Device and method for individually influencing the layer growth of a layer deposited on a substrate in a CVD reactor receiving a plurality of substrates

Abstract

The invention relates to a device and a method for the simultaneous treatment of a plurality of substrates (15) arranged in a process chamber (2) around a gas inlet member (3), wherein the substrates (15) are rotated at a rotational speed about an axis of rotation (D) during the feeding in of a first process gas through first gas outlet openings (4) of the gas inlet member (3), wherein a second process gas, different from the first process gas, is fed into the process chamber (2) through at least one second gas outlet opening (5) arranged upstream of the substrates (15) in relation to the flow direction (S) of the flow of the first process gas, wherein the first and second process gases flow over the substrates in the process chamber (2) in the flow direction (S) and there cause a growth or a change in the layer composition of one layer each on the substrates (15). In order to increase the uniformity of the layers deposited simultaneously on different substrates (15), according to the invention the second process gas is fed into an outlet sector (α) limited to an angular range around the axis of rotation (D) and is pulsed into the process chamber (2) in a manner synchronised with the rotational speed.

Description

Description Device and method for individually influencing the layer growth of a layer deposited on a substrate in a CVD reactor accommodating a plurality of substrates field of technology

[0001] The invention relates to a method for the simultaneous treatment of a plurality of substrates arranged in a process chamber in a particularly circular arrangement around a gas inlet element, wherein during the feeding of a first process gas through first gas outlet openings of the gas inlet element, the substrates or the gas inlet element are rotated at a speed about an axis of rotation running through the gas inlet element, wherein a second process gas is fed into the process chamber through at least one second gas outlet opening arranged upstream of the substrates with respect to the flow of the first process gas, wherein the first and second process gas flow in the process chamber in a flow direction over the substrates and there cause the growth or the change in a layer composition of a respective layer on the substrates.

[0002] The invention further relates to a device for carrying out a method with a gas inlet element arranged in a process chamber with first gas outlet openings for the outlet of a first process gas into the process chamber, with a susceptor having a plurality of storage locations for substrates arranged in a circular arrangement around the gas inlet element, wherein the susceptor or the gas inlet element can be driven in rotation by a rotary drive at a speed about an axis of rotation running in particular through the gas inlet element, and with at least one second gas outlet opening arranged upstream of the storage locations relative to the flow of the first process gas for the outlet of a second process gas into the process chamber. State of the art

[0003] DE 10 2019104433 A1 describes a device and a method for depositing layers on substrates, each of which is arranged on a substrate holder. The substrate holders are arranged in a uniform circumferential distribution on a susceptor that is rotated about a rotational axis such that the substrates rotate at a predetermined speed around a gas inlet element arranged in the center of the susceptor. The gas inlet element has zones arranged one above the other, each of which has gas outlet openings arranged evenly around the circumference of the gas inlet element. Different process gases are fed into the process chamber of the device through these gas outlet openings. Supply lines are located below the susceptor, through which a tempering gas can be fed between a heating device and the susceptor in order to locally influence the heat flow from the heating device to the susceptor.The tempering gas can be fed into a selected outlet sector in a pulsed manner in order to locally influence the temperature of individual sectors of the susceptor.

[0004] US 2014 / 0087567 A1 discloses a gas inlet device arranged above a rotating susceptor supporting substrates, with a gas outlet surface divided into several sectors. Different process gases are fed into the process chamber via a sector each limited to an angular range around the susceptor's rotational axis.

[0005] US 2018 / 0269 078 A1 also describes a gas outlet surface of a gas inlet device divided into several sectors and arranged above a rotating susceptor. The feed of the gases through the various sectors is coordinated with the rotation of the susceptor.

[0006] It is known to drive the substrates or the substrate holders supporting the substrates around a rotational axis during coating in order to achieve homogeneous growth or a homogeneous layer composition across the entire surface of the substrates, and in particular, homogeneous dopant incorporation. It is also known to vary the feed of the process gases in synchronization with the rotational speed of the susceptor.

[0007] It has been observed that the layer composition, growth rate, or dopant concentration within the layer varies despite this measure; for example, the values ​​of the growth rate, layer composition, or dopant concentration at the center of the substrate may differ from the values ​​measured at the edge of the substrate.

[0008] DE 102023 100 077 describes a CVD device similar to the aforementioned device, wherein gas outlet openings are arranged in a pre-flow zone between the gas inlet element and the substrates, through which gas outlet openings a second process gas influencing the layer composition is fed into the process chamber in such a way that it only flows over a partial area of ​​the substrate, in order to thereby adapt the value measured in the center to the value measured at the edge of the substrate. With the second process gas, a higher partial pressure of a process gas causing the dopant incorporation can be achieved at the edge. but it is also possible to use the second process gas to reduce the partial pressure of this process gas if it leads to dilution.

[0009] Despite these measures, the above-mentioned values ​​may differ between the substrates treated simultaneously. Summary of the invention

[0010] The invention is based on the object of taking measures to standardize the layer composition, the growth rate and / or the dopant incorporation of substrates treated simultaneously in a common process chamber.

[0011] The problem is solved by the invention specified in the claims, wherein the subclaims are not only advantageous developments of the independent claims, but also independent solutions to the problem.

[0012] First and foremost, a method is proposed with which several substrates can be treated simultaneously in a process chamber of a CVD reactor. The method is, in particular, a method for depositing layers on the substrates and preferably a method for depositing SiC layers on SiC substrates or Si substrates or on layers that have already been deposited on substrates. However, the method is also suitable for depositing III-V layers on suitable substrates. The method is preferably carried out in a device that has a CVD reactor with a process chamber. The floor of the process chamber can be formed by a susceptor. The susceptor can be heated by a heating device. A heating device can be a resistance heater, an RF heater, or a lamp heater. The susceptor can be heated to a process temperature using a heating device. A first process gas is fed into the process chamber via a gas inlet element forming the center of the process chamber. The first process gas can contain several reactive gases that decompose or react with one another in the process chamber. Decomposition products of the reactive gases are deposited on the surface of the substrate, forming, in particular, crystalline or monocrystalline layers. The first process gas can also contain a dopant with which the deposited layer can be doped. For introducing the first process gas into the process chamber, a first gas supply line is provided, into which at least one reactive gas is fed from a gas mixing system having at least one first gas source.Preferably, a mixture of several reactive gases, for example a silicon-containing gas and a carbon-containing gas, for example C2H6 and SiHe together with H2, is passed through the first gas supply line. The first process gas can also contain a dopant, for example a nitrogen-containing gas, for example N2 or NH3. A rotational axis runs through the gas inlet element and in particular through the center of a gas inlet element having a cylindrical outer surface. In a preferred embodiment, the susceptor can be rotated about this rotational axis using a rotary drive. With the rotary drive, the susceptor can be rotated at a predetermined speed around the gas inlet element, which is stationary relative to the housing of the CVD reactor. According to one variant, it is provided that the gas inlet element can be rotated about a rotational axis using a rotary drive. The susceptor cannot be rotated in this variant.However, it can also be provided that the susceptor is also rotated about the same axis of rotation, in particular in the opposite direction. It can also be provided that the storage locations are formed by substrate holders, which are circular disk-shaped bodies that are driven to rotate about their axis during the deposition of the layer. For this purpose, the Substrate holders are placed in storage pockets on a broad side surface of the susceptor facing the process chamber. Purge gases can be injected into the bottom of the storage pockets, forming a gas cushion on which the substrate holder rests. The purge gases can cause the substrate holders to rotate. The process gas injected into the process chamber decomposes pyrolytically in the process chamber. The decomposition products, for example, Si and C or reaction products containing these elements, diffuse to the substrate surface. As a result, the gas phase immediately above the substrate surface becomes depleted. To prevent inhomogeneous deposition of the layer on the substrate caused by this depletion, the substrate holder carrying one or more substrates is rotated in the manner described above.Despite this measure, inhomogeneity in the layer thickness, layer composition or local dopant concentration within the layer is often unavoidable. The layer thickness, layer composition or dopant concentration within the layer can vary in a radial direction. The value of the layer thickness, layer composition or dopant concentration can be different at the edge of the layer from the value in the middle of the layer. It is also observed that the values ​​for different substrates differ from one another. In order to compensate for these inhomogeneities, i.e. the inhomogeneities within a layer and / or the inhomogeneities from substrate to substrate, the invention proposes that a second process gas be fed into the process chamber into an outlet sector limited to an angular range around the axis of rotation.The outlet sector is preferably selected such that the second process gas flow exiting from the second gas outlet openings flows only over one storage location or one substrate, or even only over a portion of a substrate. For this purpose, the second process gas is varied and, in particular, fed into the process chamber in pulsed fashion. The pulse length is dimensioned such that the quantity of second process gas fed in during the pulse flows only over the surface of a substrate or even flows only over a partial surface of a substrate. The second process gas flow is a time-varying process gas flow. The temporal variation of the second process gas flow can be repeated periodically, synchronized with the rotational speed of the susceptor or the gas inlet device around its axis. The composition of the second process gas can be changed between two consecutive pulses in such a way that two substrates arranged one behind the other in the circumferential direction are exposed to a different gas phase composition with successive gas pulses, so that the layer growth, the layer composition, or the dopant incorporation on different substrates can be influenced differently.If the exit sector is smaller than the sector of the process chamber determined by the diameter of the substrate around the axis of rotation, then only a partial area, for example the edge area of ​​a substrate, can be specifically influenced by the second process gas. The second process gas can contain the same reactive gases as the first process gas, but in this case at least one of these reactive gases preferably has a different partial pressure than the same reactive gas in the first process gas. For example, the second process gas can contain a dopant with a higher partial pressure. However, it is also possible for the second process gas to contain no dopant or no reactive gas at all, but rather to be only a diluent gas, so that the pulsed injection of the second process gas limited to an exit sector leads locally to reduced growth or reduced dopant incorporation.If, however, the second process gas has a higher partial pressure of the reactive gas, the value of the growth rate, the layer composition or the dopant incorporation can be increased locally by the pulsed injection of the second process gas limited to an exit sector.

[0013] In a further development of the invention, it is provided that the first gas outlet openings are distributed uniformly in the circumferential direction over the circumferential surface of the gas inlet element. The gas inlet element can form several zones arranged one above the other in the vertical direction, each having gas distribution chambers into which different process gases or reactive gases are fed. It can further be provided that the first process gas exits the circumferential surface of the gas inlet element uniformly in the circumferential direction, relative to the axis of rotation, and the angular range of the exit sector corresponds at most to the angular distance between two substrates lying next to one another in the circumferential direction around the axis of rotation. The pulse length can correspond at most to the duration in which a region of a susceptor carrying the substrates, corresponding to the angular distance, passes through the exit sector.The pulse length can be shorter than the time it takes for a region of the susceptor corresponding to the diameter of a substrate to pass through the exit sector. The angular range of the exit sector can also be shorter than the angular range of a sector determined by the diameter of a substrate. In this case, the effect of the second process gas can be restricted to a partial area of ​​the substrate. It can also be provided that the pulse frequency of the pulses with which the second process gas is fed into the process chamber is selected such that only one gas pulse flows over one substrate at a time. The pulse frequency can then correspond to the product of the rotational speed and the number of substrates arranged in a uniform circumferential distribution around the gas inlet element. The second process gas can vary with this pulse frequency.Each pulse can thus have a different gas composition, allowing the growth rate, layer composition, or the concentration of the simultaneously deposited layers to be individually influenced. The second process gas flow can also change continuously, with a temporally changing flow pattern periodically related to the susceptor's speed. The layer composition can be particularly effective in this case. be influenced if the layer consists of more than two components, for example three elements, such as GaAlN or the like.

[0014] In a further development of the invention, the gas inlet element has a plurality of second gas outlet openings through which different second process gases are fed into the process chamber into an outlet sector limited to an angular range around the axis of rotation and synchronized with the rotational speed. The different second gas outlet openings can be arranged side by side in the circumferential direction. However, they can also be arranged one above the other, offset in the direction of the axis of rotation of the susceptor. Each of the different second gas outlet openings can be connected to an associated second gas supply line, each of which is connected to a gas supply for a different second process gas via mass flow controllers and valves.Groups of individual gas inlet areas can thus be provided, whereby the gas inlets can be individually controlled and different gases can be fed into the process chamber through the gas inlets. Different gases can also be fed into the process chamber at different times. For example, it is possible to feed a dopant into the process chamber through a second gas outlet opening in order to change the dopant concentration in a defined circumferential section for a limited period of time. This gas outlet opening can, for example, be arranged between two further second gas outlet openings, through each of which a diluent gas, for example an inert gas, is fed in. Gas flows can also be focused by having several second gas outlet openings arranged directly next to one another.In addition, a profile of the gas flow can also be set, for example, by providing or feeding different process gas concentrations through various gas outlet openings arranged directly next to one another. The several second ones. Furthermore, gas outlet openings can also be arranged offset at a uniform angular distribution around the rotational axis of the susceptor or the gas inlet element; for example, the second gas outlet openings can be arranged offset by an angle of 120°. Such a multiple arrangement of second gas outlet openings enables better homogeneity and better wafer-to-wafer control of the dopant incorporation or crystal growth. It is also possible to position the first gas outlet openings, through which a process gas is fed into the process chamber at a uniform circumferential distribution around a rotationally symmetrical gas inlet element, at a uniform spacing on the gas outlet surface of the gas inlet element. The one or more second gas outlet openings are then preferably arranged in the spaces between the evenly distributed first gas outlet openings.However, the invention also provides that a second gas outlet opening can be arranged where a first gas outlet opening is otherwise arranged.

[0015] According to a further development of the invention, it can be provided that the gas outlet opening is arranged radially outside the gas inlet element. The gas inlet element can be arranged in the center of a process chamber. The process chamber then surrounds the gas inlet element in a circle. A gas supply line, for example a pipe, can protrude into the process chamber radially outside the gas inlet element. The pipe has an opening that forms the second gas outlet opening through which the second process gas can be fed into the process chamber. According to a further development of this variant of the invention, it can be provided that a pre-flow zone extends between the gas inlet element and a storage location for one or more substrates, through which pre-flow zone the process gas leaving the gas inlet element flows through the process chamber before reaching the storage location for the substrates.It can be provided that the second gas outlet opening is located directly in front of the storage location for the substrate. For example, A tube extends through the process chamber ceiling into the process chamber, which has a second gas outlet at its end. The second gas outlet is then spaced radially outward from the gas inlet element by the distance of a pre-flow zone.

[0016] The device can have a valve arrangement that can be controlled by a control device or regulating device. The valve arrangement can have one or more mass flow controllers and at least one changeover valve. With the changeover valve, the second process gas can be switched from a vent outlet, through which the second process gas is guided past the gas inlet element, to a run outlet, so that the second process gas flows into a gas supply line that opens into a gas distribution chamber, from which the second process gas can flow into the process chamber from the one or more second gas outlet openings. With the changeover valve, however, a gas flow having the same gas composition as the first process gas can be fed into the process chamber alternately with a gas flow having a different gas composition. The gas composition of the second process gas can be specified using a mass flow controller.

[0017] A further development of the method or device described above enables the control of a value of the growth rate, layer composition, or dopant incorporation. For this purpose, a measuring device is provided, which may have a sensor. The sensor may be an optical sensor. The measuring device can be used to determine the layer thickness, the layer composition, and / or the dopant concentration of the layer. The measuring device then measures the values ​​of the layers of each of the substrates. A control device receives this value as an input value in order to control it against a target value. For this purpose, The control device adjusts the gas composition of the second process gas individually for each of the substrates. This method ensures that the values ​​of the simultaneously deposited layers differ minimally from a target value, since the control device is configured to individually vary the value of the layer thickness, layer composition, and / or dopant concentration of the layer of each substrate based on a measured value by varying the composition of the second process gas, thereby adjusting the value to a target value. Short description of the drawings

[0018] Embodiments of the invention are explained below with reference to the accompanying drawings. They show: Fig. 1 shows a schematic sectional view of a CVD reactor 1 of a first embodiment of the invention, Fig. 2 shows the section along the line II-II in Figure 1, Fig. 3 enlarges section III-III in Figure 2, Fig. 4 shows the section along the line IV-IV in Figure 3, Fig. 5 shows a second embodiment in a representation according to Figure 1 Fig. 6 shows a third embodiment according to a section of the line VI-VI in Figure 5, Fig. 7 the view VII in Figure 6, Fig. 8 shows the section along line VIII in Figure 6, Fig. 9 is a representation according to Figure 8 of a fourth embodiment, Fig. 10 schematically shows a valve arrangement of a fifth embodiment, Fig. 11 is a representation according to Figure 6 of a sixth embodiment, Fig. 12 shows the sixth embodiment in the direction of arrow XII in Figure 11, Fig. 13 shows the section along the line XIII-XIII in Figure 11, Fig. 14 the section along the line XIV-XIV in Figure 11, Fig. 15 the section along the line XV-XV in Figure 11, Fig. 16 shows a seventh embodiment in a representation according to Figure 12, Fig. 17 shows the section along the line XVII-XVII in Figure 16, Fig. 18 the section along the line XVIII-XVIII in Figure 17, Fig. 19 shows an eighth embodiment of the invention in a representation according to Figure 6, and Fig. 20 shows a ninth embodiment of the invention in a representation according to, Fig. 21 shows a tenth embodiment of the invention similar to the fourth embodiment shown in Fig. 9, but with the second gas outlet opening 5 arranged downstream of a lead time 31. Description of the embodiments

[0019] The figures schematically show a CVD reactor known per se or details of such a CVD reactor, in which the details are limited to the elements essential for explaining the invention.

[0020] A CVD reactor 1 has a gas-tight housing containing a process chamber 2. The process chamber 2 is bounded at the top by a process chamber ceiling 20 and at the bottom by a susceptor 16. The process chamber ceiling 20 and the susceptor 16 can be made of coated graphite.

[0021] Below the susceptor 16 is a heating device 19, with which the susceptor 16 and the process chamber 2 located above it can be heated. The susceptor 16 can be driven in rotation about a rotation axis D at a predetermined speed by a rotary drive 29. The susceptor 16 carries a plurality of substrate holders 17 arranged in a circular arrangement about the rotation axis D, each of which can form a storage location for one or more substrates. In the exemplary embodiment, each substrate holder 17 carries a substrate 15. The substrate holders 17 are located in pockets in the broad side surface of the susceptor 16 and can be heated by gas cushions (not shown). supported and driven to rotate around its axis of symmetry. The heating device 19 can be an RF coil that generates eddy currents within the susceptor 16 to heat it.

[0022] A gas outlet element 18 is arranged around the circumferential edge of the susceptor 16, which runs on a circular line, with which gas fed into the process chamber 2 or decomposition products can be pumped out of the process chamber 2 by means of a vacuum pump (not shown).

[0023] At the center of the process chamber 2 is a gas inlet element 3, which is stationary relative to the housing of the CVD reactor 1 and can be made of quartz or another suitable material. At least two gas supply lines 8, 9 open into the gas inlet element 3 to feed a first process gas into the gas inlet element 3 through the gas supply line 8 into a gas distribution chamber 6. The gas inlet element 3 has a circumferential surface 3' extending on an outer surface of a circular cylinder, which has a plurality of first gas outlet openings 4 through which the first process gas can flow into the process chamber 2. The first process gas flows through the process chamber 2 essentially in a radial direction. Figure 2 denotes the flow direction with S.

[0024] A gas source arrangement is provided, which has at least a first gas source 10 and at least a second gas source 12. The mass flow of the first process gas or a second process gas can be adjusted by means of mass flow controllers 11, 13. The first process gas can, for example, contain reactive gases with which a layer can be deposited on the substrates 15. For example, the reactive gases can be silane or disilane, as well as methane or ethane, in order to deposit a SiC layer. The first process gas can contain a dopant, for example nitrogen or ammonia or another gas containing an element of main group V.

[0025] The first gas outlet openings 4 are arranged on the circumferential surface 3' of the gas inlet element 3 in such a way that a gas flow that is as homogeneous as possible emerges from the gas inlet element 3 in the radial direction and flows over the substrates 15.

[0026] A switching valve 14 makes it possible to feed the second process gas into the process chamber 2 in pulsed form. Furthermore, the means described below are provided for limiting the outlet sector a, into which the second process gas is fed into the process chamber 2, to an angular range around the rotation axis D, so that the pulses of the second process gas interact only with individual substrates 15 or even only with partial areas of a substrate 15.

[0027] The composition of the second process gas differs from the composition of the first process gas in such a way that in the regions of the substrates 15 in which the second process gas acts on the substrate, the layer thickness, the layer composition, or the dopant incorporation changes differently than in the regions in which the second process gas does not act on the substrate. With the switching valve 14, the gas pulses can be specifically fed into the process chamber 2 such that they only flow over partial regions of a single substrate 15 or only over a single substrate 15. With the mass flow controller 13, which is arranged between the second gas source 12 and the switching valve 14, the composition of the second process gas can be changed so quickly that successive pulses flowing over successive substrates 15 in the direction of rotation differ from one another. have different compositions, so that the growth rate, the layer composition or the dopant incorporation can be specifically influenced in relation to the substrate.

[0028] A measuring device 26 is provided, which in particular has an optical sensor with which the layer thickness, the layer composition, or the dopant concentration of the layer can be measured along an optical path 27, which can run through the process chamber ceiling 20. The value thus individually measured for each substrate 15 passing beneath the sensor of the measuring device 26 can be used to control the mass flow controller 13 in order to vary the partial pressure of the reactive gas contained in the second process gas such that the measured value is regulated towards a target value. In this way, it is possible to avoid or reduce deviations in layer thicknesses, layer compositions, or substance concentrations that would otherwise occur from substrate to substrate.

[0029] Figure 2 shows an embodiment in which the exit sector a extends over a smaller angular range than the angular range ß, which is defined by the diameter of a substrate 15. With such a small exit sector, individual regions of the substrate surface can be influenced with the second process gas. For example, the dopant concentration can be increased only in an edge region by ensuring that the gas pulse fed into this exit sector a flows only over the edge region of the substrate 15 and has an increased or decreased concentration of the reactive gas that causes the dopant incorporation.

[0030] In other embodiments it is provided that the angular range over which the exit sector a extends is at least smaller than a Sector ö defined by the angular range by which two substrates 15 are spaced from each other. With such a limitation of the exit sector a and a limitation of the pulse duration, it is possible to individually influence only one complete substrate surface with the second process gas.

[0031] In the embodiment illustrated in Figures 1 to 4, the second process gas is fed into a second gas distribution chamber 7, which, like the first gas distribution chamber 6, is located within the gas inlet element 3. The gas distribution chambers 6, 7 are separated from one another by a partition wall 21. The first gas outlet openings 4 originate from the first gas distribution chamber. Second gas outlet openings 5 ​​originate from the second gas distribution chamber 7 and extend only over a limited circumferential angle, so that the outlet sector a can be defined by the arrangement of the second gas outlet openings 5.

[0032] In the embodiment shown in Figure 5, the second process gas is fed into the process chamber 2 through a gas outlet opening 5, which is arranged within the process chamber ceiling 20.

[0033] The embodiment illustrated in Figures 6 to 8 shows a gas inlet element 3 having three first gas distribution chambers 6, 6', 6" arranged vertically one above the other, into which different reactive gases can be fed together with a carrier gas through first gas supply lines 8, 8', 8". For example, the two gases forming the layer and additionally a dopant can be fed into the various gas distribution chambers 6, 6', 6".

[0034] In an area limited to a circumferential section of the gas inlet element 3, there is a second gas distribution chamber 7, into which the second process gas can be fed through a second gas supply line 9. The second process gas can be fed into the process chamber from second gas outlet openings 5. Here, too, one or more second gas outlet openings 5 ​​can be arranged on the circumferential surface 3' in such a way that the second process gas is fed into the process chamber 2 in a manner limited to the above-described outlet sector a.

[0035] The embodiment shown in Figure 9 differs essentially from the embodiment shown in Figures 1 to 4 and 6 to 8 in that the supply line 9 extends as a pipe through the process chamber ceiling 20 and opens into the process chamber 2 with a second gas outlet opening 5.

[0036] Figure 10 schematically shows a valve arrangement. A first process gas can be provided using the mass flow controllers 25. The first process gas can comprise two reactive gases forming the layer and a reactive gas containing a dopant. This gas mixture is fed into the first gas distribution chamber 6 using a first mass flow controller 11. However, the reactive gases can also be fed separately into the multiple gas distribution chambers 6, 6', 6" shown in Figure 8.

[0037] A portion of this gas mixture is fed to a first inlet of a switching valve 14 by a further mass flow controller 22. The switching valve 14 has a second inlet to which the second process gas, controlled by a second mass flow controller 13, is fed. The switching valve 14 can optionally introduce either the gas provided by the mass flow controller 13 or by the mass flow controller 22 into a vent outlet 23 or into a run outlet 24, so that alternately either the second process gas or the first process gas can be restricted to an outlet sector a through the one or more gas outlet openings 5 ​​and fed into the process chamber 2 for a predetermined pulse duration.

[0038] The sixth embodiment shown in Figures 11 to 15 essentially corresponds to the embodiment shown in Figures 6 to 8. Unlike there, however, the gas inlet element 3 has three different second gas distribution chambers 7, 7', 7", formed by partition walls 21, which are arranged circumferentially offset from one another. From each of the three second gas distribution chambers 7, 7', 7", a second gas outlet opening 5, 5', 5" emerges, through which different gases, for example a reactive gas and an inert gas or different reactive gases, even in different concentrations, can be fed into the process chamber 2. The feeding of these additional second gases also takes place in a temporally varied and pulsed manner, as previously described.

[0039] Each of the two further gas distribution chambers 7, 7', 7" is connected to an individual second gas supply line 9, 9', 9" with, for example, a mass flow controller and a gas source. Thus, several mutually different second gas sources 12 can be provided, with which, using mass flow controller 13 and switching valves 14, an individual second gas flow is provided, which exits the gas inlet element 3 at different locations.

[0040] In the exemplary embodiment, it is possible, for example, to feed a dopant through the middle second gas outlet opening 5' and to feed an inert gas into the process chamber 2 through the two outer second gas outlet openings 5, 5". A pulsed gas flow can be fed into the process chamber through each of the second gas outlet openings 5, 5', 5", whereby the pulses can be generated simultaneously or at different times. This makes it possible, for example, to focus a "dopant beam".

[0041] In the embodiment shown in Figures 11 to 15, the gas outlet openings 5, 5', 5" are arranged vertically one above the other and are offset in the circumferential direction. However, it is also possible to arrange the plurality of second gas outlet openings 5, 5', 5" directly vertically one above the other.

[0042] In the embodiment shown in Figures 16 to 18, three second gas outlet openings 5, 5', 5", each connected to individual gas sources, are arranged next to one another at a vertical level. Within the gas distribution chambers 6, 6', second gas distribution chambers 7, 7", formed by tubes, extend, each connected to an individual gas source via second gas supply lines 9, 9', 9". Each second gas distribution chamber 7, 7" is connected to one of the second gas outlet openings 5, 5', 5", arranged next to one another in the circumferential direction.

[0043] According to an embodiment not shown, the pipes forming second gas distribution chambers 7, 7" can also run within the gas inlet member 3 in such a way that two or more second gas outlet openings 5, 5', 5" are arranged vertically one above the other at a circumferential position.

[0044] The eighth embodiment shown in Figure 19 shows a variant of the embodiment shown in Figures 6 to 7, in which three second gas distribution chambers 7, 7', 7" are arranged in a uniform circumferential distribution around the center of the gas inlet element 3. The advantage of such a multiple arrangement is better homogeneity of the layers deposited on the substrates and enables better wafer-to-wafer control of the layer properties. Here, it can also be provided that different second process gases are fed into the process chamber through the different second gas outlet openings 5, 5', 5" in a different temporal pulse sequence or variation. However, it is also possible to feed the same process gas or the same inert gas into the process chamber 2 through the multiple second gas outlet openings 5, 5', 5".Here too, the feed is pulsed or varied in the manner described above.

[0045] According to a further embodiment, the first gas outlet openings 4 are evenly distributed over the entire circumferential surface of the gas inlet element 3, i.e., over the gas outlet surface formed by the gas inlet element 3. Adjacent first gas outlet openings are thus each equidistant from one another. An intermediate surface 30 thus extends between adjacent first gas outlet openings 4, with all intermediate surfaces 30 being substantially identical in design. According to the invention, a second gas outlet opening 5 is located in at least one of these intermediate surfaces 30. Figure 20 shows such an embodiment.

[0046] Furthermore, it can be provided that the second gas outlet opening 5 is arranged downstream of the gas inlet element 3. The gas inlet element gan 3 can be arranged in the center of a process chamber 2. The process chamber then surrounds the gas inlet element 3, as shown, for example, in Figure 21.

[0047] An annular pre-flow zone 31 is arranged around the essentially cylindrical gas inlet element 3, over which the first process gas flows, exiting from the first gas outlet openings. In this pre-flow zone 31, the first process gas can heat up. This occurs through heat transfer from the susceptor 16 to the gas.

[0048] The second gas outlet opening 5 is located here at the downstream end of the feed zone 31. The second gas outlet opening 5 is located directly upstream of a storage area supporting a substrate 15. The flow of the second process gas exiting the second gas outlet opening 5 thus extends over a very narrow angular range.

[0049] In the exemplary embodiment, only one second gas outlet opening is provided. However, several second gas outlet openings 5 ​​may also be provided, each arranged directly upstream of a storage location for a substrate 15.

[0050] Similar to the exemplary embodiment illustrated in Figure 9, a tube protrudes from the process chamber ceiling 20 into the process chamber 2, into which a second process gas flow is fed by means not illustrated. The tube extends to immediately above the upper side of the susceptor 16 facing the process chamber 2. The mouth of the tube, which forms the second gas outlet opening 5, points in a downstream direction relative to the first process gas flow. In the exemplary embodiment, the mouth 5 points approximately toward the center of the storage location 17.

[0051] In the embodiment, the second gas outlet opening 5 is located approximately at the level of the lowest gas distribution chamber 6 ZZ.

[0052] In the previously described embodiments, however, instead of the susceptor 16, the gas inlet element 3 can also be driven in rotation about the rotation axis D. The susceptor 16 can then be stationary relative to the housing 1 or can also be rotated about the same rotation axis D. The gas inlet element 6 and the susceptor 16 can be driven in rotation in opposite directions. In this variant, the second gas distribution chamber 7, 7', 7" orbits the rotation axis D.

[0053] This variant is also conceivable with a combination of the variant shown in Figure 9, in which case the second gas supply line 9 can be stationary relative to the housing 1 and the susceptor 16 can rotate relative to the housing 1. In addition, the gas inlet element 3 can also rotate about the rotation axis D.

[0054] This variant is also conceivable with regard to the embodiment shown in Figure 21.

[0055] In the case of a rotary-driven gas inlet element 3, all gas supply lines 8, 8', 8 ZZ , 9, 9 Z , 9 ZZ be nested, whereby the axis of rotation D can pass through the innermost tube of the nested tubes of the supply lines.

[0056] The above statements serve to explain the inventions covered by the application as a whole, which constitute the state of the art. at least through the following combinations of characteristics, whereby two, several or all of these combinations of characteristics can also be combined, namely:

[0057] A method which is characterized in that the second process gas is fed into the process chamber 2 into an outlet sector a which is limited to an angular range around the axis of rotation D and which varies synchronously with the speed.

[0058] A method which is characterized in that the first process gas emerges uniformly from a circumferential surface 3' of the gas inlet element 3 in the circumferential direction, relative to the axis of rotation D, and the angular range of the exit sector S corresponds at most to the angular distance ö between two substrates 15 lying next to one another in the circumferential direction around the axis of rotation D and the pulse length corresponds at most to the duration in which a region of a susceptor 16 carrying the substrates 15, corresponding to the angular distance ö, passes through the exit sector a.

[0059] A method which is characterized in that the pulse length is shorter than the duration in which a sector ß of the susceptor 16 corresponding to the diameter of a substrate 15 passes through the exit sector a and / or that the angular range of the exit sector a is shorter than the angular range of a sector ß determined by the diameter of a substrate 15.

[0060] A method which is characterized in that the pulse frequency of the pulses with which the second process gas is fed into the process chamber 2 corresponds to the product of the rotational speed and the number of substrates 15 arranged in a circle around the rotation axis D in a uniform circumferential distribution.

[0061] A method characterized in that the mass flow of the second process gas varies with the pulse frequency.

[0062] A method characterized in that the second process gas influences a dopant incorporation or a layer composition.

[0063] A process characterized in that the first process gas influences a growth rate of the layer.

[0064] A method which is characterized in that during the feeding of the second process gas a value of the growth rate, the layer composition and / or the dopant incorporation is measured with a sensor 26 and the mass flow of the second process gas is varied with a control device 28 to achieve a desired value.

[0065] A method which is characterized in that a plurality of second gas outlet openings 5, 5', 5" are provided vertically one above the other and / or next to one another in the circumferential direction, through which a different second process gas or process gases with different temporal variation are fed into the process chamber 2, wherein the plurality of second gas outlet openings 5, 5', 5" are arranged so as to be limited to an outlet sector a which is limited around the axis of rotation D or are arranged so as to be distributed in the circumferential direction around an axis of the gas inlet element 3.

[0066] A device which is characterized in that the at least one second gas outlet opening 5 is arranged in such a way that the flow of the second process gas emerging therefrom enters the process chamber 2 only via an outlet sector a limited to an angular range around the axis of rotation D, and is operable by a control device 28 in such a way that the flow of the second process gas is fed into the process chamber 2 at a pulsed speed.

[0067] A device which is characterized in that the first gas outlet openings 4 are arranged uniformly distributed over a circumferential surface 3' of the gas inlet member 3 and the angular range of the outlet sector a corresponds at most to the angular distance ö between two bearing locations 17 lying next to one another in the circumferential direction around the axis of rotation D.

[0068] A device characterized in that the at least one second gas outlet opening 5 is arranged in the peripheral surface 3' of the gas inlet member 3.

[0069] A device which is characterized in that the at least one second gas outlet opening is arranged in a process chamber ceiling 20 or is the mouth of a supply line 9 which projects into the process chamber 2 in a region between the gas inlet element 3 and the storage locations 17.

[0070] A device characterized by a measuring device 26 for determining a value of the growth rate, the layer composition and / or the dopant incorporation and a control device 28 with which the mass flow of the second process gas can be varied to achieve a desired value.

[0071] A device characterized by a valve arrangement comprising one or more mass flow controllers 11, 13, 22, 25 and a switching valve 14 for controlling the pulsed mass flow of the second process gas.

[0072] A device characterized in that a plurality of second gas outlet openings (5, 5', 5"), each connected to a different second gas source (12) or a different mass flow controller (11), are arranged vertically one above the other and / or offset from one another in the circumferential direction about an axis of the gas inlet element, wherein a plurality of second gas outlet openings (5, 5', 5") are arranged in a restricted manner on an outlet sector (a), are arranged in a uniform circumferential distribution around a center of the gas inlet element (3) or have different distance angles from one another.

[0073] All disclosed features are essential to the invention (individually, but also in combination with one another). The disclosure of the application hereby fully incorporates the disclosure content of the associated / attached priority documents (copy of the prior application), also for the purpose of incorporating features of these documents into claims of the present application. The subclaims, even without the features of a referenced claim, characterize independent inventive developments of the prior art with their features, in particular for filing divisional applications based on these claims. The invention specified in each claim may additionally comprise one or more of the features provided in the above description, in particular with reference numerals, and / or specified in the list of reference numerals.The invention also relates to designs in which individual features mentioned in the above description are not implemented, in particular insofar as they are clearly unnecessary for the respective intended use or can be replaced by other technically equivalent means. List of reference symbols 1 CVD reactor 17 substrate holder / storage space 2 Process chamber 18 Gas outlet device 3 Gas inlet element 19 Heating device 3' peripheral area 20 process chamber ceiling 4 first gas outlet opening 21 partition wall 5 second gas outlet opening 22 mass flow controller 5' second gas outlet 23 Vent- outlet 5" second gas outlet 24 Run outlet 6 first gas distribution chamber 25 mass flow controller 6' gas distribution chamber 26 sensor / measuring device 6" gas distribution chamber 27 optical path 7 second gas distribution chamber 28 control device / control unit 7' second gas distribution chamber direction 7" second gas distribution chamber 29 rotary drive 8 first gas supply line 30 intermediate surface 8' gas supply line 31 flow zone 8" gas supply line 9 second gas supply line 9' second gas supply line 9" second gas supply line D rotation axis 10 first gas source a outlet sector 11 Mass flow controller ß sector 12 second gas source ö angular distance 13 Mass flow controller S Flow direction 14 Changeover valve 15 Substrat 16 Susceptor

Claims

Claims 1. A method for the simultaneous treatment of a plurality of substrates (15) arranged in a process chamber (2) around a gas inlet element (3), wherein, during the feeding of a first process gas through first gas outlet openings (4) of the gas inlet element (3), the substrates (15) or the gas inlet element (3) are rotated at a speed about a rotational axis (D), wherein a second process gas different from the first process gas is fed into the process chamber (2) through at least one second gas outlet opening (5) arranged upstream of the substrates (15) with respect to the flow direction (S) of the flow of the first process gas, wherein the first and second process gases flow over the substrates in the process chamber (2) in the flow direction (S) and there cause a growth or a change in the layer composition of a respective layer on the substrates (15),wherein the second process gas is fed into an outlet sector (a) limited to an angular range around the rotational axis (D), characterized in that the first process gas exits uniformly from a circumferential surface (3') of the gas inlet element (3) in the circumferential direction, relative to the rotational axis (D), and the angular range of the exit sector (S) corresponds at most to the angular distance (θ) between the centers of two substrates (15) lying next to one another in the circumferential direction around the rotational axis (D), wherein the second process gas varies synchronously with the rotational speed and is fed into the process chamber (2) in pulsed form, wherein the pulse length corresponds at most to the duration in which a region of a susceptor (16) carrying the substrates (15) corresponding to the angular distance (θ) passes through the outlet sector (a).

2. Method according to claim 1, characterized in that the pulse length is shorter than the duration in which a pulse corresponding to the diameter of a substrate tes (15) corresponding sector (ß) of the susceptor (16) passes through the exit sector (a) and / or that the angular range of the exit sector (a) is smaller than the angular range of a sector (ß) determined by the diameter of a substrate (15).

3. Method according to one of the preceding claims, characterized in that the pulse frequency of the pulses with which the second process gas is fed into the process chamber (2) corresponds to the product of the rotational speed and the number of substrates (15) arranged in a uniform circumferential distribution in a circle around the axis of rotation (D).

4. Method according to claim 3, characterized in that the mass flow of the second process gas varies with the pulse frequency.

5. Method according to one of the preceding claims, characterized in that the second process gas influences a dopant incorporation or a layer composition.

6. Method according to one of the preceding claims, characterized in that the first process gas influences a growth rate of the layer.

7. Method according to one of the preceding claims, characterized in that during the feeding of the second process gas, a value of the growth rate, the layer composition and / or the dopant incorporation is measured with a sensor (26) and the mass flow of the second process gas is varied with a control device (28) to achieve a desired value.

8. Method according to one of the preceding claims, characterized in that the second process gas is fed into the process chamber (2) at a point remote from the first gas outlet openings (4) in the flow direction of the first process gas, wherein it is provided in particular that the point is arranged downstream of a feed zone (31) and / or immediately upstream of a zone in which one or more storage locations (17) for substrates (15) are arranged.

9. Method according to one of the preceding claims, characterized in that a plurality of second gas outlet openings (5, 5', 5") are provided vertically one above the other and / or next to one another in the circumferential direction, through which a different second process gas or process gases with different temporal variation are fed into the process chamber (2), wherein the plurality of second gas outlet openings (5, 5', 5") are arranged so as to be limited to an outlet sector (a) limited around the axis of rotation (D) or are arranged distributed in the circumferential direction around an axis of the gas inlet member (3).

10. Apparatus for carrying out a method according to one of the preceding claims, with a gas inlet element (3) arranged in a process chamber (2), with first gas outlet openings (4) for the outlet of a first process gas into the process chamber (2), with a susceptor (16) having a plurality of storage locations (17) for substrates (15) arranged around the gas inlet element (3), wherein the susceptor (16) or the gas inlet element (3) can be driven in rotation about a rotational axis (D) by a rotary drive (29) at a speed, and with at least one second gas outlet opening (5) arranged upstream of the storage locations (17) with respect to the flow of the first process gas, for the outlet of a second process gas into the process chamber (2), characterized in that that the at least one second gas outlet opening (5) is arranged such that the flow of the second process gas emerging therefrom enters the process chamber (2) only via an outlet sector (a) limited to an angular range around the axis of rotation (D), and can be operated by a control device (28) such that the flow of the second process gas is fed into the process chamber (2) in a pulsed manner at the rotational speed.

11. Device according to claim 10, characterized in that the first gas outlet openings (4) are arranged distributed uniformly over a circumferential surface (3') of the gas inlet member (3) and the angular range of the outlet sector (a) corresponds at most to the angular distance (ö) between two storage locations (17) lying next to one another in the circumferential direction around the axis of rotation (D).

12. Device according to one of claims 10 or 11, characterized in that the at least one second gas outlet opening (5) is arranged in the peripheral surface (3') of the gas inlet member (3).

13. Device according to one of claims 10 to 12, characterized in that the at least one second gas outlet opening is arranged in a process chamber ceiling (20) or is the mouth of a supply line (9) which projects into the process chamber (2) in a region between the gas inlet element (3) and the storage locations (17).

14. Device according to one of claims 10 to 13, characterized by a measuring device (26) for determining a value of the growth rate, the layer composition and / or the dopant incorporation and a control device (28) with which the mass flow of the second process gas can be varied to achieve a desired value.

15. Device according to one of claims 10 to 14, characterized by a valve arrangement having one or more mass flow controllers (11, 13, 22, 25) and a switching valve (14) for controlling the pulsed mass flow of the second process gas.

16. Device according to one of claims 10 to 15, characterized in that a plurality of second gas outlet openings (5, 5', 5"), each connected to a different second gas source (12) or a different mass flow controller (11), are arranged vertically one above the other and / or offset from one another in the circumferential direction about an axis of the gas inlet element, wherein a plurality of second gas outlet openings (5, 5', 5") are arranged in a restricted manner on an outlet sector (a), are arranged in a uniform circumferential distribution around a center of the gas inlet element (3) or have different distance angles from one another.

17. Device according to one of claims 10 to 16, characterized in that the one or more second gas outlet openings (5) are arranged downstream of a gas inlet zone (31), wherein the gas inlet zone (31) extends in the flow direction of the first process gas from the gas inlet element (3) to a storage location (17) for a substrate (15) and / or that the second gas outlet opening arranged remote from the gas inlet element (3) in the flow direction of the first process gas has a vertical distance from a surface of the susceptor (16) which lies in the region of a vertical height of a lowest gas inlet zone (6").

18. Method or device characterized by one or more of the characterizing features of one of the preceding claims.

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