Gas inlet device for CVD reactors

Abstract

To provide a gas inlet device for a CVD reactor having a gas inlet member fixable to a fixing portion having gas supply conduits.SOLUTION: A gas inlet device for a CVD reactor 1 including a gas inlet member 2 fixable to a fixing portion 3 having gas supply conduits 5 includes a plurality of gas distribution levels arranged one above the other, each level having a plurality of disk-shaped gas distributors 4.1, 4.2, 4.3, 4.4 arranged one above the other, having each gas distribution level having a gas distribution wall 6 surrounding a gas distribution chamber with a gas outlet openings 7 fluidly connected to a gas distribution chamber separated into three ring-shaped parts 8', 8", 8'", and the mouths of the individual gas inlet channels open into the gas distribution chamber and the gas distribution chambers of the different gas distribution levels are separated from each other by a separating base 11, and flow barriers 12, 12' are arranged between the openings of the gas inlet channels and the gas distribution wall.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a gas inlet device for a CVD reactor, comprising a gas inlet member fixable to a fixing part having gas supply conduits and having a plurality of gas distribution levels arranged one above the other, each having a gas distribution wall with a gas outlet opening, the gas outlet openings being in fluid communication with a gas distribution chamber surrounded by the gas distribution wall, wherein the gas inlet channels open into the gas distribution chamber, and the gas distribution chambers of the gas distribution levels are separated by a separating base, wherein the gas inlet channels are arranged, in particular, in a columnar central part of the gas inlet member.

[0002] The invention further relates to a CVD reactor provided with such a gas inlet device. [Background technology]

[0003] A quartz gas inlet element is described in Patent Document 1. The gas inlet element described therein has a central body arranged around the axis of the gas inlet element. A plurality of concentrically arranged gas inlet channels extend through the central region of the gas inlet element, opening into an opening extending over the entire circumference. The openings of the gas inlet channels are connected to a ring-shaped gas distribution chamber surrounding the central portion, which is separated by a separating base into a plurality of vertically arranged gas distribution levels. The radially outer edge of each gas distribution chamber is surrounded by a gas distribution wall, which has a plurality of gas passage holes that open into gas outlet openings through which process gases can be supplied to the process chambers of a CVD reactor. Each of the gas distribution chambers can be supplied with a separate process gas. Different process gases can flow into the process chambers connected to the gas inlet element, separated from each other at different heights. In the process chamber, the substrate is placed on a susceptor that is heated from below, and the substrate can have a III-V layer, a group IV layer, or a group II-VI layer deposited thereon by MOCVD.

[0004] Patent documents 2, 3, 4, and 5 disclose methods for constructing quartz bodies. A quartz blank with a polished surface is first treated with a laser beam. The laser beam is then generated in ultrashort pulses and focused. The focal point passes through the volume of the quartz blank, for example, line by line, in a writing-like motion. At the focal point, the laser beam reaches an intensity exceeding a threshold intensity, causing a material modification of the quartz material. The modified material can then be removed with a liquid etchant, for example, a potassium hydroxide solution. From the prior art, it is known to use these methods to create liquid channels for nozzle bodies of spray heads or spray cans. It is also known to create cavity structures in components for projection exposure systems. It is also known to create microchannels, shaped holes, notches, etc. in transparent components such as quartz glass, borosilicate glass, sapphire, and ruby ​​using a method called SLE (Selective Laser-Induced Etching). Further prior art documents include Patent documents 6, 7, 8, and 9. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 10 2008 055 582 A1 [Patent Document 2] German Patent No. 100 29 110 [Patent Document 3] European Patent No. 3 036 061 [Patent Document 4] German Utility Model Application Publication No. 20 2017 002 851 [Patent Document 5] DE 10 2018 202 687 A1 [Patent Document 6] DE 10241964 [Patent Document 7] DE 10241964 [Patent Document 8] German Patent Application Publication No. 102014104218 [Patent Document 9] US Patent Application Publication No. 2009 / 0260569 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is based on the object of constructing a gas inlet element of the type described above in a manner that is advantageous for use. In particular, it is provided to configure the gas inlet element. The object of the present invention is to configure the gas inlet element in a manner that is easier to handle and that also makes the technical finishing and assembly easier. Furthermore, it provides a method for realizing shapes of the gas inlet element that have not been possible up to now. [Means for solving the problem]

[0007] This problem is solved by the invention as set forth in the claims, the dependent claims not only indicating advantageous further developments of the invention as set forth in each dependent claim, but also indicating independent solutions to the problem.

[0008] First and essentially, according to a first aspect of the present invention, at least one of a plurality of gas distribution levels, preferably arranged one above the other, has a flow barrier. The flow barrier extends through the gas distribution chamber so as to separate the gas distribution chamber into an upstream section adjacent to the opening of the gas inlet channel and a downstream section. The downstream section can be adjacent to a further flow barrier. However, the downstream section can also be adjacent to the gas distribution wall. The flow barrier preferably has a ring-like shape, and particularly preferably a circular ring-like shape, surrounding a central section having the opening of the gas inlet channel. However, the flow barrier can also be directly adjacent to the gas distribution wall. The flow barrier has gas passage channels that open into the gas passage holes in the gas distribution wall. The gas passage channels have a smaller cross section than the gas passage holes. The gas passage channels can be gas passage holes through which process gas can flow from the upstream section of the gas distribution chamber to the downstream section of the gas distribution chamber. The flow barrier forms a pressure barrier, resulting in a higher gas pressure upstream of the flow barrier than downstream of the flow barrier. This results in a uniform gas flux exiting the flow barrier across the gas outlet surface of the flow barrier. The gas passage holes are preferably arranged on the gas outlet surface of the flow barrier with a substantially uniform distribution. The gas outlet surface of the flow barrier is preferably a circumferential surface, such as the gas outlet surface of the gas distribution wall, and is in particular the outer surface of a cylinder. The holes can have a diameter of less than 0.1 mm, less than 0.2 mm, less than 0.5 mm, less than 1 mm, less than 2 mm, or less than 3 mm. However, the gas passage channels of the flow barrier can also be gaps.

[0009] According to a second aspect of the present invention, each of the gas distribution levels arranged one above the other is formed by a disk-shaped gas distribution section. In this case, the gas distribution section is preferably formed by a gas distribution body / section. The gas distribution section can be formed in the shape of a circular disk. The gas distribution wall is materially integrally or materially uniformly connected to the separation base, in which case the separation base has a circular disk shape. A central section can stand up from the separation base. The central section is particularly pedestal-shaped and forms the opening of the gas inlet channel opening into the gas distribution chamber. The central section can have an upward-facing main surface extending in a plane, in which case the upper edge of the gas distribution wall can also extend. The gas distribution bodies / sections preferably have substantially the same shape. They preferably have a flat lower surface. The gas distribution bodies / sections are stacked one on top of the other so that the main surface of the central part of the lower gas distribution body / section is flush with the lower surface of the separation base of the upper gas distribution body / section. In this case, the gas distribution chamber is closed both below and above by the separation base, in particular by the upwardly facing upper surfaces of the gas distribution walls being sealedly connected to the lower surface of the separation base, so that at least two gas distribution bodies / sections are positioned above each other. The gas distribution chamber is preferably only open in the radial direction, in which case it opens radially outward via the gas passage holes in the gas distribution walls and radially inward via the openings of the gas inlet channels. It is further provided that at least one of the gas distribution bodies / sections has one through-hole in its center. The through-hole is open to both the upper and lower main surfaces of the separation base, so that the through-hole can connect the opening of the gas channel of the lower gas distribution body / section with the through-hole of the upper gas distribution body / section. Thus, the multiple gas through-holes arranged one above the other form a gas inlet channel.

[0010] A further aspect of the invention relates to the configuration of the central hole in the gas inlet member, which can be a purge channel or a fixing hole for a fixing screw.

[0011] A further aspect of the present invention relates to fixing a gas inlet member to a fixing part. The fixing part can be fixed to a ceiling part of a reactor wall, in which case the ceiling part can be removed from the lower part of the reactor housing for reactor maintenance. In this case, the gas inlet member is lifted out of the process chamber. According to the present invention, the gas inlet member is fixed to the fixing part by a fixing means inserted into a fixing hole of the gas inlet member. It is particularly provided that the gas distribution level is formed by a substantially disk-shaped gas distribution body / section. A fastening hole for receiving a fastening element, which may be a screw, extends through the gas distribution body / section. The fastening hole may be a central hole extending through the center of the gas distribution body / section. The gas distribution bodies / sections may be materially uniformly connected to one another. However, they may also be materially integrally connected to one another. Thus, the entire gas inlet element may be composed of several parts. However, it may also be made in one piece. The gas inlet element is preferably formed as a rotationally symmetrical body and has a central fastening hole. In this case, several gas inlet channels may extend circumferentially around the fastening hole, which open into different gas distribution levels. However, instead of or in combination with the central fixing holes, off-center fixing holes can be provided, by means of which the gas inlet element can be fixed to a fixing surface. The off-center fixing holes can in particular be arranged in a flange portion that projects radially beyond the gas distribution wall, by means of which the gas inlet element can be fixed to a support.

[0012] According to a further aspect of the invention, it is provided that the gas inlet channels formed from the cylindrical central portion of the gas inlet member do not extend concentrically with one another, but are spaced apart from one another in the circumferential direction about axes which may be the axes in the drawings. According to the invention, the gas inlet channels are located next to one another in a cross section through the central portion. The openings of the different gas inlet channels are offset from one another in the circumferential direction about the central portion. The openings preferably face radially outward. This embodiment provides, in particular, that the central portion is surrounded by at least one flow barrier, so that the gas flow can be substantially uniformly distributed in the circumferential direction through gas passage holes extending on the circumferential surface of the flow barrier, which gas passage holes open into the downstream part of the gas distribution chamber, from where the process gas can flow through the passage holes in the gas distribution wall into the process chamber.

[0013] As described above, the gas inlet element formed according to the present invention can be made from quartz. However, it can also be made from metal, in particular stainless steel. If the gas inlet element is made from stainless steel, it is preferably made in multiple parts. In that case, the individual parts of the gas inlet element are firmly connected, for example by a screw connection, or materially connected, for example by a welded seam. The gas passage holes can be formed by drilling. However, in a preferred embodiment of the present invention, the gas inlet element is made from quartz. Here too, the individual components of the gas inlet element, i.e., the gas distribution wall, the separating base, the pedestal-like central part, and the flow barrier, can be produced separately from one another and then joined together with a suitable material closure, for example, borosilicate glass. In a similarly preferred embodiment, the gas inlet element has several disk-shaped gas distributors arranged one above the other, which can be formed integrally. They can be milled out of a disk-shaped quartz body, in particular by the SLE (selective laser-induced etching) method. In this method, in a first process step, a local material modification of a homogeneous quartz blank is performed. For this purpose, an ultrashort-pulse laser beam is focused to a focal point in the micrometer range, which is guided through the volume of the quartz body by moving the laser beam relative to the quartz workpiece. A multi-photon process results in the material modification of the quartz material at the focal point of the laser beam. In a second process step, the modified material can be removed with an etching solution. The etching solution is preferably a liquid, such as KOH. This method allows the production of a gas distribution wall, its gas passage holes, a central base, its gas supply conduit, and a flow barrier extending between the center and the gas distribution wall and including its passage holes in the disk-shaped quartz base body. The disk-shaped gas distributors / parts thus produced, which are materially one piece, can then be stacked one on top of the other and, in particular, bonded to one another in a materially uniform manner. In a particularly preferred variant of the invention, the gas distributors are connected to one another in a materially integrated manner. To manufacture a gas inlet member made from such a homogeneous, one-piece quartz blank, the SLE method, as described above, is used. In this manufacturing method, a solid quartz body having a polished surface is first prepared. A cavity is then exposed using a focused laser beam. The exposed material is then removed using an etching solution. If the gas inlet member has a flange, as described above, the flange can be materially integrated with the gas distributor and can also be manufactured using the SLE method. These and other embodiments of the present invention are described in more detail with respect to the following drawings. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 1 shows, substantially diagrammatically in longitudinal section, the structure of a CVD reactor equipped with a gas inlet member 2 according to a first embodiment of the invention. [Figure 2] FIG. 2 is a perspective view showing five gas distributors 4.1, 4.2, 4.3, 4.4, 4.5 arranged one above the other to form the gas inlet member 2. In FIG. [Figure 3] FIG. 3 is a diagram of the gas inlet member. [Figure 4] FIG. 4 shows a second exemplary embodiment of a gas inlet member similar to FIG. [Figure 5] FIG. 5 is an enlarged view of the V cross section of FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a gas inlet member according to a second exemplary embodiment of the present invention. [Figure 8] FIG. 8 is a view similar to FIG. 5 of a further exemplary embodiment of a gas inlet member. [Figure 9] FIG. 9 is a view similar to FIG. 5 of a further exemplary embodiment of a gas inlet member. DETAILED DESCRIPTION OF THE INVENTION

[0015] FIG. 1 shows a schematic diagram of a CVD reactor, with a process chamber 20 in which a CVD deposition process can be performed. Semiconductor layers, in particular, can be deposited on a plurality of substrates 21. The substrates 21 can be made of a III-V compound, silicon, sapphire, or other suitable material. One or more layers composed of elements from a group IV semiconductor, a group III-V semiconductor, or a group II-VI semiconductor can be deposited on the substrates. Various process gases are introduced into the process chamber 20 through a gas inlet member 2 using a carrier gas, such as H or a noble gas. In this case, the process gases can include hydrides of group V semiconductors, group IV semiconductors or organometallic compounds of group IV semiconductors, or group III semiconductors. A susceptor 19, such as a coated graphite susceptor supporting the substrates 21, is heated from below by a heater 24 to a process temperature. The process gases, supplied to the center of the process chamber 20 using the gas inlet member, thermally decompose on the surfaces of the substrates arranged in a circle around the center, thereby forming, in particular, monocrystalline layers. The process gas flowing radially through the process chamber 20 exits the process chamber 20 through a gas outlet 22 that surrounds the susceptor 19. The gas outlet 22 is connected to a suction pump (not shown).

[0016] The susceptor 19 rests on a support disk 32 which is supported by a support tube 33. By means not shown, the susceptor 19, which is only shown diagrammatically in Figure 1, can be rotated about an axis.

[0017] Reference numeral 34 denotes a diffusion barrier between the heating device 24 and the susceptor 19 .

[0018] Inside the reactor housing 1 is a process chamber ceiling 23 through which a fixture 3 projects into the process chamber 20. A gas inlet member 2 is fixed to the fixture 3, which may be made of metal, in particular stainless steel.

[0019] The gas inlet member 2 may be made of metal, in particular stainless steel. Preferably, however, the gas inlet member 2 is made of quartz. The gas inlet member 2 may be made of metal, in particular a non-ferrous metal or stainless steel. Preferably, however, the gas inlet member 2 is made of a ceramic material, in particular quartz.

[0020] In the gas inlet member 2 shown in Figure 1, the lower part of the gas inlet member 2 having the gas outlet opening fits into a recess 25 in the susceptor 19. The upper part of the gas inlet member 2, which forms a flange 36, can be materially connected to the lower region. A through hole forming the purge channel 17' extends through the center of the gas inlet member 2. Reference numeral 35 indicates schematically a fastening hole, which can be used to fasten the gas inlet member 2 on a support member by means of a screw passing through the fastening hole 35.

[0021] In the exemplary embodiment shown in FIG. 4, the fixing part 3 is shown having a lower part 3″ and an upper part 3′″. Here, however, the lower part 3″ can also be a materially integral part of the gas inlet member 2. Here, fixing screws are shown in fixing holes 35 which are screwed into threaded holes in the upper part 3′″.

[0022] The fixing part 3 has a substantially flat, downward-facing fixing surface 3' facing the susceptor 19. In the exemplary embodiment, the central region of the fixing surface 3' has five centrically arranged gas channels, which are connected to the gas inlet channels 9.1, 9.2, 9.3, 9.4, and 9.5 of the gas inlet member 2, respectively. The gas inlet channels 9.1, 9.2, 9.3, 9.4, and 9.5 surround fixing holes 27, in which nuts 28 are rotationally fixedly mounted and supported on springs 29. The threads of fixing screws 30 are threaded into the nut 28, the head of which is supported on a base plate 31, in particular made of quartz. Between the base plate 31, which rests in the recess 25 of the susceptor 19, and the fixing surface 3' of the fixing part 3, there are five disk-shaped gas distributors 4.1, 4.2, 4.3, 4.4, and 4.5. They are substantially identical in shape, but differ from one another in the shape of their central portions 15. The base plate 31 can also be made of a ceramic material, a non-ferrous metal, and especially stainless steel. The gas distributors 4.1 to 4.5, arranged one above the other, serve different purposes. The two upper gas distributors 4.1 and 4.2 supply Cl2 to the process chamber 20 for cleaning. The lower gas distributors 4.3 to 4.5 supply process gas to the process chamber 20.

[0023] The upper edge of the gas distributor 4.1 located in the uppermost position is sealed against the fixing surface 3' by a seal (not shown). The part indicated by 3'' in FIG. 4 forms a sealing adapter.

[0024] The gas distribution bodies / parts 4.1, 4.2, 4.3, 4.4 and 4.5 shown in FIG. 2 each have a disk-shaped base plate, which forms a separation base 11, by which the gas distribution bodies 4.1, 4.2, 4.3, 4.4 and 4.5 arranged above and below are separated from each other.

[0025] A circular ring-shaped gas distribution wall 6 extends around the circular edge of the separation base 11 and has a plurality of uniformly distributed gas passage holes 13. The gas passage holes 13 have a diameter of less than 3 mm, in particular less than 1 mm. Each radially extending gas passage hole 13 opens into one gas outlet opening 7. The height of the gas distribution bodies 4.1, 4.2, 4.3, 4.4, 4.5, measured in the axial direction of the gas inlet member 2 (relative to the axis on the drawing), can be between 5 mm and 2 cm. The width of the radially extending gas distribution wall 6 (relative to the axis on the drawing) can also be between 0.5 cm and 2 cm. However, the wall thickness of the gas distribution wall 6 can also be less than 0.5 cm, in particular 1 mm.

[0026] The gas distribution wall 6 surrounds a gas distribution chamber 8 that extends around a central portion 15. In the exemplary embodiment, the gas distribution chamber 8 is separated into three ring-shaped portions 8′, 8″, and 8′″. A first portion 8′ of the gas distribution chamber 8 extends from the gas distribution wall 6 to a flow barrier 12 that is disposed concentrically with the gas distribution wall 6. A second flow barrier 12′ extends radially inward from the portion 8′ of the gas distribution chamber 8 that is surrounded by the flow barrier 12, also extending concentrically with the gas distribution wall 6, and surrounds the portion 8′″ of the gas distribution chamber 8 that is adjacent to the central portion 15. The flow barriers 12, 12′ have the same height as the gas distribution wall 6 and, in the exemplary embodiment, the same radial width. The distance between two adjacent flow barriers 12, 12' or between the central portion 15 and the flow barrier 12' or between the flow barrier 12 and the gas distribution wall 6 is greater than the wall thickness of the flow barrier 12, 12' or the gas distribution wall 6. The radial width of the portions 8', 8", 8'" of the gas distribution chamber 8 is in particular greater than 1 cm. The wall thickness of the flow barriers 12, 12' can vary. The wall thickness can be greater than the radial length of the spaces 8', 8", 8'" between the flow barriers 12, 12'. The radial width of the portions 8', 8", 8'" of the gas distribution chamber 8 can also be less than 5 mm.

[0027] In the exemplary embodiment shown in FIG. 9, the ring-shaped flow barrier 12 , 12 ′ is even directly adjacent to the gas distribution wall 6 .

[0028] 2, the ring-shaped flow barriers 12, 12' have gas passage holes 14, 14' uniformly distributed in the circumferential direction. The diameter of the gas passage holes 14, 14' can be the same as that of the gas passage holes 13. However, it is also provided that the gas passage holes 14' of the inner flow barrier 12' have a smaller diameter than the gas passage holes 14 of the outer flow barrier 12, and that the gas passage holes 13 of the gas distribution wall 6 have a larger diameter than the gas passage holes 14 of the flow barrier 12. The flow barriers 12, 12' create a pressure difference between the upstream and downstream parts of the gas distribution chamber 8.

[0029] It is particularly provided that the gas passage holes 14, 14' in the flow barriers 12, 12' are offset from one another and are not aligned with one another. The same applies to the gas passage holes 14 in the flow barrier 12 and the gas passage holes 13 in the gas distribution wall 6. The gas passage holes 14 extend offset from and are not aligned with the gas passage holes 13.

[0030] The central portion 15 is formed as a pedestal and has the same axial height as the flow barriers 12, 12' or the gas distribution wall 6, so that the upper surfaces of the flow barriers 12, 12' and the gas distribution wall 6 lie in the same plane, within which the main surface of the pedestal 15 also extends.

[0031] Each pedestal has an opening 10 through which the gas inlet channels 9.1, 9.2, 9.3, 9.4, 9.5 assigned to each gas distribution body 4.1, 4.2, 4.3, 4.4, 4.5 open into the radially inner part of the gas distribution chamber 8. The openings 10 can extend from the upper surface of the separation base 11 to the lower surface of the separation base 11 of the gas distribution body above it.

[0032] In the exemplary embodiment shown in Figure 4, the gas distributor 4.1, which is located at the top position and directly connected to the fixed surface 3', has four through-holes 16 arranged circumferentially around the fixed hole 17, which are assigned to gas inlet channels 9.2, 9.3, 9.4, 9.5, respectively. The gas inlet channel 9.1 assigned to the top gas distributor / part 4.1 opens into an opening 10 in front of which a flow straightening wall 18 is located.

[0033] In the exemplary embodiment shown in FIG. 1, the upper surface of the gas distribution body 4.1 located in the uppermost position is materially integrally connected to a flange portion 36 through which a plurality of gas supply conduits 5 extend.

[0034] Viewed from above, the second gas distributor 4.2 has only three through holes 16, each of which belongs to a gas inlet channel 9.3, 9.4, and 9.5. The gas inlet channel 9.2 here also opens into an opening 10, in front of which a flow straightening wall 18 is located, and which opening 10 is arranged circumferentially offset relative to the opening 10 of the gas distributor 4.1.

[0035] The gas distributor 4.3, arranged below the gas distributor 4.2, still has only two through-holes 16, which are assigned to the gas inlet channels 9.4 and 9.5. The gas inlet channel 9.3 here opens into an opening 10, which is arranged offset relative to the opening 10 of the gas distributor 4.2.

[0036] The gas distributor 4.4, located below the gas distributor 4.3, has only one through-hole 16, which is assigned to a gas inlet channel 9.5. The gas inlet channel 9.4 here opens into an opening 10, which is arranged circumferentially offset relative to the opening 10 of the gas distributor 4.3.

[0037] The gas distributor 4.5 arranged in the lowest position does not have through holes 16. In the central part 15 of the gas distributor 4.5 arranged in the lowest position, the gas inlet channel 9.5 opens into an opening 10 which is again arranged offset in the circumferential direction.

[0038] The openings 10 of all the gas distributors 4.1 to 4.5 are open at different orientations relative to the axis of the gas inlet member 2 on the drawing.

[0039] On the underside of the gas distributor / part 4.5 located in the lowest position there is a base plate 31 provided with a recess for receiving the screw head of the fixing screw 30.

[0040] It is considered advantageous that the gas inlet member 2 can be removed from the fixed part 3 simply by loosening the fixing screws 30 .

[0041] It is further considered advantageous that any of the individual gas distribution bodies 4.1, 4.2, 4.3, 4.4, and 4.5 can be machined "from solid" from a quartz blank. It is further considered advantageous that the entire gas inlet member 2, including the gas distribution bodies 4.1, 4.2, 4.3, 4.4, and 4.5, which are materially integrally connected to one another, can be machined from a single blank. Thus, the gas distribution bodies 4.1, 4.2, 4.3, 4.4, and 4.5 are the gas distribution portions of the gas inlet member 2, which are materially integrally connected to one another.

[0042] For the production of the gas inlet member 2, the above-mentioned SLE method is preferably used. In this case, a highly focused and ultrashort-pulsed laser beam is used to material-modify volumetric regions of a quartz blank, as if by writing. These volumetric regions are the gas passage holes 13, the gas passage holes 14 and 14', the portions 8', 8", and 8'" of the gas distribution chamber 8, the gas inlet channels 9.1, 9.2, 9.3, 9.4, and 9.5, their openings 10, and the fixing holes 17. After the material has been modified, an etching solution is used to remove the modified material from the quartz body. The exemplary embodiment of the gas inlet member 2 shown in FIG. 1 can be produced entirely from a blank using the SLE process.

[0043] This manufacturing method is also considered particularly advantageous as it minimizes the number of assembled parts.

[0044] The exemplary embodiment shown in Figure 7 is a gas inlet member 2 having two gas distribution chambers 8 arranged one above the other, which are separated by a flow barrier 12 into two parts, namely one upstream part 8" and one downstream part 8'. However, it is also possible to arrange several gas distribution chambers one above the other, each of which can be supplied by a gas channel. Gas inlet channels 9.1, 9.2 open into each gas distribution chamber 8. The substantially cylindrical gas inlet member 2 has gas passage holes 13, 14, 14' on its cylindrical surface, thereby forming the gas distribution wall 6. The two gas distribution chambers 8 are separated from each other by a separating base 11. A base plate 31 forms the base of the lower gas distribution chamber 8.

[0045] The gas inlet member 2 is made of a single piece of quartz. The cavity is fabricated using the SLE process.

[0046] 8 shows a further variant of the gas inlet member, according to which the flow barrier 12 has a lower height than the gas distribution wall 6. Between the lower surface of the separating base 11 and the upper surface of the ring-shaped flow barrier 12, a gas passage channel 14" is formed. This is a circumferential gap. However, in a variant not shown, this gap may also be divided azimuthally by webs.

[0047] In the exemplary embodiment shown in FIG. 9, the flow barrier 12″ is directly adjacent to the gas distribution wall 6. In this exemplary embodiment, the gas passage holes 14 with a small cross section open into the gas passage holes 13 with a larger cross section which extend to the gas outlet openings 7.

[0048] The flow barriers 12, 12', 12" illustrated in the exemplary embodiment form a pressure barrier. The openings 10 of the gas inlet channels 9.1 to 9.5 are arranged eccentrically with respect to the extension direction of the gas distribution wall 6. Therefore, the flow distances between the openings and the gas passage holes 13 are various. To avoid uneven gas flow into the process chamber 20 through the gas outlet openings 7 due to the eccentric arrangement of the openings 10, the gas passage holes 14, 14', 14" are dimensioned so that a higher pressure is generated inside the gas distribution chamber 8 than outside the gas distribution chamber 8 and this overpressure is sufficiently large, and so that the flow barriers 12, 12', 12" uniformize the process gas flow into the process chamber 20. In other words, the same amount of gas per unit area enters the process chamber from the entire gas outlet surface formed by the cylindrical outer surface.

[0049] The foregoing is intended to describe the invention as a whole, which independently advances the prior art by at least the following combination of features, of which two or more or all may be combined:

[0050] A gas inlet device characterized in that at least one first flow barrier 12, 12' having one or more gas passage holes 14, 14' extends into at least one gas distribution chamber 8 between the gas inlet channels 9.1, 9.2, 9.3, 9.4, 9.5 and the gas distribution wall 6.

[0051] A gas inlet device characterized in that a flow barrier (12, 12') surrounds a central part (15) having openings (10) for the gas inlet channels (9.1, 9.2, 9.3, 9.4, 9.5).

[0052] A gas inlet device characterized in that at least two flow barriers (12, 12') are arranged one behind the other in the flow direction, and in that the at least two flow barriers (12, 12') and in particular the gas distribution wall (6) are arranged concentrically around a central portion (15).

[0053] 1. A gas inlet device, characterized in that at least one flow barrier (12, 12') separates the gas distribution chamber (8) into an upstream portion (8", 8'") and a downstream portion (8', 8"); or the flow barrier (12") has a gas passage channel (14") directly adjacent to the gas passage hole (13) in the gas distribution wall (6) with a larger cross section opening into the gas outlet opening (7).

[0054] Each gas distribution level is formed as a disk-shaped gas distribution section 4.1, 4.2, 4.3, 4.4, 4.5, in which the gas distribution wall 6 is connected with the edge of the separation base 11 in at least sealing contact, and a central section 15 having openings 10 of the gas inlet channels 9.1, 9.2, 9.3, 9.4, 9.5 stands up from the separation base 11, in which case the upward-facing main surface 15' of the central section 15 of the gas distribution section 4.2, 4.3, 4.4, 4.5 are located flush with or connected to the underside of the separation base (11) of the upper gas distribution section (4.1, 4.2, 4.3, 4.4), and the through holes (16) in the central parts (15) of the upper gas distribution sections (4.1, 4.2, 4.3, 4.4) are in fluid communication with the openings (10) of the gas inlet channels (9.2, 9.3, 9.4, 9.5) of the lower gas distribution sections (4.2, 4.3, 4.4, 4.5) and open to the upper main surface (15').

[0055] A gas inlet device, characterized in that the separating base (11) is materially and integrally connected to the central part (15) and / or the gas distribution wall (6).

[0056] A gas inlet device characterized in that the central part (15) is formed by a pedestal.

[0057] 1. A gas inlet device according to claim 1, wherein each gas distribution level is formed by a disk-shaped gas distribution portion 4.1, 4.2, 4.3, 4.4, 4.5 and is provided with holes 17, 17' extending entirely through the gas inlet member 2.

[0058] A gas inlet device characterized in that the holes (17) form fixing holes for fixing the gas inlet member (2) to the fixing part (3) or the holes (17) form purge channels (17').

[0059] 1. A gas inlet device, characterized in that the disk-shaped gas distribution sections 4.1, 4.2, 4.3, 4.4, 4.5 arranged one above the other are gas distribution bodies, in particular materially integral or materially uniformly connected to one another.

[0060] 1. A gas inlet device, characterized in that the gas inlet channels (9.1, 9.2, 9.3, 9.4, 9.5) are located next to each other in a cross section through the central portion (15), and the openings (10) of the different gas inlet channels (9.1, 9.2, 9.3, 9.4, 9.5) are arranged offset from each other in the circumferential direction around the central portion (15).

[0061] A gas inlet device characterized in that the gas inlet channels 9.1, 9.2, 9.3, 9.4, 9.5 are arranged around a central fixing hole 17.

[0062] 1. A gas inlet device characterized in that the gas inlet element is made of quartz and that the materially integral gas distributor / part 4.1, 4.2, 4.3, 4.4, 4.5 or the materially integral gas inlet element is produced by selective laser-induced etching, in which material modification takes place at the focus of a focused laser beam and the modified material is removed by an etching solution.

[0063] 10. A method according to claim 9, wherein the gas inlet member 2 with the gas distributor 4.1, 4.2, 4.3, 4.4, 4.5 or with a plurality of gas distributor sections 4.1, 4.2, 4.3, 4.4, 4.5, respectively, is produced integrally by selective laser-induced etching.

[0064] 1. A method according to claim 1, wherein the openings (10) are arranged in the gas distribution chamber (8) in such a way that the process gas flow emerging from the openings (10) covers flow distances of different lengths to the individual gas passage holes (13) and at least one flow barrier (12, 12', 12") in the gas distribution chamber (8) homogenizes the process gas exiting from the gas outlet openings (7).

[0065] All disclosed features are essential to the invention (not only on their own but also in combination with one another). The disclosure of any related / attached priority documents (copies of prior applications) is also fully incorporated into the disclosure of this application, with the aim of including the features of these documents in the claims of this application. Dependent claims are characterized by an independent, inventive further development of the prior art, even without the features of the claims to which they refer, in order to file a divisional application based on these claims, in particular. The invention specified in each claim may additionally have one or more features specified in the preceding description, in particular those given reference signs and / or specified in the sign explanations. The present invention also relates in particular to design forms in which some of the features mentioned in the preceding description are not implemented, insofar as they can be clearly omitted for the respective purpose of use or replaced by other technically equivalent means. [Explanation of symbols]

[0066] 1 CVD reactor 2 Gas inlet member 3 Fixed part 3' fixed surface 4.1, 4.2, 4.3, 4.4, 4.5 Gas distributor / unit 5 Gas supply pipelines 6 Gas distribution wall 7 Gas outlet opening 8 Gas Distribution Room 8', 8” downstream section 8'” upstream section 9.1, 9.2, 9.3, 9.4, 9.5 Gas inlet channels 10 aperture 11 Separation Base 12, 12' Flow Barrier 13 Gas passage hole 14, 14' gas passage holes 14" gas passage channel 15 Center, pedestal 15' Main surface 16 through holes 17 Fixing hole 17' Purge Channel 18 Rectification wall 19 Susceptor 20 Process Chamber 21 PCB 22 Gas outlet 23 Process chamber ceiling 24 Heating device 25 recess 26 Gas outlet opening 27 Fixing hole 28 Nut 29 Spring 30 Fixing screw 31 Base Plate 32 Support disc 33 Support pipe 34 Diffusion Barrier 35 Fixing hole 36 Flange part

Claims

1. A gas inlet device for a CVD reactor (1) having a gas inlet member (2) with a plurality of gas distribution levels arranged one above the other, comprising: Each of said gas distribution levels has a gas distribution wall (6) with gas outlet openings (7) arranged in a peripheral region, Each of said gas outlet openings (7) is in fluid communication with a gas distribution chamber (8); a plurality of gas inlet channels (9.1, 9.2, 9.3, 9.4, 9.5) each having an opening (10) opening into each of the gas distribution chambers (8) at different gas distribution levels; In the gas inlet device, the gas distribution chambers (8) of the different gas distribution levels are separated from each other by respective separation bases (11), 1. A gas inlet device comprising: a gas inlet channel having a plurality of openings arranged at different gas inlet levels, the openings being offset from one another in a circumferential direction about a central axis of the central portion of the gas inlet channel;

2. 2. Gas inlet device according to claim 1, characterized in that the gas inlet channels (9.1, 9.2, 9.3, 9.4, 9.5) and the openings (10) are arranged around a central hole (17, 17').

3. 3. A gas inlet device according to claim 2, characterized in that the central hole (17, 17') forms a purge channel.

4. 4. A gas inlet device according to any one of claims 1 to 3, characterized in that the gas inlet member (2) is attached to a fixing part (3) having a flange part (36) that projects radially beyond the gas distribution wall (6).

5. 5. A gas inlet device according to claim 4, characterized in that it comprises fixing holes (35) arranged in the flange portion (36).

6. 6. Gas inlet device according to claim 4 or 5, characterized in that the fixing part (3) is made of metal.

7. Gas inlet device according to any one of the preceding claims, characterized in that the separating base (11) is materially and integrally connected to the gas distribution wall (6).

8. Gas inlet device according to any one of the preceding claims, characterized in that the central part (15) is formed by a pedestal.

9. Gas inlet device according to any one of the preceding claims, characterized in that each of said gas distribution levels is formed from a disk-shaped gas distribution portion (4.1, 4.2, 4.3, 4.4, 4.5).

10. 10. A gas inlet device according to any one of claims 1 to 9, characterized in that the gas inlet member (2) is made of quartz.

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