JP2020064978A - Gas phase film deposition device - Google Patents

Abstract

To provide a gas phase film deposition device which can improve the distribution of the film thickness and film quality, suppress the accumulation on an opposite surface, improve the material utilization efficiency and reduce the frequency of maintenance.SOLUTION: A reactor 10 is configured so that a susceptor 110 is arranged in a chamber 100. A gas introduction part 20 for introducing process gas is provided on an upstream side of the chamber 100. In introduction paths 20A-20C separated by partition plates 22A, 22B, the height dc of a third flow channel 24C on the opposite surface side is set to be larger than the heights da, db of other flow channels 24A, 24B. With this, a substrate 124 side viewed from the second flow channel 24B supplied with group III elements becomes relatively closer, and an opposite surface member 134 side becomes further. Accordingly, more group III elements arrive on the substrate side surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vapor phase film forming apparatus for forming a thin film on a substrate by vapor phase epitaxy, and more specifically to improvement of material utilization efficiency and suppression of deposits on a facing surface.

  In a vapor phase film forming apparatus, for example, a horizontal or revolving type MOCVD (metal organic chemical vapor deposition) apparatus, a three-channel type injector having three process gas introduction parts and three flow channels. The (injection part) is often used. For example, FIG. 3 of Patent Document 1 below, FIG. 2 of Patent Document 2 and FIG. 1 of Patent Document 3 disclose a vapor phase growth apparatus in which the heights (or widths) of the injector openings are substantially the same. According to the structure disclosed in FIG. 1 of Patent Document 4 below, the height of the lower flow path among the three divided flow paths is set to be considerably larger than the height of the upper or center flow path. . According to the patent document, the device is a so-called face-down type device in which the surface of the substrate faces downward, and the substrate is placed on the susceptor. Further, a surface (opposing surface) opposed to the substrate or the susceptor is formed by an opposed surface member. As mentioned above, although the lowest flow path height on the facing surface side is large in the injector part, the facing surface height is extended to the injector part, and the height from there to the lower partition plate is When considered as the channel height, it is almost the same as the central channel height. It should be noted that, in the patent document, the reason or the like regarding the height of the lower flow path is not described, and it is interpreted as being expressed in this way for convenience. FIG. 1 of Patent Document 5 below discloses an injector of a MOCVD reactor in which the vertical height of the gas flow passage adjacent to the floor or the ceiling is lower than the vertical height of the central gas flow passage.

  To summarize the above, regardless of face-up or face-down, if three vertically aligned flow channels are defined as a first flow channel, a second flow channel, and a third flow channel in order from the side closer to the substrate / susceptor, In the conventional form, the height of the third flow path is equal to or smaller than the height of the other flow paths. Further, in the conventional structure of the three-channel type, the group III material is always from the second channel, the group V material is only the first channel (Patent Documents 1, 2, 3, 4), or the first channel and the third channel. It is supplied from two of the paths (Patent Document 5). Further, as a matter of course, not only the material gas but also these process gases include a carrier gas of an amount required and a gas species (hydrogen, nitrogen, etc.) required. In the present application, these gases will be collectively referred to as process gas.

  In recent years, one having more than three channels has been proposed. For example, Non-Patent Document 1 proposes a structure having five flow paths, and Patent Document 6 proposes a structure having six flow paths. According to the above definition of the channel, in Non-Patent Document 1, the Group III material is supplied from the second channel and the fourth channel of the five channels. Further, in Patent Document 6, Group III is supplied from the third flow path and the fourth flow path out of the six flow paths. Introduction of Group III material from the flow path closest to the susceptor (first flow path) and the flow path closest to the facing surface (the fifth flow path in the former case and the sixth flow path in the latter case) closest to the facing surface is avoided. From these similarities, it can be said that these are all three-channel development types. In the present specification, an improvement mainly based on a three-channel type injector will be described, but the concept can be applied to a structure having four or more channels in a form to develop it.

Special table 2013-507779 JP 2011-155046 JP JP 2008-177187 JP JP-A-9-260291 Special Table 2007-524250 Publication JP 2012-190902 JP Proceedings of CS MANTEC Conference 2013, p.399-402

  FIG. 13 (A) schematically shows a basic sectional structure of a three-channel injector according to the conventional structure. This sectional structure can be applied to both horizontal furnaces and autorotating furnaces. A horizontal furnace is a type in which a gas flow flows in one direction, and a substrate normally operates only in revolution. In the auto-revolution furnace, the process gas is introduced from the center of the flat cylindrical reactor and flows radially toward the outer periphery. The substrates are arranged on the same circumference and rotate about their axes. It can be considered that the cross-sectional structure of FIG. 13B continues in the depth direction in the horizontal furnace in the range of the reactor width, and the cross-sectional structure makes one round in the auto-revolution furnace. Since the cross-sectional structure is the same, the horizontal furnace and the revolving furnace exhibit similar properties, and therefore the effects of the present invention can be applied to any type of furnace in the same manner.

A horizontal material gas flow path is formed by the susceptor 900 and the facing surface 904. By supplying a process gas for film formation from the injector 910 to this gas channel, film formation is performed on the substrate (wafer) 902 provided on the susceptor 900. The injector 910 is divided into three parts by partition plates 912 and 914, and first to third gas passages are formed therein. The heights of these first to third flow paths are d1 to d3, respectively. The following gases, for example, are introduced into each of the first to third flow paths to form a film on the substrate 902.
a, 1st channel: Group V element + H2 (and / or N2)
b, 2nd channel: Group III element + H2 (and / or N2)
c, third flow path: H2 (and / or N2, V group element)

  Although the concept of the deposition rate distribution is important in the present invention, in the film formation of the III-V group compound semiconductor, the III group element controls the deposition rate of the film. Although the group V element is also a material for the semiconductor film, the group V element has a high vapor pressure and can be deposited only when it meets the group III element. Therefore, in consideration of the deposition rate, the group V element is positioned as a subordinate. In many cases, the MOCVD method is performed under the condition of so-called mass transport rate control, in which the transport of the group III material mainly by diffusion controls the deposition rate. Therefore, the present invention basically assumes this condition. Even if the material transport is not completely rate-controlled, the effect of the present invention can be obtained in the same manner as long as it does not largely deviate from the rate.

  By the way, the film deposit 920 is generated not only on the target substrate 902 but also on the susceptor 900 and the facing surface 904. Of these, the deposition on the susceptor 900 is inevitable in principle, but the deposition on the facing surface 904 should be reduced as much as possible. If there is a large amount of deposits on the facing surface 904, the utilization efficiency of the material decreases accordingly. Further, since the deposit 920 on the facing surface 904 causes deterioration of process reproducibility and particle problems, it is necessary to perform maintenance (replacement) on the facing surface side at a constant frequency. When the amount of deposition on the facing surface 904 is large, the maintenance frequency increases. As described above, since there are problems such as a decrease in material efficiency and an increase in maintenance frequency, it is desirable to suppress the deposit 920 on the facing surface 904 side. In addition, in the deposition rate curve in the process gas flow direction (left and right direction in FIG. 13), a steep slope is not preferable, and a gentle slope is preferable. This is because if the inclination of the deposition rate curve is steep, it is difficult to optimize the film quality distribution such as film thickness, crystallinity and impurity concentration even if the substrate 902 is rotated.

In the conventional structure, in order to reduce the amount of deposits on the facing surface, it is conceivable to increase the flow rate F3 of the third flow path on the facing surface side. Here, a simulation was performed assuming a conventional reactor model as shown in FIG. 13 (A) based on a horizontal furnace. As shown in FIG. 13B, the heights d1, d2 and d3 of the first, second and third flow paths are all equal to 4 mm. Further, when the flow rates of the first, second, and third flow paths are represented by F1, F2, and F3, respectively, the flow rate conditions of the executed simulation are the following three conditions # 1 to # 3.
# 1: F1 = F2 = F3 (F1, F2 and F3 are equal)
# 2: F1 = F2, F3 = 2 × F1 (only F3 is twice F1 = F2)
# 3: F1 = F2, F3 = 4 × F1 (only F3 is four times F1 = F2)
Under these conditions, flow and material concentration distribution simulations were performed. The flow direction was defined as the x direction, and the vertical direction was defined as the z direction, the gas flow simulation was performed using the Navier-Stokes equation, and the group III element substance concentration distribution simulation was performed by solving the advection diffusion equation. When solving the advection-diffusion equation, the boundary condition that the material concentration is zero on both the susceptor side and the facing surface side is used, based on the assumption of the rate-determining substance transport.

  Since the temperature of the facing surface is lower than the temperature of the susceptor or the substrate, the temperature may be slightly out of the mass transport rate-determining state, but the degree is generally not large. In particular, in the film formation of a nitride-based III-V group semiconductor that is performed at a high temperature of 1000 ° C. or higher, the facing surface temperature is also a temperature sufficient to be the mass transport rate controlling. Therefore, the above boundary condition setting is appropriate. By the way, if the opposite surface side is also mass transport-controlled, the same amount of deposition as on the susceptor side occurs on the opposite surface. If the mass transfer rate is deviated from, the amount of deposition will decrease. However, from actual experience, the amount of deposition on the facing surface is considerably large, which is close to the rate of mass transport. This deposition on the facing surface not only causes a reduction in material efficiency due to the consumption of the material there, but also increases the frequency of maintenance of the facing surface and raises the cost.

  By the simulation, the result as shown in FIG. 14 was obtained. Here, the case where F3 is twice # 2 is omitted and only the same size of # 1 and four times # 3 are shown. First, regarding the flow pattern of the air flow, the results shown in FIG. 2A-1 for # 1 and the results shown in FIG. 2A-2 for # 3 were obtained. Regarding the concentration distribution of the material substances, the results shown in FIG. 2B-1 in the case of # 1 and the results shown in FIG. 2B-2 in the case of # 3 were obtained.

  FIG. 15 shows the simulation result of the deposition rate distribution in the flow direction. The deposition rate can be calculated from the obtained material concentration distribution by the equation D · (dc / dz). Here, D is the diffusion coefficient of the material molecule, z is the direction perpendicular to the substrate, C is the concentration of the material molecule, and (dc / dz) is the concentration gradient of the material substance in the z direction on the substrate surface. . In FIG. 15 (A), graphs GA1 to GA3 show the deposition rate distributions on the substrate surface side under the respective flow rate conditions # 1 to # 3, and in FIG. 15 (B), graphs GB1 to GB3 show the deposition rate distributions on the facing surface side. The deposition rate under the flow rate conditions # 1 to # 3 is shown. Comparing these graphs, the amount of deposition on the facing surface certainly decreases as F3 increases, and it can be said that this is a preferable result.

  However, at the same time, it can also be seen that the deposition rate on the upstream side of the substrate surface side (susceptor side) is extremely high. When the flow rate F3 of the third flow passage is increased, the flow from the second flow passage to which the group III element is supplied is pushed toward the susceptor due to the local pressure increase near the injector outlet. As a result, the deposition rate becomes excessively high, especially at the upstream side. This excessive upstream deposition rate causes deterioration of the uniformity of film thickness and film quality, and destabilization of the reactor state due to an increase in upstream deposition. As described above, in the conventional structure, it is difficult to reduce the deposition amount on the facing surface without sacrificing the uniformity of the film thickness and the film quality, to increase the material efficiency and to reduce the maintenance frequency.

  The present invention has been made in view of the above points, and suppresses the deposition on the facing surface without causing the deterioration of the distribution of the film thickness and the film quality and the occurrence of the turbulence, thereby improving the material efficiency and the maintenance. It is an object of the present invention to provide a vapor phase film forming apparatus capable of reducing the frequency of the above.

  The present invention relates to a susceptor for holding a film formation substrate in a chamber having a material gas introduction part and an exhaust part, and an opposing surface for forming a film formation space in a horizontal direction with respect to the susceptor and the film formation substrate. In a vapor-phase film forming apparatus in which a surface member is arranged, the material gas introduction part is provided with a plurality of flow paths, and the gas introduction part has n introduction ports and flow paths. And an average introduction position of the group III supply from the injector is set closer to the film forming substrate side than the facing surface member side.

  In another invention, a susceptor for holding a film formation substrate and a film formation space horizontal to the susceptor and the film formation substrate are formed in a chamber having a material gas introduction part and an exhaust part. A vapor phase film forming apparatus in which a facing surface member is arranged, wherein the gas introduction part includes an injector having n introduction ports and channels, and the gas is introduced from the i-th channel counted from the substrate. When the supply rate of the group III element is Si and the central height of the i-th channel from the substrate is Hi, the average height Ha at which the group III element is introduced is Ha = Σ (Si · Hi) Is represented by / ΣSi, or the average height Ha is Ha <L / 2, preferably Ha <L / 3, where L is the flow path height near the substrate. To do.

  According to one of the main modes, the n is 3. When the first to third flow path heights are set to da to dc, respectively, dc> da and dc> db, or dc ≧ da + db. Alternatively, when the flow path height of the first introduction port, the flow path height of the second introduction port, and the apparent flow path height of the third introduction port are da, db, and dwc, respectively, It is characterized in that dwc> da and dwc> db, or dwc ≧ da + db.

  According to another mode, a III-V group compound semiconductor is formed on the substrate by a metal organic vapor phase film forming method. Alternatively, the object to be formed on the substrate is a nitride-based compound semiconductor. The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

  According to the present invention, since the position where the group III is introduced is relatively close to the substrate side and relatively far from the facing surface side, the turbulent flow can be achieved without increasing the flow velocity difference at the injector outlet. It is possible to suppress the deterioration of the film thickness distribution and the film quality distribution and the deposition of the material on the facing surface without causing the occurrence of the above, and to improve the material utilization efficiency and reduce the frequency of maintenance.

It is a figure which shows the principal cross section of Embodiment 1 of the vapor phase film-forming apparatus of Example 1 of this invention. It is a figure which shows the board | substrate arrangement | positioning on the susceptor of the said Embodiment 1, and the principal part of an injector. It is a figure which shows the principal cross section of Embodiment 2 of the vapor phase film-forming apparatus of the said Example 1. It is a figure which shows the board | substrate arrangement | positioning on the susceptor of the said Embodiment 2, and the principal part of an injector. It is a figure which shows the principal cross sections of Embodiment 3 of the vapor phase film-forming apparatus of the said Example 1. It is a figure which shows the simulation model of the said Example 1. 5 is a diagram showing a simulation result of a flow pattern and a material concentration distribution based on the simulation model of Example 1. FIG. 5 is a graph showing a simulation result of a deposition rate based on the simulation model of Example 1. It is a figure which shows the principal part of Example 2 of this invention. It is a figure which shows the simulation model of the said Example 2. FIG. 7 is a diagram showing a simulation result of a flow pattern and a material concentration distribution based on the simulation model of the second embodiment. 9 is a graph showing a simulation result of a deposition rate based on the simulation model of Example 2. It is a figure which shows the principal part and simulation model of the conventional vapor phase film-forming apparatus. It is a figure which shows the simulation result of the flow pattern and material concentration distribution based on the said conventional simulation model. It is a graph which shows the simulation result of the deposition rate based on the said conventional simulation model.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

  First, a first embodiment of the present invention will be described with reference to FIGS. Since there are three basic forms or types in this embodiment, first, the configuration of each form will be described. In addition, the same code | symbol shall be used for the component which has a function in common in each form.

  <First Embodiment> FIG. 1 shows a main cross section of a horizontal furnace which is a first embodiment of a vapor phase film forming apparatus of the present invention, and FIG. 2 shows a plan view of a susceptor. In these figures, the reactor 10 has a configuration in which a susceptor 110 is arranged in a chamber 100. The center of the susceptor 110 is connected to a rotating shaft 112, and the susceptor 110 is rotated in the chamber by rotationally driving the rotating shaft 112 with a revolution motor 114. A seal 116 such as an O-ring is provided between the revolution motor 114 and the lower chamber wall 102 to maintain airtightness.

  In the susceptor 110, one relatively large substrate 124 is arranged as shown in FIG. 2 (A), or a plurality of relatively small substrates 124 are arranged as shown in FIG. 2 (B). Examples of the substrate 124 include, for example, gallium arsenide, indium phosphide, sapphire, silicon carbide, and silicon wafer in the example of compound semiconductor. Returning to FIG. 1, a base plate 115 is arranged around the susceptor 110, and basically forms a bottom surface of the reaction space together with the susceptor 110 and the substrate 124. Note that this is the case of face-up, and in the case of face-down, the upper surface is formed on the contrary.

  A heater 130 for heating the substrate 124 is provided below the substrate holder 120, and a reflector 132 is provided around the heater 130. By these reflectors 132, the heat of the heater 130 is reflected toward the substrate 124, and the heating efficiency is improved.

  An exhaust port 140 is provided on the downstream side (right side in FIG. 1) of the gas flow. On the other hand, a facing surface member 134 is provided inside the upper chamber wall 104. The above configuration is the same as that of the conventionally known reactor.

  By the way, in the present embodiment, the gas introduction part 20 for introducing the gas (process gas) for film formation is provided on the upstream side (left side in FIG. 1) of the chamber 100. The introduction part 20 is composed of an introduction path 20A on the bottom side, which is on the substrate side, an introduction path 20B on it, and an introduction path 20C on the opposite surface side, which is further above it. These introduction paths 20A to 20C are separated in the chamber by partition plates 22A and 22B. That is, the introduction path 20A is connected to the first flow path 24A (counted from the substrate surface side) by 22A. The introduction path 20B is connected to the second flow path 24B by the partition plates 22A and 22B. Further, the introduction path 20C is connected to the third flow path 24C by the partition plate 22B and the facing surface member 134.

  Here, in the present embodiment, among the first flow paths 24A to 24C, the height dc of the third flow path 24C on the top, that is, the facing surface side, is the height of the other flow paths 24A and 24B. It is set larger than da and db. That is, it is set so that “dc> da and dc> db”, preferably “dc ≧ da + db”. That is, by increasing the height dc of the third flow path 24C, the substrate 124 side as viewed from the second flow path 24B to which the group III element is supplied is relatively close, and the facing surface member 134 side is further away. Therefore, a larger amount of group III element reaches the substrate surface side.

  When the substrate 124 is arranged on the susceptor 110 and the revolution motor 114 is driven, the rotating shaft 112 rotates and the susceptor 110 rotates. Then, the heater 130 is energized to heat the substrate 124.

In this state, the inside of the chamber 100 is evacuated by a vacuum pump or the like, and the process gas for film formation is introduced through the introduction paths 20A to 20C. For example, like the background art described above,
a, Introduction path 20A: Group V element + H2 (and / or N2)
b, introduction path 20B: Group III element + H2 (and / or N2)
c, introduction path 20C: H2 (and / or N2, V group element)
To introduce.

  <Embodiment 2> FIG. 3 shows a main cross section of an auto-revolution furnace according to Embodiment 2, FIG. 4 (A) shows a plane of a susceptor, and FIG. The plane of the inlet is shown. In these figures, the reactor 11 has a configuration in which a susceptor 110 is arranged in a chamber 101. The center of the susceptor 110 is connected to a rotating shaft 112, and the susceptor 110 is rotated in the chamber by rotationally driving the rotating shaft 112 with a revolution motor 114. A seal 116 such as an O-ring is provided between the revolution motor 114 and the lower chamber wall 102 to maintain airtightness.

  A plurality of substrate holders 120 are rotatably provided on the susceptor 110 via bearings 122. In this embodiment, as shown in FIG. 4A, five substrate holders 120 are provided. A substrate 124 such as a silicon wafer is placed on the substrate holder 120. In addition, a rotating gear 126 is provided on the outer peripheral side of the susceptor 110, and gear teeth provided on the inner peripheral side of the rotating gear 126 and a gear provided on the outer peripheral side of the substrate holder 120. The teeth are engaged. Then, when the revolution motor 114 is rotated, the rotation gear 126 is rotated, whereby the substrate holder 120 is rotated. Various known techniques such as Japanese Patent Laid-Open No. 2002-175992 may be applied as a method of such revolution of the substrate 124.

  A heater 130 for heating the substrate 124 is provided below the substrate holder 120, and a reflector 132 is provided around the heater 130. By these reflectors 132, the heat of the heater 130 is reflected toward the substrate 124, and the heating efficiency is improved.

  An exhaust port 140 is provided on the lower chamber wall 102 on the outer side (outer peripheral side) of the susceptor 110. The exhaust port 140 has a configuration in which a plurality of holes are arranged at equal intervals when seen in a plan view. On the other hand, a facing surface member 134 is provided inside the upper chamber wall 104. The above configuration is the same as that of the conventionally known reactor.

  By the way, in the present embodiment, the gas introduction part 21 for introducing the gas for film formation is provided in the upper chamber wall 104 at the center of the chamber 100. The gas introduction part 21 is composed of a central introduction passage 21A, an introduction passage 21B formed around the introduction passage 21A, and an introduction passage 21C formed around the introduction passage 21B. These introduction paths 21A to 21C are bent in the radial direction inside the chamber by partition plates 23A and 23B. That is, the introduction path 21A is bent by the susceptor 110 and the partition plate 23A and is connected to the first flow path 24A. The introduction path 21B is bent by the partition plates 23A and 23B and is connected to the second flow path 24B. Further, the introduction path 21C is bent by the partition plate 23B and the facing surface member 134 and is connected to the third flow path 24C. The first flow path 24A, the second flow path 24B, and the third flow path 24C are counted from the susceptor side.

  Also in the present embodiment, the height dc of the third flow path 24C on the top, that is, the facing surface side, of the first flow paths 24A to 24C is the height da, db of the other flow paths 24A, 24B. Is set larger than. That is, it is set so that “dc> da and dc> db”, preferably “dc ≧ da + db”. That is, by increasing the height dc of the third flow path 24C, the substrate surface side viewed from the second flow path 24B to which the group III element is supplied is relatively close, and the facing surface member 134 side is further away. Therefore, a larger amount of group III element reaches the substrate surface side.

  A substrate 124 is arranged on the substrate holder 120 of the susceptor 110. When the revolution motor 114 is driven, the rotating shaft 112 rotates and the susceptor 110 rotates. As a result, the substrate holder 120, that is, the substrate 124, rotates about the rotation shaft 112 (revolution). On the other hand, the substrate holder 120, that is, the substrate 124 is rotated with respect to the rotation gear 126 on the outer peripheral side of the susceptor 110 (rotation). If necessary, the heater 130 is energized to heat the substrate 124.

In this state, the inside of the chamber 101 is evacuated by a vacuum pump or the like, and the gas for film formation is introduced through the introduction paths 21A to 21C. For example, like the background art described above,
a, Introduction path 21A: Group V element + H2 (and / or N2)
b, Introduction path 21B: Group III element + H2 (and / or N2)
c, introduction path 21C: H2 (and / or N2, V group element)
To introduce.

  Third Embodiment Next, a third embodiment will be described with reference to FIG. Consider the case where the group III element is introduced from the substrate through the second flow path and the fourth flow path in all five flow paths as in Non-Patent Document 1 described above. In the case of such a structure, if a relatively large amount of group III element is supplied from the second channel and a relatively small amount of group III element is supplied from the fourth channel, an operation similar to that of the present invention is achieved. It is self-evident to play. Further, in Patent Document 6, the group III element is introduced from the third flow path and the fourth flow path. However, if the supply rate of the group III element from the fourth flow path is made higher, an action similar to that of the present invention is obtained. It is obvious to play.

  Considering these, the concept of the present invention can be generalized so that it can be applied to the case of an injector having four or more flow paths. That is, as shown in FIG. 5, there are a total of n channels, and the supply rate of the group III element from the i-th channel counted from the substrate side is the Si, i-th flow using the subscript i. If the central height of the road is represented by Hi, the average height Ha (average) at which the group III element is introduced is represented by the equation Ha = Σ (Si · Hi) / ΣSi. If the flow path height near the substrate 124 is L, and Ha <L / 2 (that is, Ha is closer to the substrate than the flow path center height), the effect of the present invention can be obtained. Furthermore, it is more preferable that Ha <L / 3. The reason why the average introduction height is less than ⅓ of the entire flow path is that the third flow path height of 16 mm, which gave good results in Example 1 described later, is ⅔ of the total flow path height of 24 mm. Comes from that.

<Operation of First Embodiment> Next, the operation of the present embodiment will be described with reference to FIGS. 6 to 8. In order to facilitate understanding, a reactor model based on a horizontal furnace and having dimensions as shown in FIG. 6 is assumed. Although it is basically the same as the conventional simulation model described above, only the height dc of the third flow path is different from the conventional simulation model. That is, the heights of the first flow path 24A, the second flow path 24B, and the third flow path 24C are da, db, and dc, respectively, and the heights of the first flow path 24A, the second flow path 24B, and the third flow path 24C are The flow rates are represented by F1, F2, and F3, respectively, and the simulation conditions are described as # A1, # A2, and # A3 below. Note that # A1 is reference data, which is the same as the condition # 1 of the conventional simulation described above.
# A1: da = db = 4 mm, dc = 4 mm, F1 = F2 = F3
# A2: da = db = 4 mm, dc = 8 mm, F1 = F2, F3 = 2 × F1
# A3: da = db = 4 mm, dc = 16 mm, F1 = F2, F3 = 4 × F1

  Regarding conditions # A2 and # A3, the height dc of the third flow passage 24C is 8 mm, which is twice the other, and 16 mm, which is four times the height, and the flow rate F3 of the third flow passage 24C is the average. In order to maintain the flow velocity, the flow rate was set to 2 times and 4 times, respectively, depending on the height. Under such conditions, a gas flow simulation and a group III element substance concentration distribution simulation were performed. The simulation method is the same as in the case of the conventional simulation described above.

  As a result, the result of the gas flow simulation has the patterns shown in FIGS. 7 (A-1) and (A-2). (A-1) is a flow pattern when the height dc of the third flow path 24C is 8 mm, and (A-2) is the flow pattern when the height dc of the third flow path 24C is 16 mm. It is a flow pattern when it does. Since the average flow velocity of the gas in the third flow passage 24C is made equal to the average flow velocity in the other flow passages 24A and 24B, no turbulence is generated. Further, (B-1) and (B-2) in the figure are material concentration distributions corresponding to the conditions of (A-1) and (A-2) in the figure, respectively. As can be seen from this, the amount of the group III element substance introduced from the second flow path 24B reaching the surface of the facing surface member 134 is reduced.

  FIG. 8 shows the result of the deposition rate distribution of the material substance obtained from the concentration distribution of the material substance in the flow channels of FIGS. 7 (B-1) and (B-2). The horizontal axis represents the flow direction, and the vertical axis represents the deposition rate. In FIG. 8A, graphs G11 to G13 show the deposition rates on the substrate surface side under the conditions # A1 to # A3. Comparing these graphs, as the height dc of the third flow path 24C increases, the deposition rate on the upstream side relatively decreases, and the gradient becomes gentle as a whole. This is advantageous for the uniformity of film thickness distribution and film quality distribution. As shown in FIG. 6, when the upstream end of the substrate 124 is 140 mm and a 4-inch substrate is used, the average deposition rate in this range is the fastest under condition # A3. That is, it can be seen that the greater the height dc of the third flow path 24C, the better the material utilization efficiency. Further, in FIG. 8B, graphs G21 to G23 show the deposition rates on the facing surface side under the conditions # A1 to # A3. Comparing these graphs, it can be seen that the deposition rate on the facing surface side significantly decreases as the height dc of the third flow path 24C increases. Thus, according to the condition # A3, the amount of deposition on the facing surface is reduced, and the maintenance frequency of the facing surface member can be reduced.

As described above, according to the present embodiment, among the flow paths 24A to 24C, the height dc of the third flow path 24C on the facing surface side is set to the height of the other first flow path 24A and the second flow path 24B. Since it is set to be larger than the heights da and db, the following effects can be obtained.
a. The deposition rate of the material substance becomes gentle, the distribution of the film thickness and the film quality is improved satisfactorily, and the utilization efficiency of the material substance is improved.
b, In particular, since the distance from the second flow path 24B to the facing surface member 134 is increased, the amount of the group III element introduced from the second flow path 24B reaching the facing surface is reduced, and the amount of deposition on the facing surface is reduced. Is reduced. Therefore, the frequency of maintenance of the susceptor 110 can be reduced. Moreover, since the average flow velocity is made uniform between the flow paths, no flow turbulence occurs.

  The effect of the present invention is further enhanced by further increasing the height dc of the third flow path 24C. However, in order to maintain the average flow velocity from the third flow passage 24C, the gas consumption increases in proportion to the flow passage height. The supply gas of the third flow path 24C is basically inexpensive because it mainly contains nitrogen and hydrogen, but if the flow rate is too large, it affects the cost. There will also be a need to increase the capacity of vacuum pumps. Further, when the height dc of the third flow passage 24C increases, the flow passage height of the entire flow passages 24A to 24C also increases, but then there is a risk that the gas flow becomes unstable, such as the occurrence of natural convection. It is preferable that the height dc of the third flow path 24C be appropriately selected by comprehensively considering these points. The height dc of the third flow path 24C shown by the above simulation is set to 16 mm, that is, about 2/3 of the total flow path height, which is one of the powerful options.

  Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9A shows a main part of this embodiment, in which the thickness of the facing surface member 334 is set with respect to the flow paths 34A, 34B, 34C of the injector 30 formed by the partition plates 32A, 32B. By making it thinner, the surface is made to recede and the space near the substrate 124 is expanded. The heights d2a, d2b, d2c of the flow paths 34A, 34B, 34C are arbitrary, and may be, for example, d2a = d2b = d2c, which is often seen in the past. The partition plate height is extended to the vicinity of the substrate 124, and the difference in height from the opposing surface is defined as the apparent height dwc of the third flow path 34C. Therefore, even if "d2a = d2b = d2c", "dwc> d2a = d2b" near the substrate 124. Of course, dwc ≧ d2a + d2b may be set.

  The facing surface member 334 as in the present embodiment may of course be manufactured by dimensioning as described above from the beginning, but as shown in FIGS. 9 (B-1) and (B-2), Good. Even in the conventional chamber structure, the injector 31 and the facing surface member 134 are often separated as shown in FIG. The facing surface member 134 is attachable / detachable in daily operation by an automatic transport mechanism or the like. On the other hand, the injector 31 is usually fixed to the chamber by screwing or the like. Therefore, it is difficult to replace it in daily operation, and relatively large-scale maintenance is required when replacing it.

  On the other hand, it is considered that the height d3 of the third flow path 24C in Example 1 described above has an appropriate numerical value depending on the type of the target film forming process. Then, for example, when trying to perform various kinds of processes (for example, target film type and film laminated structure are different) with the same device, it is necessary to replace the injector according to each process type, Complicated work is required. However, in the case of the configuration shown in FIG. 2B-2, if a plurality of facing surface members 334 having different shapes are prepared, the heights of various heights dwc can be changed without replacing the injector 31 by replacing them. Can be realized. Further, it can be easily applied to an existing device having a conventional configuration. If the configuration of FIG. 10A has a similar effect to that of the first embodiment, the height dwc can be changed within the range of daily operation, so that process conditions can be set and a plurality of processes can be performed by the same device. It has great advantages, such as when a seed needs to be implemented.

Here, a reactor model based on a horizontal furnace and having dimensions as shown in FIG. 10 is assumed. The height of each flow path was fixed to d2a = d2b = d2c = 4 mm, and the apparent height dwc of the third flow path 34C was changed to perform a simulation. As in the case of the first embodiment, the flow rates of the first flow path 34A, the second flow path 34B, and the third flow path 34C are represented by F1, F2, and F3, respectively. B2 and # B3. The condition # B1 is reference data, which is the same as the case of the conventional simulation # 1 described above.
# B1: dwc = 4 mm, F1 = F2 = F3
# B2: dwc = 8 mm, F1 = F2, F3 = 2 × F1
# B3: dwc = 16 mm, F1 = F2, F3 = 4 × F1

  A two-dimensional simulation of the gas flow pattern and the material concentration based on such conditions resulted in the pattern shown in FIG. (A-1) and (A-2) in the figure are flow patterns in the case of conditions # B2 and # B3 respectively, and (B-1) and (B-2) in the figure are conditions # B2 and # B2, respectively. # B3 is a material substance concentration distribution in the case of # B3. Regarding the flow pattern, although some distortion is observed in a limited region immediately after the outlets of the flow paths 34A to 34C, it does not reach turbulence or vortex flow, which is within the allowable range. From there onwards, the flow stabilizes immediately due to the effect of widening the flow channel. From FIGS. 2B-1 and 2B-2, similarly to the first embodiment, the arrival of the group III element substance introduced from the second flow path 34B on the surface of the facing surface member 334 is reduced. I know that

  FIG. 12 shows the result of the deposition rate distribution of the material substance obtained from the concentration distribution of the material substance in the flow channel of FIG. 7B. The horizontal axis represents the flow direction, and the vertical axis represents the deposition rate. In FIG. 12A, graphs G31 to G33 show the deposition rates on the substrate surface side under the conditions # B1 to # B3. Comparing these graphs, the larger the apparent height dwc of the third flow path 34C, the lower the deposition rate on the upstream side, and the gentler the gradient as a whole. This is advantageous for the uniformity of film thickness distribution and film quality distribution. As shown in FIG. 10, if the upstream end of the substrate 124 is 140 mm and a 4-inch substrate is used, # B3 has the highest average deposition rate in this range. That is, it can be seen that the larger the height dwc, the better the material efficiency. Further, in FIG. 12B, graphs G41 to G43 show the deposition rates on the facing surface side under the conditions # B1 to # B3. Comparing these graphs, it can be seen that the deposition rate on the facing surface side significantly decreases as the apparent height dwc of the third flow path 34C increases.

  Thus, according to this embodiment, the same effect as that of the above embodiment can be obtained. Further, according to the present embodiment, as shown in FIG. 9, the same effect can be obtained by replacing only the facing surface member that is detachable for maintenance without changing the conventional injector. There is an advantage that you can.

The present invention is not limited to the above-described embodiments, and various changes can be made without departing from the gist of the present invention. For example, the following is also included.
(1) The shapes and dimensions shown in the above embodiments are examples, and may be appropriately changed as necessary.
(2) In the above-described embodiment, the auto-revolution type vapor phase film forming apparatus and the horizontal type vapor phase film forming apparatus have been described as examples, but the present invention forms a horizontal film forming space (flow channel). It is applicable to all reactors. In particular, the substrate surface and the facing surface may be arranged upside down. That is, it is applicable to both face-up with the substrate surface facing upward and face-down facing downward.
(3) The materials of the respective parts, the process gas, the facing surface temperature control gas, and the purge gas shown in the above embodiment are also examples, and can be appropriately changed within the range where the same effect is exhibited.

  According to the present invention, among the plurality of flow paths of the gas introduction portion, the height of the flow path on the facing surface side, or the apparent height, from the injector by means such as making it larger than other flow paths. Since the average introduction position of the group III element supply is set to be close to the substrate side and far from the facing surface side, not only the material efficiency is improved, but also the distribution of the film thickness and the film quality can be easily improved, and the turbulent flow can be prevented. It is possible to suppress the deposition of the material on the facing surface and reduce the frequency of maintenance without generating it. For example, it is suitable for film formation by a metal organic vapor phase film formation method, particularly for forming a nitride-based compound semiconductor.

10, 11: Reactors 20, 21: Gas introduction parts 20A to 20C, 21A to 21C: Introductory passages 22A, 22B, 23A, 23B: Partition plates 24A to 24C, 34A to 34C: Flow passages 30, 31: Injectors 32A, 32B : Partition plates 100, 101: Chamber 102: Lower chamber wall 104: Upper chamber wall 110: Susceptor 112: Rotating shaft 114: Revolution motor 115: Base plate 116: Sealing 120: Substrate holder 122: Bearing 124: Substrate 126: For rotation Gear 130: Heater 132: Reflector 134: Opposed surface member 140: Exhaust port 334: Opposed surface member 900: Susceptor 902: Substrate 904: Opposed surface 910: Injector 912, 914: Partition plate 920: Deposit

Claims (7)

A susceptor for holding a film formation substrate and a facing surface member forming a film formation space in a horizontal direction with respect to the susceptor and the film formation substrate are arranged in a chamber having a material gas introduction part and an exhaust part. A vapor phase film forming apparatus,
The material gas introduction unit includes a plurality of flow paths,
The gas introduction part includes an injector having n introduction ports and a flow path,
The vapor phase film forming apparatus, wherein the average introduction position of the group III supply from the injector is set to a position closer to the film forming substrate side than to the facing surface member side. A susceptor for holding a film formation substrate and a facing surface member forming a film formation space in a horizontal direction with respect to the susceptor and the film formation substrate are arranged in a chamber having a material gas introduction part and an exhaust part. A vapor phase film forming apparatus,
The gas introduction part includes an injector having n introduction ports and a flow path,
When the supply rate of the group III element from the i-th channel counted from the substrate is Si and the central height of the i-th channel from the substrate is Hi, the average height Ha at which the group III element is introduced is Ha. Is represented by Ha = Σ (Si · Hi) / ΣSi, or
When the flow path height near the substrate is L, the average height Ha is Ha <L / 2, preferably Ha <L / 3.
A vapor phase film forming apparatus characterized by the above.   The vapor deposition apparatus according to claim 1 or 2, wherein the n is 3.   The vapor phase film formation according to claim 3, wherein dc> da and dc> db, or dc ≧ da + db, where the first to third flow path heights are da to dc, respectively. apparatus.   When the flow path height of the first introduction port, the flow path height of the second introduction port, and the apparent flow path height of the third introduction port are da, db, and dwc, respectively, dwc> 4. The vapor phase film forming apparatus according to claim 3, wherein da and dwc> db, or dwc ≧ da + db.   The vapor deposition apparatus according to claim 1, wherein a III-V group compound semiconductor is deposited on the substrate by a metal organic vapor deposition method.   The vapor deposition apparatus according to any one of claims 1 to 5, wherein an object to be deposited on the substrate is a nitride-based compound semiconductor.