JP5301965B2 - Vapor growth equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor deposition apparatus which suppresses variation in the oscillation wavelength of a nitride base compound semiconductor element to be manufactured and manufactures a plurality of nitride base compound semiconductor elements having high yield from one semiconductor substrate. <P>SOLUTION: The vapor deposition apparatus 101 includes: a substrate holder 108 holding a semiconductor substrate 107 placed thereon; and a heater heating the semiconductor substrate 107 from below the substrate holder 109, wherein a face of the substrate holder 108, the face being confronted with the semiconductor substrate 107, is formed so as to have almost the same shape as that of the warpage of the face of the semiconductor substrate 107, the face being confronted with the substrate holder 108. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vapor phase growth apparatus, and more particularly, to a vapor phase growth apparatus provided with a substrate holder for holding a substrate.

  Nitride-based III-V group compound semiconductor crystals represented by GaN, AlN, InN, and mixed crystals thereof have a direct band gap and are expected to be used for semiconductor light emitting devices. In particular, a mixed crystal of InGaN can emit light having a wavelength ranging from ultraviolet light to red light. For this reason, light-emitting diode elements and blue-violet laser diode elements having wavelengths from ultraviolet light to green light using AlGaN mixed crystals have already been put into practical use. These semiconductor light-emitting elements are widely considered to be applied to high-density optical discs, full-color displays, and environmental / medical fields.

  Further, as a method for manufacturing a semiconductor light emitting device such as a light emitting diode device or a laser diode device, this MOCVD method in which a metal organic chemical vapor deposition (hereinafter referred to as MOCVD method) is generally used. A vapor phase growth apparatus that performs thin film growth of a compound semiconductor by using a metal is called an MOCVD apparatus.

  FIG. 21 is a cross-sectional view illustrating the configuration of a reaction chamber of a conventional typical MOCVD apparatus. In the conventional MOCVD apparatus 501, a tubular flow channel 503 is provided in the reaction chamber 502 in order to efficiently guide the source gas onto the substrate. Both ends of the flow channel 503 are opened toward the outside of the reaction chamber 502, and the openings form gas supply ports 517 and gas discharge ports 518 at both ends of the flow channel 503. In addition, an opening is formed at a substantially central portion in the longitudinal direction of the flow channel 503 so that the surface of the semiconductor substrate 507 placed on the substrate holder 508 faces the inside of the flow channel 503. Then, the raw material gas containing the film forming raw material component introduced into the flow channel 503 from the gas supply port 517 comes into contact with the surface of the semiconductor substrate 507 to react and form a film, and a compound semiconductor thin film is formed on the surface of the semiconductor substrate 507. The The source gas that has not contributed to the reaction on the surface of the semiconductor substrate 507 is discharged from the gas discharge port 518 to the outside of the reaction chamber 502.

  At this time, a heater 509 for heating the semiconductor substrate 507 is provided below the substrate holder 508 that holds the semiconductor substrate 507 so that the semiconductor substrate 507 is heated so as to be in an optimum reaction state for crystal growth. it can. A soaking plate 515 is usually provided between the heater 509 and the substrate holder 508. The soaking plate 515 conducts heat from the heater 509 uniformly to the substrate holder 508. Note that the heat equalizing plate 515 can be omitted if the heat from the heater 509 can be directly conducted uniformly over the entire area of the semiconductor substrate 507.

  However, the MOCVD apparatus 501 has a problem in that the crystallinity and layer thickness of the compound semiconductor thin film grown on the semiconductor substrate 507 are not uniform over the entire semiconductor substrate 507, resulting in a decrease in manufacturing yield.

  In response to such a problem, the present inventor, when a source gas containing a film forming raw material component contacts and reacts on the surface of the semiconductor substrate 507, the surface temperature of the semiconductor substrate 507 is not within the same substrate surface. Due to the uniformity, the crystallinity and layer thickness of the growing compound semiconductor thin film become non-uniform in the plane of the semiconductor substrate 507, and the oscillation wavelength of the nitride-based compound semiconductor device produced varies. I found out.

  Further, the reason why the surface temperature of the semiconductor substrate 507 is non-uniform in the surface is that the warped shape of the semiconductor substrate 507 differs for each semiconductor substrate 507, and the degree of contact between the semiconductor substrate 507 and the substrate holder 508 is different. .

  For example, in the GaN substrate disclosed in Patent Document 1 by the present inventor, in order to solve the problem that the surface flatness of the grown compound semiconductor thin film deteriorates, a digging region composed of stripe-shaped grooves is formed on the semiconductor substrate 507. Then, a compound semiconductor thin film is grown on the surface of the semiconductor substrate 507 to form a nitride compound semiconductor element. However, the semiconductor substrate 507 on which the digging region composed of stripe-shaped grooves is formed has different warp shapes before and after the compound semiconductor thin film is grown.

  FIG. 22 is a histogram showing the amount of warpage of the semiconductor substrate 507 before the compound semiconductor thin film is formed on the GaN substrate disclosed in Patent Document 1 by the present inventor. Here, the GaN substrate having a negative curvature at the center shown in FIG. 22 is a concave substrate that is warped in the direction opposite to the direction in which the compound semiconductor is deposited. When the substrate is placed on the horizontal plate, the warped shape is such that the end of the GaN substrate contacts and the center of the substrate is lifted. At this time, the distance between the horizontal plate and the central portion of the substrate that is lifted is defined as the amount of warpage. As shown in FIG. 22, the semiconductor substrate 507 before the compound semiconductor thin film is formed has a warp in the vicinity of the center thereof, and the warp direction and the warp amount vary greatly from substrate to substrate. For this reason, when the semiconductor substrate 507 having such a shape is placed on the substrate holder 508 with the film formation surface facing upward, the heat conducted from the heater 509 to the substrate holder 508 enters the substrate surface of the semiconductor substrate 507. Heat conduction was unevenly performed, and the surface temperature of the semiconductor substrate 507 was uneven within the substrate surface.

  FIG. 23 is a top view of a conventional semiconductor substrate, and FIG. 24 is a diagram showing the amount of warpage before thin film formation is performed on the XX ′ line and the YY ′ line of the semiconductor substrate shown in FIG. FIG. 25 is a diagram showing a warpage amount after thin film formation is performed on the XX ′ line and the YY ′ line of the semiconductor substrate 507 shown in FIG. Here, a plurality of digging regions are periodically formed in the Y direction at intervals of 350 μm by a method similar to the manufacturing method disclosed in Patent Document 1, and the digging region is turned off in the Y direction. The semiconductor substrate is processed to have an angle θa of −0.28 °, an off angle θb in the X direction of −0.03 °, an opening width of the digging region of 3 μm, and a depth of 3 μm. In addition, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate 507 at <11-20>, and the Y direction is a digging region formed on the semiconductor substrate 507 at <1-100>. The horizontal direction. The “digging area” means a recess processed into a stripe shape on the surface of the semiconductor substrate 507 disclosed in Patent Document 1. As shown in FIGS. 24 and 25, the semiconductor substrate 507 in which the digging region is formed before and after the thin film formation is deformed into a convex shape in the X direction and a concave shape in the Y direction, and the warpage of the substrate in the X and Y directions. There is a big difference in quantity. In particular, the warpage of the semiconductor substrate 507 in the X direction of the semiconductor substrate 507 is reversed before and after the thin film formation is performed.

  FIG. 26 is a top view of a substrate holder constituting a conventional vapor phase growth apparatus, FIG. 27 is a cross-sectional view taken along line XX ′ shown in FIG. 26, and FIG. 28 is shown in FIG. It is sectional drawing along line YY '. As shown in FIGS. 26 to 28, when the semiconductor substrate 507 deformed into a convex shape in the X direction and a concave shape in the Y direction shown in FIG. 25 is placed on the substrate holder 508, the semiconductor substrate 507 is convex in the X direction. Since the end of the semiconductor substrate 507 is in contact with the substrate holder 508 in the X direction, a gap is formed between the bottom surface of the semiconductor substrate 507 and the substrate mounting surface 508a of the substrate holder 508. Arise. For this reason, the semiconductor substrate 507 is formed by the heat conduction through the contact portion between the substrate holder 508 and the semiconductor substrate 507 and the radiant heat corresponding to the size of the gap between the substrate mounting surface 508a of the substrate holder 508 and the bottom surface of the semiconductor substrate 507. The surface of the semiconductor substrate 507 was heated unevenly within the surface, and the temperature of the surface of the semiconductor substrate 507 was uneven within the surface.

  Further, a plurality of nitride semiconductor laser elements are produced by dividing the plurality of semiconductor substrates 507 deformed into a convex shape in the X direction and a concave shape in the Y direction shown in FIGS. The in-plane distribution of the oscillation wavelength in the semiconductor substrate 507 before the element division is summarized in the graphs of FIGS. 29 shows the in-plane distribution of the oscillation wavelength along the line X-X ′ shown in FIG. 23, and FIG. 30 shows the in-plane distribution of the oscillation wavelength along the line Y-Y ′ shown in FIG. 23. As shown in the graphs of FIGS. 29 and 30, the wavelength deviation of the nitride-based semiconductor laser element has a variation of a maximum σ = 1.9 nm in the standard deviation σ, and the wavelength of each substrate has a maximum σ in the standard deviation σ. = There was a variation of 2.5 nm. In addition, when FIGS. 23 to 25 are compared with FIGS. 29 and 30, the gap between the substrate placement surface 508a of the substrate holder 508 and the semiconductor substrate 507 is large, and the distance between the substrate placement surface 508a and the semiconductor substrate 507 is large. It can be seen that in the nitride semiconductor laser element obtained from the part where the distance is long, the oscillation wavelength becomes longer according to the distance. For this reason, since the radiant heat from the substrate holder 508 is reduced at a portion where the distance between the semiconductor substrate 507 and the substrate mounting surface of the substrate holder 508 is increased, the surface temperature of the semiconductor substrate 507 is lowered. It is considered that the oscillation wavelength of the nitride semiconductor laser element obtained in this way has become longer, and nonuniformity of the entire distribution of the oscillation wavelength in the semiconductor substrate surface has occurred.

  Further, as another cause of the non-uniform surface temperature of the semiconductor substrate 507, the contact surface between the heater 514 and the substrate holder 508 or a soaking plate is caused by the problem of the manufacturing accuracy of the substrate holder 508 and the heater 514. For example, the degree of contact varies depending on the flatness and mirror surface of the contact surface between 515 and the substrate holder 508. When the processing accuracy of the contact surface between the substrate holder 508 and the heater 514 or the contact surface between the substrate holder 508 and the soaking plate 515 is poor and the flatness is uneven, the soaking plate 515 is provided for each heater 514. Every time, the degree of adhesion with the substrate holder 508 varies. As a result, variation occurs in the heat conduction to the substrate holder 508, the temperature distribution in the surface of the substrate holder 508 becomes non-uniform, and the amount of heat radiation to the semiconductor substrate 507 changes to change the in-plane of the semiconductor substrate 507. The temperature was uneven.

JP 2006-134926 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to suppress variation in the oscillation wavelength of a nitride-based compound semiconductor device to be manufactured, and to make a non-defective product from a single semiconductor substrate. It is an object of the present invention to provide a vapor phase growth apparatus capable of producing a plurality of nitride compound semiconductor elements having a high ratio.

  In order to achieve the above object, in the vapor phase growth apparatus according to the first configuration of the present invention, the source gas supply port, the source gas exhaust port, and the opening disposed between the source gas supply port and the source gas exhaust port A flow channel for flowing the source gas from the source gas supply port toward the source gas exhaust port, a substrate holder on which the substrate is placed facing the opening of the flow channel, and a lower portion of the substrate holder Provided with a heater for heating the substrate, and the substrate holder has at least one surface facing the substrate to be placed that is substantially the same as the shape of the substrate warp or in accordance with the shape of the substrate warp. It is characterized by having a stepped shape with the above steps.

  According to the first configuration, since the surface of the substrate holder that faces the substrate is formed to have substantially the same shape as the warp of the substrate, the distance between the facing substrate holder and the substrate is substantially the same in the substrate surface. Thereby, the radiant heat from the substrate holder conducts heat substantially uniformly within the substrate surface. Therefore, the surface temperature of the substrate can be made substantially uniform within the substrate surface, and the crystallinity of the compound semiconductor thin film that grows when the source gas containing the deposition source component contacts and reacts on the substrate surface to form a film. In addition, the layer thickness is made uniform over the entire substrate, and variations in the oscillation wavelength of the nitride-based compound semiconductor device to be produced can be suppressed.

  Further, the vapor phase growth apparatus according to the second configuration of the present invention is characterized in that a plurality of first protrusions for supporting the substrate are provided on a surface facing the substrate to be placed.

  According to the second configuration, even when the warpage shape of the substrate is different for each substrate, the substrate can be held so as not to come into contact with the substrate holder by supporting the substrate by the plurality of first convex portions. Thereby, it is possible to prevent the surface temperature of the substrate from becoming uneven in the substrate surface due to the difference in contact with the substrate holder for each substrate. In addition, when placing a substrate whose warped shape is deformed before and after thin film formation, the height of the first convex portion is set high enough to prevent the substrate and the substrate holder from contacting each other when the substrate is deformed. It is possible to prevent the substrate and the substrate holder from contacting each other before and after the thin film is formed. As a result, even when a substrate whose warping shape is deformed before and after thin film formation is placed on the substrate holder, the surface temperature of the substrate becomes non-uniform in the substrate plane due to the degree of contact between the substrate and the substrate holder. Can be prevented. In addition, a board | substrate can be hold | maintained by providing two 1st convex parts on a board | substrate holder, and a board | substrate can be hold | maintained more stably by providing three or more points. Here, the top of the first convex part comes into contact with the substrate when supporting the substrate, but from the viewpoint of the stability of holding the substrate, the top of the first convex part has a length of 5 mm or more when viewed in plan. It is preferable that it is comprised so that it may have 1 mm or more of width. Also, by providing a high height for the first convex portion, which is the distance from the substrate mounting surface of the substrate holder to the top of the first convex portion, the substrate and the substrate holder can be brought into contact before and after thin film formation is performed. The height of the first convex portion is set to 5 in consideration of heat conducted from the substrate holder to the substrate through the first convex portion and heatability due to heat radiation from the substrate holder to the substrate. It is preferable to provide the thickness of ˜5000 μm, and it is more preferable to provide the thickness of 50 to 2,000 μm. When a plurality of first protrusions are provided, the height of each first protrusion does not necessarily have to be equal, and the height of each first protrusion may be changed according to the shape of the warp of the substrate.

  The vapor phase growth apparatus according to the third configuration of the present invention further includes a soaking plate disposed between the substrate holder and the heater, and the soaking plate has a surface facing the substrate holder, It is characterized in that it is substantially the same as the shape of the surface facing the soaking plate, or is stepped with at least one step.

  According to the third configuration, the shape of the surface of the soaking plate disposed between the substrate holder and the heater is substantially the same as the shape of the surface of the substrate holder facing the soaking plate. The distance between the soaking plates facing each other and the substrate holder is substantially the same in the plane. As a result, the radiant heat from the heat equalizing plate or the heat from the contact surface conducts heat to the substrate holder substantially uniformly within the surface, and the surface of the substrate holder facing the substrate is the surface of the heat equalizing plate facing the substrate holder. It can be heated to a temperature distribution according to the shape of the warp. Therefore, the substrate can be heated so that the surface temperature is substantially uniform in the substrate plane, based on the relationship between the shape of the surface of the soaking plate facing the substrate holder and the distance between the substrate holder and the substrate in the substrate plane. Nitride-based compounds produced by uniformizing the crystallinity and layer thickness of the growing compound semiconductor thin film over the entire area when the source gas containing the film-forming raw material components contacts and reacts and forms a film on the substrate surface. Variations in the oscillation wavelength of the semiconductor element can be suppressed.

  In the vapor phase growth apparatus according to the fourth configuration of the present invention, the surface of the soaking plate facing the substrate holder is substantially the same as the shape of the warp of the substrate, or at least 1 according to the shape of the warp of the substrate. It is characterized by being formed in a staircase shape having two or more steps.

  According to the fourth configuration, when the substrate is placed on the substrate holder, the surface of the substrate facing the substrate holder is substantially the same as the shape of the surface of the heat equalizing plate facing the substrate holder. The distance between the substrate and the substrate is substantially the same in the substrate surface via the substrate holder. Thereby, heat can be conducted from the soaking plate to the substrate substantially uniformly in the substrate surface via the substrate holder, and the surface temperature of the substrate can be made substantially uniform in the substrate surface. Therefore, the surface temperature of the substrate can be made substantially uniform within the substrate surface, and the crystallinity of the compound semiconductor thin film that grows when the source gas containing the deposition source component contacts and reacts on the substrate surface to form a film. In addition, the layer thickness is made uniform over the entire substrate, and variations in the oscillation wavelength of the nitride-based compound semiconductor device to be produced can be suppressed.

  In the vapor phase growth apparatus according to the fifth configuration of the present invention, the soaking plate is not in contact with the substrate holder on the surface.

  According to the fifth configuration, since the soaking plate and the substrate holder are not in contact with each other, the substrate holder can be heated by radiant heat from the soaking plate. For this reason, the heat from the soaking plate can be uniformly conducted in the plane to the substrate holder. This prevents the in-plane temperature of the substrate holder from becoming uneven due to the difference in contact between the substrate holder and the soaking plate, and the substrate holder is heated substantially uniformly by the radiant heat from the soaking plate. be able to.

  Further, the vapor phase growth apparatus according to the sixth configuration of the present invention is characterized in that a plurality of second convex portions in contact with the substrate holder are provided on a surface facing the substrate holder.

  According to the sixth configuration, even if the degree of contact differs depending on the flatness or mirror surface of the contact surface between the substrate holder and the heat equalizing plate due to the problem of manufacturing accuracy of the substrate holder or the heat equalizing plate, the substrate holder is formed by the second convex portion. Can be supported so as not to come into contact with the soaking plate. This prevents the in-plane temperature of the substrate holder from becoming uneven due to the difference in contact between the substrate holder and the soaking plate, and the substrate holder is heated substantially uniformly by the radiant heat from the soaking plate. be able to. In addition, when providing two or more 2nd convex parts, even if it changes the height of each 1st convex part according to the shape of a soaking plate and a substrate holder, the height of each 2nd convex part does not necessarily need to be equal equally. Good.

  In the first to sixth configurations, instead of processing the substrate holder or the heat equalizing plate so as to be substantially the same as the shape of the warp of the substrate, at least one or more in accordance with the shape of the warp of the substrate. Even when the substrate holder or the heat equalizing plate is processed into a stepped shape having steps, the same effects as those of the first to sixth configurations can be obtained. In this case, as the number of steps (steps) is increased, the surface of the processed substrate holder or the soaking plate approximates the shape of the warp of the substrate and becomes substantially the same. For example, the surface of the substrate holder that faces the substrate is divided into a plurality of surfaces in a lattice shape, and a step (step) is provided between adjacent divided surfaces so that the distance between each divided surface and the facing substrate is substantially the same. By processing in a staircase pattern, the substrate can be heated so that the in-plane temperature of the substrate becomes uniform due to the radiant heat from each divided surface. Thereby, the surface temperature of the substrate can be heated more uniformly in the substrate surface, and when the source gas containing the film forming raw material component contacts and reacts on the substrate surface, the compound semiconductor thin film that grows The crystallinity and the layer thickness are uniform over the entire substrate, and variations in the oscillation wavelength of the nitride-based compound semiconductor device to be produced can be suppressed. Further, the shape of the step (step) can be processed into an arbitrary shape, and the shape of the dividing surface is preferably a square shape or a circular shape. It is also possible to process a plurality of steps by combining square and circular surfaces. Moreover, each division surface may be inclined according to the shape of the warp of the opposing substrate. In addition, the dividing surface is not limited to the case of dividing into a plurality of grids, and only the surface facing the center of the substrate is recessed in a stepped shape with one step in a square shape, or the dividing surface is formed by projecting. Also good.

  Since the vapor phase growth apparatus of the present invention is provided with means for reducing temperature variations in the substrate surface due to variations in the amount of warpage of the substrate, the crystallinity and layer thickness of the thin film, particularly the substrate surface of the emission wavelength of the active layer It is possible to ensure uniformity in the inside.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. In the following embodiment, an example in which the present invention is applied to an MOCVD apparatus which is an example of a vapor phase growth apparatus will be described.

(First embodiment)
FIG. 1 is a cross-sectional view of a reaction chamber of a vapor phase growth apparatus according to a first embodiment of the present invention, and FIG. 2 is a substrate holder constituting the vapor phase growth apparatus according to the first embodiment of the present invention shown in FIG. 3 is a sectional view taken along line XX ′ shown in FIG. 2, and FIG. 4 is a sectional view taken along line YY ′ shown in FIG. Here, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate at <11-20>, and the Y direction is relative to the digging region formed on the semiconductor substrate at <1-100>. Horizontal direction. First, the MOCVD apparatus 101 according to the first embodiment of the present invention will be described with reference to FIGS.

  In the MOCVD apparatus 101 of the first embodiment, as shown in FIG. 1, a tubular flow channel 103 is provided in a reaction chamber 102 in order to efficiently introduce a source gas onto a substrate, and gas is supplied at both ends of the flow channel 103. A port 117 and a gas discharge port 118 are formed. In addition, an opening is formed at a substantially central portion in the longitudinal direction of the flow channel 103 so that the surface of the semiconductor substrate 107 placed on the substrate holder 108 faces the inside of the flow channel 103. A substrate rotation mechanism 111 is installed, and the substrate rotation mechanism 111 rotates the semiconductor substrate 107 together with the substrate holder 108 by the rotation of the substrate rotation mechanism 111. Thereby, by forming a thin film on the surface of the semiconductor substrate 107 while rotating the substrate rotating mechanism 111, the crystallinity and the layer thickness of the compound semiconductor thin film formed over the entire area of the semiconductor substrate 107 can be made uniform. In addition, a heater 109 for heating the semiconductor substrate 107 is provided below the substrate holder 108 that holds the semiconductor substrate 107, and the semiconductor substrate 107 can be heated so as to be in an optimal reaction state for crystal growth. . The reaction chamber 102 is provided with an automatic loading / unloading machine (not shown) for automatically loading / unloading the semiconductor substrate 107 and the substrate holder 108.

  As shown in FIG. 2, four first convex portions 105 are provided on the upper surface of the substrate holder 108 at the same circumferential angle with respect to the rotation center of the substrate holder 108, and these first convex portions 105 are provided on the semiconductor substrate. 107 is supported in a floating state. As a result, it is possible to prevent the surface temperature of the semiconductor substrate 107 from becoming uneven in the substrate plane due to the difference in contact between the semiconductor substrate 107 and the substrate holder 108. In this embodiment, the semiconductor substrate 107 in which the digging region is formed in the Y direction is supported by the two first convex portions 105 in the Y direction, and the digging region is formed by the remaining two first convex portions 105. And support in the X direction, which is the vertical direction. Note that the positional relationship between the first protrusion 105 and the extending direction of the digging region formed in the semiconductor substrate 107 is not limited to the above case, and can be changed according to the warp shape of the semiconductor substrate 107. For example, FIG. 5 is a top view of the substrate holder constituting the vapor phase growth apparatus according to the first embodiment of the present invention shown in FIG. 1, but as shown in FIG. Even if each first protrusion 105 is rotated and placed on the substrate holder 108 so as to have an angle of 45 ° with respect to the two first protrusions 105 arranged in a line (direction), the semiconductor substrate The in-plane temperature 107 can be heated uniformly. The first protrusion 105 can hold the semiconductor substrate 107 by providing two points on the substrate holder 108, and can hold the semiconductor substrate 107 more stably by providing three or more points. Here, the top of the first protrusion 105 abuts the semiconductor substrate 107 when supporting the semiconductor substrate 107. From the viewpoint of the stability of holding the semiconductor substrate 107, the top of the first protrusion 105 is viewed in a plan view. In this case, it is preferable to have a length of 5 mm or more and a width of 1 mm or more.

  Further, as shown in FIGS. 3 and 4, the first convex portion 105 is sufficiently high so that the substrate holder 108 and the semiconductor substrate 107 do not come into contact with each other when the semiconductor substrate 107 is deformed by thin film formation. Specifically, the first convex portion 105 has a height of about 100 μm. Thereby, it is possible to prevent the semiconductor substrate 107 and the substrate holder 108 from contacting each other before and after the thin film is formed. Therefore, even when the semiconductor substrate 107 whose warping shape is deformed before and after the thin film formation is placed on the substrate holder 108, the surface temperature of the semiconductor substrate 107 depends on the degree of contact between the semiconductor substrate 107 and the substrate holder 108. It is possible to prevent non-uniformity in the plane. The semiconductor substrate 107 and the substrate before and after the thin film formation is performed by providing a high height for the first convex portion 105, which is a distance from the substrate placement surface 108 a of the substrate holder 108 to the top portion of the first convex portion 105. Although it is possible to prevent the holder 108 from coming into contact, the heat conduction from the substrate holder 108 to the semiconductor substrate 107 through the first convex portion 105 and the heat radiation due to the heat radiation from the substrate holder 108 to the semiconductor substrate 107 are improved. Considering this, the height of the first convex portion 105 is preferably provided so as to be 5 to 5000 μm, and more preferably provided so as to be 50 to 2000 μm.

  Further, as shown in FIGS. 3 and 4, the substrate mounting surface 108a of the substrate holder 108 facing the semiconductor substrate 107 is warped of the surface of the semiconductor substrate 107 facing the substrate holder 108 after the thin film is formed. In order to make it substantially the same shape as the above, it is processed into a shape that is 0 μm in the X direction and 40 μm in the Y direction. By forming the substrate mounting surface 108a in such a shape, when the semiconductor substrate 107 before thin film formation is placed on the substrate holder 108a, the distance between the opposing substrate holder 108 and the semiconductor substrate 107 is the semiconductor Although the substrate 107 is not uniform within the substrate surface, the distance between the opposing substrate holder 108 and the semiconductor substrate 107 after the thin film is formed and the semiconductor substrate 107 is deformed is substantially uniform within the substrate surface of the semiconductor substrate 107. Become. Thereby, after the substrate is deformed, the radiant heat from the substrate holder 108 is thermally conducted to the semiconductor substrate 107 substantially uniformly in the substrate surface, and the surface temperature of the semiconductor substrate 107 can be heated substantially uniformly in the surface. Since the warpage direction and the warpage amount of the semiconductor substrate 107 vary greatly from one substrate to another, the shape of the warpage of the substrate mounting surface 108a is determined from the maximum value of the assumed substrate warpage amount. The in-plane distribution of the surface temperature of the semiconductor substrate 107 due to variations in the amount of warpage can be prevented.

  Instead of processing the substrate mounting surface 108a so as to be substantially the same as the warp shape of the semiconductor substrate 107, a stepped shape having at least one step according to the warp shape of the semiconductor substrate 107 is provided. The same effect can be obtained even when the substrate mounting surface 108a is processed. In this case, as the number of steps (steps) increases, the processed substrate mounting surface 108a approximates the warped shape of the semiconductor substrate 107 and becomes substantially the same. For example, the substrate mounting surface 108a is divided into a plurality of surfaces in a grid pattern, and steps are provided on adjacent divided surfaces so that the distances between the divided surfaces and the semiconductor substrate 107 facing each other are substantially the same. By processing into the shape, the semiconductor substrate 107 can be heated so that the in-plane temperature of the substrate becomes uniform due to the radiant heat from each divided surface. Further, the shape of the step (step) can be processed into an arbitrary shape, and the shape of the dividing surface is preferably a square shape or a circular shape. It is also possible to process a plurality of steps by combining square and circular surfaces. Moreover, each division surface may be inclined according to the shape of the warp of the semiconductor substrate 107 facing each other. In addition, the dividing surface is not limited to the case of dividing into a plurality of grids, and only the surface facing the center of the substrate is recessed in a stepped shape with one step in a square shape, or the dividing surface is formed by projecting. Also good.

  Next, by a method similar to the manufacturing method disclosed in the patent document (Japanese Patent Laid-Open No. 2006-134926), a plurality of digging regions extending in the Y direction are periodically formed in the X direction with an interval of 350 μm, Semiconductor substrate 107 in which the Y-direction off-angle θa of the digging region is −0.28 °, the X-direction off-angle θb is −0.03 °, the opening width of the digging region is 3 μm, and the depth is 3 μm. Is mounted on the substrate holder 108 provided with the first convex portion 105 of the MOCVD apparatus 101 of the first embodiment, and a plurality of nitride semiconductor thin films are formed on the semiconductor substrate 107 under a predetermined growth condition by MOCVD. A nitride semiconductor growth layer was stacked. The semiconductor substrate 107 in which the digging region is formed is a substrate in which the warpage shape before and after the thin film formation is substantially the same as the warpage amount shown in FIGS.

  The semiconductor substrate 107 on which the nitride semiconductor growth layer is formed in this manner is divided into chips to produce a plurality of nitride semiconductor laser elements, and the oscillation wavelength plane of the semiconductor substrate 107 before the division is divided into each nitride semiconductor laser element. The internal distribution is summarized in the graphs of FIG. 6 and FIG. 6 shows the in-plane distribution of the oscillation wavelength along the line X-X ′ shown in FIG. 2, and FIG. 7 shows the in-plane distribution of the oscillation wavelength along the line Y-Y ′ shown in FIG. 2. Note that a specific method for stacking the nitride semiconductor growth layer and a specific method for manufacturing the nitride semiconductor laser element are implemented using a patent document (Japanese Patent Laid-Open No. 2006-134926) and a well-known technique. The description is omitted below. From the graphs of FIGS. 6 and 7, the standard deviation σ of the in-wavelength distribution of the nitride-based semiconductor laser element could be suppressed to a variation of σ = 0.59 nm. Accordingly, the measurement values shown in FIGS. 29 and 30 obtained by stacking the nitride semiconductor growth layers using the substrate holder in which the shape of the mounting surface is formed in a planar shape regardless of the shape of the warp of the semiconductor substrate; In comparison, the variation in each oscillation wavelength was kept low, and a very high production yield result could be obtained.

  8 to 10 are views for explaining a modification of the vapor phase growth apparatus according to the first embodiment, FIG. 8 is a top view of the substrate holder, and FIG. 9 is an XX shown in FIG. FIG. 10 is a cross-sectional view taken along the line YY ′ shown in FIG. 8. Here, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate at <11-20>, and the Y direction is relative to the digging region formed on the semiconductor substrate at <1-100>. Horizontal direction.

  In the modification of the first embodiment shown in FIGS. 8 to 10, a substrate holder 608 for mounting a semiconductor substrate 607 in which no digging region is formed is used, and the shape of the substrate mounting surface 608 a is a thin film. The processed semiconductor substrate 607 is processed so as to have substantially the same shape as the warp. For this reason, as shown in FIGS. 9 and 10, the semiconductor substrate 607 is processed to be recessed by 40 μm downward in the X direction and 40 μm downward in the Y direction. After the deformation of the semiconductor substrate 607, the distance between the semiconductor substrate 607 and the substrate holder 608 Are designed to be substantially the same in the substrate plane. The configuration other than the substrate holder 607 is the same as that of the vapor phase growth apparatus 101 of the first embodiment, and a description thereof will be omitted.

  Here, a semiconductor substrate 607 on which no digging region is formed is placed on the substrate holder 108, and a nitride semiconductor comprising a plurality of nitride semiconductor thin films on the semiconductor substrate 607 under a predetermined growth condition by MOCVD. When a plurality of nitride semiconductor laser elements are produced by stacking the growth layers and dividing the semiconductor substrate 607 on which the nitride semiconductor growth layer is formed into chips, a plurality of nitride semiconductor laser elements are formed on the semiconductor substrate 607 before the division of each nitride semiconductor laser element. The standard deviation σ of the oscillation wavelength in-plane distribution could be suppressed to a variation of σ = 0.55 nm.

  Further, when a plurality of nitride semiconductor laser elements are formed by laminating nitride semiconductor growth layers by a similar method using a substrate holder having a mounting surface formed in a flat shape, each nitride semiconductor laser element is obtained. The standard deviation σ of the oscillation wavelength in-plane distribution in the semiconductor substrate before the division was σ = 1.37 nm. That is, after the thin film is formed as described above, the substrate mounting surface 108a or the substrate mounting surface 608a is processed into a shape substantially the same as the warped shape of the deformed semiconductor substrate 107 or the semiconductor substrate 607. When a substrate is placed on a substrate holder and a source gas containing a film forming raw material component contacts and reacts on the surface of the semiconductor substrate, a thin film is formed and the semiconductor substrate is deformed. The distance from the semiconductor substrate is substantially uniform within the substrate surface of the semiconductor substrate. Thereby, after the deformation of the semiconductor substrate, the radiant heat from the substrate holder is thermally conducted to the semiconductor substrate substantially uniformly in the substrate surface, and can be heated so that the surface temperature of the semiconductor substrate becomes substantially uniform in the surface. The crystallinity and layer thickness of the growing compound semiconductor thin film are made uniform over the entire semiconductor substrate, and variations in the oscillation wavelength of the nitride compound semiconductor element to be manufactured can be suppressed.

(Second Embodiment)
11 is a top view showing a substrate holder constituting the vapor phase growth apparatus according to the second embodiment, FIG. 12 is a cross-sectional view taken along line XX ′ shown in FIG. 11, and FIG. 12 is a cross-sectional view taken along line YY ′ shown in FIG. Here, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate at <11-20>, and the Y direction is relative to the digging region formed on the semiconductor substrate at <1-100>. Horizontal direction. A MOCVD apparatus 201 according to the second embodiment of the present invention will be described with reference to FIGS.

  In the MOCVD apparatus 201 of the second embodiment, as shown in FIGS. 11 to 13, a soaking plate 215 is disposed between the substrate holder 208 and the heater 209 in the reaction chamber, and the semiconductor substrate 207 of the substrate holder 208 and The substrate mounting surface 208a, which is an opposing surface, is formed in a flat shape. Further, the surface of the soaking plate 215 that faces the substrate holder 208 is substantially the same as the shape of the warp of the semiconductor substrate 207 after the thin film is formed. However, it is processed into a shape in which the X direction protrudes upward by 5 μm and the Y direction decreases downward by 40 μm. Further, the contact surface of the substrate holder 208 with the soaking plate 215 is processed according to the shape of the soaking plate 215. That is, the surface of the soaking plate 215 facing the substrate holder 208 is substantially the same as the shape of the surface of the substrate holder 208 facing the soaking plate 215, and the soaking plate 215 and the substrate holder 208 are in contact with each other. There is no gap between the soaking plate 215 and the substrate holder 208. For this reason, heat can be uniformly conducted from the soaking plate 215 to the substrate holder 208. Since the warpage direction and the warpage amount of the semiconductor substrate 207 vary greatly from one substrate to another, the shape of the substrate mounting surface 208a is determined by determining the shape of the substrate mounting surface 208a from the maximum value of the warpage amount in the X direction and the Y direction. It is possible to prevent the in-plane distribution of the surface temperature of the semiconductor substrate 207 from being uneven due to variations in the amount of warpage for each substrate 207.

  Instead of processing the surface of the soaking plate 215 facing the substrate holder 208 so as to be substantially the same as the shape of the warp of the semiconductor substrate 207 after the thin film is formed, the shape of the warp of the semiconductor substrate 207 is changed. The same effect can be obtained even when processing into a stepped shape having at least one step (step). In this case, as the number of steps (steps) increases, the surface of the processed heat equalizing plate 215 facing the substrate holder 208 approximates the shape of the warp of the semiconductor substrate 107 and becomes substantially the same. Further, the shape of the step (step) can be processed into an arbitrary shape, and the shape of the dividing surface is preferably a square shape or a circular shape. It is also possible to process a plurality of steps by combining square and circular surfaces. Moreover, each division surface may be inclined according to the shape of the warp of the semiconductor substrate 207 facing each other. In addition, the dividing surface is not limited to the case of dividing into a plurality of grids, and only the surface facing the center of the substrate is recessed in a stepped shape with one step in a square shape, or the dividing surface is formed by projecting. Also good.

  The surface of the substrate holder 208 on the side of the soaking plate 215 is processed according to the shape of the soaking plate 215, but the surface on the side of the semiconductor substrate 207 is formed in a flat shape. For this reason, the heat of the soaking plate 215 is conducted to the substrate holder 208 in contact, and the substrate mounting surface 208a can be heated with an in-plane temperature distribution corresponding to the warp shape of the soaking plate 215. At this time, the shape of the warp of the surface of the heat equalizing plate 215 facing the substrate holder 208 is substantially the same as the shape of the warp of the surface of the semiconductor substrate 207 facing the substrate holder 208, so that the substrate mounting surface 208 is the result. In particular, the semiconductor substrate 207 can be heated to a temperature distribution that can be heated substantially uniformly within the substrate surface by radiant heat.

  In addition, four first convex portions 205 are provided on the upper surface of the substrate holder 208 at equal circumferential angles with respect to the rotation center of the substrate holder 208, and these first convex portions 205 support the semiconductor substrate 207 in a floating state. As a result, it is possible to prevent the surface temperature of the semiconductor substrate 207 from becoming nonuniform within the substrate surface due to the difference in contact between the semiconductor substrate 207 and the substrate holder 208. At this time, the semiconductor substrate 207 in which the digging region is formed in the Y direction is supported by the two first convex portions 205 in the Y direction, and the remaining two first convex portions 205 are perpendicular to the digging region. Support in a certain X direction.

  Further, the first convex portion 205 has a sufficient height so that the substrate holder 208 and the semiconductor substrate 207 do not come into contact with each other when the semiconductor substrate 207 is deformed by thin film formation. Specifically, the first convex portion 205 has a height of about 200 μm.

  Further, since the radiant heat is inversely proportional to the square of the distance, the distance between the planar substrate placement surface 208a and the warped semiconductor substrate 207 is adjusted by adjusting the height of the first convex portion 205 to place the substrate placement. The influence of the heating distribution due to the radiant heat from the surface 208a to the semiconductor substrate 207 can be adjusted. Therefore, in this embodiment, when the substrate placement surface 208a is not heated with a temperature distribution corresponding to the distance in the substrate surface between the substrate placement surface 208a and the semiconductor substrate 207, the height of the first convex portion 205 is increased. The surface temperature of the semiconductor substrate 207 can be made substantially uniform in the substrate surface by adjusting the intensity of the heating distribution in the substrate surface due to the radiant heat from the substrate mounting surface 208a.

  Here, by a method similar to the manufacturing method disclosed in the patent document (Japanese Patent Laid-Open No. 2006-134926), a plurality of digging regions extending in the Y direction are periodically formed in the X direction with an interval of 350 μm, The semiconductor substrate 207 processed in such a manner that the off angle θa in the Y direction of the digging region is −0.33 °, the off angle θb in the X direction is −0.06 °, the opening width of the digging region is 3 μm, and the depth is 3 μm. Is mounted on the substrate holder 208 of the MOCVD apparatus 201 of the second embodiment, and the semiconductor substrate 207 is grown on the semiconductor substrate 207 by a MOCVD method under a predetermined growth condition. Layers were laminated.

  Thus, when the semiconductor substrate 207 on which the nitride semiconductor growth layer is formed is divided into chips to produce a plurality of nitride semiconductor laser elements, the oscillation wavelength in the semiconductor substrate 207 before the division of each nitride semiconductor laser element is obtained. The standard deviation σ of the in-plane distribution could be suppressed to a variation of σ = 0.65 nm.

  In addition, the surface of the soaking plate facing the substrate holder is formed in a planar shape, and nitride semiconductor growth is performed using the substrate holder in which the mounting surface is formed in a planar shape regardless of the warp shape of the semiconductor substrate. When a plurality of nitride semiconductor laser elements were fabricated by stacking layers, the standard deviation σ of the oscillation wavelength in-plane distribution in the semiconductor substrate before the division of each nitride semiconductor laser element had a variation of σ = 1.37 nm. . That is, as described above, after the thin film is formed, the surface of the heat equalizing plate 215 facing the substrate holder 208 is processed into the substantially same shape as the warped shape of the deformed semiconductor substrate 207, thereby forming the substrate holder 208. When the semiconductor substrate 207 is placed on the surface of the semiconductor substrate 207 and a source gas containing a film forming raw material component is brought into contact with the surface of the semiconductor substrate 207 to react and form a film, after the thin film is formed and the semiconductor substrate 207 is deformed, soaking is performed. The distance between the surface of the plate 215 facing the substrate holder 208 and the semiconductor substrate 207 is substantially uniform within the substrate surface of the semiconductor substrate 207. As a result, heat from the soaking plate 215 is thermally conducted substantially uniformly in the substrate surface of the semiconductor substrate 207 via the substrate holder 208, and the surface temperature of the semiconductor substrate 207 can be substantially uniform in the substrate surface. . Then, the surface temperature of the semiconductor substrate 207 can be heated so as to be substantially uniform within the substrate surface, and the crystallinity and layer thickness of the compound semiconductor thin film grown thereafter are uniformized over the entire area of the semiconductor substrate 207, and thus formed nitride Variation in the oscillation wavelength of the compound semiconductor device can be suppressed.

(Third embodiment)
FIG. 14 is a top view of the substrate holder constituting the vapor phase growth apparatus according to the third embodiment, FIG. 15 is a cross-sectional view taken along the line XX ′ shown in FIG. 14, and FIG. It is sectional drawing along the YY 'line shown in FIG. Here, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate at <11-20>, and the Y direction is relative to the digging region formed on the semiconductor substrate at <1-100>. Horizontal direction. With reference to FIGS. 14-16, the MOCVD apparatus 301 of 3rd Embodiment of this invention is demonstrated.

  In the MOCVD apparatus 301 of the third embodiment, as shown in FIGS. 14 to 16, a soaking plate 315 is disposed between the substrate holder 308 and the heater 309 in the reaction chamber, and the semiconductor substrate 307 of the substrate holder 308 The substrate mounting surface 308a, which is an opposing surface, has a convex shape of 5 μm upward in the X direction and a concave of 40 μm downward in the Y direction so as to have substantially the same shape as the warpage of the semiconductor substrate 307 after the thin film is formed. It is processed into a shape. Further, the surface of the soaking plate 315 facing the substrate holder 308 is also made substantially the same as the warped shape of the semiconductor substrate 307 after the thin film is formed, so that the X direction protrudes upward by 5 μm and the Y direction decreases downward. It is processed into a 40 μm concave shape. Further, the contact surface with the heat equalizing plate 315 is processed in accordance with the shape of the heat equalizing plate 315 so that the substrate holder 308 contacts the heat equalizing plate 315 with the surface. That is, the surface of the soaking plate 315 facing the substrate holder 308 is substantially the same as the shape of the surface of the substrate holder 308 facing the soaking plate 315, and the soaking plate 315 and the substrate holder 308 are in contact with each other. There is no gap between the soaking plate 315 and the substrate holder 308. For this reason, heat can be uniformly conducted from the soaking plate 315 to the substrate holder 308. Since the warpage direction and the warpage amount of the semiconductor substrate 307 vary greatly from one substrate to another, the shape of the substrate mounting surface 308a is determined by determining the shape of the substrate placement surface 308a from the maximum value of the warpage amount in the X direction and the Y direction. It is possible to prevent the in-plane distribution of the surface temperature of the semiconductor substrate 307 from being uneven due to variations in the amount of warpage for each substrate 307.

  The surface of the substrate holder 308 on the heat equalizing plate 315 side is processed according to the shape of the heat equalizing plate 315, and the surface on the semiconductor substrate 307 side is formed in substantially the same shape as the warped shape of the semiconductor substrate 307. . For this reason, the distance between the semiconductor substrate 307 and the substrate placement surface 308a and the distance between the substrate placement surface 308a and the surface of the soaking plate 315 facing the substrate holder 308 in the substrate surface are substantially uniform. As a result, the substrate placement surface 308a is heated substantially uniformly within the surface by heat conduction from the soaking plate 315, and the semiconductor substrate 307 is heated substantially uniformly within the substrate surface by radiant heat from the substrate placement surface 308a. Can do.

  Instead of processing the substrate mounting surface 308a and the surface of the soaking plate 315 facing the substrate holder 308 so as to be substantially the same as the warped shape of the semiconductor substrate 307 after thin film formation, the semiconductor substrate The same effect can be obtained when the substrate mounting surface 308a and the surface facing the substrate holder 308 of the soaking plate 315 are processed into a stepped shape having at least one step according to the shape of the warp 307. Can be obtained. In this case, as the number of steps is increased, the processed substrate mounting surface 308a and the surface of the heat equalizing plate 315 facing the substrate holder 308 approximate to the warped shape of the semiconductor substrate 307 and are substantially identical. To do. For example, the substrate mounting surface 308a and the surface of the heat equalizing plate 315 facing the substrate holder 308 are each divided into a plurality of surfaces in a lattice shape so that the distance between each divided surface and the semiconductor substrate 307 facing each other is substantially the same. By processing the adjacent divided surfaces in steps with steps, the substrate placement surface 308a is heated substantially uniformly within the surface by heat conduction from the heat equalizing plate 315, and the substrate placement surface. The semiconductor substrate 307 can be heated substantially uniformly within the substrate surface by the radiant heat from 308a. At this time, it is not necessary to process the substrate mounting surface 308a and the surface of the soaking plate 315 facing the substrate holder 308 in the same way, and the respective shapes are processed so that the semiconductor substrate 307 is heated substantially uniformly in the surface. You may do it.

  Further, four first convex portions 305 are provided on the upper surface of the substrate holder 308 at equal circumferential angles with respect to the rotation center of the substrate holder 308, and these first convex portions 305 support the semiconductor substrate 307 in a floating state. Accordingly, it is possible to prevent the surface temperature of the semiconductor substrate 307 from becoming nonuniform within the substrate surface due to the difference in contact between the semiconductor substrate 307 and the substrate holder 308. At this time, the semiconductor substrate 307 in which the digging region is formed in the Y direction is supported in the Y direction by the two first convex portions 305 and the remaining two first convex portions 305 are perpendicular to the digging region. Support in a certain X direction.

  Further, the first convex portion 305 is sufficiently high so that the substrate holder 308 and the semiconductor substrate 307 do not come into contact with each other when the semiconductor substrate 307 is deformed by thin film formation. Specifically, the first convex portion 305 has a height of about 100 μm.

  Although the radiant heat is inversely proportional to the square of the distance, the substrate placement surface 308a of the present embodiment is substantially the same as the shape of the warp of the semiconductor substrate 307. Therefore, depending on the distance between the substrate placement surface 308a and the semiconductor substrate 307. The intensity of the heating distribution due to radiant heat from the substrate mounting surface 308a to the semiconductor substrate 307 in the substrate plane does not change. For this reason, the height of the 1st convex part 305 can be adjusted low, and the semiconductor substrate 307 can be heated strongly by the radiant heat from the board | substrate mounting surface 308a in a board | substrate surface.

  Here, by a method similar to the manufacturing method disclosed in the patent document (Japanese Patent Laid-Open No. 2006-134926), a plurality of digging regions extending in the Y direction are periodically formed in the X direction with an interval of 350 μm, Semiconductor substrate 307 processed to have an off angle θa in the Y direction of −0.33 °, an off angle θb in the X direction of −0.06 °, an opening width of the dug region of 3 μm, and a depth of 3 μm. Is mounted on the substrate holder 308 of the MOCVD apparatus 301 of the third embodiment, and the semiconductor substrate 307 is grown on the semiconductor substrate 307 by a MOCVD method under a predetermined growth condition. Layers were laminated.

  Thus, when the semiconductor substrate 307 on which the nitride semiconductor growth layer is formed is divided into chips to produce a plurality of nitride semiconductor laser elements, the oscillation wavelength in the semiconductor substrate 307 before the division of each nitride semiconductor laser element is obtained. The standard deviation σ of the in-plane distribution could be suppressed to a variation of σ = 0.50 nm.

  In addition, the surface of the soaking plate facing the substrate holder is formed in a planar shape, and nitride semiconductor growth is performed using the substrate holder in which the mounting surface is formed in a planar shape regardless of the warp shape of the semiconductor substrate. When a plurality of nitride semiconductor laser elements were fabricated by stacking layers, the standard deviation σ of the oscillation wavelength in-plane distribution in the semiconductor substrate before the division of each nitride semiconductor laser element was a variation of σ = 1.37 nm. . That is, as described above, after the thin film is formed, the surface of the substrate mounting surface 308a and the surface of the heat equalizing plate 315 facing the substrate holder 308 are processed into substantially the same shape as the warped shape of the semiconductor substrate 307 to be deformed. As a result, when the semiconductor substrate 307 is placed on the substrate holder 308 and the source gas containing the deposition source component contacts and reacts on the surface of the semiconductor substrate 307, a thin film is formed and the semiconductor substrate 307 is After the deformation, the distance between the semiconductor substrate 307 and the substrate placement surface 308a in the substrate surface and the distance between the substrate placement surface 308a and the surface of the heat equalizing plate 315 facing the substrate holder 308 become substantially uniform. As a result, the substrate placement surface 308a is heated substantially uniformly within the surface by heat conduction from the soaking plate 315, and the semiconductor substrate 307 is heated substantially uniformly within the substrate surface by radiant heat from the substrate placement surface 308a. Thereafter, the crystallinity and layer thickness of the growing compound semiconductor thin film are made uniform over the entire substrate, and variations in the oscillation wavelength of the nitride-based compound semiconductor element to be manufactured can be suppressed.

(Fourth embodiment)
FIG. 17 is a top view of the substrate holder constituting the vapor phase growth apparatus according to the fourth embodiment, FIG. 18 is a cross-sectional view taken along the line XX ′ shown in FIG. 17, and FIG. It is sectional drawing along the YY 'line shown in FIG. Here, the X direction is a direction perpendicular to the digging region formed on the semiconductor substrate at <11-20>, and the Y direction is relative to the digging region formed on the semiconductor substrate at <1-100>. Horizontal direction. With reference to FIGS. 17-19, the MOCVD apparatus 301 of 4th Embodiment of this invention is demonstrated.

  In the MOCVD apparatus 401 of the fourth embodiment, as shown in FIGS. 17 to 19, a soaking plate 415 is disposed between the substrate holder 408 and the heater 409 in the reaction chamber, and the semiconductor substrate 407 of the substrate holder 408 The substrate mounting surface 408a, which is an opposing surface, has a convex shape that is 5 μm upward in the X direction and 40 μm downward in the Y direction so as to have substantially the same shape as the warpage of the semiconductor substrate 407 after the thin film is formed. It is processed into a shape. Further, the surface of the soaking plate 415 facing the substrate holder 408 is also made substantially the same as the warped shape of the semiconductor substrate 407 after the thin film is formed, so that the X direction protrudes upward by 5 μm and the Y direction decreases downward. It is processed into a 40 μm concave shape. Further, the surface of the substrate holder 408 facing the soaking plate 415 is processed according to the shape of the soaking plate 415, and four second convex portions 406 are provided on the soaking plate 415. The part 406 supports the substrate holder 408 in a floating state. That is, the surface of the heat soaking plate 415 facing the substrate holder 408 is substantially the same as the shape of the surface of the substrate holder 408 facing the heat soaking plate 415, and the heat soaking plate 415 and the substrate holder 408 are formed in such a shape. By molding, when the semiconductor substrate 407 is placed on the placement surface 408a of the substrate holder 408, the substrate holder 408 is heated by the radiant heat from the soaking plate 415, and the semiconductor substrate 407 is radiated from the substrate placement surface 408a. Can be heated. Since the warpage direction and the warpage amount of the semiconductor substrate 407 vary greatly from one substrate to another, the shape of the substrate mounting surface 408a is determined by determining the shape of the substrate placement surface 408a from the maximum value of the warpage amount in the X direction and the Y direction. It is possible to prevent the in-plane distribution of the surface temperature of the semiconductor substrate 407 from being uneven due to variations in the amount of warpage for each substrate 407.

  At this time, since both the substrate mounting surface 408a and the surface of the heat equalizing plate 415 facing the substrate holder 408 are formed in substantially the same shape as the warpage of the semiconductor substrate 407, the semiconductor substrate 407 and the substrate in the substrate surface are formed. The distance between the mounting surface 408a and the distance between the substrate mounting surface 408a and the surface of the soaking plate 415 facing the substrate holder 408 are substantially uniform. Further, since the second convex portion 406 provided on the soaking plate 415 supports the substrate holder 408 in a floating state, heat from the soaking plate 415 can be conducted to the substrate holder 408 by radiant heat. . For this reason, non-uniform heat conduction from the soaking plate 415 to the substrate holder 408 due to poor processing accuracy of the contact surface between the soaking plate 415 and the substrate holder 408 can be prevented. As described above, the substrate placement surface 408a is heated substantially uniformly within the surface by the radiant heat from the heat equalizing plate 415, and the semiconductor substrate 407 is heated substantially uniformly within the substrate surface by the radiant heat from the substrate placement surface 408a. Can do.

  Instead of processing the substrate mounting surface 408a and the surface of the soaking plate 415 facing the substrate holder 408 so as to be substantially the same as the warped shape of the semiconductor substrate 407 after thin film formation, the semiconductor substrate The same effect can be obtained even when the substrate mounting surface 408a and the surface facing the substrate holder 308 of the soaking plate 415 are processed into a stepped shape having at least one step according to the shape of the warp 407. Can be obtained. In this case, as the number of steps is increased, the processed substrate mounting surface 408a and the surface of the soaking plate 415 facing the substrate holder 408 approximate to the warped shape of the semiconductor substrate 407 and are substantially identical. To do. For example, the substrate mounting surface 408a and the surface of the soaking plate 415 facing the substrate holder 408 are each divided into a plurality of surfaces in a lattice shape so that the distance between each divided surface and the semiconductor substrate 407 facing each other is substantially the same. By processing the adjacent divided surfaces in steps with steps, the substrate placement surface 408a is heated substantially uniformly within the surface by heat conduction from the soaking plate 415, and the substrate placement surface. The semiconductor substrate 407 can be heated substantially uniformly in the substrate plane by the radiant heat from 408a. At this time, it is not necessary to process the substrate mounting surface 408a and the surface of the soaking plate 415 facing the substrate holder 408 in the same manner, and the respective shapes are processed so that the semiconductor substrate 407 is heated substantially uniformly within the surface. You may do it.

  Further, four first convex portions 405 are provided on the upper surface of the substrate holder 408 at equal circumferential angles with respect to the rotation center of the substrate holder 408, and these first convex portions 405 support the semiconductor substrate 407 in a floating state. As a result, it is possible to prevent the surface temperature of the semiconductor substrate 407 from becoming uneven in the substrate surface due to the difference in contact between the semiconductor substrate 407 and the substrate holder 408. At this time, the semiconductor substrate 407 in which the digging region is formed in the Y direction is supported in the Y direction by the two first convex portions 405, and the remaining two first convex portions 405 are perpendicular to the digging region. Support in a certain X direction.

  The first convex portion 405 is sufficiently high to prevent the substrate holder 408 and the semiconductor substrate 407 from contacting each other when the semiconductor substrate 407 is deformed by forming a thin film. Specifically, the first convex portion 405 has a height of about 100 μm.

  Although the radiant heat is inversely proportional to the square of the distance, the substrate mounting surface 408a of the present embodiment is substantially the same as the shape of the warp of the semiconductor substrate 407, and therefore depends on the distance between the substrate mounting surface 408a and the semiconductor substrate 407. The intensity of the heating distribution due to radiant heat from the substrate mounting surface 408a to the semiconductor substrate 407 in the substrate surface does not change. Therefore, the semiconductor substrate 407 can be strongly heated by radiant heat from the substrate mounting surface 408a in the substrate surface by adjusting the height of the first convex portion 405 to be low. Similarly to the first convex portion 405, the second convex portion 406 also has a substantially equal distance between the opposing surfaces of the heat equalizing plate 415 and the substrate holder 408, so that the height of the second convex portion 406 is high. The substrate holder 408 can be strongly heated by radiant heat from the soaking plate 415 in the substrate surface by adjusting the height to be low.

  Here, by a method similar to the manufacturing method disclosed in the patent document (Japanese Patent Laid-Open No. 2006-134926), a plurality of digging regions extending in the Y direction are periodically formed in the X direction with an interval of 350 μm, Semiconductor substrate 407 processed to have an off angle θa in the Y direction of −0.33 °, an off angle θb in the X direction of −0.06 °, an opening width of the dug region of 3 μm, and a depth of 3 μm. Is mounted on the substrate holder 408 provided with the first convex portion 405 of the MOCVD apparatus 401 of the fourth embodiment, and the semiconductor substrate 407 is nitrided on the semiconductor substrate 407 under a predetermined growth condition by MOCVD. A nitride semiconductor growth layer comprising a thin semiconductor film was laminated.

  The semiconductor substrate 407 thus formed with the nitride semiconductor growth layer is divided into chips to produce a plurality of nitride semiconductor laser elements, and the oscillation wavelength plane of the semiconductor substrate 407 before the division of each nitride semiconductor laser element The internal distribution is summarized in the graph of FIG. FIG. 20 shows the in-plane distribution of the oscillation wavelength along the line X-X ′ shown in FIG. 17. From the graph of FIG. 20, the standard deviation σ of the in-wavelength distribution of the nitride-based semiconductor laser device can be suppressed to a variation of σ = 0.1 nm, and the wavelength for each substrate is σ = 2.5 nm at the maximum with the standard deviation σ. There was a variation.

  In addition, the surface of the soaking plate facing the substrate holder is formed in a planar shape, and nitride semiconductor growth is performed using the substrate holder in which the mounting surface is formed in a planar shape regardless of the warp shape of the semiconductor substrate. A plurality of nitride semiconductor laser elements are formed by stacking layers, and the standard deviation σ of the in-plane distribution of the oscillation wavelength in the semiconductor substrate before the division of each nitride semiconductor laser element has a variation of σ = 1.37 nm. .

  That is, as described above, after the thin film is formed, the surface of the substrate mounting surface 408a and the soaking plate 415 facing the substrate holder 408 is processed into substantially the same shape as the warped shape of the semiconductor substrate 407 to be deformed. Thus, when the semiconductor substrate 407 is placed on the substrate holder 408 and the source gas containing the deposition source component contacts and reacts on the surface of the semiconductor substrate 407, a thin film is formed and the semiconductor substrate 407 is After the deformation, the distance between the semiconductor substrate 407 and the substrate placement surface 408a in the substrate surface and the distance between the substrate placement surface 408a and the surface of the heat equalizing plate 415 facing the substrate holder 408 become substantially uniform. Further, four second convex portions 406 are provided on the soaking plate 415, and these second convex portions 406 support the substrate holder 408 in a floating state. As a result, the substrate mounting surface 408a is heated substantially uniformly within the surface by the radiant heat from the soaking plate 315, and the semiconductor substrate 407 is heated approximately uniformly within the substrate surface by the radiant heat from the substrate mounting surface 408a. The crystallinity and layer thickness of the growing compound semiconductor thin film can be made uniform over the entire substrate, and variations in the oscillation wavelength of the nitride-based compound semiconductor device to be produced can be suppressed.

It is sectional drawing of the reaction chamber of the vapor phase growth apparatus by 1st Embodiment of this invention. It is a top view of the substrate holder which comprises the vapor phase growth apparatus by 1st Embodiment of this invention. FIG. 3 is a cross-sectional view taken along line X-X ′ in FIG. 2. FIG. 3 is a cross-sectional view taken along line Y-Y ′ of FIG. 2. It is a top view which shows the modification of the substrate holder which comprises the vapor phase growth apparatus by 1st Embodiment of this invention. 3 is an in-plane distribution of oscillation wavelengths along the line X-X ′ in FIG. 2. 3 is an in-plane distribution of oscillation wavelengths along the line Y-Y ′ in FIG. 2. It is a top view which shows the modification of the substrate holder which comprises the vapor phase growth apparatus by 1st Embodiment of this invention. It is sectional drawing along the X-X 'line | wire of FIG. FIG. 9 is a cross-sectional view taken along line Y-Y ′ of FIG. 8. It is a top view of the substrate holder which comprises the vapor phase growth apparatus by 2nd Embodiment of this invention. It is sectional drawing along the X-X 'line | wire of FIG. FIG. 12 is a cross-sectional view taken along line Y-Y ′ of FIG. 11. It is a top view of the substrate holder which comprises the vapor phase growth apparatus by 3rd Embodiment of this invention. It is sectional drawing along the X-X 'line | wire of FIG. FIG. 15 is a cross-sectional view taken along line Y-Y ′ of FIG. 14. It is a top view of the substrate holder which comprises the vapor phase growth apparatus by 4th Embodiment of this invention. It is sectional drawing along the X-X 'line | wire of FIG. It is sectional drawing along the Y-Y 'line | wire of FIG. 18 is an in-plane distribution of oscillation wavelengths along the line X-X ′ in FIG. 17. It is sectional drawing of the reaction chamber of the conventional vapor phase growth apparatus. It is a histogram which shows the curvature amount of the semiconductor substrate before forming a compound semiconductor thin film. It is a top view of a semiconductor substrate. It is a figure which shows the curvature amount before thin film formation is performed in the X-X 'line | wire and Y-Y' line | wire of the semiconductor substrate shown in FIG. It is a figure which shows the curvature amount after thin film formation was performed in the X-X 'line | wire and Y-Y' line | wire of the semiconductor substrate 107 shown in FIG. It is a top view of the substrate holder which comprises the conventional vapor phase growth apparatus. FIG. 27 is a cross-sectional view taken along line X-X ′ of FIG. 26. FIG. 27 is a cross-sectional view taken along line Y-Y ′ of FIG. 26. 24 is an in-plane distribution of oscillation wavelengths along the line X-X ′ in FIG. 23. 24 is an in-plane distribution of oscillation wavelengths along the line Y-Y ′ in FIG. 23.

Explanation of symbols

101 501 MOCVD apparatus 102 502 Reaction chamber 103 503 Flow channel 105, 205, 305, 405, 505 First convex portion
406, 506 Second convex portion 107, 207, 307, 407, 507 Semiconductor substrate 108, 208, 308, 408, 508 Substrate holder 109 509 Heater 111 511 Substrate rotation mechanism 115, 215, 315, 415, 515 Soaking plate 117 517 Gas supply port 118 518 Gas exhaust port

Claims (4)

A raw material gas supply port, a raw material gas exhaust port, and an opening disposed between the raw material gas supply port and the raw material gas exhaust port, and the raw material from the raw material gas supply port toward the raw material gas exhaust port A flow channel for flowing gas;
A substrate holder on which a substrate is placed so as to face the opening of the flow channel;
A heater provided at a lower part of the substrate holder for heating the substrate,
Distributing a soaking plate between the substrate holder and the heater,
The vapor phase growth apparatus characterized in that the soaking plate has a surface facing the substrate holder formed in accordance with the shape of warping of the substrate after the thin film is formed .   The vapor phase growth apparatus according to claim 1, wherein the substrate holder has a plurality of first protrusions that support the substrate on a surface facing the substrate to be placed. 3. The vapor phase growth apparatus according to claim 1 , wherein a surface of the substrate holder that faces the soaking plate is formed in accordance with a warping shape of the soaking plate . 4. 4. The vapor phase growth apparatus according to claim 1, wherein the substrate holder and the soaking plate are arranged with a gap formed therebetween via a plurality of second convex portions . 5.

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