JP3893615B2 - Vapor phase growth apparatus and epitaxial wafer manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vapor phase growth apparatus for vapor phase growth of a silicon single crystal thin film on a main surface of a silicon single crystal substrate, and an epitaxial wafer manufacturing method realized using the vapor phase growth apparatus.
[0002]
[Prior art]
A silicon epitaxial wafer in which a silicon single crystal thin film (hereinafter simply abbreviated as “thin film”) is formed on the main surface of a silicon single crystal substrate (hereinafter simply abbreviated as “substrate”) by vapor phase growth is a bipolar IC. And widely used in electronic devices such as MOS-IC. With the miniaturization of electronic devices, the demand for flatness of the main surface of the epitaxial wafer that forms the elements is becoming stricter. Factors affecting the flatness include the flatness of the substrate and the film thickness distribution of the thin film. By the way, in recent years, for example, in the manufacture of an epitaxial wafer having a diameter of 200 mm or more, a single-wafer type vapor phase growth apparatus is becoming mainstream instead of a method of batch processing a plurality of wafers. In this method, a single substrate is rotated and held horizontally in a reaction vessel, and a thin film is grown in a vapor phase while supplying a source gas substantially horizontally and in one direction from one end to the other end of the reaction vessel.
[0003]
In the single-wafer type vapor phase growth apparatus as described above, an important factor for achieving uniform film thickness of the thin film to be formed is the flow rate or flow rate distribution of the source gas in the reaction vessel. In a single wafer type vapor phase growth apparatus, a source gas is usually supplied from a gas inlet formed at one end of a reaction vessel via a gas supply pipe, and after the source gas flows along the substrate surface, the vessel It is structured to be discharged from the discharge port on the other end side. In the vapor phase growth apparatus having such a structure, in order to reduce flow rate unevenness, a dispersion plate having a large number of holes is provided on the downstream side of the gas introduction port, or a partition plate for partitioning the gas flow in the width direction is provided. An apparatus has been proposed.
[0004]
Further, in Patent Document 1 below, the source gas from the gas introduction port is caused to flow toward the outer peripheral surface of the bank member arranged around the susceptor that supports the substrate, and over the bank member in the form of getting over the bank member. A configuration of an apparatus for supplying a source gas is disclosed. The gist of this method is to disperse the raw material gas by applying the raw material gas flow to the outer peripheral surface of the bank member, thereby eliminating the uneven flow rate.
[0005]
[Patent Document 1]
JP-A-7-193015
[0006]
[Problems to be solved by the invention]
According to the apparatus described in Patent Document 1, the raw material gas that has hit the outer peripheral surface of the bank member is a flow that attempts to get over the bank member, and a flow that is directed laterally along the outer surface. To form. In this case, it is important for eliminating the uneven flow rate that the raw material gas is evenly dispersed along the outer circumferential surface of the bank member and the width direction by the lateral flow. However, depending on the shape of the outer peripheral surface of the bank member, the source gas is not necessarily uniformly distributed in the width direction, and the flow may be biased. In particular, when the shape of the outer peripheral surface of the bank member is a symmetrical cylindrical surface, the flow distribution of the gas flow tends to be a symmetrical distribution. Therefore, flow unevenness is likely to occur at the same position on the left and right with respect to the rotation axis of the substrate, and the influence of flow unevenness on the left and right overlaps at a specific position in the radial direction of the rotating substrate, leading to a large film thickness abnormality. It becomes easy.
[0007]
An object of the present invention is to provide a vapor phase growth apparatus capable of effectively reducing the influence of the flow rate distribution and thus ensuring a good film thickness distribution, and an epitaxial wafer using the same, by a relatively simple mechanism. It is to provide a manufacturing method.
[0008]
[Means for solving the problems and actions / effects]
In order to solve the above problems, the vapor phase growth apparatus of the present invention is:
A vapor phase growth apparatus for vapor phase growing a silicon single crystal thin film on a main surface of a silicon single crystal substrate,
It has a reaction vessel body with a gas inlet formed on the first end side in the horizontal direction and a gas outlet formed on the second end side, and the source gas for forming the silicon single crystal thin film is introduced into the gas. After the raw material gas flows along the main surface of the silicon single crystal substrate, which is introduced into the reaction vessel main body through the mouth and rotated and held substantially horizontally in the internal space of the reaction vessel main body, it is discharged from the gas discharge port. Configured as
While the silicon single crystal substrate is disposed on a disk-shaped susceptor that is rotationally driven in the internal space, the dam member is disposed in a positional relationship that surrounds the susceptor and that the upper surface coincides with the upper surface of the susceptor.
Furthermore, the gas inlet port is opened in a shape facing the outer peripheral surface of the bank member, and after the source gas from the gas inlet hits the outer peripheral surface of the bank member and rides on the upper surface side, the silicon single crystal substrate on the susceptor Configured to flow along the main surface of the
In the vapor phase growth apparatus in which a baffle in which a gas flow hole is formed is disposed between the gas inlet and the bank member,
The gas circulation hole is configured to include a plurality of main circulation holes and a rectification hole having an opening area smaller than that of the main circulation holes.
[0009]
In the vapor phase growth apparatus, the raw material gas that has passed through the gas flow hole of the baffle advances relatively straight reflecting the position of the gas flow hole and reaches the bank member. The source gas that has reached the bank member collides with the outer peripheral surface of the bank member and is dispersed. The present invention is characterized in that the gas flow hole of the baffle is composed of a main flow hole and a rectifying hole having a smaller opening area than that in order to eliminate the density of the raw material gas generated at that time. is there. The rectifying hole has an opening area smaller than that of the main flow hole, and the amount of the raw material gas to be circulated is smaller than that of the main flow hole. That is, by appropriately adjusting the formation position of the flow straightening holes, the flow of the raw material gas that has reached the bank member through the main flow holes is adjusted by the flow of the raw material gas from the straightening holes, and the flow rate distribution of the raw material gas flowing on the substrate Can be made uniform. Thereby, a silicon single crystal thin film having a very uniform film thickness distribution can be obtained.
[0010]
In order to solve the problem, the vapor phase growth apparatus of the present invention includes:
A vapor phase growth apparatus for vapor phase growing a silicon single crystal thin film on a main surface of a silicon single crystal substrate,
A reaction vessel body having a gas inlet formed on the first end side in the horizontal direction and a gas outlet formed on the second end side, and a raw material gas for forming a silicon single crystal thin film is the gas. After the source gas flows along the main surface of the silicon single crystal substrate, which is introduced into the reaction vessel body from the introduction port and rotated and held substantially horizontally in the internal space of the reaction vessel body, it is discharged from the gas discharge port. Configured to
While the silicon single crystal substrate is disposed on a disk-shaped susceptor that is rotationally driven in the internal space, the dam member is disposed in a positional relationship that surrounds the susceptor and that the upper surface coincides with the upper surface of the susceptor.
Furthermore, the gas inlet port is opened in a shape facing the outer peripheral surface of the bank member, and after the source gas from the gas inlet hits the outer peripheral surface of the bank member and rides on the upper surface side, the silicon single crystal substrate on the susceptor Configured to flow along the main surface of the
In the vapor phase growth apparatus in which a baffle in which a gas flow hole is formed is arranged between the gas inlet and the bank member,
When the virtual center line along the flow direction of the source gas from the first end of the reaction vessel main body to the second end perpendicular to the rotation axis of the susceptor is taken as the horizontal reference line, the reaction vessel main body has a width A column that divides the flow of the source gas in the direction to the left and right with respect to the horizontal reference line is provided on the upstream side of the flow direction of the source gas and on the downstream side of the baffle with respect to the bank member,
The gas flow holes include a plurality of main flow holes and a pair of rectification holes having an opening area smaller than that of the main flow holes, and the plurality of main flow holes and the pair of rectification holes include a horizontal reference line. It is formed side by side in the width direction so as to be symmetric with respect to the plane including the rotation axis,
The pair of rectifying holes is formed on the outside of the main circulation hole closest to the column among the plurality of main circulation holes.
[0011]
In the vapor phase growth apparatus, the raw material gas that has passed through the gas flow hole of the baffle travels relatively straight reflecting the position of the gas flow hole and reaches the bank member. The source gas that has reached the bank member collides with the outer peripheral surface of the bank member and is dispersed. In the present invention, in order to eliminate the density of the raw material gas generated at that time, baffles are provided with rectifying holes having an opening area smaller than that of the main flow holes. Since the main flow hole and the rectifying hole are formed symmetrically with respect to the plane including the horizontal reference line and the rotation axis, the flow distribution on the left and right sides of the substrate is also generally symmetrical.
[0012]
The rectifying hole has an opening area smaller than that of the main flow hole, and the amount of the raw material gas to be circulated is smaller than that of the main flow hole. That is, by appropriately adjusting the formation position of the rectifying hole, the flow of the raw material gas that has reached the bank member through the main flow hole is adjusted by the flow of the raw material gas from the rectifying hole. In particular, it is considered that in the vicinity of the support provided for maintaining the strength of the reaction vessel main body, the raw material gas is affected by the support and the flow distribution is likely to become dense. Therefore, the present inventors have found that a flow distribution of the source gas flowing on the substrate can be made uniform when a pair of rectifying holes are provided on the outside of the main circulation hole closest to the support column. . That is, by using a vapor phase growth apparatus provided with such a baffle, a silicon single crystal thin film having a uniform film thickness distribution can be obtained.
[0013]
The top surface of the bank member is assumed to be in a positional relationship that coincides with the top surface of the susceptor, but this does not necessarily mean that the top surface of the bank member and the top surface of the susceptor are completely aligned, up to about 2 mm. The difference in position is considered to be the same.
[0014]
The epitaxial wafer manufacturing method of the present invention also includes a silicon single crystal substrate placed in a reaction vessel of the vapor phase growth apparatus, and a raw material gas is circulated in the reaction vessel to form a silicon single crystal on the silicon single crystal substrate. An epitaxial wafer is obtained by vapor phase epitaxial growth of a crystal thin film.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 4 schematically show an example of a vapor phase growth apparatus 1 of the present invention for vapor phase growth of a silicon single crystal thin film on the main surface of a silicon single crystal substrate. 1 is a side cross-sectional view thereof, FIG. 2 is an enlarged view of the vicinity of the raw material gas introduction portion of FIG. 1, FIG. 3 is a plan view of the vapor phase growth apparatus 1 of FIG. It is a disassembled perspective view which partially cuts and shows the principal part. As shown in FIG. 1, the vapor phase growth apparatus 1 has a reaction in which a gas introduction port 21 is formed on the first end portion 31 side in the horizontal direction and a gas discharge port 36 is formed on the second end portion 32 side. It has a container body 2. The raw material gas G for forming a thin film is introduced into the reaction vessel main body 2 from the gas inlet 21 and is along the main surface of the substrate W rotated and held substantially horizontally in the internal space 5 of the reaction vessel main body 2. Then, the gas is discharged from the gas discharge port 36 through the discharge pipe 7.
[0016]
As shown in FIG. 1, a disc-shaped susceptor 12 that is rotationally driven by a motor 13 around a vertical rotation axis O is disposed in the internal space 5 of the reaction vessel body 2, and a shallow seat formed on the upper surface thereof. Only one substrate W for manufacturing a silicon epitaxial wafer is disposed in the bore 12b. That is, the vapor phase growth apparatus 1 is configured as a single wafer type vapor phase growth apparatus. The substrate W has a diameter of, for example, 100 mm or more. In addition, infrared heating lamps 11 for heating the substrate are arranged at predetermined intervals above and below the reaction vessel main body 2 corresponding to the arrangement region of the substrate W.
[0017]
In the internal space 5, a bank member 23 is disposed so as to surround the susceptor 12 as shown in FIG. As shown in FIG. 2, the bank member 23 is arranged in a positional relationship in which the upper surface 23 a substantially coincides with the upper surface 12 a of the susceptor 12 (and eventually the main surface of the substrate W). As shown in FIG. 1, the gas inlet 21 is opened in a shape facing the outer peripheral surface 23b of the bank member 23, and the raw material gas G from the gas inlet 21 is shown in FIG. 2 or FIG. As described above, after hitting the outer peripheral surface 23b of the bank member 23 and riding on the upper surface 23a side, the current flows along the main surface of the substrate W on the susceptor 12. In the present embodiment, the outer peripheral surface 23 b of the bank member 23 has a cylindrical surface shape corresponding to the shape of the susceptor 12. A plate-shaped preheating ring 22 for heat equalization formed in a plate shape is disposed along the inner peripheral edge of the bank member 23, and the upper surface 12 a of the susceptor 12 disposed inside thereof is an upper surface 22 a ( It is substantially the same plane as that of FIG. In the inner space 5, an upper lining material 4 having substantially the same diameter as that of the bank member 23 is disposed so as to form a pair with the bank member 23.
[0018]
As shown in FIG. 1, in the vapor phase growth apparatus 1, in the flow direction of the source gas G from the first end 31 of the reaction vessel body 2 to the second end 32 perpendicular to the rotation axis O of the susceptor 12. A virtual center line along the horizontal line is defined as a horizontal reference line HSL. A direction perpendicular to both the horizontal reference line HSL and the rotation axis O of the susceptor 12 is defined as a width direction WL. Thereby, a plane α (reference plane α) including the horizontal reference line HSL and the rotation axis O is determined.
[0019]
Next, as shown in FIG. 3, a baffle 26 in which a gas flow hole serving as a flow path for the source gas G is formed between the gas inlets 21 </ b> A and 21 </ b> B and the bank member 23. As shown in FIG. 4, the gas flow hole includes a plurality of main flow holes 26 a and rectifying holes 26 b having an opening area smaller than those main flow holes 26 a. When the pressure of the raw material gas G that tries to pass through each hole is equal, the flow amount of the raw material gas G is necessarily larger in the main circulation hole 26a having a larger opening area than the rectifying hole 26b. The flow straightening hole 26b in which the flow rate of the raw material gas G is smaller than the main flow hole 26a is suitable for finely correcting the flow of the raw material gas G. That is, the flow of the raw material gas G that has reached the bank member 23 through the main flow hole 26a is adjusted by the flow of the raw material gas G from the rectifying hole 26b, and the flow distribution of the raw material gas G flowing on the substrate W is made uniform. be able to.
[0020]
As shown in FIG. 4, the baffle 26 has a plate shape. In the present embodiment, one long quartz plate is used as the baffle 26. However, it is also possible to configure the baffle with a plurality of members individually corresponding to the gas introduction ports 21A and 21B. Further, the main circulation hole 26a and the rectifying hole 26b penetrate the baffle 26 in the thickness direction, and each has a cylindrical shape with a constant diameter. As a ratio of the opening area of the main flow hole 26a and the rectifying hole 26b, for example, it is desirable that the opening area of the rectifying hole 26b is 1/16 or more and 1/2 or less of the opening area of the main flow hole 26a. When converted into the diameter of a circle, the diameter of the rectifying hole 26b is 1/4 or more (1/2) the diameter of the main flow hole 26a. ^-1 Adjust appropriately within the following range. If the rectifying hole 26b is too small compared to the main flow hole 26a, the effect of adjusting the flow of the source gas G may not be sufficiently obtained. On the other hand, if it is too large, rather than adjusting the flow of the raw material gas G, the flow is largely changed, and it may be difficult to make the flow rate distribution uniform.
[0021]
FIG. 5 shows a front view of several baffles. FIG. 5A shows the baffle 26 provided in the vapor phase growth apparatus 1 shown in FIGS. FIG. 5B shows another preferred form of baffle 261. As shown in FIG. 5A, the main flow hole 26a and the rectifying hole 26b are formed side by side in the width direction WL so as to be symmetric with respect to the plane α including the horizontal reference line HSL and the rotation axis O. . In this way, it is only necessary to consider the formation position of the rectifying hole 26b only in the width direction WL. When the position of one rectifying hole 26b is determined, the position of one rectifying hole 26b on the opposite side across the horizontal reference line HSL is determined. Since the position is naturally determined, it also saves time spent on fine adjustment during construction. FIG. 5C shows a conventional baffle 262 in which only the main flow hole 26a is formed.
[0022]
By the way, as shown in FIG. 3, the reaction vessel main body 2 has a column 33 that divides the flow of the raw material gas G in the width direction WL to the left and right with respect to the horizontal reference line HSL. Upstream of the baffle 26 and downstream of the baffle 26. The column 33 is important for maintaining the strength of the reaction vessel main body 2, but is not welcomed from the viewpoint of uniforming the flow rate distribution. This is because the column 33 is shaded to cause uneven flow. In this case, if the flow straightening hole 26b is formed outside the main flow hole 26a closest to the support column 33 in the width direction WL (see FIGS. 5 (a) and 5 (b)), the flow rate unevenness considered to be caused by the support column 33 is effective. Can be reduced.
[0023]
In an actual manufacturing site, there is also an apparatus that has a tendency to collect a large amount of source gas G toward the horizontal reference line HSL due to deterioration over time. For such a device, the effect of making the flow rate distribution uniform may be higher when the rectifying hole 26b is formed on the innermost side. However, a desirable effect can be expected even in the forms of FIGS.
[0024]
As shown in FIGS. 1, 3, and 4, the vapor phase growth apparatus 1 includes gas guide members 24 </ b> R and 24 </ b> L that guide the raw material gas G from the gas introduction ports 21 </ b> A and 21 </ b> B toward the bank member 23. Yes. Since such gas guide members 24R and 24L are disposed between the gas inlets 21A and 21B and the bank member 23, the baffle 26 includes the gas guide members 24R and 24L and the gas inlets 21A and 21B. Will be placed between. Further, the gas guide members 24R and 24L are arranged with the strut 33 interposed therebetween, and the inside thereof is respectively provided by gas guide member side partition plates 34R and 34L that further partition the flow of the raw material gas G in the width direction WL. The inner guide path 24T and the outer guide path 24S are separated. And the baffle hole 26b is provided corresponding to the inner side guide path 24T. In other words, the rectifying hole 26b is a gas flow hole opened in the inner guide path 24T. When the rectifying hole 26b is provided corresponding to the inner guide path 24T, the effect of adjusting the flow of the raw material gas G is higher than when the rectifying hole 26b is provided corresponding to the outer guide path 24S. This is advantageous for achieving a uniform distribution. However, it is not ineffective to provide the outer guide path 24S.
[0025]
Further, when considering the column 33 as a reference, as shown in FIG. 5A, the rectifying hole 26 b is adjacent to the main flow hole 26 a closest to the column 33, that is, the main column closest to the column 33. It can be provided between the circulation hole 26a and the second closest main circulation hole 26a. According to this embodiment, by adjusting the flow of the source gas G from the innermost main circulation hole 26a and the flow of the source gas G from the outer main circulation hole 26a, the influence of the support column 33 is made as small as possible. be able to. In the form of FIG. 5A, only one pair of rectifying holes 26b is provided. However, the present invention is not limited to this. For example, as shown in another form of FIG. A plurality of pairs of rectifying holes 26b may be provided.
[0026]
As shown in FIG. 3, gas inlets 21 </ b> A and 21 </ b> B are formed respectively corresponding to the right gas guide member side partition plate 34 </ b> R and the left gas guide member side partition plate 34 </ b> L. Specifically, the raw material gas G is guided to the internal space 5 of the reaction vessel main body 2 from the gas introduction ports 21A and 21B via the gas pipe 50. In the present embodiment, the gas pipe 50 branches into an inner pipe 53 that supplies gas to the inner guide path 24T and an outer pipe 51 that also supplies gas to the outer guide path 24S. The mass flow controllers (MFC) 54 and 52 can be controlled independently. Here, a manual valve may be used instead of the MFCs 54 and 52. The inner pipe 53 and the outer pipe 51 are further divided into branch pipes 56 and 56 and branch pipes 55 and 55, respectively, and the inner gas inlets 21A and 21A and the outer gas inlets are provided on both sides of the horizontal reference line HSL. 21B and 21B are opened.
[0027]
Further, as shown in FIG. 4, the gas guide members 24R, 24L are quartz cylindrical members having laterally long cross sections that open to the gas introduction port 21 side and the bank member 23 side, respectively. The plates 34R and 34L are arranged such that the upper end surface and the lower end surface of the upper surface plate 24a and the lower surface plate 24b, which are disposed substantially parallel to each other, are welded or point-supported. The gas guide members 24R and 24L, in which the gas guide member side partition plates 34R and 34L are integrated, are detachably arranged with respect to the reaction vessel main body 2, so that, for example, the positions of the gas guide member side partition plates 34R and 34L are changed. If it is desired to change, it can be easily handled by replacing the gas guide members 24R and 24L.
[0028]
On the other hand, as shown in FIG. 3, on the outer peripheral surface 23b of the bank member 23, there is a bank that divides the flow of the source gas G at a plurality of locations in the width direction WL in a form distributed symmetrically with respect to the horizontal reference line HSL. Member side partition plates 35R and 35L are arranged. Source gas G ₁ , G ₂ Is easy to escape in the width direction WL when riding on the upper surface 23a of the bank member 23. Therefore, by providing the bank member side partition plates 35R and 35L together with the gas guide member side partition plates 34R and 34L, the raw material gas G is provided. ₁ , G ₂ It has succeeded in arranging the direction of the flow appropriately. In the present embodiment, the bank member-side partition plates 35R and 35L are arranged on the left and right sides of the horizontal reference line HSL.
[0029]
As shown in FIG. 4, an arcuate notch 23k is formed by notching the outer peripheral edge of the upper surface 23a of the bank member 23 in a concave shape in the section facing the gas guide members 24R and 24L. As shown in FIG. 1, the reaction vessel main body 2 includes a lower vessel 2b and an upper vessel 2a. The upper lining material 4 is arranged along the inner circumferential surface of the upper vessel 2a, and the bank member 23 is arranged along the inner circumferential surface of the lower vessel 2b. Yes. As shown in FIG. 2, the bottom surface 23c of the notch 23k is substantially coincident with the extension of the inner surface of the lower surface plate 24b of the gas guide members 24R and 24L, and serves as a gas guide surface. The source gas G hits the side surface 23b of the notch 23k and rides on the upper surface 23a. The upper lining material 4 includes a first surface 4a that faces the upper surface 23a of the bank member 23, a second surface 4b that faces the side surface 23b of the notch 23k, and a third surface 4c that also faces the bottom surface 23c. A gas passage 51 having a crank-like cross section is formed between the step portion 4d and the notch portion 23k. As shown in FIG. 4, the bank member-side partition plates 35R and 35L are formed in an L shape corresponding to the gas passage 51 (or a crank shape extending to the upper surface 23a side). According to this structure, the flow of the raw material gas G is easily crushed in the lateral direction by passing through the narrow L-shaped gas passage 51, and it is possible to make it difficult for the flow rate distribution to be extremely biased.
[0030]
Hereinafter, an epitaxial wafer manufacturing method using the vapor phase growth apparatus 1 will be described. As shown in FIGS. 1 to 4, the substrate W is placed on the susceptor 12 in the reaction vessel 2, and after performing pretreatment such as natural oxide film removal as necessary, an infrared heating lamp is rotated while the substrate W is rotated. 11 to the predetermined reaction temperature. In this state, the source gas G is circulated from the gas inlets 21A and 21B into the reaction vessel 2 at a predetermined flow rate, and a silicon single crystal thin film is vapor-phase epitaxially grown on the substrate W, thereby obtaining an epitaxial wafer. .
[0031]
The source gas G is for vapor-phase growth of a silicon single crystal thin film on the substrate W described above. ₃ , SiCl ₄ , SiH ₂ Cl ₂ , SiH ₄ Or the like selected from silicon compounds such as The source gas G contains B as dopant gas ₂ H ₆ Or PH ₃ H as dilution gas ₂ , N ₂ , Ar and the like are appropriately blended. In addition, when substrate pretreatment (for example, removal of a natural oxide film or attached organic substances) is performed prior to the vapor phase growth of the thin film, HCl, HF, ClF ₃ , NF ₃ A pretreatment gas obtained by diluting a corrosive gas appropriately selected from the above with a diluent gas is supplied into the reaction vessel main body 2, or H ₂ High-temperature heat treatment is performed in the atmosphere.
[0032]
The operation when the source gas G is circulated in the reaction vessel 2 will be described. The source gas G passes through the baffle 26 and passes between the gas guide member side partition plates 34R and 34L. ₁ And the outer gas flow G that also passes outside ₂ And flow toward the outer peripheral surface 23b of the bank member 23. Gas flow G hitting the outer peripheral surface 23b ₁ And G ₂ Rides on the upper surface 23 a of the bank member 23, flows along the main surface of the substrate W, is collected in the discharge pipe 7 through the discharge-side gas guide member 25, and is discharged.
[0033]
6 shows the gas flow G ₁ It is a conceptual diagram explaining how to flow. FIG. 6A shows a case where a conventional baffle 262 (see FIG. 5C) is used. Gas flow G after hitting the outer peripheral surface 23b of the bank member 23 from the main flow hole 26a ₁ Rides on the upper surface 23a of the bank member 23 while proceeding in various directions. At this time, the gas flow G from the adjacent main circulation holes 26a, 26a ₁ They overlap each other and tend to cause flow unevenness. On the other hand, as shown in FIG. 6B, when a baffle 26 provided with a rectifying hole 26b is used, a small amount of gas flow G from the rectifying hole 26b is used. ₁ Is the gas flow G from the adjacent main circulation holes 26a, 26a. ₁ It is considered that a strong flow overlap is prevented, and as a result, a uniform flow distribution is achieved.
[0034]
In the present specification, the main flow hole 26a and the rectifying hole 26b are symmetric with respect to the horizontal reference line. However, for example, a positional shift of about 1 to 2 mm, a minute difference in shape and size is a symmetric concept. Shall be included.
[0035]
[Experimental example]
(Simulation experiment by computer)
In the vapor phase growth apparatus 1 shown in FIGS. 1 to 4, the growth rate distribution of the silicon single crystal thin film when the silicon single crystal thin film is vapor phase epitaxially grown on the silicon single crystal substrate W was estimated by computer simulation. Further, for comparison with this, a conventional vapor phase growth apparatus in which the baffle 26 is changed to the baffle 262 (see FIG. 5C) is used for vapor phase epitaxial growth of the silicon single crystal thin film on the silicon single crystal substrate W. In this case, the growth rate distribution of the silicon single crystal thin film was also estimated. The setting conditions and the like are as described below.
[0036]
Fluent Ver 6.0 (obtained from Fluent Asia Pacific)
(Size)
・ Reaction vessel diameter = 300 mm
・ Reaction vessel height = 20 mm
・ Heave member height (height from the bottom surface 23c of the notch 23k to the upper surface 23a of the bank member 23) = 16 mm
・ Silicon single crystal substrate diameter = 200mm
(Growth temperature)
・ Silicon single crystal substrate ... 1400K
・ Reaction vessel top surface ... 700K
(Raw material gas)
・ Trichlorosilane: 3 mol%
・ Hydrogen: 7 mol%
(Raw material gas flow)
・ Inner guideway: 30 liters / minute (standard condition)
・ External guideway: 20 liters / minute (standard condition)
[0037]
FIG. 7 is a contour diagram showing the growth rate distribution obtained from the above-mentioned computer simulation. FIG. 7A shows the vapor phase growth apparatus 1 of the present invention, and FIG. This is the case of a vapor phase growth apparatus. Since it is assumed that the silicon single crystal substrate W does not rotate, the contour line with a slower growth rate is shown as it proceeds to the right side in the figure. In the case of the conventional vapor phase growth apparatus, the contour line is greatly undulated, whereas in the case of the vapor phase growth apparatus 1 of the present invention, the contour line repeatedly repeats the small undulation.
[0038]
(Experiment using actual machine)
A silicon single crystal substrate W having a diameter of 200 mm produced by the CZ method was placed in the vapor phase growth apparatus 1 shown in FIGS. This vapor phase growth apparatus 1 is equipped with the baffle 26 shown in FIG. Then, the silicon single crystal thin film was vapor-phase epitaxially grown on the silicon single crystal substrate W by the following procedure. For comparison, the baffle 26 is changed to a conventional baffle 262 (see FIG. 5C), and a silicon single crystal thin film is vapor-phase epitaxially grown on the silicon single crystal substrate W in the same procedure. .
[0039]
First, the infrared heating lamp 11 (see FIG. 1) was energized, and after the temperature of the substrate W reached 1100 ° C., the natural oxide film on the surface of the substrate W was removed. Thereafter, while maintaining the temperature of the substrate W at 1100 ° C., hydrogen gas containing trichlorosilane gas as a source gas is supplied into the reaction vessel from the inner gas introduction port 21A and the outer gas introduction port 21B, and the silicon W is supplied onto the substrate W. Crystal thin films were grown by vapor phase epitaxy. In addition, the total supply flow rate of the source gas at the inner gas inlet 21A and the outer gas inlet 21B was fixed at 50 liters / minute as a value in the standard state. In addition, the supply flow rate ratio between the inner gas inlet 21A and the outer gas inlet 21B is changed variously to grow a silicon single crystal thin film, and the one having the optimum film thickness distribution is selected. The silicon single crystal thin film was grown while monitoring the film thickness with a target thickness of 6 μm.
[0040]
Next, the film thickness distribution profile in the diameter direction of the obtained substrate with a thin film, that is, a silicon epitaxial wafer was measured by the FT-IR method and plotted on a graph. FIG. 8A shows the measurement result for the silicon epitaxial produced by the vapor phase growth apparatus 1 of the present invention, and FIG. 8B shows the measurement result for the silicon epitaxial wafer produced by the conventional vapor phase growth apparatus. It is.
[0041]
The silicon epitaxial wafer produced by the vapor phase growth apparatus 1 according to the present invention showed a more uniform film thickness distribution than the silicon epitaxial wafer produced by the conventional vapor phase growth apparatus. Further, assuming that the maximum film thickness value of the silicon single crystal thin film is tmax and the minimum film thickness value is tmin, the value defined by 100 × (tmax−tmin) / (tmax + tmin) is the film thickness distribution (± %), A value of ± 0.5 (%) was derived from the profile of FIG. On the other hand, the silicon epitaxial wafer produced by the conventional vapor phase growth apparatus was ± 1.5 (%). In this experiment, a silicon single crystal substrate having a diameter of 200 mm was used, but it is needless to say that the same effect can be obtained for a substrate having a diameter of 300 mm.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an example of a vapor phase growth apparatus of the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of the vapor phase growth apparatus of the present invention.
FIG. 3 is a plan view of the vapor phase growth apparatus of the present invention.
FIG. 4 is an exploded perspective view showing a main part of the vapor phase growth apparatus of the present invention with a part cut away.
FIG. 5 is an enlarged front view of several baffles.
FIG. 6 Gas flow G ₁ The conceptual diagram explaining how to flow.
FIG. 7 is a contour map showing a growth rate distribution obtained from a computer simulation.
FIG. 8 is a graph showing the film thickness distribution of a silicon single crystal thin film.
[Explanation of symbols]
1 Vapor growth equipment
2 Reaction vessel body
5 Internal space
12 Susceptor
12a Top surface of susceptor
21 Gas inlet
23 Embankment member
23a Upper surface of the bank member
24R, 24L Gas guide member
24T inside guideway
24S outside guideway
26,261 baffle
26a Main distribution hole
26b Rectification hole
31 First end
32 Second end
33 prop
34R, 34L Gas guide member side partition plate
36 Gas outlet
W substrate
G Raw material gas
O rotation axis
HSL horizontal reference line
WL width direction
α Reference plane (plane including horizontal reference line and rotation axis)

Claims (5)

A vapor phase growth apparatus for vapor phase growing a silicon single crystal thin film on a main surface of a silicon single crystal substrate,
A reaction vessel body having a gas inlet formed on the first end side in the horizontal direction and a gas outlet formed on the second end side, and a raw material gas for forming a silicon single crystal thin film is the gas. After the source gas flows along the main surface of the silicon single crystal substrate, which is introduced into the reaction vessel body from the introduction port and is rotated and held substantially horizontally in the internal space of the reaction vessel body, the gas Configured to be discharged from the outlet,
The silicon single crystal substrate is disposed on a disk-shaped susceptor that is rotationally driven in the internal space, and the bank member is disposed in a positional relationship that surrounds the susceptor and that the upper surface coincides with the upper surface of the susceptor. And
Further, the gas introduction port opens in a shape facing the outer peripheral surface of the bank member, and after the raw material gas from the gas inlet hits the outer peripheral surface of the bank member and rides on the upper surface side, Configured to flow along the main surface of the silicon single crystal substrate,
In the vapor phase growth apparatus in which a baffle in which a gas flow hole is formed is disposed between the gas inlet and the bank member,
The gas flow hole includes a plurality of main flow holes and a flow straightening hole having a smaller opening area than the main flow holes ,
A virtual center line along the flow direction of the source gas from the first end of the reaction vessel main body to the second end perpendicular to the rotation axis of the susceptor is defined as a horizontal reference line, and the horizontal reference When the direction perpendicular to both the line and the rotation axis is the width direction,
The main flow hole and the rectifying hole are formed side by side in the width direction so as to be symmetric with respect to a plane including the horizontal reference line and the rotation axis.
The reaction vessel main body has a column that divides the flow of the source gas in the width direction to the left and right with respect to the horizontal reference line, upstream of the bank member in the flow direction of the source gas and downstream of the baffle. In preparation for
The rectifying hole is formed on the outer side in the width direction with respect to the main circulation hole closest to the support column . The gas guide member is disposed across the support column and guides the source gas from the gas inlet toward the bank member, and the inside of the gas guide member further flows the source gas in the width direction. It is separated into an inner guide path and an outer guide path by a partitioning plate on the gas guide member side to partition,
The vapor phase growth apparatus according to claim 1, wherein the rectifying hole is provided corresponding to the inner guide path . 3. The vapor phase growth apparatus according to claim 1, wherein the rectifying hole is provided outside the main circulation hole located closest to the support column . A vapor phase growth apparatus for vapor phase growing a silicon single crystal thin film on a main surface of a silicon single crystal substrate,
A reaction vessel body having a gas inlet formed on the first end side in the horizontal direction and a gas outlet formed on the second end side, and a raw material gas for forming a silicon single crystal thin film is the gas. After the source gas flows along the main surface of the silicon single crystal substrate, which is introduced into the reaction vessel body from the introduction port and is rotated and held substantially horizontally in the internal space of the reaction vessel body, the gas Configured to be discharged from the outlet,
The silicon single crystal substrate is disposed on a disk-shaped susceptor that is rotationally driven in the internal space, and the bank member is disposed in a positional relationship that surrounds the susceptor and that the upper surface coincides with the upper surface of the susceptor. And
Further, the gas introduction port opens in a shape facing the outer peripheral surface of the bank member, and after the raw material gas from the gas inlet hits the outer peripheral surface of the bank member and rides on the upper surface side, Configured to flow along the main surface of the silicon single crystal substrate,
In the vapor phase growth apparatus in which a baffle in which a gas flow hole is formed is disposed between the gas inlet and the bank member ,
When a virtual center line along the flow direction of the source gas from the first end of the reaction vessel main body to the second end perpendicular to the rotation axis of the susceptor is a horizontal reference line, The reaction vessel main body has a support column that divides the flow of the source gas in the width direction to the left and right with respect to the horizontal reference line, upstream of the bank member and in the downstream of the baffle. Prepared,
The gas flow hole includes a plurality of main flow holes and a pair of rectification holes having an opening area smaller than that of the main flow holes, and the plurality of main flow holes and the pair of rectification holes are the horizontal reference. Formed side by side in the width direction so as to be symmetric with respect to a plane including the line and the rotation axis,
The pair of flow straightening holes is formed on the outside of the main circulation hole closest to the support column among the plurality of main circulation holes . 5. The silicon single crystal substrate is disposed in the reaction vessel of the vapor phase growth apparatus according to claim 1, and the raw material gas is circulated in the reaction vessel so as to be on the silicon single crystal substrate. An epitaxial wafer is obtained by vapor phase epitaxially growing the silicon single crystal thin film.

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