Liquid material vaporizer apparatus and gas ejection device

Abstract: A vaporizer apparatus is disclosed which enables to efficiently vaporize a liquid material for the production of high dielectric thin film devices by allowing a sufficient dwell time for complete vaporization of the feed liquid, to prevent degradation of the feed gas after vaporization and to provide a stable supply of the vaporized feed gas to the substrate. The vaporizer apparatus comprises an outer member having a cylindrical inner surface, an inner member having a cylindrical outer surface opposing to the cylindrical inner surface of the outer member, and a feed material passage having a spiral configuration is formed on at least one of the cylindrical inner surface and the cylindrical outer surface. The feed material passage communicates with a feed liquid entry opening and a feed gas exit opening. A heating device is provided for heating at least one of the outer member and inner member.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates in general to a vaporizer apparatus for vaporizing a liquid material for providing a gaseous material for chemical vapor deposition apparatus, for example, and relates in particular to a vaporizer apparatus suitable for producing a vapor material for making a thin film having a high dielectric constant such as barium or strontium titanate. Description of the Related Art In recent years, there has been a remarkable advancement in circuit density of integrated circuit devices produced by the semiconductor industries, and intense development activities are in progress in anticipation of gega-bit order DRAMs replacing the prevailing mega-bit order DRAMs of today. Dielectric thin film materials used to make high capacitance devices necessary for DRAMs have, in the past, included silicon oxide or silicon nitride films of dielectric constant less than 10, tantalum pentaoxide (Ta 2 O 5 ) films of dielectric constant of approximately 20; however, newer materials such as barium titanate (BaTiO 3 ) or strontium titanate (SrTiO 3 ) or mixtures of these compounds appear to be more promising. In order for making such thin films, chemical vapor deposition (CVD) process is deemed to be promising, and in this case, it is necessary that a feed gas must ultimately be supplied in a stable gas stream to a substrate disposed in a reaction vessel. In order to stabilize the vaporization characteristics, the feed gas is derived by heating a liquid source, produced by dissolving in some organic solvent (for example, THF) such materials as Ba(DPM) 2 or Sr(DPM) 2 which are solid at normal temperature. A conventional vaporizer apparatus is disclosed in Japanese Patent Application Laid Open Publication No. H6-310444 , for example, in which a liquid material or an atomized liquid material is injected into a chamber-type vaporizer which is heated by a heater. It is also disclosed a vaporizing plate in front of an injection nozzle for providing an improved heat conductivity for a better vaporization efficiency. The vaporized gas prepared in the vaporizer is led into a reactor (film depositing chamber) through a feed gas distribution pipe, is then led to the ejection head to be mixed with a reactive gas (oxidizing gas) supplied from the reactive gas delivery pipe, and the vapor jet is directed to the substrate to produce a reaction so as to deposit a thin film (oxide film) on the substrate. The feed gas used in such a deposition apparatus for making high dielectric films have the following intrinsic properties to present certain operational difficulties. They are: (1) vaporization and decomposition temperatures are close together; (2) a difference exists in the vaporization temperatures between the film producing gas and the organic solvent; and (3) the vapor pressures are all very low. These characteristics cause difficulty in vaporizing the material and maintaining the stable flow of vaporized gas. In the conventional technology, because the heat for vaporization is supplied by conduction from vaporizer plates disposed on the walls or interior of a box-shaped vaporizer, the vaporization efficiency from liquid to gas phase is not adequate. Also, the pressure within the reaction vessel is of the order of several torrs, for example 5 torr, resulting in a large difference in the pressures between the vaporizer and the reaction vessel. Therefore, as the gas passes through the vaporizer, the feed gas pressure is gradually reduced, and, because the reduction in pressure is accompanied by volume expansion, the velocity of the feed gas through the vaporizer is gradually accelerated, presenting a chance that the feed gas passes through the vaporizer at high velocity without being completely vaporized. Therefore, to prevent such a phenomenon and to vaporize the feed material completely within the vaporizer, it is necessary to provide sufficient dwell time for the feed gas to be vaporized; however, the size of the vaporizer necessary to accomplish such an objective becomes too large, and the length of the feed gas distribution pipe, from the vaporizer to the film depositing chamber, becomes too long, and creating a problem that chances for premature precipitation reaction from the gas phase are increased. This further created a cost problem for additional equipment and maintenance work for maintaining the feed gas distribution pipe at a high temperature. Furthermore, if the feed gas and the reactive gas are delivered into the reaction vessel through separate delivery systems, the distributions of the feed gas and the reactive gas above the substrate surface can be non-uniform, causing a product quality problem of compositional or thickness non-uniformity in the film on the substrate which is a direct reflection of that of the feed gas. JP-A-2-145 768 discloses a closed vaporizing vessel which is surrounded by external heating elements. Raw liquid is introduced via an inlet pipe into a part of the vessel from which said liquid flows down along an inner wall of the vessel provided with spiral ruggedness. The raw gas obtained in the vaporization part is mixed with a carrier gas introduced from the inlet pipe and the gaseous mixture is delivered through an outlet pipe. EP 0 533 201 A relates to a liquid vaporization valve which is used together with a vacuum chamber, a source liquid tank, a liquid flow rate controller and a heater. DE 41 07 756 A refers to an apparatus for growing a thin metal layer. A reaction chamber contains a gas ejection plate. A reducing carrier gas, for instance H 2 , is supplied via an apparatus, and a container contains feed material. The container is heated by means of a heating apparatus together with a valve. Another heating apparatus is built into the gas ejection plate and is connected with a heat exchanger. In accordance with the present invention, a gas ejection device as set forth in claim 1 is provided. Preferred embodiments of the invention are disclosed in the dependent claims 2 to 16. SUMMARY OF THE INVENTION It is an object of the present invention to provide a vaporizer apparatus which enables to efficiently vaporize a liquid material for the production of high dielectric thin film devices by allowing a sufficient dwell time for complete vaporization of the feed liquid, to prevent degradation of the feed gas after vaporization and to provide a stable supply of the vaporized feed gas to the substrate. Another object of the present invention is to develop a compact vaporizer to enable efficient mixing of the feed gas and reactive gas. These objects have been achieved by the gas ejection device as defined in claim 1. The vaporizer of the gas ejection device presented above enables a high efficiency to be achieved in converting a feed liquid to a feed gas, by forcing the liquid material through a long flow passage and improving the contact efficiency. An aspect of the apparatus is that the outer member and the inner member are arranged relatively rotatable, the apparatus comprising a drive source to rotate at least one of the outer member and the inner member. The vaporizer enables a high efficiency to be achieved by improving the contact efficiency of the material with the heated wall by rotation. The presence of the pressure generation section allows to maintain a back pressure in the upstream section of the flow passage so as to prevent premature evaporation of organic solvent as well as to provide a sufficient retention time within the flow passage to further assure a complete conversion of the feed liquid to a feed gas. An aspect of the apparatus is that the inner and outer members are attached to a reaction vessel at a downstream location of the feed material passage. Accordingly, the film deposition section and the vaporizer section are made into a unit to save space and shorten the delivery distance over which the vaporized feed gas must be transported as well the distance for the heating medium flow path. Another aspect of the apparatus is that a mixing space is provided at a location downstream of the feed material passage for mixing a feed gas, descending through the feed material passage, with a reactive gas introduced from an external source, thereby allowing the feed gas and the reactive gas to be mixed in the mixing space close to the jetting nozzle to prevent degradation of the process gas. Still another aspect of the apparatus is that the pressure generation section is provided to communicate with a downstream end of the feed material passage, and is provided with an impeller which rotates in an interior of the mixing space. Accordingly, the impeller serves to block the free flow of the feed material to maintain the back pressure in the upstream section, as well as to perform complete mixing of the feed gas and reactive gas in the impeller to produce a uniformly mixed process gas to be introduced into the gas ejection head. Still another aspect of the apparatus is that the pressure generation section comprises a convexoconcave formed on at least one of the inner member and the outer member, accordingly, the back pressure can be maintained because of the fine spacing of the convexoconcave serves to block the unimpeded or free flow of the feed material. Still another aspect of the apparatus is that a gas ejection head having nozzles for producing a feed gas flow onto a substrate is communicated with a downstream end of the feed material passage, so that the vapor path distance is shortened. Still another aspect of the apparatus is that the gas ejection head is formed as a unit with a rotating member, accordingly, the vaporized feed gas (or a mixture of feed gas and reactive gas) is mixed inside the gas ejection head to shorten the flow path to prevent a degradation of the process gas, thereby improving the uniformity of the deposit. Still another aspect of the apparatus is that a stepped section is formed at a location downstream of the feed material passage provided on one of the members and the pressure generation section is comprised by a centrifugal impeller provided in the stepped section, accordingly, the centrifugal impeller is used to serve as the pressure generation section to reverse the flow of feed gas, thereby preventing free flow of the feed material to maintain the upstream pressure. Still another aspect of the apparatus is that the outer member is stationary and the inner member is rotated, accordingly, the centrifugal force serves to improve the contact efficiency. In another aspect of the invention, a gas ejection device for ejecting feed gas onto a substrate disposed in a reaction vessel comprises a vaporizer section for generating a feed gas by heating a liquid material and a gas ejection head section for producing a flow of the feed gas onto the substrate, wherein the vaporizer section and the gas ejection head section are arranged to form a thermally homogeneous unit. Accordingly, the vaporized feed gas does not suffer any temperature variations during its transport to the gas ejection head section. It follows that the problem of premature precipitation reaction and plugging of the passages are prevented, thereby enabling the vaporized feed gas to undergo a stable deposition reaction to produce a high quality thin film product. An aspect of the feed gas ejection device is that the vaporizer section and the gas ejection head section shares a common casing, thus allowing the vaporized feed gas to be supplied directly to the gas ejection head in a short flow passage without being subjected to variations in temperature, accordingly, premature reaction or precipitation can be avoided before the feed gas in introduced into the film depositing compartment. An aspect of the feed gas ejection device is that the casing is provided with a heating medium passage common to the vaporizer section and the gas ejection head section, accordingly, both the vaporizer section and the ejection head section can be maintained at a constant temperature. An aspect of the feed gas ejection device is that the vaporizer section comprises: an outer member having a cylindrical inner surface, an inner member having a cylindrical outer surface opposing to the cylindrical inner surface of the outer member, a feed material passage having a spiral configuration formed on at least one of the cylindrical inner surface and the cylindrical outer surface, the feed material passage communicating with a feed liquid entry opening and a feed gas exit opening; and a heating device for heating at least one of the outer member and inner member. Accordingly, the same type of geometry for confining the feed material is effective in producing completely vaporized feed gas. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an overall cross sectional view of the a first embodiment of the apparatus. Figure 2 is a graph showing a pressure distribution along the flow path of the feed material in the embodiment shown in Figure 1. Figure 3 is an enlarged view of the essential parts of Figure 1. Figure 4 is another embodiment of the atomizing section or vaporizer section used in the vaporizer apparatus of the present invention. Figure 5 is another embodiment of the vaporizer apparatus. Figure 6 is still another embodiment of the vaporizer apparatus. Figure 7 is a schematic view of centrifugal vanes in the embodiment apparatus shown in Figure 6. DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 is a schematic diagram of a gas ejection apparatus comprising a vertical type vaporizer section unitized with a gas ejection head, and this example shows a type in which the feed material flows from the top to the bottom of the apparatus. An outer shell (outer member) 1, planar base section 2 and the upper motor section 3 are made of a heat resistant material such as metals as a unit, and its upper terminal end section is closed with a ceiling plate 4. An inner shell (inner member) 5 disposed inside the outer shell 1 with a narrow space therebetween, is also made of a heat resistance material such as metals. The clearance between the outer and inner shells 1, 5 is selected so as to provide a minimum possible path distance provided along the wall while preventing the outer and inner shells to contact during rotation as well as . The entire apparatus is designed to permit quick assembly and disassembly and minimize the short circuit flow of the fluid along the inner surface of the outer shell 1. In the top section of the outer shell 1, a plurality of feed entry openings 6 for atomized liquid material are provided to extend tangentially and to open at circumferentially equidistant positions. The number and the location of the feed entry openings 6 should be determined case by case according to the requirements of the system. The outer shell 1 is provided with a large diameter section 7 located slightly above the base section 2, for accommodating a ring-shaped gas dwelling section 8 having reactive gas entry openings 9 for supplying reactive gas to the gas dwelling section 8 and gas communication holes 10 communicating the gas dwelling section 8 with the internal space of the outer shell 1. Line protrusions 11 of a trapezoidal cross sectional shape extend downward in a spiral manner on the outer peripheral surface of the inner shell 5, thereby forming a groove 12 spirally extending between the line protrusions 11 in a similar manner. The grooves 12 constitute spiral flow passages 13 disposed between the outer and inner shells 1, 5 to provide flow path for descending feed material from the feed entry openings 6. The flow passage 13 extends downward from the feed entry openings 6, and the inner shell 5 are made to extend slightly beyond the feed entry openings 6 which is provided with a protrusion ring 14 to prevent the feed liquid to overflow. On the interior wall of the outer shell 1, there is provided a heating medium passage 16 over the entire lower regions, below the feed entry openings 6, to serve as a heating device, and also provided is a control device to control the temperature and flow rate of the heating medium flowing in the heating medium passage 16. Additionally, thermal insulating materials are provided, as necessary, on the outer surface of the outer shell 1. The inner shell 5 is coupled to a drive shaft (rotor) 18 of a drive motor 17 housed in the motor section 3 of the outer shell 1 so that the inner shell 5 can be rotated by the drive motor 17. The drive shaft 18 is freely supported on a magnetic bearing 19 while maintaining a given spacing therebetween. At both upper and lower sides of the magnetic bearing 19, there are provided touchdown bearings 20 for supporting the drive shaft 18, in case the magnetic bearing 19 is made inoperative due to emergency situations such as power outage. The direction of rotation of the inner shell 5 is chosen to be the direction which would successively force the feed material downward along the spiral flow passages 13. Regarding the magnetic bearing 19, it is usual to adopt an active control type magnetic bearing, but it is not necessary to restrict to this type, and other types for example, a passive type based on permanent magnets may also be used. The touchdown bearing 20, is usually ball bearings, but, because the surrounding temperature is high, it is preferable to use ceramic bearings. It is not necessary to restrict to ball bearings, and other types of bearings such as slide bearings may be used. In a location facing the gas communication hole 10 in the inner shell 5, there is provided a mixing space 21, and at the bottom end of the inner shell 5, there is an integrally connected gas ejection head 23 of a hollow disc design, having a plurality of jetting nozzles 22. The gas ejection head 23 protrudes below the base section 2 of the outer shell 1 into the film deposition compartment 25 of a sealed vessel 26 so that its lower surface, having the jetting nozzles 22, faces the film deposition compartment 25. In other words, the vaporizer apparatus is attached to the sealed vessel 26 so as to cover its upper open section with the base section 2. The gas ejection head 23 is disposed so as to face the substrate 28 such as a semiconductor wafer held on a pedestal 27. The sealed vessel 26 is provided with a discharge port 29 for externally discharging the spent gas. On the outer surface of the inner shell 5 at both top and bottom ends of an inner passage 24, there are provided respective pressure generation sections 32a, 32b formed by a plurality of finely spaced depression sections 30 and protrusion sections 31 which fit into the interior space between the depression sections 30. The upper pressure generation section 32a is used to produce a back pressure for the feed gas which is gradually vaporized while flowing down along the flow passage 13 by the action of the rotating inner shell 5, by blocking uninterrupted downward flow of the feed gas. The pressure changes in this section will be explained with reference to Figure 2. At the feed entry opening 6 (location a), the environmental pressure is chosen to prevent a separation of the organic solvent, about 500 torr for example, and the vaporized feed gas is injected from the jetting nozzles 22 (location c) of the gas ejection head 23 into the film deposition compartment 25 maintained at about 5 torr. The function of the upper pressure generation section 32a is to maintain the upstream pressure by preventing uninterrupted downward flow of the feed material. Thus, it is designed to provide a sudden drop in pressure at about the boundary region (location b) of the upper pressure generation section 32a. The presence of the pressure generation section 32a at the bottom region of the flow passage 13 allows a sufficient dwell time for the feed material in the flow passage 13 so that the feed material (mist mixed with vapor) can have ample contact time with the heated wall to undergo a complete conversion to vapor, and the vaporized gas can expand under progressively reducing pressures. This approach prevents sudden expansion of the feed gas that results in the feed material passing through the flow passage 13 without undergoing a full phase change process of a feed liquid converting to a feed gas. On the other hand, the lower pressure generation section 32b serves a sealing function to prevent quick escape of process gas produced by mixing the feed gas with the reactive gas in the mixing space 21. The vaporizer apparatus is operated by supplying atomized or partially atomized feed material to the feed entry openings 6, and for this purpose, this apparatus is operated in conjunction with an atomizing device comprising an ultrasonic vibrator 33 supplied with feed liquid drops through a nozzle 35 and a carrier gas, such as argon, supplied through another nozzle 34 to carry the atomized feed. The space 36 located in the bottom region of the atomizing device is for trapping liquid or solid residues. It should be noted that other atomizing arrangements such as that shown in Figure 4 is also applicable. In this known device having a double fluid passage nozzle 39, in which an outer nozzle 37 for carrier gas and an inner nozzle for feed gas are used together, and mist may be produced by a known mist spray method. Other approaches include a hot plate 40 to partially vaporize the mist delivered through a double fluid passage nozzle 39. The operation of the vaporizer apparatus will be explained below. The vaporizer apparatus is assembled by attaching the base section 2 of the outer shell 1 to the top opening section of the sealed vessel 26, having the film deposition compartment 25, to seal off the opening section. First, a liquid material is prepared by dissolving a feed material which is solid at room temperature, such as Ba(DPM) 2 or Sr(DPM) 2 , in an organic solvent (e.g. THF) for stabilization of vapor properties. The liquid material is atomized in the atomizer described above (note, the device in Figure 4 will produce partially atomized, partially vaporized feed) and is introduced into the vaporizer apparatus through the feed entry opening 6, while simultaneously activating the drive motor 17 to rotate the inner shell 5. The liquid material then enters the flow passages 13 provided on the outer surface of the inner shell 5, and following its rotation, the fluid feed is progressively forced downward, and along the descending way, comes into contact with the heated wall of the outer shell 1, and is gradually vaporized through thermal exchange. The feed material descends while undergoing a spiraling motion, and the liquid material in a form of mist particles is scattered outward by the centrifugal force of rotation, and the mist particles are preferentially forced to contact the wall surface of the outer shell 1 to promote vaporization through thermal exchange. Also, the cross-sectional profile of the flow passage 13 is elongated in the axial direction, so that a large contact area with the wall is assured, and the thermal exchange process is further promoted. The interior volumes of all the flow passages 13 are selected to be the same throughout so as to prevent the formation of precipitation particles. The feed material delivered along the flow passages 13 is then prevented from continuing to freely descend down when it enters into the upper pressure generation section 32a comprising a plurality of depressions 30 and coupling protrusions 31. In other words, the feed material is allowed to dwell within the flow passage 13 for a certain duration of time without expanding under the high ambient pressure. As the feed material is completely vaporized, the gassified feed material gradually leaks through the upper pressure generation section 32a and enters into the mixing space 21. The completely gassified feed material expands upon entering the mixing space 21, and mixes with the reactive gas (oxidizing gas) introduced from the reactive gas entry openings 9. The mixed process gas now enters into the gas ejection head 23 through the inner passage 24 of the inner shell 5. The process gas is directed to the surface of the substrate such as a semiconductor wafer 28 through the jetting nozzles 22 of the gas ejection head 23 disposed inside the film deposition compartment 25 to form a thin film on its surface. During the process, because the pressure within the film deposition compartment 25 is about 5 torr, for example, the process gas prepared in mixing space 21 is quickly accelerated under the driving force of the pressure gradient and enters rapidly into the gas ejection head 23 to be jetted out downward from the jetting nozzles 22. During this operation, the gas ejection head 23 is rotated along with the inner shell 5, and the rotation action promotes homogenization of the process gas by stirring and mixing of the feed gas with the reactive gas by the effect of the rotational force. Further, the centrifugal force acting on the mixing process gas promotes uniform flow of the process gas on the entire surface of the substrate 28, thereby producing a film of uniform thickness and quality on the surface of the substrate 28. The spent gas is exhausted externally from the discharge port 29 provided on the sealed vessel 26. As explained above, in the vaporizing apparatus of this embodiment, the vaporizer is integrally formed with the gas ejection head 23, and is assembled into a common casing, i.e., with the outer shell 1 and the base section 2. Therefore, the vaporized feed material is supplied directly to the gas ejection head through a short passage without passing through distribution pipes. Further, the feed gas is heated and kept warm by a heating device common to the vaporizer and the gas ejection head 23 which are thus thermally homogeneous, thereby preventing temperature variation during the transport step of the feed gas. Accordingly, the feed gas is able to prevent premature reaction or forming precipitation particles before reaching the deposition compartment, thus promoting the stable vapor phase deposition reaction in the film deposit compartment, without plugging of the passage or forming unwanted particles causing potential contamination of the products. Figure 5 shows another embodiment of the vaporizing apparatus. In this model, the gas ejection head 41 is fixed to underside of the base plate 2 which also serves as the ceiling for the sealed vessel 26, and a mixing section 42 formed therebetween. In the gas ejection head 41, there is a plurality of jetting nozzle 43, and an oil circulation passage 44 surrounding the jetting nozzles 43. The temperature of the oil is maintained at about 250 °C by such means as a temperature sensor and a controller device. In this embodiment, the function of pressure generation is served by an impeller 45, which is sized to fit into the inner passage 24 and is coupled to the bottom end of the inner shell 5. Above the base plate 2, there are provided a reactive gas entry opening 46 to admit the reactive gas, gas dwell section 47 and a communication passage 48 to communicate the gas dwell section 47 with the mixing space 42. Also, the inner shell is made hollow to reduce its weight, and the heating device is a high frequency heater 49a provided on the interior of the outer shell 1 and a coil heater 49b wound on the outer surface of the outer shell 1. In this embodiment, the feed material is forced to descend progressively along the flow passage 13, by the action of the rotating inner shell 5, and is gradually vaporized and leaks into the mixing space 45. The action of the impeller 45 rotating as a unit with the inner shell 5 blocks the free downward motion of the feed material, and the feed gas is made to dwell in the flow passage 13 without expanding and maintaining a high ambient pressure, and after complete vaporization has been achieved, the vapor enters into the mixing space 42. Within the mixing space 42, the admitted reactive gas and the feed gas are subjected to ample stirring and mixing by the rotational action of the impeller 45, thereby preventing variations in film thickness and quality caused by the compositional distribution in the feed and reactive gas. Figures 6 and 7 show still another variations in the vaporizer apparatus. In this embodiment, the bottom of the inner shell is provided with a reduced diameter section 51 with an intervening stepped surface 50, and the reduced diameter section 51 is surrounded with reactive gas entry openings 52, a gas dwell section 53 and communication holes 54. The stepped surface 50 is provided with a pressure generation section constituted by a centrifugal impeller 56 having a plurality of vanes 55. The centrifugal impeller 56 is arranged so as to reverse the flow of descending gas stream, so that the feed gas descending along the flow passage 13 is prevented from flowing freely past the pressure generation section. Therefore, the feed material can maintain a high pressure and dwells within the flow passage 13 without expansion, and after complete vaporization, the feed gas enters into the mixing space 42. In this embodiment, the mixing space 42 is made larger than the impeller 45. This impeller 45 is primarily for stirring and mixing the feed gas and the reactive gas, rather than for reversing the flow of the mixed process gas. In the apparatus shown in Figures 5, 6, the vaporizer apparatus forms a unit with the gas ejection head 23, and the mixed process gas does not undergo plugging or premature precipitation, thus promoting a stable vapor phase deposition reaction in the film deposition compartment. Although a certain preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

Claims: A gas ejection device for ejecting feed gas onto a substrate (28) disposed in a reaction vessel (26) comprising a vaporizer section for generating a feed gas by heating a liquid material and a gas ejection head section for producing a flow of said feed gas onto said substrate (28), wherein said vaporizer section comprises: an outer member (1) having a cylindrical inner surface and an inner member (5) having a cylindrical outer surface opposing to said cylindrical inner surface of said outer member, said outer member (1) and said inner member (5) being arranged relatively rotatable; a feed material passage (13) having a spiral configuration formed on at least one of said cylindrical inner surface and said cylindrical outer surface, said feed material passage (13) communicating with a feed liquid entry opening (6) and a feed gas exit opening (22); a heating device (16) for heating at least one of said outer member (1) and inner member (5); and a pressure generation section (32a, 32b) provided on a downstream section of said feed material passage (13) for maintaining a back pressure of said feed gas descending within said feed material passage (13) assisted by said relative rotation between said outer member (1) and said inner member (5). A gas ejection device according to claim 1, wherein said apparatus comprises a drive source (17) to rotate at least one of said outer member (1) and said inner member (5). A gas ejection device according to claim 1 or 2, wherein said outer member (1) and said inner member (5) are attached to said reaction vessel (26) at a downstream location of said feed material passage (13). A gas ejection device according to any one of the claims 1 to 3, wherein a mixing space (21,42) is provided at a location downstream of said feed material passage (13) for mixing said feed gas, descending through said feed material passage (13), with a reactive gas introduced from an external source. A gas ejection device according to any one of the claims 1 to 4, wherein said pressure generation section communicates with a downstream end of said feed material passage (13), and is provided with an impeller (45) which rotates in an interior of said mixing space. A gas ejection device according to any one of the claims 1 to 4, wherein said pressure generation section comprises a convexoconcave (30,31) formed on at least one of said outer member (1) and said inner member (5). A gas ejection device according to any one of the claims 1 to 6, further comprising a gas ejection head having nozzles (22) for producing a feed gas flow onto said substrate (28), said gas ejection head being communicated with a downstream end of said feed material passage (13). A gas ejection device according to claim 7, wherein said gas ejection head is formed as a unit with one of said outer member (1) and said inner member (5) which is being rotated. A gas ejection device according to any one of the claims 1 to 4, 7 and 8, wherein a stepped section (50) are formed at a location downstream of said feed material passage (13) provided at least on said outer member (1) and said inner member (5) and said pressure generation section is comprised by a centrifugal impeller (56) provided in at least one of said stepped sections. A gas ejection device according to any one of the claims 1 to 9, wherein said outer member (1) is stationary and said inner member (5) is rotated. A gas ejection device according to any of the preceding claims, wherein said vaporizer section and said gas-ejection head section are arranged to form a thermally homogeneous unit. A gas ejection device according to claim 11, wherein said vaporizer section and said gas ejection head section shares a common casing. A gas ejection device according to claim 11 or 12, wherein said casing is provided with a heating medium passage (16) common to said vaporizer section and said gas ejection head section. A gas ejection device according to claim 11, wherein said vaporizer section and said gas ejection head section share a common flow conditioning space (8;47;53) for accommodating volume expansion effects produced by a liquid-to-gas phase change and distributing a feed gas to a plurality of nozzles (22) of said gas ejection head section. A gas ejection device according to claim 14, wherein said flow conditioning space is provided with a supply passage (9;48;52) for introducing a gas different than said feed gas. A gas ejection device according to any of the preceding claims, wherein said vaporizer section and said gas ejection head section are shrouded in a thermal insulation unit.

Inventors: FUKUNAGA YUKIO, HONGO AKIHISA, MURAKAMI TAKESHI, OGURE NAOAKI, FUKUNAGA, YUKIO, HONGO, AKIHISA, MURAKAMI, TAKESHI, OGURE, NAOAKI
Applicants: EBARA CORP, EBARA CORPORATION
Application year: 1997
Main classification: C23C16
IPC codes: C23C16