阅读说明：本技术 具有用于局部影响基座温度的器件的cvd反应器 (CVD reactor with means for locally influencing the susceptor temperature ) 是由 P.S.劳弗 于 2020-02-10 设计创作，主要内容包括：本发明涉及一种用于对基材进行热处理的设备和方法,设备具有可由加热装置(13)加热的和可由转动驱动器(20)围绕转动轴线(A)转动驱动的用于容纳至少一个基材的基座(5)。为了补偿转动的基座(5)上的局部的温度差异,设置有器件(14、14’、15、16),所述器件用于局部限制从或到基座(5)的热传输,并且与基座(5)的转动运动同步地影响热传输。尤其规定,通过馈入开口(14’)以脉冲方式周期性地将具有变化的导热特性的调温气体馈入基座(5)和冷却机组(30)之间的间隙(10)中。(The invention relates to a device and a method for the thermal treatment of substrates, comprising a susceptor (5) which can be heated by a heating device (13) and which can be driven in rotation about a rotation axis (A) by a rotation drive (20) for receiving at least one substrate. In order to compensate for local temperature differences on the rotating susceptor (5), means (14, 14', 15, 16) are provided for locally limiting the heat transfer from or to the susceptor (5) and influencing the heat transfer synchronously with the rotational movement of the susceptor (5). In particular, it is provided that a temperature-control gas with varying heat-conducting properties is fed in a pulsed manner periodically into the gap (10) between the base (5) and the cooling unit (30) via the feed opening (14').)

1. An apparatus for the thermal treatment of substrates, having a susceptor (5) which can be heated by a heating device (13) and which can be driven in rotation about a susceptor rotation axis (a) by a rotation drive (20), having a substrate holder (7) for accommodating at least one substrate, having means (14, 14') for locally limiting the temperature of the susceptor (5) and influencing the temperature of the susceptor synchronously with the rotational movement of the susceptor (5), characterized in that the means periodically change the thermal conductivity properties of a medium arranged between the susceptor (5) and a tempering set in a pulsed manner.

2. Method for the thermal treatment of substrates, wherein a susceptor (5) carries at least one substrate, is heated by a heating device (13) and is driven in rotation about an axis of rotation (a), wherein the temperature of the susceptor (5) is influenced synchronously with the rotational movement at locally limited locations, characterized in that the thermal conductivity properties of a medium arranged between the susceptor (5) and a tempering set are changed locally and periodically in a pulsed manner.

3. An apparatus for the thermal treatment of substrates, having a susceptor (5) which can be heated by a heating device (13) and which can be driven in rotation about a susceptor rotation axis (A) by a rotation drive (20), the susceptor carrying at least one substrate holder (7) which is arranged eccentrically with respect to the susceptor axis of rotation (A) and is rotatable about a substrate holder axis of rotation (B) for accommodating at least one substrate, the device has means (14, 14') for influencing the heat-conducting properties of a medium arranged between the base (5) and the temperature control unit in the region of a heat-affected zone (17), characterized in that the heat-affected zone (17) is an area arranged relative to the susceptor rotation axis (A) in a radial inner or outer or rotation trajectory of the substrate holder rotation axis (B) around the susceptor rotation axis (A).

4. A method for the heat treatment of substrates, wherein a susceptor (5) is rotationally driven about a susceptor rotation axis (a) and carries at least one substrate holder (7) which is arranged eccentrically with respect to the susceptor rotation axis (a), rotates about a substrate holder rotation axis (B) and carries at least one substrate, wherein the heat-conducting properties of a medium arranged between the susceptor (5) and a temperature-control unit are influenced by means (14, 14') within the region of a heat-affected zone (17), characterized in that the heat-affected zone (17) is a region which is arranged relative to the susceptor rotation axis (a) radially inside or radially outside or on the rotation trajectory of the substrate holder rotation axis (B) about the susceptor rotation axis (a).

5. The device according to claim 1 or 3 or the method according to claim 2 or 4, characterized in that, as the cycle time of the susceptor (5) is periodically within a time which is smaller than the cycle time of the susceptor (5) or within a time which is greater than the cycle time of the susceptor (5), more heat is conducted into or out of the susceptor (5) than in the region of the susceptor (5) adjacent thereto in the position-limited heat-affected zone (17), or means are provided for this purpose.

6. The apparatus or the method according to one of the preceding claims, characterized in that the tempering group is a cooling group (30) and/or that the cooling group is formed by a cooling channel of an RF induction coil (13), wherein an electromagnetic alternating field is generated with the RF induction coil (13), which electromagnetic alternating field induces eddy currents in the electrically conductive material of the susceptor (5) for heating the susceptor.

7. The apparatus or the method according to one of the preceding claims, characterized in that tempering gas is fed into the gap (10) between the base (5) and the tempering unit or between the cooling unit (30) through a feed opening (14 '), either periodically in a pulsed manner or at a constant flow rate, and/or tempering gas with periodically varying heat-conducting properties is fed into the gap (10) between the base (5) and the tempering unit, and/or a gas feed line (14) is led into the feed opening (14'), into which gas with high heat-conducting properties or gas with lower heat-conducting properties is fed or can be fed selectively by means of a diverter valve (28).

8. The apparatus or method according to any of the preceding claims, characterized in that the gap (10) through which a continuous first gas flow (S1) of flushing gas flows through which a second gas flow (S2) of tempering gas is fed into the first gas flow (S1) is constructed by a sealing plate (8) arranged between the heating device (13) and the bottom side of the susceptor (5), wherein the first gas flow (S1) and the second gas flow (S2) form a third gas flow (S3) between the substrate holder (7) for supporting the substrate and the heating device (13), the flow rate of which is greater than the circumferential velocity of the susceptor (5) on the radially outer edge of the substrate holder (7).

9. The apparatus or method according to any one of the preceding claims, characterized in that a plurality of heat-affected zones (17) are provided, in which heat is introduced or removed periodically in a pulsed manner, wherein the heat-affected zones (17) are arranged at different azimuthal angles to each other with respect to the center of the base (5) and/or at different radial distances from the center of the base (5).

10. The apparatus or method according to any one of the preceding claims, characterized in that at least one heat-affected zone (17) is arranged in a circumferential region around the center of a base (5) in which a plurality of substrate supports are located, on which heat is introduced or removed periodically in a pulsed manner.

11. The apparatus or method according to any one of the preceding claims, characterized in that the heat affected zone (17) is limited to an angular range of at most 90 degrees, 60 degrees, 45 degrees, 30 degrees or 15 degrees around the axis (a).

12. The apparatus or method according to any one of the preceding claims, characterized in that a temperature measuring point (31, 31') is arranged radially outside and/or radially inside the heat affected zone for measuring the temperature of the surface of the base (5).

13. The apparatus or method according to any one of the preceding claims, wherein the tempering gas has a flow direction directed radially inwards or radially outwards with respect to the susceptor rotation axis (a).

14. The apparatus or the method according to one of the preceding claims, characterized in that a plurality of feed openings (14 ') are provided at different radial distances from one another relative to the base rotation axis (a), wherein one or more tempering gases can be fed in selectively through one or more feed openings (14').

15. An apparatus or method characterised by one or more of the characterising parts of any of the preceding claims.

Technical Field

The invention relates to a device for the thermal treatment of substrates, comprising a susceptor that can be heated by a heating device and can be driven in rotation about a rotation axis by a rotation drive for receiving at least one substrate.

The invention also relates to a method for the thermal treatment of substrates, in which method a susceptor carries at least one substrate, is heated by heating means and is driven in rotation about an axis of rotation.

Background

Document US 8,249,436B 2 describes a device and a method in which heat is introduced locally to a susceptor rotating about an axis of rotation in a limited manner by means of a pulsed laser beam.

Apparatuses and methods of the aforementioned type are also known, for example from the document DE 102009044276 a 1. An apparatus of the aforementioned type is embodied by a CVD reactor having a gas-tight housing in which a process chamber is located. The bottom of the process chamber is constructed from a base which can be driven in rotation about an axis of rotation. On the susceptor there are a plurality of substrate holders which are distributed uniformly circumferentially around a central gas inlet mechanism, which substrate holders each carry a substrate and are kept in suspension under the rotational drive of a flushing gas flow. The susceptor rotates over a heating device, which is an induction coil cooled by a coolant. The temperature of the bottom side of the susceptor is measured by a first pyrometer. The temperature of the substrate placed on the substrate holder is measured with a second pyrometer. The induction coil generates a high frequency alternating field that generates eddy currents in the susceptor made of graphite so that the susceptor can be heated to a process temperature. Due to the lack of manufacturing techniques, the material of the base does not have a uniformly distributed conductivity, thereby forming a region with low conductivity and a region with high conductivity. Thus, the different resistances oppose locally the eddy currents induced in the susceptor, thereby heating the susceptor locally differently. In the case of an average temperature of 65 ℃, the temperature difference within the susceptor may be 5 to 8K. The technical challenge is to design the lateral temperature profile of the top side of the susceptor, on which the substrate is arranged, as uniformly as possible.

A CVD reactor is known from DE 102011055061 a1, in which a gas mixture consisting of strongly and weakly thermally conductive gases can be fed into the gap between the heating device and the bottom side of the susceptor.

The prior art also includes the following documents: DE 102005056536A 1, DE 102009043960 a1, DE 102011053498 a1, DE 102013109155 a1, DE 102014104218 a1, DE 102017105333 a1, US 2018/0182635 a1, US 5468299 a.

Disclosure of Invention

The invention is based on the object of providing measures which make it possible to compensate for local temperature differences in the susceptor.

This object is achieved by the invention specified in the claims, the dependent claims not only representing advantageous embodiments of the invention specified in the dependent claims, but also representing individual solutions to the object.

Firstly and primarily, it is proposed to provide means with which the heat inflow to the susceptor or the heat discharge from the susceptor is changed periodically in a pulsed manner in at least one locally limited heat-affected zone. The device operates in synchronism with the rotational movement of the base. With the method according to the invention the heat transfer from or to the susceptor is locally limited and effected synchronously with the rotary movement of the susceptor. The heat affected zone is locally fixed relative to the housing of the device. The heat affected zone extends over an azimuthal angular range that is preferably less than an angular range occupied by the substrate support of the susceptor about a center of rotation of the susceptor. The heat is supplied or supplied to the heat-affected zone of the rotating susceptor in a pulsed duration, which is selected such that the heat is transferred to the rotating susceptor only at points which are not sufficiently heated in view of the locally higher electrical conductivity of the material of the susceptor, i.e. at cooler points. The apparatus has a controller that cooperates with the rotation angle detection to detect the local rotation angle of the base using the rotation angle detection. The controller synchronizes the thermal influence with the rotational movement of the susceptor, for example, such that the same region is always subjected to thermal loading during each rotation of the susceptor. The heat flow, which is fixed in position relative to the housing, preferably loads the same heat-affected zone of the base in each rotation of the base. According to the invention, the thermal conductivity of the medium is periodically changed in the region of the heat-affected zone. In particular, it is proposed that the medium extends between the base and the temperature control unit. It is particularly preferably proposed that, in the region of the heat-affected zone, the heat-conducting properties of the material arranged between the susceptor and the cooling aggregate are influenced periodically in a pulsed manner, wherein the cycle time is the cycle time of one rotation of the susceptor and the pulse width is smaller than the cycle time. For this purpose, it is provided, in particular, that a gap extends between the base and the temperature control unit, through which gap the flushing air flow passes. One or more local feed openings can be provided in the gap, through which the tempering gas is fed into the gap. A purge gas having a first thermal conductivity may be continuously flowed through the gap. The second purging gas, which has a different thermal conductivity than the first purging gas, is fed in a pulsed manner periodically with local limitation through the feed opening. In particular, it is provided that the first purging gas flowing continuously through the gap is hydrogen, i.e. a gas having a high thermal conductivity, and that nitrogen, i.e. a gas having a lower thermal conductivity, is fed in through the feed opening. However, other gas pairs, such as helium and argon, may also be used. The cooling unit is preferably formed by a liquid-cooled induction coil, with which the susceptor is heated. Eddy currents are generated in a susceptor made of graphite or another heat-conducting material by means of an induction coil, which is arranged, in particular, helically, in a plane parallel to the plane of extension of the susceptor. The local size of the eddy currents is related to the slightly varying thermal conductivity properties of the material of the susceptor, so that the electromagnetic alternating field generated by the induction coil generates a locally varying energy flow within the susceptor, which results in a local temperature difference. In order to form the above-mentioned gap into which the tempering gas is fed, a plate can be provided which extends between the susceptor and the induction coil with a small gap distance with respect to the underside of the susceptor. Such gaps are provided in the prior art for forming diffusion barriers. A flushing gas flow flows through the gap from the radially inner side in the direction of the exhaust device arranged radially outside, which flushing gas flow prevents process gas fed into the process chamber arranged above the susceptor from entering the region in which the induction coil is located. The tempering gas is fed into the diffusion barrier formed by the continuous gas flow. The flow rate of the purge gas through the gap is greater than the circulation rate of the susceptor at the level of the radially outer edge of the substrate support. The flow of flushing gas through the gap is particularly large, so that complete gas exchange takes place in the gap when the susceptor exceeds the heat affected zone. However, instead of the periodic switching on of the temperature-control gas, it can also be provided that a constant gas flow is passed through the feed opening, which is controlled under valve control either to the first gas flow or to the second gas flow. For this purpose, it is particularly advantageous if a gas line is fed into the feed opening, into which gas line gas having a high thermal conductivity or gas having a lower thermal conductivity is selectively fed by means of a valve. In a further embodiment of the invention, it is proposed that the plurality of heat-affected zones are arranged in a circumferential direction around a center of the base, which coincides with the axis of rotation of the base. In combination or separately, however, it can also be provided that a plurality of heat-affected zones are arranged one behind the other in the radial direction with respect to the center of rotation of the base, wherein the heat-affected zones are either supplied with heat from the heat radiators or are zones with variable heat-conducting properties. In a further embodiment of the invention, it can be provided that the heat-affected zone is located on a circumferential line on which the substrate holder is located. This achieves the result that only the radially outer region of the rotating substrate holder is influenced by the heat-affected zone, so that the temperature profile on the substrate holder can also be adjusted by this measure. In particular, it is therefore provided that the means for influencing the heat transfer only influence the radially outer edge of the substrate holder. The temperature measuring points, with which the surface temperature of the susceptor can be measured, in particular at the bottom side of the susceptor, can be arranged in different radial positions. In particular, it is provided that temperature measuring points are arranged radially inside and radially outside the heat-affected zone. In particular, it is provided that the surface temperature of the susceptor is measured at the temperature measuring point by means of a pyrometer. In particular, optical waveguides are used for this purpose.

According to a variant of the invention having independent features, it is proposed that, in order to influence the radial temperature profile of the substrate carried by the substrate support which is rotationally driven about the substrate support axis of rotation, the heat-affected zone is radially offset from the rotation path of the substrate support axis of rotation about the center of the rotationally driven susceptor. It is particularly proposed here that the heat-affected zone is located radially inside the rotation path or preferably radially outside the rotation path relative to the axis of rotation of the base. In particular, it is provided here that the medium whose thermal conductivity is to be changed is a gas located between the base and the temperature control unit, wherein the RF induction coil cooled by means of the coolant is considered as a temperature control unit. In a further variant, it is provided that the heat-affected zone is located exactly on the rotational path of the axis of rotation of the substrate holder. In a variant of the invention, the thermal conductivity properties do not need to be changed periodically in a pulsed manner. It is particularly advantageous if the substrate holder bears exactly a substrate with a round shape, wherein the center point of the substrate is located in the axis of rotation of the substrate holder. With this variant, the radial temperature profile of the substrate can be set in a targeted manner. In order to influence the heat-conducting properties of the medium arranged between the base and the temperature control unit, it is provided in particular that the temperature control gas is fed into the gap between the base and the temperature control unit or between the unit and the plate arranged between the base and the temperature control unit via a gas outlet arranged radially outside the rotation path, radially inside the circulation path or on the rotation path. In this case, it can be provided that the flow direction of the tempering gas is directed in the radial direction away from the rotational path of the axis of rotation of the substrate holder. In the gas outlet arranged radially outside the rotation trajectory, a flow direction in a radially outward direction is achieved. In the gas outlet arranged radially inside the rotation trajectory, the flow direction is directed radially inwards. However, it is also possible that the flow direction is directed in a radially outward direction with respect to the substrate holder axis of rotation even in the case of a gas outlet arranged radially inside the rotation trajectory.

Drawings

Embodiments of the invention are subsequently explained with reference to the drawings. Wherein:

FIG. 1 schematically shows in a longitudinal section a CVD reactor and a susceptor 5 arranged therein;

fig. 2 shows a diagram according to fig. 1 of a first embodiment of the invention with a base 5;

fig. 3 shows a top view of the base 5 of the first embodiment of the invention;

fig. 4 shows a diagram according to fig. 1 of a second embodiment of the invention;

fig. 5 shows a top view of a base 5 of a second embodiment of the invention;

FIG. 6 shows the time course of the periodic pulse effect on the heat input or heat output on the heat affected zone on the susceptor 5;

fig. 7 shows a diagram according to fig. 2 of a third embodiment of the invention;

fig. 8 shows a diagram according to fig. 2 of a fourth embodiment of the invention;

fig. 9 shows a diagram according to fig. 2 of a fifth embodiment of the invention;

fig. 10 shows a diagram according to fig. 2 of a seventh embodiment of the invention;

fig. 11 shows a diagram of a further embodiment according to fig. 4.

Detailed Description

A CVD reactor of this type (see fig. 1) has a CVD reactor housing 1 which is gas-tight, can be made of stainless steel and can have cooled walls. The CVD-reactor housing has, in particular, a cover 2, a side wall 3 which can be of cylindrical design, and a base 4 opposite the cover 2. The cover 2, side walls 3 and bottom 4 may be cooled.

The process gas can be fed into the process chamber by means of the gas inlet means 6. The process chamber is bounded upward by a process chamber cover 11 and downward by the base 5. The susceptor 5 is made of graphite or of another electrically conductive material and can be driven in rotation about an axis a about the carrier 12. A rotary drive 20 is used for this purpose. A rotation sensor, not shown, is provided, with which the respective rotational angular position of the base 5 can be determined. The rotation angle is transmitted to a controller, not shown.

Below the susceptor 5 there is a heating device 13, which is constructed from a liquid-cooled induction coil, with which an RF field is generated, which induces eddy currents in the susceptor 5, which eddy currents lead to heating of the susceptor to the process temperature. Typically, the treatment temperature is in the range of 600 to 1000 ℃.

The top side of the susceptor 5 facing the process chamber has a plurality of recesses arranged in the circumferential direction around the center of the susceptor 5, in which recesses are respectively located substrate holders 7 which carry substrates on their top side facing the process chamber, which substrates can be coated with a monocrystalline material by introducing process gases, such as organometallic compounds of the group III metals and hydrides of the group V metals. The surface temperature of the substrate is measured by the first pyrometer 21. The process gas flows through the process chamber in the radially outward direction and is discharged by means of an exhaust device 9 which surrounds the susceptor 5 in an annular manner.

At the measuring point 31, the surface temperature of the susceptor 5 is measured by means of the second pyrometer 22. The temperature measurement values measured by the first pyrometer 21 and the second pyrometer 22 are transmitted to a control device, not shown. The power fed into the induction coil 13 is regulated by a regulating device in order to maintain the substrate temperature or the susceptor temperature at a desired value.

The thermal energy fed into the base 5 leaves the base through the process chamber, on the one hand, towards the process chamber cover 2 or in the radial direction towards the side wall 3. However, the maximum heat flow of the susceptor 5 enters the cooling water flowing through the induction coil 13. The induction coil 13 thus forms a cooling unit with its cooling channels 30 in order to extract heat from the susceptor 5.

In the exemplary embodiment shown in fig. 2 and 3, a gap 10 through which gas can flow is formed between the base 5 and the heating device 13 by means of a sealing plate 8 arranged below the base 5. The radially outer edge of the sealing plate 8 is supported on a step 19 of the exhaust mechanism 9. The first gas flow S1 can flow from the radially inside into the gap 10, which forms a diffusion barrier with which process gas is prevented from reaching the region of the reactor housing in which the induction coil 13 is located. Hydrogen is commonly used for this purpose.

At least at one peripheral position, radially inside the peripheral region, in which the substrate holder 7 is located, a feed opening 14 'is provided, into which feed opening 14' the gas line 14 opens, by means of which the second gas flow S2 can be fed into the gap 10. Preferably, nitrogen is used for this purpose. A pulsed nitrogen gas flow according to fig. 6 can be fed into the gap 10 by means of a valve, not shown, so that a tempering gas with a temporally different heat transfer resistance flows through the gap 10 below the substrate holder 7 synchronously with the rotational movement of the susceptor 5. The air flow S3 is formed by the two air flows S1 and S2, and affects the heat transfer from the base 5 to the cooling pack 30. The gas flow S2 is synchronized with the rotational movement of the susceptor 5 so that nitrogen gas is mixed with the hydrogen gas flow S1 as the gas flow S2 only when a specific substrate holder 7 among the plurality of substrate holders 7 moves within the angular range through which the gas flow S3 having the gas flow S2 flows. Since nitrogen gas has a lower thermal conductivity than hydrogen gas, less heat is absorbed from the susceptor 5 below the substrate holder 7 than at other portions on the remaining substrate holder 7. It is thus possible to compensate for local cooling points of the susceptor 5. In this variant, the heat-affected zone is located in a predetermined radial position relative to the axis of rotation a of the base 5 and in an azimuthal position fixed relative to the housing relative to the axis of rotation a of the substrate holder. Since the heat influence is carried out synchronously with the rotation of the susceptor 5, the heat-affected zone 17 is also fixed in position relative to the susceptor 5, since the heat transfer to the same substrate holder 7 is always correspondingly influenced.

Fig. 3 and 4 show a second embodiment of the invention. It is provided here that hydrogen or nitrogen can be fed selectively into the gas line 14 by means of the changeover valve 27. Reference numerals 28 and 29 denote mass flow controllers with which the nitrogen or hydrogen flow can be adjusted. The valve 27 may be a directional valve which directs a respective further gas flow in a "valve line".

This valve arrangement may also be provided in other embodiments. It is also possible to provide only one mass flow controller which feeds, for example, a specific amount of nitrogen into the gap 10 as the second gas stream S2.

In the exemplary embodiment shown in fig. 3 and 4, it is furthermore provided that the feed openings 14' are located in a peripheral ring region in which the substrate holders 7 are located, which are each arranged in a rotationally driven manner on an air cushion in a recess in the top side of the base 5. The feed openings 14' are offset radially outward, in particular with respect to the center of the substrate holder 7, so that only the radially outer region of the substrate holder 7 is subjected to temperature influences by the temperature-regulating gas fed into the gap 10 and the gas flow S3 formed there. Due to the rotational movement of the substrate holder 7, the radially outer region can be temperature-controlled in this case and a temperature profile can thus be generated.

The flow velocity of the gas stream S3 in this example is so high that each substrate holder 7 can be individually temperature influenced by a correspondingly short pulse and a large number of pulses with possibly different pulse widths. For this reason, the flow rate of the gas flow S3 under the substrate holder 7 is preferably greater than the circulation speed of the susceptor on the radially outer edge of the substrate holder 7 with respect to the rotation axis a of the susceptor 5. Preferably, however, the flow rate S3 is at least twice the circulation rate. The gas stream S3 is preferably about 20 cm/S.

Fig. 4 furthermore shows two temperature measuring points 31, 31 ', wherein temperature measuring point 31 is arranged radially inside feed-in opening 14' and temperature measuring point 31 'is arranged radially outside feed-in opening 14'. However, this arrangement of the two temperature measuring points 31, 31' can also be provided in other exemplary embodiments shown in fig. 2 and 3. In particular, it is provided that the temperature is measured at the measurement points 31, 31' by means of a pyrometer. For this purpose, optical waveguides 24, 26, which are connected to a pyrometer, not shown, are guided in the tubes 23, 25.

In the embodiment shown in fig. 7, the plurality of heat-affected zones and in particular the plurality of feed-in openings 14' are arranged in a circumferential direction around the axis of rotation a of the base 5, wherein the arrangement is evenly distributed.

The fourth embodiment shown in fig. 8 shows a plurality of heat-affected zones or feed-in openings 14' which are each arranged in a radial position in the center of the peripheral zone in which the substrate holder 7 is located. However, in a variant of the exemplary embodiment shown there, the feed openings 14' can also be arranged only below some of the substrate holders 7 or only below one of the substrate holders 7. Alternatively, the feed openings 14' shown on the rotation path of the substrate holder axis of rotation in the exemplary embodiment shown in fig. 8 can be arranged radially offset. The feed-in opening 14' can thus be located radially inside or radially outside the rotation trajectory with respect to the center of the base 5. The flow direction of the tempering gas emerging from the feed opening or openings 14' can be directed not only radially inward, but also radially outward with respect to the axis of rotation of the susceptor.

In the embodiment shown in fig. 9, a plurality of heat-affected zones or feed openings 14' are arranged one after the other in the radial direction. Feed opening 14' may be selectively operable. The substrate holder 7 can be rotated about a substrate holder axis of rotation and in particular carries in each case only one disk-shaped substrate. In this exemplary embodiment, it can be provided that the flow of tempering gas emerging from the selected feed opening 14' emerges non-pulsatory, i.e. constantly, into the interspace between the underside of the susceptor and the heating device or the cooling unit. In this variant, however, it is also possible for the tempering gas to be discharged from one or more of the feed openings 14' synchronously and in pulses with the rotary movement of the susceptor. However, it is also possible for the gas flow to exit through the feed opening 14' without a pulse. Different gas flows and/or different gas types can also be discharged from feed opening 14' in a pulsed or non-pulsed manner. For this purpose, it is particularly advantageous if the plurality of feed openings 14' are arranged offset in the circumferential direction with respect to the center of the base 5. Through different feed openings 14', different gases or mixtures of different gases can also be discharged at different pulse rates from one another.

In the embodiment shown in fig. 10, the feed-in opening 14' is arranged in the radially outermost region of the peripheral region in which the substrate holder 7 is located. The heat-affected zone or the feed-in opening 14' can here even be arranged radially outside the zone in which the substrate holder 7 is located.

The at least one heat affected zone 17 is limited to a range of angles about the axis a. The angular range of orientation is at most 90, 60 or 45 degrees, or preferably at most 30, 20 or at most 15 degrees.

The exemplary embodiment shown in fig. 11 corresponds essentially to the exemplary embodiment shown in fig. 4, wherein, however, it is provided that the feed opening 14 is located radially outside the substrate holder rotational axis B about which the substrate holder 7 is rotationally driven. For this purpose, the substrate support 7 is located on an air cushion which is fed with angular momentum into the gap between the substrate support 7 and the base 5, so that the substrate support 7 is in rotation. The substrate holder 7 here preferably carries a circular substrate. The center point and the axis of rotation B preferably coincide here.

The gas flow fed into gap 10 through feed opening 14 flows through gap 10 in an outward direction. The gas flow can also be fed in here constantly or synchronously with the rotation of the base 5.

The optical waveguide 24 may be located in a tube 23, which tube 23 feeds a first gas flow S1, which may be nitrogen, for example, into the gap 10. The tube 23 is arranged radially inside the rotation locus of the substrate holder rotation axis B with respect to the rotation axis a of the susceptor 5. In the region radially outside the trajectory of rotation, feed openings 14' are present for feeding in gases having different thermal conductivity properties, for example hydrogen, in order to provide different heat transfer characteristics in the gap 10 in the region radially outside the substrate holder 7 than in the region in the center of the substrate holder axis of rotation B,

in a variant that is not shown, however, the feed opening 14' can also be arranged radially inside the axis of rotation B of the substrate holder 7 and in the vicinity of the axis of rotation a of the base 5. The axis of rotation B of the substrate holder 7 shows a circle of revolution about the axis of rotation of the susceptor 5 within the reactor housing 1. The feed opening 14' can also be located on the rotation trajectory.

The embodiments described above serve to illustrate the invention covered by the present application as a whole, which extends the prior art at least in each case independently of the following combinations of features, wherein two, more or all of the combinations of features can also be combined, namely:

an apparatus, characterized in that the device periodically changes the heat conducting properties of a medium arranged between the base 5 and the temperature conditioning pack in a pulsed manner.

A method is characterized in that the heat conducting properties of a medium arranged between a base 5 and a temperature-regulating aggregate are locally and periodically changed in a pulsed manner.

An apparatus is characterized in that the heat affected zone 17 is an area arranged in or outside or on a rotation trajectory of the substrate holder rotation axis B around the susceptor rotation axis a with respect to the susceptor rotation axis a.

A method is characterized in that the heat affected zone 17 is an area arranged in or outside or on the rotation trajectory of the substrate holder rotation axis B around the susceptor rotation axis a with respect to the susceptor rotation axis a.

An apparatus or a method is characterized in that, as a function of the cycle time of the susceptor 5, periodically more heat is conducted into or out of the susceptor 5 in the position-limited heat-affected zone 17 than in the region of the susceptor 5 adjacent thereto, within a time which is less than the cycle time of the susceptor 5 or greater than the cycle time of the susceptor 5, or means are provided for this purpose.

An apparatus or a method is characterized in that the tempering unit is a cooling unit 30, which is formed in particular by a cooling channel of an RF induction coil 13, wherein an electromagnetic alternating field is generated by means of the RF induction coil 13, which induces eddy currents in the electrically conductive material of the susceptor 5 for heating the susceptor.

An apparatus or a method is characterized in that a temperature control gas is fed into the gap 10 between the base 5 and the temperature control unit, in particular the cooling unit 30, either periodically in a pulsed manner or at a constant flow rate through a feed opening 14 ', wherein it is provided in particular that the temperature control gas having a periodically changing heat conductivity is fed in, wherein it is provided in particular that a gas feed line 14 opens into the feed opening 14', wherein a gas having a high heat conductivity or a gas having a lower heat conductivity is fed or can be fed into the gas feed line selectively by means of a diverter valve 28.

An apparatus or a method is characterized in that the gap 10 is formed by a sealing plate 8 arranged between a heating device 13 and the bottom side of the susceptor 5, through which gap a continuous first gas flow S1 of flushing gas flows, and in that a second gas flow S2 of tempering gas is fed into the first gas flow S1, wherein the first gas flow S1 and the second gas flow S2 form a third gas flow S3 between the substrate holder 7 for supporting the substrate and the heating device 13, the flow rate of the third gas flow being greater than the circumferential velocity of the susceptor 5 on the radially outer edge of the substrate holder 7.

An apparatus or a method is characterized in that a plurality of heat-affected zones 17 are provided, in which heat is periodically conducted in or out in a pulsed manner, wherein the heat-affected zones 17 are arranged at different azimuthal angles to each other with respect to the central arrangement of the base 5 and/or at different radial distances from the center of the base 5.

An apparatus or a method is characterized in that at least one heat-affected zone 17 is arranged in a circumferential region around the center of the susceptor 5, in which a plurality of substrate holders are located, on which heat is introduced or removed periodically in a pulsed manner.

An apparatus or a method, characterized in that the heat affected zone 17 is limited to an angular range of at most 90, 60, 45, 30 or 15 degrees around the axis a.

An apparatus or a method is characterized by temperature measuring points 31, 31' arranged radially outside and/or radially inside the heat affected zone for measuring the temperature of the surface of the susceptor 5.

An apparatus or a method is characterized in that the tempering gas has a flow direction directed radially inwards or radially outwards with respect to the susceptor rotation axis A.

An apparatus or a method is characterized in that a plurality of feed openings 14 'are provided at different radial distances from each other with respect to the base rotation axis A, wherein one or more tempering gases can be fed in selectively through one or more feed openings 14'.

All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of this application also fully encompasses the disclosure of the associated/appended priority documents (copies of the prior application) and is intended to include the features of these documents in the claims of this application. The dependent claims, even if they do not have the features of the cited claims, characterize independent inventive developments of the prior art with their features, in particular in order to propose divisional applications based on these claims. The invention specified in each claim may additionally have one or more of the features specified in the above description, in particular with reference numerals and/or in the list of reference numerals. The invention also relates to several design forms in which some of the features mentioned in the foregoing description are not implemented, in particular in general they are obviously not necessary for the respective purpose of use, or may be replaced by other technically equivalent means.

List of reference numerals