CVD reactor with temperature adjustable gas inlet region

Abstract

The CVD reactor is arranged in a reactor housing and has a susceptor (2) forming the floor of a process chamber (1), and a gas inlet member (3) with at least one gas inlet region (4, 4'), a heating device (6) arranged below the susceptor (2) for generating a temperature difference between the body (7) and the process chamber ceiling (15), a plurality of substrate carriers (12) positioned a short distance in the flow direction from the gas inlet member (3) and each for accommodating a substrate (14) to be coated, and a plurality of flow region plates (10) arranged between the gas inlet member (3) and the substrate carrier (12).

Description

[Technical field]

[0001] The invention relates to a CVD reactor having a susceptor arranged in a reactor housing and forming the floor of a process chamber, a gas inlet member with at least one gas inlet area, a heating device arranged below the susceptor for creating a temperature difference between the body and the ceiling of the process chamber, a number of substrate carriers located away from the gas inlet member in a flow direction and each for accommodating a substrate to be coated, and a number of flow field plates arranged between the gas inlet member and the substrate carrier, the flow field temperature of each surface of the flow field plates facing the process chamber being individually adjustable by selection or adjustment of a heat transfer medium, the heat transfer medium arranged immediately upstream in the flow direction of each of the multiple substrate carriers being individually adjustable independently of the adjacent heat transfer mediums.

[0002] The invention further relates to a method for depositing, in particular a doped layer, on a substrate in a CVD reactor, in which a process gas is supplied to a gas inlet member and enters a process chamber through a gas inlet region of the gas inlet member, the floor of which is formed by a susceptor, which is heated by a heating device arranged below the susceptor so as to create a temperature difference between the process chamber ceiling and the susceptor. The process gas flows in a flow direction towards a substrate supported on a substrate carrier and is pre-decomposed on the flow region plates in the flow region of the process chamber between the gas inlet member and the substrate carrier, the decomposition products forming a layer. The flow region temperature of the surface facing the process chamber of each flow region plate arranged immediately upstream in one flow direction of the substrate carrier is adjusted by selection or adjustment of a heat transfer medium arranged between the susceptor body and the flow region plate, respectively. [Background technology]

[0003] A typical CVD reactor and a typical method are described in US Pat. No. 5,999,336. Flow field plates are located between a gas inlet member and substrate carriers arranged on an arc around the gas inlet member, with each flow field plate adjacent to two substrate carriers. The flow field plates are supported on the body of a susceptor. A horizontal gap extends between the body and the flow field plate, into which a heat transfer gas can be supplied to affect the heat transfer from the susceptor heated by a heating device to the cooled process chamber ceiling by changing the thermal conductivity of the gas. The flow field temperature can be adjusted by this effect.

[0004] In the patent US 2005 / 0133991, a CVD reactor is described. The substrate is placed on a multi-part susceptor and coated with a semiconductor layer. For this purpose, a process gas consisting of organometallic III and V components is introduced into the process chamber via a gas inlet member. This occurs with the aid of a carrier gas, for example hydrogen. The susceptor is heated from below to a temperature between 500° C. and more than 1,000° C. The process chamber ceiling is actively cooled, so that a vertical temperature gradient is formed inside the susceptor. The temperature of the surface of the substrate carrier and the temperature of the surface of the flow field plate are determined by the permanent vertical heat flow from the heating device below the susceptor to the cooling device above the susceptor. The heat transfer properties between the body and the substrate carrier and / or the flow field plate are thus important for the surface temperature of the substrate carrier and the substrate supported on the substrate carrier as well as the surface temperature of the flow field. The flow field plate is arranged vertically spaced from the body. As a result, a horizontal gap is generated, which forms a heat transfer barrier. In the prior art, the surface temperature of the flow field plate depends on the vertical gap width of a presettable horizontal gap.

[0005] US Patent No. 5,999,333 describes an MOCVD reactor in which the thermal conductivity associated between the ceiling panel and the heat dissipation member differs locally, and in particular in the radial direction. According to this arrangement, a purge gas flows through a horizontal gap between the ceiling panel and the heat dissipation member. The purge gas may be formed from a mixture of gases with different thermal conductivity capabilities, which may be, for example, hydrogen and nitrogen.

[0006] In US Pat. No. 5,399,436 the influence of the flow region temperature and of the gas phase reactions within the flow region is described on the layer growth in a growth region adjacent to the flow region in the flow direction, in which the substrate is located.

[0007] US Pat. No. 5,399,433 and US Pat. No. 5,499,443 also describe a substrate holder provided with channels through which a gas phase heat transfer medium flows.

[0008] In patent document 7, an apparatus and method for controlling the surface temperature of a substrate in a process chamber is described, which is specifically designed to supply a heat transfer medium into a horizontal gap, which forms a gas cushion on which the substrate carrier rotates.

[0009] In particular, when depositing doped SiC layers, small variations in the flow region temperature have a substantial effect on dopant incorporation. As a result, in a deposition process in which a layer is simultaneously deposited on multiple substrates supported by substrate carriers, small deviations in the flow region temperature from the target value result in large differences in the dopant concentration in the deposited layer. Tolerances in the gas inlet regions of the gas inlet member and other components of the susceptor can result in flow region temperature differences in adjacent flow regions, which can cause layers deposited during the deposition process to have different dopant concentrations from one another. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] DE 10 2014 104 218 A1 [Patent Document 2] DE 103 23 085 A1 [Patent Document 3] DE 10 2010 000 554 A1 [Patent Document 4] DE 10 2011 002 146 A1 [Patent Document 5] U.S. Patent No. 6,001,183 [Patent Document 6] DE 36 33 386 A1 [Patent Document 7] DE 10 2006 018 514 A1 Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a means by which the flow region temperature can be adjusted individually for each substrate and / or substrate carrier.

[0012] While in the prior art the flow region temperature could only be adjusted by the gas flow, in the present invention, for example due to the fact that the heat transfer to the flow region plates can also be preset individually in each flow region, it is possible in particular to accommodate deviations of the flow temperature in individual, possibly adjacent, flow regions from a target temperature or an average temperature, for example due to tolerances. The heat transfer medium may be an element or property physically assigned to the flow field, and may be adjusted before the deposition process is performed, for example through the use of appropriate flow field plates or by individual selection of the gap height of the horizontal gap. However, this may also be achieved by supplying an individually mixed heat transfer gas to the horizontal gap during the deposition process. To this end, an open inlet for the heat transfer gas is provided upstream of each substrate carrier. This results in an outflow from the supply channel, which supplies the individually mixed heat transfer gas to the horizontal gap. In the gas mixing device, a plurality of mass flow controllers are provided, at least one mass flow controller individually assigned to at least each supply channel. Using the at least one mass flow controller, an individually mixed heat transfer gas can be supplied to each supply channel, thereby allowing individual adjustment of the surface temperature of the flow region plate for each flow region positioned in front of the substrate carrier. According to the invention, the number of flow field plates is provided to be equal to the number of substrate carriers. The flow field temperature may be adjusted by passive adjustment means, e.g. spacers. The heat transfer gas may be provided in a horizontal gap, the height of which is adjusted by spacers. Alternatively, a heat transfer medium may be provided between the flow field plates and the body. The heat transfer mediums have individual heat transfer capabilities. To increase the flow field temperature, the heat transfer medium may be replaced by a heat transfer medium with a higher heat transfer capability. To decrease the flow field temperature, the heat transfer medium may be replaced by another one with a lower heat transfer capability. The horizontal gap height may be adjusted individually by various spacers that determine the horizontal gap height. The flow field plate may be placed directly on the body, resulting in a zero horizontal gap. The spacers may result in gap heights of 0.5 mm, 0.75 mm, 1 mm, etc. However, it is also possible to have very narrow horizontal gaps, with gap heights lower than 0.5 mm. Thus, for example, a gap height of 0.7 mm compared to a gap height of 0 mm results in a temperature difference of about 20 K. When using this method or apparatus to deposit silicon carbide, this gap height variation can affect dopant levels by as much as 50%. Fine tuning is possible through the selection of the gas mixture flowing through the horizontal gap. A CVD reactor designed in accordance with the present invention can include multiple flow region plates that are identical to one another, where the individual flow region plates, particularly two such plates, differ from one another in their heat transfer characteristics. At least two flow region plates may be provided to differ in terms of their material thickness or in terms of spacers. However, as in the present invention, the flow region plates may be designed independently of one another, whereby spacers of different thicknesses are arranged under the two different flow region plates, thereby providing different gap heights. Furthermore, heat transfer media with mutually different heat transfer properties may be arranged to be arranged between the body and the flow region plates in the two different flow regions. The methods of the present invention are designed, among other things, such that individual flow field plates may be replaced with other flow field plates having different heat transfer properties, or spacers or heat transfer members are replaced prior to the deposition process.

[0013] In the above-mentioned embodiment, passive measures are implemented for each substrate carrier to adapt the flow region temperature. A further aspect of the invention relates to active temperature influencing elements. These temperature influencing elements may be locally arranged heating devices. Such kind of flow region heating devices may be laser heaters, for example laser diode heaters. However, the flow region heating devices may also be local resistive heaters. The flow region heating devices may be fixedly attached to the housing of the CVD reactor or to the process chamber ceiling. If the flow region heating devices are attached to the housing outside the process chamber, the process chamber ceiling may comprise a hole through which the laser beam generated by the flow region heating devices passes onto the surface of the flow region plate facing towards the process chamber. The impact point of the laser beam is on the flow region plate. At the point where the laser beam impacts the flow region plate, its surface temperature increases. The flow region heating device, the laser, can be synchronized with the rotational movement of the susceptor by a control device and the laser beam can be switched on and off, so that only selected flow region plates are partially heated. However, the flow region plate or a region of the flow region plate may be equipped with a resistive heater. Such a resistive heater may be integrated into the body of the susceptor. It may also be integrated into the flow region plate. However, the resistive heater may be arranged in the gap between the flow region plate and the body of the susceptor. Furthermore, the flow region heating device may be provided to be arranged below the susceptor. The flow region heating device may be equipped with a laser, so that the underside of the susceptor is partially heated. Such a flow region heating device can rotate together with the susceptor. The heating device may for example be arranged at the end of an arm which is attached to a support member and rotates together with the susceptor. A heating device may be assigned to each substrate carrier respectively in order to individually control the temperature of the flow regions arranged upstream of the substrate carrier. The invention also relates to a method in which heat is directed to at least some of the flow regions respectively by separate heating devices, in which case this is carried out by means of multiple heating devices or by just one heating device. The heating devices each assigned to a substrate carrier are preferably controlled by a controller to direct supplemental heat to a flow region located upstream of each substrate carrier, although such a controller may also control a single heating device to provide heat to a selected flow region in conjunction with the rotation of the susceptor.

[0014] For further design features of the CVD reactor, reference is made to US Pat. No. 6,399,323 cited in the introduction, the disclosure of which is incorporated herein by reference.

[0015] The method of the invention is particularly suitable for depositing SiC layers on a substrate in a CVD reactor. However, the invention also includes the deposition of GaN layers, GaAs layers, GaP layers or mixed crystals from Ga, N, As, P, In or other elements of main groups III and V. Furthermore, the method includes the deposition of layers of elements of main groups VI and II as well as the deposition of elements of main groups IV. [Brief description of the drawings]

[0016] In the following, the invention will be explained in more detail with reference to exemplary embodiments and with reference to the figures. [Figure 1] FIG. 1 is a substantially schematic diagram of a half-section of an MOCVD reactor according to the present invention. [Diagram 2] FIG. 2 is a schematic plan view of the susceptor 2 taken along the line II-II. [Diagram 3] FIG. 3 shows a second exemplary embodiment in the context of FIG. [Figure 4] FIG. 4 is a detail of a plan view of the susceptor 2 in the perspective of FIG. [Diagram 5] FIG. 5 is a view in the perspective of FIG. 1 for a third exemplary embodiment. [Figure 6] FIG. 6 is a schematic diagram of a gas mixing system for supplying gases. [Figure 7] FIG. 7 is a view in the perspective of FIG. 1 relating to a fourth embodiment of the present invention. [Figure 8] FIG. 8 is a view from the perspective of FIG. 1 relating to a fifth embodiment of the present invention. [Figure 9] FIG. 9 is a view from the perspective of FIG. 2 relating to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1 and 2 show schematic diagrams of the basic components for the description of an MOCVD reactor. The housing of the MOCVD reactor in which the components shown in Figs. 1 and 2 are arranged is not shown. It is a housing that is sealed and isolated from the outside, into which open a number of gas supply lines, a liquid coolant supply line, and a gas exhaust line. The gas supply lines, not shown, connect the supply line sections 5, 5' to a gas mixing system that includes storage containers in which process gases and carrier gases are stored. However, the process gas and the carrier gas may be stored separately from the gas mixing system, for example in a central gas supply. The central gas supply is connected to the gas mixing system via a supply line. Carbon-containing gas and silicon-containing gas, for example a hydrocarbon or silicon-hydrogen compound, are stored as process gas. In an alternative method, AsH 3 , N.H. 3 , PH 3 , trimethyl-gallium, trimethyl-indium, trimethyl-aluminium and other hydrides or organometallic compounds can be stored therein. These are fed to the gas inlet member 3 via feed line sections 5, 5' using valves and mass flow controllers, and process gases flow separately from mutually perpendicularly arranged gas inlet areas 4, 4' into the process chamber 1. More than two feed line sections 5, 5' may be provided.

[0018] The energy supply is connected to a heating device which comprises one or more heating zones and produces heat supplied from below to the body 7 of the susceptor 2. A permanent heat flow is created from the heating device 6 to the cooled process chamber ceiling 15, which creates a vertical temperature gradient within the susceptor 2.

[0019] The body 7 supports a number of substrate carriers 12 arranged with a uniform angular distribution. The substrate carriers 12 are disk-shaped and rotatable about a rotation axis 13. They may be supported by a gas cushion, which also rotates the substrate carriers 12. It is formed by gas being supplied at a supply point 19 via a supply channel 20 into a horizontal gap between the underside of the substrate carriers 12 and the upper side of the body 7.

[0020] The surface areas of the body 7 not covered by the substrate carrier 12, which may be made entirely from graphite, quartz or a suitable metal, are covered by plates 10, 27. In the exemplary embodiment, the radially outer areas are covered by an outer plate 27.

[0021] The radially inner area is covered by a number of flow area plates 10. In an exemplary embodiment, six flow area plates 10 and six substrate carriers 12 are provided. In this connection, one flow area plate 10 is individually assigned to each substrate carrier 12. The flow area plates 10 thus entirely cover each part of the disk-shaped susceptor 2 on which the substrate carriers 12 are arranged. The entire surface between the substrate carriers 12 and the central gas inlet member 3 is taken up by the flow area plates 10. The flow area plates 10 adjoin one another and form a radially extending joint 22. The joint 22 may extend along the border between the two outer plates 27. The joint 22 passes through the center of the intermediate space between two adjacent substrate carriers 12. The flow area plates 12 can be replaced individually.

[0022] The material of the flow region plate 10 and / or the outer plates 27 may be the same as the material from which the body 7 is made. The central plate 8 preferably consists of quartz, while the annular member, the substrate carrier 12 and the flow region plate 10 preferably consist of graphite, preferably coated graphite.

[0023] The flow field plate 10 abuts the substrate carrier 12 forming a vertical gap, and abuts the gas inlet member 3 forming a vertical gap. The flow field plate 10 is maintained vertically spaced from the body 7 by spacer means, not shown, but known from the documents cited in the introduction. This forms a horizontal gap consisting of a number of portions 11, 11'. The horizontal gap 11 may form a cooled portion immediately adjacent the gas inlet member 3 and a heated portion immediately adjacent the substrate carrier 12.

[0024] The underside of the flow field plate 10 may be designed to be flat. In an embodiment not shown, the underside of the flow field plate 10 may be provided with a stepped structure.

[0025] In the radial direction between each substrate carrier 12 and the gas inlet member 3 there may be at least one feed point 8 for heat transfer gas which is fed to the feed point 8 via a feed channel 21 .

[0026] 6 is a schematic diagram of a gas mixing system 27 with a total of six mass flow controllers 30, 31 arranged in pairs, only two of which are shown. By means of the mass flow controllers 30, 31, a heat transfer gas may be mixed from two inert gases, for example nitrogen and hydrogen, each of which has a specific heat transfer capability different from the other. The gas mixtures, individually made available by the mass flow controllers 30, 31, are fed into one of a total of six feed channels 21. In this embodiment, a feed channel 21 is assigned to each of the six flow field plates 10 so that individual heat transfer gas flows associated with individual substrate carriers 12 can be fed into the horizontal gaps 11, 11' between the body portion 7 and the flow field plates 10.

[0027] In the embodiment shown in FIG. 1, a part of the horizontal gap 11' is located radially inside the feed point 8 and a part of the horizontal gap 11 is located downstream of the feed point 8. The heat transfer gas may be supplied through a columnar support member 18 which can be driven in rotation to rotate the susceptor 2 about the axis of rotation 17. The gases can be supplied to the supply channels 21 independently of each other so that each flow region can be temperature controlled separately. Mixtures of two gases which are significantly different from each other in terms of heat transfer properties can be supplied to the supply channels 21 independently of each other. The heat transfer properties of the part 11' of the horizontal gap to which the gas is supplied vary depending on the mixing ratio of the two gases.

[0028] The individual flow field plates 10 can be replaced with flow field plates 10 having different thermal conductivity characteristics. Thus, the apparatus of the present invention can include flow field plates 10 that differ from one another in terms of thermal conductivity characteristics, and in particular that are made from different materials.

[0029] In addition, the gas mixing system 2 7 may include mass flow controllers 32, the number of which corresponds to the number of substrate carriers 12. Gases made available by the mass flow controllers 32 are fed into a feed channel 20 which terminates at a feed point 19.

[0030] In the embodiment shown in Figures 3 and 4, the height of the horizontal gap 11 is determined by the spacers 23, 24. The spacers may have heights of 0.5 mm, 0.75 mm, and 1 mm, or multiples thereof. In particular, the spacers 23, 24 may be made of ceramic or other materials. In particular, the flow field plate 10 is provided to be supported by three spacers 23, 24. The spacers 23, 24 may be selected from a group of different thicknesses, in which case the ... 4 The thicknesses of the respective members are different at equal intervals in the range of 0.1 mm to 0.5 mm, thereby enabling fine stepwise adjustment of the height of the horizontal gap 11.

[0031] Spacers 23, 24 of different thicknesses can be combined with flow region plates 10 with different material thicknesses, so that the upper side of the flow region plate 10 facing the process chamber 1 extends at a uniform height. Thus, adjacent flow region plates 10 may be supported by spacers 23, 24 of different material thicknesses and different heights relative to one another.

[0032] However, spacers 23, 24 are also provided which are integrally or at least fixedly connected to the underside of the flow field plate 10. In this exemplary embodiment, horizontal gaps 11 of different heights can be obtained by replacing individual flow field plates 10.

[0033] In the embodiment illustrated in FIG. 5, the intermediate space between the underside of the flow region plate 10 and the upper side of the body 7 is filled by a heat transfer member 25. In this situation, the heat transfer member 25 may have the same bottom shape as the flow region plate 10. Here again, the heat transfer member 25 may be provided with mutually different material thicknesses and in combination with the flow region plates 10 with mutually different material thicknesses, so that the upper side of the flow region plate 10 extends at a uniform height. The different heat transfer members 25 may be made of mutually different materials. The materials differ in terms of their heat transfer capacity. Thus, the CVD reactor according to the invention may include heat transfer members 25 of the same structure with different heat transfer capacities. Different flow region plates 10 may be provided with different specific heat transfer capacities. In the embodiment illustrated in FIG. 5, it may not be necessary to supply a heat transfer gas between the flow region plate 10 and the body 7.

[0034] 7 shows a fourth exemplary embodiment according to the present invention, in which the surface of the flow region plate 10 facing the process chamber can be actively heated. A heating device 36 is provided which is a laser. The laser 36 is mounted on the housing of the CVD reactor 9. A laser beam 38 generated by the laser 36 can be directed through a hole 37 in the process chamber ceiling 15 onto the surface of the flow region plate 10. The surface of the flow region plate 10 is partially heated at the impact point of the laser beam 38.

[0035] A controller (not shown) is provided which synchronizes the laser 36 with the rotational movement of the susceptor 2 such that with each rotation of the susceptor 2, the same flow region plate 10 is locally heated by the laser beam 38. In this manner, the laser 36 is switched on and off one or more times by the controller in conjunction with the rotation of the susceptor 2.

[0036] However, it is also possible to mount the laser 36 in the process chamber 15. Here too, the laser beam 38 reaches the process chamber ceiling 15 via a hole 37. This is not necessary if the laser 36 is mounted below the process chamber ceiling 15.

[0037] In the exemplary embodiment illustrated in Fig. 8, the susceptor 2 is heated from below by a local heating device 36. The local heating device 36 may be a laser generating a laser beam 38 which impinges on the underside of the susceptor 2 in the region of the flow field plate 10, in particular on the underside of the body 7. In this exemplary embodiment, a laser 36 is provided which rotates with the susceptor 2. For this purpose, it may be fixedly attached to the susceptor 2 or, as shown in Fig. 8, may be attached to the shaft 18 by means of an arm 39.

[0038] In this exemplary embodiment, a number of heating devices 36 may be provided, in particular one heating device 36 assigned to each substrate carrier 12 respectively.

[0039] In the exemplary embodiment illustrated in FIG. 9, each of the individual resistance heaters 40 is assigned to each of the plurality of substrate carriers 12. The resistance heater 40 is disposed upstream of each substrate carrier and may be part of the flow region plate 10. However, the resistance heater 40 may be disposed inside the main body 7 of the susceptor 2. Further, it is also possible that the resistance heater 40 is disposed between the flow region plate 10 and the main body 7.

[0040] A control device is provided, whereby the heating devices 36, 40 can be operated so that the surface temperatures of all the substrates supported by the substrate carrier 12 are substantially the same, and heating power is supplied to the heating devices 36, 40.

[0041] In the embodiments illustrated in FIGS. 7 to 9, it is not necessary for each individual flow region plate 10 to be assigned to each substrate carrier 12. In these embodiments, a single flow region plate 10 may be assigned to a plurality of substrate carriers 12 as in the prior art case.

[0042] Regarding the design of the CVD reactor according to the present invention, or regarding further features of the method, refer to Patent Document 1 cited in the introduction section, and its disclosure is incorporated into the entire present disclosure, especially for the purpose of including features in the claims.

[0043] The above is intended to contribute to the description of the invention that falls within the scope of the present application, which independently advances the related technologies through at least the combination of the following features, and among the combinations of the above features, two, a plurality, or all can also be combined.

[0044] A CVD reactor, characterized in that a flow region plate 10 separated from other flow region plates 10 is assigned to each of the plurality of substrate carriers 12.

[0045] A CVD reactor, characterized in that the gap height of the horizontal gaps 11, 11' extending between the flow region plate 10 and the main body 7 is adjustable.

[0046] The gap height can be adjusted by different spacers 23, 24 or by connecting the flow field plate 10 to another flow field plate 10. 0 A CVD reactor characterized in that it is adjustable by replacing

[0047] A CVD reactor characterized in that heat transfer members (25) having mutually different heat transfer capabilities can be inserted between the flow region plate (10) and the main body (7).

[0048] A CVD reactor characterized in that at least one supply channel 20, 21 opens into a horizontal gap 11, 11' between the body 7 and the flow region plate 10, through which a heat transfer gas supplied by a gas mixing device can be supplied into the horizontal gap 11, 11'.

[0049] A CVD reactor, characterized in that at least one supply channel 20, 21 terminates in front of each substrate in the flow direction, and an individual mixture of heat transfer gas consisting of two gases having mutually different heat transfer capacities can be supplied to each of these supply channels 20, 21, and for this purpose each supply channel 20, 21 is provided with at least one mass flow controller 31, 32 for controlling the mass flow rate of the heat transfer gas.

[0050] A CVD reactor characterized in that flow region plates (10) are arranged annularly around a gas inlet member (3) and substrate carriers (12) are respectively arranged radially outside the flow region plates (10), the flow direction is radial, and gas outlets (26) are arranged radially outside the substrate carriers (12).

[0051] The method according to claim 1, characterized in that a flow field plate (10) separate from the other flow field plates (10) is assigned to each of a plurality of substrate carriers (12).

[0052] 8. A method using the CVD reactor according to claims 1 to 7, characterized in that the flow region temperature is adjusted by selection of suitable spacers 23, 24, a suitable flow region plate 10, a suitable heat transfer member, and / or a suitable heat transfer gas.

[0053] A CVD reactor characterized in that the flow regions can be individually heated.

[0054] A method characterized in that heat is directed individually to at least some of the flow regions by separate heating devices 36, 40.

[0055] A CVD reactor or method, characterized in that the flow region is heatable by a flow region heating device, where the flow region heating device may be a laser 36 or a resistive heater 40.

[0056] A CVD reactor characterized in that the flow region heating device 36 is fixedly arranged on the housing or process chamber ceiling 15 of the CVD reactor 9 and / or the flow region heating device 36 is connected to the susceptor 2 in a manner that rotates therewith and / or is mounted below the susceptor 7.

[0057] All disclosed features are essential to the invention (both for themselves and in combination with one another). The disclosure of the present application includes in its entirety the disclosure content of the relevant / attached priority documents (copies and earlier applications), also with a view to incorporating the features of these documents into the claims of the present application. The dependent claims are characterized by an independent, inventive further development of the prior art, even without the features of the claims cited, in particular in order to file a divisional application on the basis of these claims. The invention specified in each claim may additionally have one or more features specified in the preceding description, in particular those given reference signs and / or specified in the explanation of the signs. The present invention also relates in particular to embodiments in which individual ones of the features mentioned in the preceding description are not implemented, insofar as they are obviously unnecessary for the respective purpose of use or can be replaced by other means having the same technical effect. [Explanation of symbols]

[0058] 1. Process chamber 2 Susceptor 3 Gas inlet member 4 Gas inlet area 4' Gas inlet area 5 Supply line section 6 Heating device 7 Main unit 8 Supply Points 9. CVD Reactor 10 Flow Area Plate 11 Horizontal Gap 11' Horizontal Gap 12 PCB Carrier 13 Rotation axis 14 Substrate 15 Process chamber ceiling 16 Cooling Channels 17 Rotation axis 18 Support member 19 Supply Points 20 Supply Channel 21 Supply Channel 22 Joint 23 Spacer 24 Spacer 25 Heat transfer materials 26 Gas outlet 27 Gas Mixing System 28 Mass Flow Controller 29 Mass Flow Controller 30 Mass Flow Controller 31 Mass Flow Controller 32 Mass Flow Controller 33 Adjustment device 35 Gas Source 36 Laser heating element 37 holes 38 Laser Beam 39 Arm 40 resistance heater

Claims

1. 1. A CVD reactor comprising: a susceptor (2) disposed in the reactor housing and forming a floor of the process chamber (1); a gas inlet member (3) with at least one gas inlet area (4, 4'); a heating device (6) disposed below the susceptor (2) for generating a temperature difference between the body (7) and a process chamber ceiling (15); a plurality of substrate carriers (12) positioned at a distance in the flow direction from the gas inlet member (3) and each for receiving a substrate (14) to be coated; a plurality of flow region plates (10) disposed between the gas inlet member (3) and the substrate carrier (12); the flow field temperature of each surface of the flow field plate (10) facing the process chamber (1) is adjustable by selection or adjustment of the heat transfer medium (11); In the CVD reactor, the heat transfer medium (11) arranged upstream in the flow direction of the plurality of substrate carriers (12) is independently adjustable. A CVD reactor, characterized in that one flow region plate (10) separate from each of the other flow region plates (10) is assigned to each of a plurality of said substrate carriers (12).

2. 2. The CVD reactor of claim 1, wherein a horizontal gap (11, 11') extending between the flow region plate (10) and the body (7) has an adjustable gap height.

3. 3. The CVD reactor of claim 2, wherein the gap height is adjustable by different spacers (23, 24) or by replacing one flow field plate (10) with another flow field plate (10).

4. 4. The CVD reactor according to claim 1, wherein a replaceable heat transfer member (25) is disposed between the body (7) and the flow region plate (10).

5. 5. A CVD reactor according to any one of claims 1 to 4, characterized in that at least one supply channel (21) opens into a horizontal gap (11, 11') between the body (7) and the flow region plate (10), whereby a heat transfer gas supplied by a gas mixing device can be supplied into said horizontal gap (11, 11').

6. 5. The CVD reactor according to claim 4, characterized in that at least one supply channel (21) opens in front of each substrate carrier (12) in the flow direction and can supply each of these supply channels (21) with an individual mixture of heat transfer gas consisting of two gases with mutually different heat transfer capacities, and for this purpose each supply channel (21) is equipped with at least one mass flow controller (31, 32) for controlling the mass flow rate of the heat transfer gas.

7. said flow region plate (10) being arranged annularly around said gas inlet member (3); the substrate carrier (12) being disposed radially outward of each of the flow field plates (10); the flow direction is radial; and 7. The CVD reactor of claim 1, wherein a gas outlet (26) is disposed radially outward of the substrate carrier (12).

8. 8. A CVD reactor as described in any one of claims 1 to 7, characterized in that flow region plates (10) having mutually different heat conduction capabilities, spacers (23, 24) having mutually different thicknesses, or heat transfer members (25) having mutually different heat conduction capabilities are arranged in two mutually different flow regions.

9. 9. A CVD reactor according to any one of claims 1 to 8, characterized in that the flow region in which the flow region plate (10) is arranged is individually heatable.

10. 10. The CVD reactor of claim 9, wherein the flow region is heatable by a flow region heating device, the flow region heating device being a laser (36) or a resistive heater (40).

11. 11. The CVD reactor according to claim 10, characterized in that the flow region heating device (36) is arranged on the housing of the CVD reactor (9) or on the process chamber ceiling (15) and / or the flow region heating device (36) is connected to the susceptor (2) in a manner that rotates together with the susceptor (2) and / or is arranged below the susceptor (7).

12. A method for depositing a doped layer, in particular a SiC layer, on a substrate (14) in a CVD reactor, comprising the steps of: A process gas is supplied to a gas inlet member (3) and enters the process chamber (1) through a gas inlet area (4, 4') of the gas inlet member (3), the floor of the process chamber (1) is formed by a susceptor (2), the susceptor (2) is heated by a heating device (6) arranged below the susceptor (2) so as to create a temperature difference between the process chamber ceiling (15) and the susceptor (2), the process gas flows in a flow direction towards the substrate (14) supported on the substrate carrier (12) and is pre-decomposed on a flow field plate (10) in a flow field of the process chamber (1) between the gas inlet member (3) and the substrate carrier (12), the decomposition products forming a layer; The method, wherein the flow field temperature of the surface of each of the flow field plates (10) facing the process chamber (1) located immediately upstream in the flow direction of one of the substrate carriers (12) is adjusted by selection or adjustment of a heat transfer medium (11), A method according to claim 1, characterized in that one flow field plate (10) separate from each of the other flow field plates (10) is assigned to each of said plurality of substrate carriers (12).

13. 13. The method according to claim 12, wherein a CVD reactor according to any of claims 1 to 7 is used and the flow field temperature is adjusted by selection of suitable spacers (23, 24), suitable flow field plates (10), suitable heat transfer members, and / or suitable heat transfer gases.

14. 14. The method according to claim 12 or 13, characterized in that heat is transferred individually to at least some of the flow regions in which a flow region plate (10) is arranged by separate heating devices (36, 40).

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