JP7336841B2 - Vapor deposition system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vapor deposition apparatus for forming a thin film on a substrate by vapor deposition, and more specifically, to improvement of material utilization efficiency and suppression of deposits on the opposing surface.

Vapor deposition equipment, for example, horizontal or revolving type MOCVD (metal organic chemical vapor deposition) equipment, a three-channel injector with three process gas inlets and three channels (injection part) is often used. For example, FIG. 3 of Patent Document 1, FIG. 2 of Patent Document 2, and FIG. 1 of Patent Document 3 disclose vapor phase growth apparatuses in which the height (or width) 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 channel among the three divided channels is set considerably higher than the height of the upper or central channel. . In this patent document, the apparatus is a so-called face-down type apparatus in which the surface of the substrate faces downward, and the substrate is placed on a susceptor. Also, a surface (opposing surface) facing the substrate or susceptor is formed by the facing surface member. As described above, although the height of the lowest channel on the side of the opposing surface is large in the injector section, the height of the opposing surface is extended to the injector section, and the height from there to the lower partition plate is lowered. Considering the channel height, it is almost the same as the central channel height. In addition, in the same patent document, the reason for increasing the height of the lower flow path is not described, and it is interpreted that it is expressed in this way for the sake of convenience. FIG. 1 of Patent Document 5 discloses an injector of an MOCVD reactor in which the vertical height of the gas channels adjacent to the floor or ceiling is lower than the vertical height of the central gas channel.

To summarize the above, regardless of whether face-up or face-down, if the three vertically arranged flow paths are defined as the first flow path, the second flow path, and the third flow path in order from the side closest to the substrate/susceptor, Conventionally, the height of the third channel is equal to or less than the height of the other channels. In addition, in the three-channel type conventional structure, the group III material is always supplied from the second channel, the group V material is supplied only from the first channel (Patent Documents 1, 2, 3, and 4), or the first channel and the third channel (Patent Document 5). In addition to the material gas, these process gases naturally contain a carrier gas of a required amount and a required gas type (hydrogen, nitrogen, etc.). In the present application, these gases are collectively referred to as process gases.

In recent years, there have also been proposals for more than three channels. For example, Non-Patent Document 1 proposes a structure with five channels, and Patent Document 6 proposes a structure with six channels. According to the definition of the flow path, in Non-Patent Document 1, the group III material is supplied from the second flow path and the fourth flow path among the five flow paths. Further, in Patent Document 6, group III gases are supplied from the third and fourth channels among the six channels. Group III material introduction is avoided from the channel closest to the susceptor (the first channel) and the channel closest to the facing surface opposite it (the fifth channel in the former and the sixth channel in the latter). From the similarity, these can be said to be developments of the three-channel type. Although this document describes improvements based primarily on three-channel injectors, the concepts can be extended to configurations with four or more channels.

Japanese Patent Publication No. 2013-507779 Japanese Patent Application Laid-Open No. 2011-155046 Japanese Patent Application Laid-Open No. 2008-177187 JP-A-9-260291 Japanese Patent Publication No. 2007-524250 Japanese Patent Application Laid-Open No. 2012-190902 Proceedings of CS MANTEC Conference 2013, p.399-402

FIG. 13(A) schematically shows the basic cross-sectional structure of a three-channel injector according to the conventional structure. This cross-sectional structure is applicable to both a horizontal furnace and a revolutionary converter. A horizontal furnace is a type in which a gas flow flows in one direction, and the substrate normally moves only by revolving. In a rotary-revolutionary converter, process gas is introduced from the center of a flat cylindrical reactor and flows radially to the outer periphery. The substrates are arranged on the same circumference and rotate and revolve. In a horizontal furnace, the cross-sectional structure of FIG. 13(B) continues in the depth direction within the range of the width of the reactor, and in a rotary-revolutionary converter, the same cross-sectional structure goes around. Since the cross-sectional structure is the same, the horizontal furnace and the rotary-revolutionary converter exhibit similar properties, and therefore the effects of the present invention are equally applicable to both types of furnaces.

A horizontal material gas flow path is formed by the susceptor 900 and the facing surface 904 . A film is formed on a substrate (wafer) 902 provided on a susceptor 900 by supplying a process gas for film formation from an injector 910 to this gas flow path. The injector 910 is partitioned into three sections by partition plates 912 and 914, forming first to third gas flow paths, respectively. The heights of these first to third flow paths are d1 to d3, respectively. For example, the following gas is 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, second channel: Group III element + H2 (and/or N2)
c, third channel: H2 (and/or N2, group V element)

In the present invention, the concept of deposition rate distribution is important, and in the film formation of III-V group compound semiconductors, the group III element controls the deposition rate of the film. Although V-group elements are also materials for semiconductor films, V-group elements have high vapor pressures and can be deposited only when they meet with III-group elements. Therefore, in considering the deposition rate, the group V element is subordinately positioned. In many cases, the MOCVD process is carried out under so-called mass-transport rate-limiting conditions, in which the transport of the Group III material mainly by diffusion dominates the deposition rate. Therefore, the present invention is basically premised on this condition. Even if the substance transport rate is not completely determined, the effect of the present invention can be similarly obtained as long as it does not greatly deviate from it.

By the way, the film deposit 920 occurs not only on the target substrate 902 but also on the susceptor 900 and the opposing surface 904 . Of these, deposition on the susceptor 900 is in principle unavoidable, but deposition on the facing surface 904 should be reduced as much as possible. The more deposits on the facing surface 904, the less efficiently the material is utilized. In addition, deposits 920 on the opposing surface 904 cause deterioration of process reproducibility and particle problems, so it is necessary to perform maintenance (replacement) on the opposing surface side with a certain frequency. A large amount of deposition on the facing surface 904 increases the frequency of maintenance. Since there are adverse effects such as a decrease in material efficiency and an increase in maintenance frequency, it is desirable to suppress deposits 920 on the opposing surface 904 side. In addition, in the deposition rate curve in the flow direction of the process gas (horizontal direction in FIG. 13), a sharp slope is not preferable, and a gradual slope is better. This is because if the slope of the deposition rate curve is steep, even if the substrate 902 rotates, it will be difficult to optimize the film quality distribution such as film thickness and crystallinity/impurity concentration.

In the conventional structure, increasing the flow rate F3 of the third flow path on the side of the opposing surface is conceivable in order to reduce the amount of deposits on the opposing surface. 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. 13(B), the heights d1, d2 and d3 of the first, second and third channels 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, F3 are equal)
#2: F1 = F2, F3 = 2 x F1 (F1 = twice F2 only for F3)
#3: F1 = F2, F3 = 4 x F1 (F1 = 4 times F2 only for F3)
Under these conditions, the flow and material concentration distribution were simulated. The flow direction was defined as the x direction and the vertical direction as the z direction. Gas flow simulation was performed using the Navier-Stokes equation, and Group III element substance concentration distribution simulation was performed by solving an advection-diffusion equation. When solving the advection-diffusion equation, based on the premise of mass transport rate control, a boundary condition was used in which the material substance concentration was zero on both the susceptor side and the opposing side.

Since the temperature of the facing surface is lower than the temperature of the susceptor or substrate, it may deviate slightly from the substance transport rate-determining state, but generally the degree is not large. In particular, in the film formation of nitride-based III-V group semiconductors performed at a high temperature of 1000° C. or higher, the temperature of the facing surface is also a sufficient temperature to be rate-determining for mass transport. Therefore, the above boundary condition setting is reasonable. Incidentally, if the opposing surface is rate-determining for substance transport, the same amount of deposition occurs on the opposing surface as on the susceptor side. Although the deposition amount decreases if the mass transport rate-determining condition is not met, it can be seen from actual experience that the deposition amount on the opposite surface is considerably large, which is close to the mass transport rate-determining condition. This deposition on the facing surface not only causes a decrease in material efficiency due to material consumption there, but also increases the frequency of maintenance of the facing surface, resulting in high costs.

The simulation yielded the results shown in FIG. Here, the case of #2 with double F3 is omitted, and only the same size of #1 and four times of #3 are shown. First, as for the pattern of the airflow, the results shown in (A-1) and (A-2) in the same figure were obtained for #1 and #3, respectively. As for the concentration distribution of the material, the results shown in (B-1) and (B-2) were obtained for #1 and #3, respectively.

FIG. 15 shows simulation results of the deposition rate distribution in the flow direction. The deposition rate can be obtained from the obtained material substance concentration distribution by the formula D·(dc/dz). where D is the diffusion coefficient of the material molecules, z is the direction perpendicular to the substrate, C is the concentration of the material molecules, and (dc/dz) is the concentration gradient of the material in the z direction on the substrate surface. . In FIG. 15(A), graphs GA1 to GA3 show the deposition rate distribution under each flow rate condition #1 to #3 on the substrate surface side, and in FIG. 15(B), graphs GB1 to GB3 show each Deposition rates for flow conditions #1 to #3 are shown. Comparing these graphs, the deposition amount on the facing surface certainly decreases as F3 increases, which is a favorable result.

However, at the same time, it can also be seen that the deposition rate in the upstream portion on the substrate surface side (susceptor side) is extremely high. When the flow rate F3 of the third channel is increased, the flow from the second channel 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, especially upstream, becomes excessive. This excessive deposition rate in the upstream causes a decrease in the uniformity of film thickness and film quality, and an increase in deposits in the upstream, thereby destabilizing the state of the reactor. As described above, in the conventional structure, it was difficult to reduce the amount of deposition on the opposing surface without sacrificing the uniformity of film thickness and film quality, improve material efficiency, and reduce maintenance frequency.

The present invention focuses on the above points, and suppresses deposition on the opposing surface without causing deterioration of the distribution of film thickness and film quality or generation of turbulence, improving material efficiency and maintenance. It is an object of the present invention to provide a vapor-phase deposition apparatus capable of reducing the frequency of .

The present invention provides a susceptor for holding a film-forming substrate in a chamber having an introduction part and an exhaust part for a material gas, and a facing surface member for forming a film-forming space in the horizontal direction with respect to the susceptor and the substrate. is arranged, wherein the introduction part for the material gas includes an injector having first to third introduction ports and a flow path, and from the second introduction port, By supplying a group III element into the chamber and setting the channel height of the third inlet to be higher than the channel height of the other first and second inlets, the second introduction The average introduction position of the opening is set to a position closer to the film formation substrate side than to the facing surface member side, and the average flow velocity of the gas in the flow paths of the first to third introduction openings is made equal. .
According to one of the main modes, when the channel heights of the first to third inlets are da to dc, respectively, dc>da and dc>db, or dc≧da+db. Characterized by

According to another aspect of the present invention, a susceptor for holding a film-forming substrate and a facing surface forming a film-forming space in a horizontal direction with respect to the susceptor and the substrate are provided in a chamber having a material gas introduction portion and an exhaust portion. In the vapor phase deposition apparatus in which the member is arranged, the introduction part for the material gas includes an injector having first to third introduction ports and a flow path, and the first introduction port includes: The third inlet is located on the side of the susceptor or the substrate, the second inlet is located on the side of the opposing surface member, and the second inlet is connected to the first inlet and the third inlet. The group III element is supplied into the chamber from the second introduction port located between the ports , and a partition plate separating the second introduction port and the third introduction port extends above the substrate. By making the distance between the extension line and the opposing surface member larger than the channel height of the third inlet , the average introduction position of the second inlet is on the side of the opposing surface member. It is characterized in that the position is closer to the film-forming substrate side than the film-forming substrate.
According to one of the main modes, it is characterized in that the first to third inlets have the same channel height.

According to another aspect, a group V element is supplied from the first introduction port to form a film of a III-V group compound semiconductor on the substrate by a metal-organic chemical vapor deposition method. and

According to still another aspect, a film of a nitride-based compound semiconductor is formed on the substrate by a metal-organic chemical vapor deposition method by supplying nitrogen from the first inlet. do. The foregoing and other objects, features and advantages of the present invention will become apparent from the following detailed description and accompanying drawings.

According to the present invention, the position where group III is introduced is relatively close to the substrate side and relatively far from the opposing surface side, so that the flow velocity difference at the injector outlet is not increased. It is possible to suppress deterioration of film thickness distribution and film quality distribution and deposition of material substances on the opposing surface without causing the occurrence of , thereby improving material utilization efficiency and reducing maintenance frequency.

1 is a diagram showing a main cross section of Embodiment 1 of a vapor phase deposition apparatus of Example 1 of the present invention; FIG. FIG. 4 is a diagram showing the arrangement of substrates on the susceptor and main parts of the injector in the first embodiment; 2 is a diagram showing a main cross section of Embodiment 2 of the vapor phase deposition apparatus of Example 1. FIG. FIG. 10 is a diagram showing the arrangement of substrates on the susceptor and main parts of injectors of the second embodiment; 3 is a diagram showing a main cross section of Embodiment 3 of the vapor phase deposition apparatus of Example 1. FIG. 4 is a diagram showing a simulation model of Example 1; FIG. 4 is a diagram showing simulation results of flow patterns and material concentration distributions based on the simulation model of Example 1. FIG. 4 is a graph showing simulation results of the deposition rate based on the simulation model of Example 1. FIG. 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. FIG. 10 is a diagram showing simulation results of flow patterns and material substance concentration distributions based on the simulation model of Example 2; 4 is a graph showing simulation results of the 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. FIG. 4 is a diagram showing simulation results of flow patterns and material concentration distributions based on the conventional simulation model; 4 is a graph showing simulation results of the deposition rate based on the conventional simulation model;

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will now be described in detail based on examples.

First, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 8. FIG. Since this embodiment has three basic forms or types, the configuration of each form will be described first. In addition, suppose that the same code|symbol is used for the component which a function is common in each form.

<Embodiment 1> FIG. 1 shows a main cross section of a horizontal furnace that is Embodiment 1 of the vapor phase deposition apparatus of the present invention, and FIG. 2 shows a plane of a susceptor. In these figures, the reactor 10 has a configuration in which a susceptor 110 is arranged within a chamber 100 . The center of the susceptor 110 is connected to a rotating shaft 112, and the rotating shaft 112 is rotationally driven by a revolution motor 114 to rotate the susceptor 110 within the chamber. A sealing 116 such as an O-ring is provided between the revolving motor 114 and the lower chamber wall 102 to maintain airtightness.

On 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 compound semiconductors such as gallium arsenide, indium phosphide, sapphire, silicon carbide, and silicon wafers. Returning to FIG. 1, a base plate 115 is arranged around the susceptor 110 and basically forms the bottom surface of the reaction space together with the susceptor 110 and substrate 124 . It should be noted that this is the case of face-up, and in the case of face-down, conversely, the upper surface is formed.

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 . The heat of the heater 130 is reflected toward the substrate 124 by these reflectors 132, thereby improving the heating efficiency.

An exhaust port 140 is provided on the downstream side of the gas flow (on the right side in FIG. 1). 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 a conventionally known reactor.

By the way, in the present embodiment, a gas introduction section 20 for introducing a film-forming gas (process gas) 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 lowermost substrate side, an introduction path 20B above it, and an introduction path 20C on the opposite surface side 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 ( counted from the substrate surface side) is connected to the first flow path 24A by 22A. The introduction path 20B is connected to the second flow path 24B by partition plates 22A and 22B. Also, the introduction path 20C is connected to the third flow path 24C by the partition plate 22B and the facing surface member 134. As shown in FIG.

Here, in the present embodiment , the height dc of the third flow path 24C on the uppermost side of the flow paths 24A to 24C, that is, the height dc of the third flow path 24C on the opposite surface side is the height da, It is set larger than 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 channel 24C, the substrate 124 side viewed from the second channel 24B to which the group III element is supplied becomes relatively close, and the opposing surface member 134 side becomes farther. Therefore, more Group III elements reach the substrate surface side.

When the substrate 124 is placed 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 a process gas for film formation is introduced through the introduction paths 20A to 20C. For example, similar to 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, group V element)
to introduce

<Embodiment 2> Fig. 3 shows a main cross section of a rotary-revolutionary converter as Embodiment 2, Fig. 4(A) shows a plane of a susceptor, and Fig. 4(B) shows a plane of a susceptor. The plane of the lead-in is shown. In these figures, the reactor 11 has a structure in which a susceptor 110 is arranged within a chamber 101 . The center of the susceptor 110 is connected to a rotating shaft 112, and the rotating shaft 112 is rotationally driven by a revolution motor 114 to rotate the susceptor 110 within the chamber. A sealing 116 such as an O-ring is provided between the revolving 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 rotation gear 126 is provided on the outer peripheral side of the susceptor 110, and the gear teeth provided on the inner peripheral side of the rotation gear 126 and the gear provided on the outer peripheral side of the substrate holder 120 are connected. The teeth are meshed together. When the revolution motor 114 is rotated, the rotation gear 126 is rotated, thereby causing the substrate holder 120 to rotate. Various well-known techniques such as Japanese Patent Laid-Open No. 2002-175992 may be applied as a technique for such rotation and 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 . The heat of the heater 130 is reflected toward the substrate 124 by these reflectors 132, thereby improving the heating efficiency.

An exhaust port 140 is provided in the lower chamber wall 102 on the outside (peripheral side) of the susceptor 110 . The exhaust port 140 has a configuration in which a plurality of holes are arranged at regular intervals when viewed in plan. 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 a conventionally known reactor.

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

Also in the present embodiment, the height dc of the third flow path 24C on the uppermost side of the flow paths 24A to 24C, that is, the height dc of the third flow path 24C on the opposite surface side is higher than the heights da and db of the other flow paths 24A and 24B. , is set large. 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 channel 24C, the substrate surface side viewed from the second channel 24B to which the group III element is supplied becomes relatively close, and the opposing surface member 134 side becomes further. Therefore, more Group III elements reach the substrate surface side.

A substrate 124 is placed on the substrate holder 120 of the susceptor 110 . When the revolution motor 114 is driven, the rotary shaft 112 rotates and the susceptor 110 rotates. As a result, the substrate holder 120, that is, the substrate 124, rotates around the rotation shaft 112 (orbits). On the other hand, the substrate holder 120 , that is, the substrate 124 rotates (rotates) with respect to the rotation gear 126 on the outer peripheral side of the susceptor 110 . 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 a film-forming gas is introduced through the introduction paths 21A to 21C. For example, similar to 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, group V element)
to introduce

<Embodiment 3> Next, Embodiment 3 will be described with reference to FIG. Let us consider the case where the group III element is introduced from the second channel and the fourth channel from the substrate in all five channels, as described in Non-Patent Document 1 mentioned above. In the case of such a structure, if a relatively large amount of the group III element is supplied from the second channel and a relatively small amount of the group III element is supplied from the fourth channel, an effect similar to that of the present invention can be obtained. It is self-evident to play. Further, in Patent Document 6, the group III element is introduced from the third channel and the fourth channel, but if the group III element supply rate from the fourth channel is higher, the effect similar to that of the present invention It is self-evident to play

With these considerations in mind, the concept of the present invention can be generalized so that it is also applicable to injectors with four or more channels. That is, as shown in FIG. 5, there are n channels in total, and the supply rate of the group III element from the i-th channel counted from the substrate side is expressed as Si using the subscript i, i-th channel If the height of the center of the path is represented by Hi, the average height Ha (average) at which the group III element is introduced is expressed by the formula Ha=Σ(Si·Hi)/ΣSi. Assuming that the height of the channel near the substrate 124 is L, the effect of the present invention can be obtained if Ha<L/2 (that is, Ha is closer to the substrate than the central height of the channel). More preferably, Ha<L/3. The reason why the average introduction height is less than 1/3 of the whole is that the third flow channel height of 16 mm, which gave good results in Example 1 described later, is 2/3 of the total flow channel height of 24 mm. It comes from

<Operation of Embodiment 1> Next, the operation of the present embodiment will be described with reference to FIGS. 6 to 8 as well. In order to facilitate understanding, a reactor model with dimensions as shown in FIG. 6 based on a horizontal furnace 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 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. #A1 is reference data, which is the same as condition #1 of the above-described conventional simulation.
#A1: da=db=4mm, dc=4mm, F1=F2=F3
#A2: da=db=4mm, dc=8mm, F1=F2, F3=2×F1
#A3: da=db=4mm, dc=16mm, F1=F2, F3=4×F1

For conditions #A2 and #A3, the height dc of the third flow path 24C is 8 mm, which is twice the height of the other, and 16 mm, which is four times the height of the other. In order to maintain the flow rate, the flow rates were set to double and quadruple, respectively, depending on the height. Based on these conditions, a gas flow simulation and a III-group element material concentration distribution simulation were performed. The simulation method is the same as the conventional simulation described above.

As a result, the results of the gas flow simulation were patterns as shown in FIGS. 7(A-1) and (A-2). (A-1) shows the flow pattern when the height dc of the third flow path 24C is 8 mm, and (A-2) shows the flow pattern when the height dc of the third flow path 24C is 16 mm. This is the flow pattern when Since the average flow velocity of the gas in the third flow path 24C is made equal to the average flow velocity in the other flow paths 24A and 24B, no turbulence occurs. Also, (B-1) and (B-2) in the same figure are material substance concentration distributions corresponding to the conditions of (A-1) and (A-2) in the same figure, respectively. As can be seen from this, reaching the surface of the facing surface member 134 of the group III element substance introduced from the second channel 24B is reduced.

FIG. 8 shows the deposition rate distribution of the material obtained from the material concentration distribution in the flow channels of FIGS. 7(B-1) and (B-2). The horizontal axis is the flow direction and the vertical axis is the deposition rate. In FIG. 8A, graphs G11 to G13 show deposition rates on the substrate surface side under 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 as a whole becomes gentler. This is advantageous for the uniformity of film thickness distribution and film quality distribution. As shown in FIG. 6, if 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. Graphs G21 to G23 in FIG. 8(B) show the deposition rate on the opposing surface side under the conditions #A1 to #A3. Comparing these graphs, it can be seen that the deposition rate on the opposing surface side decreases significantly as the height dc of the third flow path 24C increases. In this way, according to condition #A3, the deposit amount on the opposing surface is reduced, and the maintenance frequency of the opposing surface member can be reduced.

As described above, according to this embodiment, among the flow paths 24A to 24C, the height dc of the third flow path 24C on the facing surface side is the height of the other first flow path 24A and the second flow path 24B. Since the values are set to be larger than da and db, the following effects can be obtained.
a. The deposition rate of the material becomes gentle, the distribution of the film thickness and film quality is improved, and the utilization efficiency of the material is improved.
b. In particular, since the distance from the second channel 24B to the opposing surface member 134 is increased, the amount of the group III element introduced from the second channel 24B reaching the opposing surface is reduced, and the amount deposited on the opposing surface is reduced. decreases. Therefore, the frequency of maintenance of the susceptor 110 can also be reduced. In addition, since the average flow velocity is the same between the channels, no turbulence occurs in the flow.

If the height dc of the third flow path 24C is further increased, the effects of the present invention are further increased. However, in order to maintain the average flow velocity from the third channel 24C, the gas consumption increases in proportion to the height of the channel. The gas supplied to the third flow path 24C is basically mainly composed of nitrogen and hydrogen, so it is inexpensive. There will also be a need to increase the capacity of the vacuum pump. Further, when the height dc of the third flow path 24C increases, the flow path height of the flow paths 24A to 24C as a whole also increases, which raises the risk of unstable gas flow such as the occurrence of natural convection. The height dc of the third flow path 24C should be appropriately selected by comprehensively considering these points. The fact that the height dc of the third channel 24C is set to 16 mm, that is, about 2/3 of the height of the entire channel, as shown in the simulation, can be said to be one of the leading choices in this sense.

Next, Embodiment 2 of the present invention will be described with reference to FIGS. 9 to 12. FIG. FIG. 9(A) shows the main part of this embodiment. By making it thinner, the surface is recessed and the space near the substrate 124 is expanded. The heights d2a, d2b, and d2c of the flow paths 34A, 34B, and 34C are arbitrary, and may be, for example, d2a=d2b=d2c, which is commonly seen in the prior art. The height of the partition plate is extended to the vicinity of the substrate 124, and the height difference from the opposing surface is defined as the apparent height dwc of the third flow path 34C. Therefore, even if "d2a=d2b=d2c", near the substrate 124, "dwc>d2a=d2b". Of course, dwc≧d2a+d2b may be satisfied.

Of course, the opposing surface member 334 as in this embodiment may be manufactured by designing the dimensions as described above from the beginning, but as shown in FIGS. good too. Also in the conventional chamber structure, the injector 31 and the opposing surface member 134 are often separated as shown in FIG. 1B-1. The opposing surface member 134 can be attached and detached in daily operation by an automatic conveying 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 according to the type of the target film formation process. Then, for example, when trying to perform various types of processes (for example, the target film type and film stack structure are different) with the same equipment, it becomes necessary to replace the injector according to each process type. Complicated work is required. However, with the configuration shown in FIG. 2B-2, if a plurality of opposing surface members 334 with different shapes are prepared, various heights dwc can be obtained by exchanging them without exchanging the injector 31. can be realized. Moreover, it can be easily applied to an existing device having a conventional configuration. If the configuration of FIG. 1(A) produces an effect similar to that of the first embodiment, it can change the height dwc within the range of daily operation, so that it is possible to set process conditions and use the same equipment for multiple processes. It has a great advantage, for example, when seeds need to be carried out.

Here, a reactor model with dimensions as shown in FIG. 10 based on a horizontal furnace is assumed. The simulation was performed by fixing the height of each channel to d2a=d2b=d2c=4 mm and changing the apparent height dwc of the third channel 34C. As with 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. Note that condition #B1 is reference data, which is the same as condition #1 in the conventional simulation described above.
#B1: dwc=4mm, F1=F2=F3
#B2: dwc=8mm, F1=F2, F3=2×F1
#B3: dwc=16mm, F1=F2, F3=4×F1

A two-dimensional simulation of the gas flow pattern and material concentration based on these conditions resulted in a pattern as shown in FIG. (A-1) and (A-2) in the same figure are the flow patterns for the conditions #B2 and #B3, respectively. This is the material concentration distribution for #B3. As for the flow pattern, although some distortion was observed in a limited area immediately after the outlets of the flow paths 34A to 34C, the flow did not reach turbulence or vortex flow, and was well within the allowable range. From there on the flow stabilizes immediately due to the effect of the flow channel widening. From (B-1) and (B-2) of the same figure, similarly to Example 1, reaching the surface of the facing surface member 334 of the group III element substance introduced from the second flow path 34B is reduced. I know there is.

FIG. 12 shows the result of the material deposition rate distribution obtained from the material concentration distribution in the flow channel of FIG. 7B. The horizontal axis is the flow direction and the vertical axis is the deposition rate. In FIG. 12A, graphs G31 to G33 show deposition rates on the substrate surface side under the conditions #B1 to #B3. Comparing these graphs, the higher the apparent height dwc of the third flow path 34C, the lower the deposition rate in the upstream, and the gradient as a whole becomes gentler. 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 greater the height dwc, the better the material efficiency. In FIG. 12(B), graphs G41 to G43 show deposition rates on the facing surface side under the conditions #B1 to #B3. A comparison of these graphs reveals that the deposition rate on the opposing surface side decreases significantly as the apparent height dwc of the third flow path 34C increases.

Thus, this embodiment can also provide the same effects as those of the above embodiment. Furthermore, according to this embodiment, as shown in FIG. 9, the same effect can be obtained by replacing only the facing surface member which is detachable for maintenance without changing the conventional injector. It has the advantage of being able to

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example:
(1) The shapes and dimensions shown in the above embodiment are examples, and may be changed as necessary.
(2) In the above-described embodiments, a rotation-revolution vapor deposition apparatus and a horizontal vapor deposition apparatus were described as examples. Applicable to reactors in general. In particular, the substrate surface and the opposing surface may be arranged upside down. That is, it is applicable to both face-up, in which the substrate surface faces upward, and face-down, in which the substrate surface faces downward.
(3) The materials, process gas, facing surface temperature control gas, and purge gas shown in the above embodiments are examples, and can be changed as appropriate within a range in which the same effects can be achieved.

According to the present invention, among the plurality of flow paths of the gas introduction section, the height of the flow path on the opposite surface side, or the apparent height thereof, is made larger than that of the other flow paths. The average introduction position of the group III element supply is set to be closer to the substrate side and farther from the opposing surface side, so that the material efficiency is improved, the distribution of the film thickness and film quality is improved, and turbulence is reduced. It is possible to suppress the deposition of materials on the opposing surface without causing such a problem, thereby reducing the frequency of maintenance. For example, it is suitable for film formation by an organometallic vapor deposition method, particularly for film formation of nitride-based compound semiconductors.

10, 11: reactors 20, 21: gas introduction parts 20A to 20C, 21A to 21C: introduction paths 22A, 22B, 23A, 23B: partition plates 24A to 24C, 34A to 34C: flow paths 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: Opposing surface member 140: Exhaust port 334: Opposing surface member 900: Susceptor 902: Substrate 904: Opposing surface 910: Injectors 912, 914: Partition plate 920: Deposits

Claims (6)

A susceptor for holding a film-forming substrate and a facing surface member forming a film-forming space in a horizontal direction with respect to the susceptor and the substrate are arranged in a chamber having a material gas introduction part and an exhaust part. A vapor phase deposition apparatus comprising
The introduction part for the material gas comprises an injector having first to third introduction ports and a flow path,
supplying a group III element into the chamber from the second inlet;
By setting the channel height of the third inlet to be higher than the channel height of the other first and second inlets, the average introduction position of the second inlet can be adjusted to the facing surface member. A position closer to the film formation substrate side than the side,
A vapor-phase deposition apparatus, wherein average flow velocities of the gas in the flow paths of the first to third inlets are equal. 2. The vent according to claim 1, wherein dc>da and dc>db, or dc≧da+db, where the heights of the flow paths of the first to third inlets are da to dc, respectively. Phase deposition equipment. A susceptor for holding a film-forming substrate and a facing surface member forming a film-forming space in a horizontal direction with respect to the susceptor and the substrate are arranged in a chamber having a material gas introduction part and an exhaust part. A vapor phase deposition apparatus comprising
The introduction part for the material gas comprises an injector having first to third introduction ports and a flow path,
The first inlet is positioned on the susceptor or film formation substrate side,
The third inlet is located on the side of the opposing surface member,
The second inlet is located between the first inlet and the third inlet,
supplying a group III element into the chamber from the second inlet;
A distance between an extension line of a partition plate that partitions the second inlet and the third inlet and extending onto the substrate and the opposed surface member is set larger than the flow channel height of the third inlet. By doing so, the average introduction position of the second introduction port is set to a position closer to the film formation substrate side than to the facing surface member side. 4. The vapor phase film deposition apparatus according to claim 3, wherein the first to third inlets have the same channel height. 4. A film of a III-V group compound semiconductor is formed on the substrate by a metal-organic chemical vapor deposition method by supplying a group V element from the first introduction port. The vapor deposition apparatus according to any one of 1. 5. The method according to any one of claims 1 to 4, wherein a film of a nitride-based compound semiconductor is formed on the substrate by a metal-organic chemical vapor deposition method by supplying nitrogen from the first inlet. or the vapor phase deposition apparatus according to any one of items.

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