toward the reaction chamber side,
In the side wall defining the width in the planar direction of the gas flow path expanding portion, the gas out of the inclination angle of the side wall with respect to the discharge direction of the reaction gas introduced from the gas supply pipe to the gas flow path expanded portion The vapor phase growth apparatus, wherein a first inclination angle of a portion located on the supply pipe side is smaller than a second inclination angle with respect to the discharge direction of a portion located on the reaction chamber side of the side wall.   Ratio of the height (H) of the portion where the reaction gas flows in the gas flow path enlargement portion to the length (L) of the gas flow passage expansion portion in the reaction gas flow direction in the gas flow passage expansion portion The vapor phase growth apparatus according to claim 1, wherein (H / L) is 0.0013 or more and 0.013 or less.   3. The vapor phase growth apparatus according to claim 1, wherein the first inclination angle of a portion of the side wall located on the gas supply pipe side is not less than 5 ° and not more than 16 °. A plurality of the gas introduction sections, and a partition section that partitions the gas flow path expansion section of one of the gas introduction sections and the gas flow path expansion section of another gas introduction section among the plurality of gas introduction sections Have
Of the partition portion, at least the region on the downstream side with respect to the flow direction of the reaction gas has the thickness of the partition portion so that the thickness is smaller than the region on the upstream side with respect to the flow direction of the reaction gas. The vapor phase growth apparatus according to any one of claims 1 to 3, wherein an uppermost straight line and a lowermost straight line related to a direction have an outer peripheral shape inclined with respect to the flow direction.   5. The gas phase according to claim 4, wherein in the region having the thickness of 0.05 mm or more in the partition portion, the gas phase according to claim 4 has a region in which an angle formed by the uppermost straight line and the lowermost straight line is 50 ° or less. Growth equipment.   6. The vapor phase growth apparatus according to claim 4, wherein the thickness of the partition portion at the most downstream end in the flow direction of the reaction gas is less than 0.05 mm.   The vapor phase growth apparatus according to any one of claims 1 to 6, wherein a flow rate of the reaction gas is 40 SLM or more and 60 SLM or less.

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