DEVICE AND METHOD TO CONTROL THE UNIFORMITY OF A GAS FLOW IN A CVD OR AN ALD REACTOR OR OF A LAYER GROWN THEREIN

Abstract

A measuring device is provided for determining the position of a susceptor in a reactor housing. The measuring device includes a central element, which can be fastened on the susceptor at a predefined location, and a plurality of sensing arms, which protrude from the central element beyond an outer periphery of the susceptor. The sensing arms respectively include a sensing section that can be brought in touching contact with a contact zone. The contact zone is formed by an inner periphery of the reactor housing or a component arranged in the reactor housing. Using the measuring device, the position of a susceptor of a CVD reactor is determined relative to the reactor housing or a component arranged in the reactor housing.

Claims

1. A measuring device for determining a position of a susceptor (3) in a reactor housing (1), the measuring device comprising: a central element (26), which is fastened on the susceptor (3) at a predefined location; and a plurality of sensing arms (29), which protrude from the central element (26) beyond an outer periphery (4) of the susceptor (3), wherein said sensing arms respectively include a sensing section (30) that is brought in touching contact with a contact zone.

2. The measuring device of claim 1, wherein the contact zone is formed by an inner periphery (2) of the reactor housing (1) or a component (21) arranged in the reactor housing (1).

3. The measuring device of claim 1, wherein the central element (26) includes centering means (27, 28) which fasten the central element (26) on the susceptor (3), and wherein the predefined location is a center of the susceptor (3).

4. The measuring device of claim 1, further comprising communication means configured to wirelessly transmit data through a wall of the reactor housing (1).

5. The measuring device of claim 4, further comprising a battery configured to provide power to the communication means.

6. The measuring device of claim 1, further comprising spring elements (33) which act upon the sensing arms (29) in a direction extending away from the central element (26).

7. The measuring device of claim 1, further comprising position-measuring elements (34) which are configured to determine the respective positions of the sensing arms (29) relative to the central element (26).

8. The measuring device of claim 7, wherein the position-measuring elements (34) are configured to determine respective distances of the sensing sections (30) from a center of the measuring device.

9. The measuring device of claim 2, wherein each of the sensing sections (30) includes a sloping flank (31).

10. The measuring device of claim 9, wherein the sloping flanks (31) of the sensing sections (30) are arranged in such a way that the sloping flanks (31) are acted upon by the inner periphery (2) of the reactor housing (1) or by the component (21) arranged in the reactor housing (1) as the opened reactor housing (1) is closed and the sensing arms (29) are displaced toward a center of the susceptor (3) due to a sliding motion of the inner periphery (2) of the reactor housing (1) or the component (21) along the sloping flanks (31), wherein the respective distances of the sensing sections (30) from the center of the susceptor (3) are determined by means of position-measuring elements (34).

11. A method for adjusting a position of a susceptor (3) relative to a reactor housing (1) or a component (21) arranged in the reactor housing (1), wherein a flow-through area (10) extends between a gap between an outer periphery (4) of the susceptor (3) and an inner periphery (2) of the reactor housing (1) or the component (21), the gap defined by a gap width (S), the method comprising: fastening a measuring device (25) on the susceptor (3) at a predetermined location on the susceptor (3), the measuring device fastened with a central element (26); scanning the inner periphery (2) of the reactor housing (1) or the component (21) with sensing sections (30) formed on sensing arms (29) that protrude from the central element (26) beyond the outer periphery (4) of the susceptor (3); determining, using the measuring device (25), the gap width (S); and adjusting, using adjusting means (13, 14, 16), the position of the susceptor (3), thereby adjusting the gap width (S).

12. The method of claim 11, further comprising: closing the reactor housing (1) which causes the inner periphery (2) of the reactor housing (1) or the component (21) arranged in the reactor housing (1) to act upon sloping flanks (31) of the sensing sections (30), which in turn causes the sensing arms (29) to be displaced towards a center of the susceptor (3); and determining, using position-measuring elements (34), the respective distances between the sensing sections (30) from the center of the susceptor (3).

13. The method of claim 12, further comprising wirelessly transmitting, via communication means, data regarding the position of the susceptor (3), as determined by the measuring device (25).

14. The method of claim 13, further comprising providing power to the communication means from a battery.

15. The method of claim 11, wherein the position of the susceptor (3) is adjusted while the reactor housing (1) is closed and at a reduced total pressure within the reactor housing (1) and/or at an elevated temperature of the susceptor (3).

16. A method for adjusting a position of a susceptor (3) relative to a reactor housing (1) or a component (21) arranged in the reactor housing (1), wherein a flow-through area (10) extends between an outer periphery (4) of the susceptor (3) and an inner periphery (2) of the reactor housing (1) or the component (21), the method comprising: adjusting with adjusting means (13, 14, 16) the position of the susceptor (3) relative to the inner periphery (2) so as to maximize a lateral uniformity of a gas flow above the susceptor or of a layer grown on one or more substrates lying on the susceptor (3).

17. The method of claim 16, wherein adjusting the position of the susceptor comprises: adjusting, in a first adjusting step, the position of the susceptor (3) while the reactor housing (1) is open; and adjusting, in one or more second adjusting steps, the position of the susceptor (3) while the reactor housing (1) is closed, the first adjusting step and the one or more second adjusting steps maximizing a lateral uniformity of the layer grown on the one or more substrates lying on the susceptor (3).

18. The method of claim 17, further comprising: varying, in a third adjusting step, a flow of a flushing gas from several flushing gas openings (18) arranged circumferentially around the susceptor (3) into the flow-through area (10) while the reactor housing (1) is closed, the varying of the flow of the flushing gas further maximizing the lateral uniformity of the layer.

19. The method of claim 18, further comprising: varying, in a fourth adjusting step, a heating power of at least two heating elements (19, 20) for heating the susceptor (3) while the reactor housing (1) is closed.

20. The method of claim 19, wherein one or more of the second, third and fourth adjusting steps are carried out at an elevated temperature and at a reduced pressure in the reactor housing (1).

21. The method of claim 20, further comprising measuring a thickness of the layer or a composition of the layer in situ at different circumferential positions of the susceptor (3) during one or more of the second, third and fourth adjusting steps.

22. The method of claim 21, further comprising repeatedly: (i) measuring properties of the layer on a peripheral portion of the susceptor (3) at the different circumferential positions of the susceptor (3); and (ii) performing one or more of the second, third and fourth adjusting steps.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention is described in greater detail below with reference to exemplary embodiments. In the drawings:

[0012] FIG. 1 schematically shows a longitudinal section through a reactor housing 1,

[0013] FIG. 2 shows an enlarged detail of FIG. 1, in which a measuring device 25 is attached to a susceptor 3,

[0014] FIG. 3 shows a section along the line III-III in FIG. 2,

[0015] FIG. 4 shows a longitudinal section through a second exemplary embodiment of a process chamber of a closed reactor housing 1, the upper part of which can be separated from a lower part in the direction of the arrow P in order to open the reactor housing,

[0016] FIG. 5 shows a perspective view of a measuring device arranged on a susceptor, and

[0017] FIG. 6 schematically shows a longitudinal section through a sensing arm 29, which is fastened on a central element 26 of the measuring device and features a sensing end 30.

DESCRIPTION OF THE EMBODIMENTS

[0018] A reactor housing 1 consists of a gastight steel housing such that the volume of the housing 1 can be evacuated. An upper housing part 1 can be separated from and, in particular, lifted off a lower housing part 1 in order to open a process chamber 9 of the reactor housing 1.

[0019] A gas inlet element 6 designed in the form of a showerhead is fastened on the upper housing part 1. It features a gas discharge surface with a plurality of gas discharge openings 7 for introducing a process gas into the process chamber 9. The process gas may consist of a carrier gas that transports reactive gases. The carrier gas may consist of a noble gas. However, hydrogen or nitrogen may also be considered as carrier gases. The carrier gas particularly transports volatile source materials that contain metals in order to grow TiSiN layers, LaOx, ZrOx, HfOx or underdoped high-K layers on a substrate 5. The flow rates of the carrier gases and the source materials are adjusted by means of a not-shown mass flow controller. The gas flows being discharged from the gas discharge openings 7 flow over the substrate 5 lying on a susceptor 3 in a radial direction referred to the center of the circular, disk-shaped susceptor 3.

[0020] The outer periphery 4 of the susceptor 3 is surrounded by a gap that extends along a circle and has a gap width S. The gap width S may vary at different circumferential positions if the outer periphery of the susceptor 3 does not extend concentric to a circular inner periphery 2 of the reactor housing 1. The inner periphery 2 does not necessarily have to be formed by the reactor housing 1, but may also be formed by a component 21 arranged within the reactor housing (see FIG. 4). The gap between the inner periphery 2 and the outer periphery of the susceptor 3 forms a flow-through area 10, through which the process gas can flow from the process chamber 9 into a housing section 11 arranged downstream of the process chamber 9. A gas suction opening 8 is arranged at this location in an eccentric position and connected to a not-shown gas suction line that in turn is connected to a vacuum pump, by means of which the hollow space of the reactor housing 1 can be evacuated or by means of which a defined total pressure can be adjusted within the process chamber 9.

[0021] The susceptor 3 is carried by a susceptor carrier 12 that is connected to a first flange 13. A second flange face 14 of a second flange 14 abuts on a first flange face 13 of the first flange 13. The first flange 13 is rigidly connected to the susceptor 3 whereas the second flange 14 is rigidly connected to the reactor housing 1. The two flanges 13, 14 can be displaced relative to one another with the aid of adjusting means. The plane flange faces 13, 14 slide on one another during this displacement. Consequently, the susceptor 3 can be displaced within the plane, in which the flow-through area 10 lies. For this purpose, the flange faces 13, 14 respectively extend parallel to the direction, in which the flow-through area 10 extends, and parallel to the upper side of the susceptor 3, which carries the at least one substrate 5 and in turn extends parallel to the gas discharge surface of the gas inlet element 6.

[0022] The flanges 13, 14 can be displaced relative to one another in the two directions, in which the flange faces 13, 14 extend, by means of several setscrews 16. Four setscrews 16 may be provided, wherein two setscrews 16 respectively lie opposite of one another in a square arrangement. The setscrews 16 have a fine-pitch thread and are respectively screwed into threaded bores 36. In this case, the threaded bores 36 may be arranged in a collar, which protrudes from the outer periphery of the first flange 13 in the direction of the second flange 14, such that the collar forms a border, near which the second flange 14 is located.

[0023] In a variation of the invention, however, it is proposed that two setscrews 16, which can be respectively actuated in directions extending perpendicular to one another, are provided and a spring element 23 is arranged opposite of each of these setscrews 16. The second flange 14 can be displaced relative to the first flange 13 against the restoring force of the spring element 23 by turning the setscrew 16 in one direction. If the setscrews 16 is turned in the opposite direction, the spring force of the spring element 23 causes a displacement of the second flange 14 in the opposite direction. The spring element 23 may be arranged in a bore of the collar and supported on a circumferential area of the second flange 14. In an opposite location of the circumferential area, an end face 16 of the setscrew 16 acts upon the circumferential periphery of the second flange 14.

[0024] A bellows 15 is provided and fastened on the reactor housing 1 with a fastening element and on the susceptor 3 with its second fastening end. For this purpose, the susceptor carrier 12 features in the exemplary embodiment a collar 24, on which the fastening element of the bellows 15 is fastened. The other fastening element of the bellows is fastened on the flange 14 on the housing side.

[0025] A flushing gas duct 17 is located vertically above the flow-through area 10 in a region radially outside the process chamber 9. The flushing gas duct 17 features a plurality of circumferentially arranged gas discharge openings 18, through which a flushing gas can be directly introduced into the flow-through area 10. The flushing gas openings 18 are located on a circular, arc-shaped line in the flow direction, namely above and approximately in the center of the continuous circular, arc-shaped flow-through area 10, such that the process gas discharged from the gas discharge openings 7 is mixed with the flushing gas radially outside the process chamber.

[0026] FIGS. 2 and 3 schematically show a measuring device 25, by means of which the relative position of the susceptor 3 within the process chamber 1 can be determined. The measuring device 25 particularly makes it possible to determine the gap width S of the flow-through area 10 at different circumferential positions. The gap width S extends in the radial direction and defines the distance between the outer periphery 4 of the susceptor 3 and the inner periphery 2 of the reactor housing 1 or of a component 21 that is arranged in the reactor housing 1 and annularly surrounds the susceptor 3 (see FIG. 4).

[0027] The measuring device 25 features a central element 26 that can be temporarily fastened on the susceptor 3 with the aid of fastening means. In the exemplary embodiment, the fastening means consist of centering elements. The centering elements in the exemplary embodiment consist of a centering pin 27 that is inserted into a centering opening 28.

[0028] Several sensing arms 29, which feature sensing sections 30 on their ends, protrude from the central element 26 in uniform circumferential distribution. In the exemplary embodiment, four sensing arms 29 protrude from the central element 26. The sensing arms 29 are preferably spring-loaded in the radial direction such that the sensing sections 30 abut on the inner periphery 2 under the influence of a spring force.

[0029] FIG. 6 schematically shows the corresponding design of the measuring device 25. The central element 26 features a measuring unit with an opening, in which one end of the sensing arm 29 is arranged. A spring element 33 acts upon the end of the sensing arm 29 in the radial direction, i.e. away from the central element 26.

[0030] A position-measuring element 34 is provided, by means of which the radial position of the sensing arm 29 relative to the central element 26 can be determined.

[0031] A communication device 35 is capable of communicating wirelessly with a not-shown transceiver. The communication device 35 features its own power supply, e.g. in the form of a battery. The communication device 35 can transmit the radial positions of the sensing arms 29 to the not-shown transceiver. It is particularly proposed that the reactor housing 1 features zones of dielectric material, through which the wireless data transmission link extends. The measuring device features a battery compartment with batteries arranged therein for its energy supply. The battery compartment may be assigned to the central element 26.

[0032] In the exemplary embodiment illustrated in FIG. 4, the sensing arm 29, particularly the sensing section 30, has a sloping flank 31. The component 21 surrounding the susceptor 3, which is rigidly connected to the reactor housing 1, has a peripheral edge 22 that acts upon the sloping flank 31 as the housing is closed opposite to the direction of the arrow P in FIG. 4 such that the sensing arm 29 can be moved into its scanning position. The sloping flanks 31 are acted upon by the peripheral edge 22 in a direction extending perpendicular to the direction, in which the sensing arm 29 extends, such that the sensing arm 29 is displaced in the direction of the center, in which the centering pin 27 is located. The peripheral edge 22 passes over the sloping flank 31 such that a periphery of the sloping flank 31 abuts on a contact zone of the component 21. The periphery of the sloping flank 31 may extend on the surface area of a cylinder.

[0033] The position-measuring elements 34 measure the radial distance of the sensing section 30 from the center of the susceptor 3 and therefore the local gap width S. The radial position of the susceptor 3 within the reactor housing 1 and therefore the local gap width S can be adjusted with the aid of the adjusting means 13, 14, 16.

[0034] The gap width S influences the gas flow from the gas inlet element 6 over the substrate 5 and into the housing volume 11, which is arranged underneath the susceptor 3 and contains the gas suction opening 8, wherein this gas flow is indicated with arrows in FIG. 1. Due to the eccentric position of the gas suction opening 8, an asymmetric gas flowreferred to the axis of the susceptor 3forms within the gas volume 11. The flow resistance of the flow-through area 10 can be locally influenced by laterally adjusting the position of the susceptor 3 and thereby varying the gap width S. The optimal position of the susceptor 3 can be determined in the closed state of the reactor housing 1 and under process pressures by means of an iteration method. Since the adjusting means feature screws 16 with a fine-pitch thread, an in-situ adjustment in the micrometer range can be realized.

[0035] According to another aspect of the invention, the gas flow in the process chamber 9 above the susceptor 3 can also be influenced by varying the flushing gas flows introduced through the flushing gas opening 18. It is particularly proposed that an overall Ar flow of 100 SCCM to 7000 SCCM flows through these flushing gas openings 18. Preferably the flow can be in a range between 500 SCCM and 4900 SCCM. Alternatively, N2 may also be used as flushing gas instead of Ar.

[0036] The flow profile can likewise be influenced due to the utilization of two heating elements 19, 20 at different radial distances from the center of the susceptor, wherein the heating elements 19, 20 are respectively supplied with different power. For this purpose, the susceptor features hollow spaces, in which a radially inner heating element 20 and a radially outer healing element 19 surrounding the inner heating element are arranged.

[0037] A circumferentially symmetric layer can be grown on the substrate 5 due to the utilization of the measuring device 25 in combination with the adjusting means 13, 14, 16. The gap width S is optimized in order to achieve this azimuthal symmetry. A radially symmetric layer profile can be adjusted between the center of the substrate 5 and its outer periphery 4 with the aid of the two heating devices 19, 20. For example, if the layer thickness in the peripheral region needs to be increased, the radially outer heating device 19 is supplied with greater heating power such that the process temperature is locally increased. The layer growth can be supplementally influenced by introducing a flushing gas through the peripheral flushing gas openings 18. The introduction of a flushing gas flow makes it possible to grow layers, the layer thickness of which is thinner in the peripheral region. This is a result of the dilution effect achieved by introducing the flushing gas.

[0038] A layer can be grown on an individual substrate 5 on the non-rotating susceptor 3. This layer is then analyzed with respect to its layer composition and its layer thickness. The result of this analysis makes it possible to deduce the direction, in which the susceptor 3 has to be adjusted within the reactor housing 1 with the aid of the adjusting means 13, 14, 16 in order to compensate asymmetries or inhomogeneities detected during the analysis. The respective heating power for operating the heating devices 19, 20, as well as the flushing gas flow through the flushing gas openings 18, is likewise optimized based on these analyses.

[0039] However, an optimization of the local gap width S based on the position of the susceptor 3 relative to the reactor housing 1 can also be realized with several substrates that are merely arranged on the peripheral region of the susceptor 3. In the iterative method, a layer is initially grown on the at least one substrate and its layer properties are analyzed, particularly in the peripheral region, in several steps. The direction, in which the susceptor 3 has to be displaced within the reactor housing 1 in order to locally vary the gap width S of the flow-through area 10 in such a way that the layer properties homogenize, is then determined based on a model calculation or experiences gained otherwise. The position of the susceptor 3 can be adjusted in a reproducible fashion due to the utilization of the described measuring device 25.

[0040] The invention pertains to a method for optimizing the uniformity of a layer grown on one or more substrates lying on the susceptor 3. In this case, the uniformity concerns the layer thickness. However, it may also concern the layer composition. In a first adjusting step, the position of the susceptor 3 is adjusted while the process chamber is open. A precision adjustment of the position of the susceptor 3 is carried out in one or more adjusting steps while the process chamber is closed. In a second adjusting step, the position of the susceptor particularly is varied within the inner periphery 2 of the reactor housing 1 or of a component arranged in the reactor housing. This takes place under process conditions, e.g. at a total pressure within the process chamber that is lowered to the process pressure and while the susceptor 3 is heated to a process temperature. Optical sensors that are not illustrated in the drawings particularly may be provided within the reactor housing 1 in order to measure the layer thickness of a layer grown on a substrate 5 arranged on the susceptor 3 on the periphery of the susceptor. This may be realized, for example, by means of an interferometer. The layer composition can be determined by means of photoluminescence measurements. A non-uniform layer growth can be detected by measuring one or more of these layer properties at different circumferential positions. A subsequent displacement of the susceptor 3 within the flow-through area 10 makes it possible to influence the flow through the flow-through area 10 in such a way that the layer growth is reduced at locations, at which an excessive layer growth was detected. This is achieved, for example, by increasing the gap width of the flow-through area 10 at this location.

[0041] The second adjusting step is successively repeated several times until the uniformity of the layer composition can no longer be maximized with this method. In this case, a layer property such as, for example, the layer thickness is initially measured at different circumferential positions of the susceptor and the position of the susceptor 3 is then suitably varied.

[0042] Non-uniformities of the layer property, e.g. the layer thickness, can be additionally compensated by carrying out a third adjusting step, in which the layer property, e.g. the layer thickness, is initially also determined at different circumferential positions and a flushing gas flow is subsequently varied at different circumferential positions such that the layer property changes at these locations during the growth of a layer. If the layer property is a layer thickness, for example, the flushing gas flow is varied at one or more circumferential positions in such a way that the layer growth is increased or decreased. An increase of the flushing gas flow at a certain circumferential position leads to a reduced layer growth rate at this location. A reduction of the flushing gas flow in turn leads to an increase of the growth rate at this location.

[0043] In a fourth adjusting step, the heating power of a radially outer heater 19 can be modified. The layer growth is reduced in a radially outer region by reducing the heating power of the radially outer heater 19. The layer growth is in turn increased by increasing the heating power of the radially outer heater 19.

[0044] The second to fourth adjusting steps, which respectively consist of a measuring step and an adjusting step, respectively can be successively repeated several times, wherein the process chamber temperature and the process chamber pressure are not changed.

[0045] The preceding explanations serve for elucidating all inventions that are included in this application and respectively enhance the prior art independently with at least the following combinations of characteristics, namely:

[0046] A device, which is characterized by adjusting means 13, 14, 16 for varying the position of the susceptor 3 relative to the reactor housing 1 or the component 21 and to thereby vary the distance S between the outer periphery 4 and the inner periphery 2, and by a measuring device 25 for determining the position of the susceptor 3 relative to the inner periphery 2.

[0047] A device, which is characterized in that the flow-through area 10 is an annular gap surrounding the susceptor 3.

[0048] A device, which is characterized in that a susceptor carrier 12 carrying the susceptor 3 features a first flange 13 with a first flange face 13 and a second flange 14 with a second flange face 14 is arranged on the reactor housing 1, wherein the first flange 13 is displaceably connected to the second flange 14, and wherein the first flange face 13 slides along the second flange face 14 during a displacement of the first flange 13 relative to the second flange 14.

[0049] A device, which is characterized in that the adjusting means feature one or more setscrews 16, which are respectively screwed into a threaded bore in the first flange 13 and engage on the second flange 14 with an end face 16.

[0050] A device, which is characterized in that one or more of the setscrews 16 act against a spring 23, which supports the second flange 14 relative to the first flange 13.

[0051] A device, which is characterized in that the susceptor carrier 12 is connected to a first end of a bellows 15, the second end of which is connected to the reactor housing 1.

[0052] A device, which is characterized by flushing gas openings 18 for introducing a flushing gas into the flow-through area 10, wherein the flushing gas openings 18 are arranged upstream of the flow-through area 10 in such a way that a process gas, which is introduced into a process chamber arranged above the susceptor 3 through a gas inlet element 6, mixes with the flushing gas in the flow-through area 10.

[0053] A device, which is characterized in that the susceptor 3 features a radially inner heating element 20 and a radially outer heating element 19 surrounding the inner heating element.

[0054] A measuring device, which is characterized by the determination of the position of a susceptor 3 in a reactor housing 1, featuring a central element 26, which can be fastened on the susceptor 3 at a predefined location, and a plurality of sensing arms 29, which protrude from the central element 26 beyond an outer periphery 4 of the susceptor 3, wherein said sensing arms respectively feature a sensing section 30 that can be brought in touching contact with a contact zone.

[0055] A measuring device, which is characterized in that the contact zone is formed by an inner periphery 2 of the reactor housing 1 or a component 21 arranged in the reactor housing 1.

[0056] A measuring device, which is characterized in that the central element 26 features centering means 27, 28, by means of which the central element 26 can be fastened in the center of the susceptor 3.

[0057] A measuring device, which is characterized in that the measuring device features communication means for the wireless data exchange through the wall of the reactor housing 1.

[0058] A measuring device, which is characterized in that the measuring device features a battery.

[0059] A measuring device, which is characterized in that the sensing arms 29 are acted upon in the direction extending away from the central element 26 by a spring element 33.

[0060] A measuring device, which is characterized by a position-measuring element 34 for determining the position of the sensing arm 29 relative to the central element 26.

[0061] A measuring device, which is characterized in that the position-measuring element 34 determines the distances of the sensing sections 30 from a center of the measuring device.

[0062] A measuring device, which is characterized in that the sensing section 30 has a sloping flank 31.

[0063] A measuring device, which is characterized in that the sloping flanks 31 of the sensing sections 30 are arranged in such a way that they are acted upon by the inner periphery 2 of the reactor housing 1 or by the component 21 arranged in the reactor housing 1 as the opened reactor housing 1 is closed and the sensing arms 29 are displaced toward a center of the susceptor 3 due to a sliding motion of the inner periphery 2 of the reactor housing 1 or the component 21 along the sloping flanks 31, wherein the distance of the sensing section 30 from the center can be determined by means of position-measuring elements 34.

[0064] A method, which is characterized in the adjustment of the position of a susceptor 3 relative to a reactor housing 1 or a component 21 arranged in the reactor housing 1, wherein a flow-through area 10 extends between an outer periphery 4 of the susceptor 3 and an inner periphery 2 of the reactor housing 1 or the component 21, wherein the distance S between the outer periphery 4 and the inner periphery 2 is determined by means of a measuring device 25 and the position of the susceptor 3 relative to the inner periphery 2 is adjusted with the aid of adjusting means 13, 14, 16, wherein the measuring device 25 is separably fastened on the susceptor 3 at a predetermined location with a central element 26, and wherein the inner periphery 2 of the reactor housing 1 or a component 21 arranged in the reactor housing 1 is scanned with sensing sections 30 formed on sensing arms 29, which protrude from the central element 26 beyond the outer periphery 4 of the susceptor 3.

[0065] A method, which is characterized in that the sensing sections 30 respectively have a sloping flank 31, which is acted upon by the inner periphery 2 of the reactor housing 1 or by the component 21 arranged in the reactor housing 1 as the opened reactor housing 1 is closed such that the sensing arms 29 are displaced in the direction of a center of the susceptor 3, and in that the distances of the sensing sections 30 from the center are determined by means of position-measuring elements 34.

[0066] A method, which is characterized in that the data on the position of the susceptor 3 determined by the measuring device is wirelessly transmitted through the wall of the reactor housing 1 with the aid of communication means.

[0067] A method, which is characterized in that the measuring device is supplied with power by a battery.

[0068] A method, which is characterized in that the position of the susceptor 3 is varied while the reactor housing 1 is closed and at a reduced total pressure within the reactor housing 1 and/or at an elevated temperature of the susceptor 3.

[0069] A method, which is characterized in that the position of the susceptor (3) is centered in that way that a gas flow above the susceptor or the lateral uniformity of a layer grown on one or more substrates located on the susceptor (3) is maximized.

[0070] A method, which is characterized in that after centering the susceptor (3) the lateral uniformity is further maximized by a flow of a flushing gas through a flushing gas opening (18) into the area located between the outer periphery (4) and the inner periphery (2).

[0071] A method, which is characterized in that after centering the susceptor (3) the uniformity is further maximized by varying the heat power of at least two heat elements (19, 20) for heating the susceptor (3).

TABLE-US-00001 List of Reference Symbols 1 Reactor housing 1 Upper housing part 1 Lower housing part 2 Inner periphery/inner wall 2 Inner periphery 3 Susceptor 4 Outer periphery 5 Substrate 6 Gas inlet element/showerhead 7 Gas discharge opening 8 Gas suction opening 9 Process chamber 10 Flow-through area 11 Housing section 12 Susceptor carrier 13 Flange 13 Flange face 14 Flange 14 Flange face 15 Bellows 16 Adjusting means/screw 16 End face 17 Flushing gas duct 18 Flushing gas opening 19 Radially outer heater 20 Radially inner heater 21 Component 22 Peripheral edge 23 Spring 24 Collar 25 Measuring device 26 Central element 27 Centering pin 28 Centering opening 29 Sensing arm 30 Sensing section 31 Sloping flank 32 Measuring unit 33 Spring element 34 Position-measuring element 35 Communication device 36 Threaded bore P Arrow S Gap width