Patent Publication Number: US-2016222510-A1

Title: Process gas supplier

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2015-0014758, filed on Jan. 30, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND 
     1. Field 
     The disclosure relates to a process gas supplier and, more particularly, to a process gas supplier capable of supplying three types of gases to a processing space using a single nozzle. 
     2. Description of the Related Art 
     A light emitting diode (LED) is a semiconductor device for converting current into light, and is widely used as a light source for displaying an image in electronic devices including information and communication devices. Particularly, compared to a conventional lighting device such as an incandescent lamp or a fluorescent lamp, the LED device is capable of reducing energy consumption by up to 90% due to a high efficiency of converting electrical energy into light energy, and thus is broadly regarded as a substitute for the incandescent lamp or the fluorescent lamp. 
     A manufacturing process of the LED device may be largely divided into an epitaxial process, a chip process, and a package process. The epitaxial process refers to a process for epitaxially growing a compound semiconductor on a substrate, the chip process refers to a process for producing an epitaxial chip by forming electrodes on parts of the epitaxially grown substrate, and the package process refers to a process for connecting a lead to the produced epitaxial chip and packaging the epitaxial chip to emit light as much as possible. 
     Among the above processes, the epitaxial process may be the most significant process which determines emission efficiency of the LED device, because defects are generated in crystals if the compound semiconductor is not epitaxially grown on the substrate and serve as nonradiative centers to lower the emission efficiency of the LED device. 
     The epitaxial process, i.e., the process for forming an epitaxial layer on the substrate, is performed using liquid phase epitaxy (LPE), vapor phase epitaxy (VPE), molecular beam epitaxy (MBE), chemical vapor deposition (CVD), or the like. Specifically, metal-organic chemical vapor deposition (MOCVD) or hydride vapor phase epitaxy (HVPE) is commonly used. 
     For this process, an epitaxial layer forming apparatus includes a process gas supplier for supplying a process gas reacting to form the epitaxial layer on the substrate, and a basic function of the process gas supplier is to stably supply the process gas. 
       FIG. 1  is a cross-sectional view of a conventional deposition layer forming apparatus  10 , and  FIG. 2  illustrates a conventional process gas supplier  40 . (a) of  FIG. 2  is a perspective view of the process gas supplier  40 , (b) of  FIG. 2  is a transparent perspective view of the process gas supplier  40 , and (c) of  FIG. 2  is a cross-sectional view of the process gas supplier  40 . 
     Referring to  FIG. 1 , the conventional deposition layer (epitaxial layer) forming apparatus  10  may include a chamber  20 , a plurality of substrate holders  30 , the process gas supplier  40 , and a metal halogen gas generator  60 . 
     The chamber  20  has a rectangular or circular shape and provides a space for forming deposition layers. The substrate holders  30  are stacked on one another with intervals therebetween. The process gas supplier  40  is provided to penetrate through central through holes (not shown) of the substrate holders  30 , and supplies process gases g′: g 1 ′ and g 3 ′ required to form deposition layers, into the chamber  20 . 
     Referring to  FIG. 2 , the process gas supplier  40  may have a double tube shape including an outer tube  41  and one or more inner tubes  42  located inside the outer tube  41 . The outer tube  41  may be used to supply a metal halogen gas g 3 ′ (e.g., a GaCl gas) through first gas supplying holes  44  into the chamber  20 , and the inner tubes  42  may be used to supply a nitriding gas g 1 ′ (e.g., an NH 3  gas) through second gas supplying holes  43  into the chamber  20 . 
     The conventional deposition layer forming apparatus  10  may receive the metal halogen gas g 3 ′ supplied from the metal halogen gas generator  60 . The metal halogen gas generator  60  includes a halogen-containing gas supplier  61  and a metal halogen gas supplier  62  provided at two ends of the metal halogen gas generator  60 , and a metal source container  65  for accommodating a metal source  66  therein. A halogen-containing gas g 2 ′ (e.g., an HCl gas) supplied through the halogen-containing gas supplier  61  into the metal halogen gas generator  60  may react the metal source  66  of the metal source container  65  to generate the metal halogen gas g 3 ′. The metal halogen gas g 3 ′ may be discharged through the metal halogen gas supplier  62  and may be supplied through a transfer tube  50  to the process gas supplier  40 . 
     The above-described conventional deposition layer forming apparatus  10  additionally includes the metal halogen gas generator  60  outside the chamber  20  to generate the metal halogen gas g 3 ′. As an example of the metal halogen gas g 3 ′, GaCl is liquefied or condensed at 600° C. or below and thus the process gas supplier  40  for supplying GaCl should be maintained at a temperature higher than 600° C. However, since the metal halogen gas generator  60  is provided outside the chamber  20 , the metal halogen gas generator  60  is not easily maintained at a high temperature, GaCl is liquefied or condensed in the process gas supplier  40 , and thus the GaCl gas is not stably supplied into the chamber  20 . In addition, since the metal halogen gas generator  60  is additionally provided outside the chamber  20 , an apparatus size is increased. 
     Furthermore, in the structure of the process gas supplier  40  of the conventional deposition layer forming apparatus  10 , since only two types of gases (e.g., a GaCl gas and an NH 3  gas) are suppliable, a doping gas (e.g., a SiH 4  gas) should be mixed with another gas to supply the same. If a doping gas supply tube (not shown) is additionally provided to solve the above problem, the whole design inside the chamber  20  should be changed to avoid interference. 
     Besides, in the structure of the process gas supplier  40  of the conventional deposition layer forming apparatus  10 , since the first and second gas supplying holes  44  and  43  supply gases into the chamber  20  in different directions (see  FIG. 2( c ) ), i.e., since the first and second gas supplying holes  44  and  43  are alternately provided along the outer circumferential surface of the chamber  20 , a reaction rate of reaction gases, i.e., the GaCl gas g 3 ′ and the NH 3  gas g 1 ′, may not be easily controlled to be uniform. 
     SUMMARY 
     The disclosure provides a process gas supplier capable of stably supplying process gases and reducing an apparatus size. 
     The disclosure also provides a process gas supplier capable of simultaneously supplying three types of gases. 
     The disclosure also provides a process gas supplier capable of supplying process gases to achieve a uniform reaction rate. 
     According to an aspect of the present invention, there is provided a process gas supplier including an outer tube providing a passage for a first process gas, a first inner tube located in the outer tube and providing a passage for a second process gas, a gas reactor located at an upper side of the outer tube, accommodating a metal source and generating a third process gas by a reaction between the second process gas and the metal source, a second inner tube located in the outer tube and providing a passage for the third process gas, a third inner tube located in the outer tube and providing a passage for a fourth process gas, one or more first gas injectors supplying the first process gas flowing in the outer tube, to a processing space outside the outer tube, one or more second gas injectors supplying the third process gas flowing in the second inner tubes, to the processing space, and one or more third gas injectors supplying the fourth process gas flowing in the third inner tubes, to the processing space. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the disclosed technology will become more apparent by describing in detail embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a cross-sectional view of a conventional deposition layer forming apparatus; 
         FIG. 2  illustrates a conventional process gas supplier; 
         FIG. 3  is a cross-sectional view of a batch-type deposition layer forming apparatus according to an embodiment of the present invention; 
         FIG. 4  is a perspective view of a process gas supplier according to an embodiment of the present invention; 
         FIG. 5  is a vertical cross-sectional view of the process gas supplier an embodiment of the present invention; and 
         FIG. 6  is a horizontal cross-sectional view of the process gas supplier an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the spirit and scope of the invention. In addition, it is to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, appropriately interpreted, along with the full range of equivalents to which the claims are entitled. In the drawings, like numerals refer to the same or similar functionality throughout the several views. 
     Embodiments of the Present Invention 
     Hereinafter, the present invention will be described in detail by explaining embodiments of the invention with reference to the attached drawings. 
       FIG. 3  is a cross-sectional view of a batch-type deposition layer forming apparatus  100  according to an embodiment of the present invention. 
     A plurality of substrates  1  loaded in the batch-type deposition layer forming apparatus  100  is not limited to a specific material and may be formed of various materials such as glass, plastic, polymer, silicon wafer, stainless steel, and sapphire. The following description assumes the substrates  1  as circular sapphire substrates used in the field of light-emitting diodes (LEDs). 
     Referring to  FIG. 3 , the batch-type deposition layer forming apparatus  100  according to the current embodiment of the present invention is configured to include a chamber  110 . The chamber  110  may be configured to seal an internal space thereof during processes and may provide a space for forming deposition layers (epitaxial layers) on the substrates  1 . The chamber  110  may be configured to maintain an optimal process condition and may be produced in a rectangular or circular shape. The chamber  110  may be formed of quartz but is not limited thereto. 
     Referring further to  FIG. 3 , the batch-type deposition layer forming apparatus  100  according to the current embodiment of the present invention may be configured to include a heater  120 . The heater  120  may be provided outside the chamber  110  to apply heat required for an epitaxial process, to the substrates  1 . For appropriate epitaxial growth on the substrates  1 , the heater  120  may heat the substrates  1  to a temperature equal to or higher than about 1,200° C. 
     In the embodiment, the substrates  1  may be heated using a halogen lamp or a resistive heating element and, preferably, using induction heating. Induction heating refers to a scheme of heating a conductive object such as metal using electromagnetic induction. To use induction heating, the heater  120  may be configured as a coil-type heater capable of induction-heating the internal space of the chamber  110 , and a plurality of susceptors  133  provided on a plurality of substrate supports  131  may be configured to include a conductive material. The substrates  1  may be heated using the coil-type heater  120  based on a principle that the susceptors  133  including a conductive material is heated as a high-frequency alternating current is applied from the coil-type heater  120  into the chamber  110 . 
     When the substrates  1  are heated using induction heating as described above, elements of the batch-type deposition layer forming apparatus  100  other than the susceptors  133  may be formed of a nonconductor (e.g., quartz). As such, since only the susceptors  133  are heated by the coil-type heater  120 , deposition on the other elements inside the chamber  110  may be minimized. 
     Referring further to  FIG. 3 , the batch-type deposition layer forming apparatus  100  according to the current embodiment of the present invention may be configured to include a lower holder  130 . The lower holder  130  may be provided inside the chamber  110  to support the substrates  1  during the epitaxial process. 
     The lower holder  130  may be configured to be rotatable inside the chamber  110 . To make the lower holder  130  rotatable, the lower holder  130  may employ a variety of known rotary force generators. As the lower holder  130  rotates inside the chamber  110 , the substrate supports  131  of the lower holder  130  also rotate. As such, concentration of process gases g: g 1 , g 3 , and g 4  at certain locations of the substrates  1  may be prevented. Consequently, the process gases g may be uniformly supplied onto the substrates  1 . 
     Referring to  FIG. 3 , the lower holder  130  may be configured to include the substrate supports  131  for mounting the substrates  1  thereon. As illustrated in  FIG. 3 , the substrate supports  131  may be configured in the form of circular plates for appropriate rotation of the lower holder  130 , but are not limited thereto. 
     Referring further to  FIG. 3 , the substrate supports  131  may be stacked on one another with intervals therebetween. In this case, the substrate supports  131  may be connected and fixed to each other by a connection member  132 . The number of the substrate supports  131  is six in  FIG. 3  but is not limited thereto. The number of the substrate supports  131  may be variously changed depending on a purpose of the embodiments. The substrate supports  131  may be formed of quartz but are not limited thereto. 
     As will be described below, in the embodiment, a process gas supplier  140  penetrating through the centers of the substrate supports  131  of the lower holder  130  supplies the process gases g. In this case, as the process gases g are supplied from the centers of the substrate supports  131 , the amount of the process gases g supplied to portions of the substrates  1  near the centers of the substrate supports  131  may be greater than that supplied to the other portions. To solve this problem, the substrates  1  mounted on the substrate supports  131  may independently rotate. In other words, the substrates  1  may separately rotate in parallel to the substrate supports  131  at different rotation speeds or in different rotation directions during the epitaxial process. The independent rotation of the substrates  1  may be performed due to rotation of the susceptors  133  for mounting the substrates  1  thereon. As the substrates  1  independently rotate, the process gases g may be uniformly supplied onto the substrates  1 . 
     Referring further to  FIG. 3 , the susceptors  133  may be individually mounted on the substrate supports  131 . The susceptors  133  may support and prevent deformation of the substrates  1  during the epitaxial process. The number of the susceptors  133  mounted on the substrate supports  131  may equal the number of the substrates  1  provided on the substrate supports  131 . 
     In addition to the function of preventing deformation of the substrates  1 , the susceptors  133  may heat the substrates  1  together with the coil-type heater  120  as described above. To this end, the susceptors  133  may be formed of a conductive material, e.g., amorphous carbon, diamondlike carbon, or glasslike carbon, and, preferably, of graphite. Graphite has a high strength and an excellent conductivity, and thus may be appropriately heated using induction heating. When the susceptors  133  are formed of graphite as described above, the surface of graphite may be coated with silicon carbide (SiC). Since SiC has an excellent high-temperature strength and hardness and a high thermal conductivity, dispersion of graphite molecules during heating may be prevented and heat may be easily transferred to the substrates  1 . 
     In addition to the function of preventing deformation of the substrates  1  and the function of heating the substrates  1 , the susceptors  133  may allow the substrates  1  to rotate as described above. To this end, the susceptors  133  may employ a variety of known rotary force generators. Furthermore, the susceptors  133  may be configured in the form of circular plates for appropriate rotation, but are not limited thereto and may have a variety of shapes depending on a purpose of the embodiments. 
     Referring further to  FIG. 3 , the batch-type deposition layer forming apparatus  100  according to the current embodiment of the present invention may be configured to include the process gas supplier  140 . The process gas supplier  140  may supply the process gases g required to form epitaxial layers, into the chamber  110 . 
     As illustrated in  FIG. 3 , in the embodiment, the process gas supplier  140  may be provided to penetrate the centers of the substrate supports  131 . In other words, as the process gas supplier  140  are provided to penetrate through central through holes  135  of the substrate supports  131 , the process gases g may be supplied from the centers of the substrate supports  131  toward the substrates  1  supported by the substrate supports  131 . By employing this configuration, the process gases g may be uniformly supplied onto the substrates  1  and thus epitaxial layers having the same quality and thickness may be formed on the substrates  1 . 
     In addition, the process gas supplier  140  may rotate during the epitaxial process. To rotate the process gas supplier  140 , the process gas supplier  140  may employ a variety of known rotary force generators. As such, concentration of the process gases g at certain locations of the substrates  1  may be prevented similarly to the effect achieved due to rotation of the lower holder  130 . Consequently, the process gases g may be uniformly supplied onto the substrates  1 . 
     Referring to  FIG. 3 , a process gas discharger  150  may discharge the process gases g to the outside of the chamber  110 . The process gas discharger  150  may be provided in a cylindrical shape surrounding the substrate supports  131 . A plurality of discharge holes  155  for discharging the process gases g may be provided in the process gas discharger  150  to correspond to the substrate supports  131 . The discharge holes  155  may be configured as slits but are not limited thereto. In addition, the number of the discharge holes  155  may be variously changed depending on a purpose of the embodiments. 
     A suction means  151  capable of sucking out the process gases g may be connected outside the process gas discharger  150  to discharge the process gases g from the discharge holes  155  to the outside of the chamber  110 . The discharge holes  155  may be located near the substrate supports  131 . By employing this configuration, the process gases g injected from the process gas supplier  140  may directly flow into the discharge holes  155  without circulating in the chamber  110  and thus excessive supply of the process gases g onto the substrates  1  may be minimized. Consequently, the process gases g may be uniformly supplied onto the substrates  1 . The discharge holes  155  may be provided with equal intervals therebetween in a horizontal direction for uniform flow of the process gases g. 
     A baffle  170  may be located under the substrate supports  131  to prevent leakage of heat generated in the chamber  110  and, more particularly, to prevent leakage of heat through the lower holder  130 . 
     A rotator  180  allows the process gas supplier  140  to rotate and may be located under the process gas supplier  140 . 
     A detailed description is now given of the structure of the process gas supplier  140  used in the batch-type deposition layer forming apparatus  100 , according to an embodiment of the present invention. The following description assumes that the process gas supplier  140  uses GaCl, NH 3 , and SiH 4  gases as the process gases g: g 1 , g 3 , and g 4  to form epitaxial gallium nitride (GaN) layers on the substrates  1  using hydride vapor phase epitaxy (HVPE), but is not limited thereto. 
       FIG. 4  is a perspective view of the process gas supplier  140  according to an embodiment of the present invention,  FIG. 5  is a vertical cross-sectional view of the process gas supplier  140  of  FIG. 4 , and  FIG. 6  is a horizontal cross-sectional view of the process gas supplier  140  of  FIG. 4 . 
     Referring to  FIGS. 4 to 6 , the process gas supplier  140  may have a multi-tube structure in which a first inner tube  142 , second inner tubes  143 , and third inner tubes  144  are included in an outer tube  141 . Although the number of the second inner tubes  143  is three and the number of the third inner tubes  144  is also three according to the current embodiment of the present invention, the numbers of the second and third inner tubes  143  and  144  are not limited thereto and may be variously changed depending on purposes and uses thereof. 
     The outer tube  141  may provide a passage of a first process gas g 1  (e.g., a nitriding gas such as an NH 3  gas). The first process gas g 1  may be supplied from an external first process gas supplier (not shown) connected to a lower part of the process gas supplier  140 , and may flow through an internal space  145  of the outer tube  141  other than spaces occupied by the first, second, and third inner tubes  142 ,  143 , and  144 . Then, the first process gas g 1  may be supplied through one or more first gas injectors  146  provided on the outer circumferential surface of the outer tube  141 , to a processing space outside the outer tube  141  (i.e., the chamber  110 ). The first gas injectors  146  may be configured as holes provided in the outer circumferential surface of the outer tube  141 . 
     The first inner tube  142  may provide a passage of a second process gas g 2  (e.g., a halogen-containing gas such as an HCl gas). The second process gas g 2  may be supplied from an external second process gas supplier (not shown) connected to the lower part of the process gas supplier  140 , and may flow through the first inner tube  142 . 
     The first inner tube  142  may be located at the center of the outer tube  141  in such a manner that the second process gas g 2  is supplied to a gas reactor  160  to be described below and a third process gas g 3  passes through the second inner tubes  143  and is supplied through second gas injectors  148 . In other words, the second process gas g 2  may be supplied upward through the first inner tube  142  located at the center of the outer tube  141 , and the third process gas g 3  may be supplied downward from the gas reactor  160  toward the substrates  1  through the second inner tubes  143  surrounding the first inner tube  142  in the outer tube  141 . 
     The second inner tubes  143  may provide passages of the third process gas g 3  (e.g., a GaCl gas). The third process gas g 3  may be supplied from the gas reactor  160  located at an upper side of the second inner tubes  143  (or the outer tube  141 ), and may flow through the second inner tubes  143 . Then, the third process gas g 3  may be supplied through the second gas injectors  148  to the processing space outside the outer tube  141  (i.e., the chamber  110 ). The second gas injectors  148  may be configured as tubes or nozzles having one-side ends connected to the second inner tubes  143  and another-side ends connected to the outer circumferential surface of the outer tube  141 . Alternatively, if the second inner tubes  143  are located to contact the inner wall of the outer tube  141 , the second gas injectors  148  may be configured as holes connected from the second inner tubes  143  to the outer circumferential surface of the outer tube  141 . 
     The third inner tubes  144  may provide passages of a fourth process gas g 4  (e.g., a doping gas such as a SiH 4  gas). The fourth process gas g 4  may be supplied from an external fourth process gas supplier (not shown) connected to the lower part of the process gas supplier  140 , and may flow through the third inner tubes  144 . Then, the fourth process gas g 4  may be supplied through one or more third gas injectors  149  provided on the outer circumferential surface of the outer tube  141 , to the processing space outside the outer tube  141  (i.e., the chamber  110 ). The third gas injectors  149  may be configured as tubes or nozzles having one-side ends connected to the third inner tubes  144  and another-side ends connected to the outer circumferential surface of the outer tube  141 . Alternatively, if the third inner tubes  144  are located to contact the inner wall of the outer tube  141 , the third gas injectors  149  may be configured as holes connected from the third inner tubes  144  to the outer circumferential surface of the outer tube  141 . 
     The number of each of the first, second, and third gas injectors  146 ,  148 , and  149  is not particularly limited and may vary depending on the purposes of the embodiments. 
     The first, second, and third gas injectors  146 ,  148 , and  149  may be located to correspond to the substrate supports  131 . In other words, the first, second, and third gas injectors  146 ,  148 , and  149  may be provided toward spaces between the substrates  1  stacked on one another in the processing space (i.e., the chamber  110 ) (or spaces between the susceptors  133 ) and thus the process gases g may be uniformly supplied. 
     In addition, as illustrated in  FIG. 6 , each of the first gas injectors  146  and each of the second gas injectors  148  may be provided toward the same direction. As such, the first process gas g 1  (e.g., a nitriding gas) injected from the first gas injectors  146  and the third process gas g 3  (e.g., a halogen gas) injected from the second gas injectors  148  may uniformly react with each other and thus epitaxial layers may be uniformly formed on the substrates  1 . 
     Although the first process gas g 1  is a nitriding gas such as an NH 3  gas, the second process gas g 2  is a halogen-containing gas such as an HCl gas, the third process gas g 3  is a metal halogen gas such as a GaCl gas, and the fourth process gas g 4  is a doping gas such as a SiH 4  gas in the above description, the process gases g are not limited thereto. A metal source  163  to be described below may include at least one of gallium (Ga) and aluminum (Al). As such, the third process gas g 3  may include at least one of metal halogen gases such as a GaCl gas, an AlCl gas, and an AlCl 3  gas, and the fourth process gas g 4  may include at least one of doping gases such as a SiH 4  gas, a Si 2 H 6  gas, and a SiH 2 Cl 2  (dichlorosilane (DCS)) gas. 
     In addition, although three types of gases, e.g., the first process gas g 1  serving as a nitriding gas, the third process gas g 3  serving as a metal halogen gas, and the fourth process gas g 4  serving as a doping gas, are supplied through the first, second, and third gas injectors  146 ,  148 , and  149  in the above description, the gases are not limited thereto. For example, the first process gas g 1  serving as a doping gas and the third process gas g 3  serving as a nitriding gas may be supplied through the first and third gas injectors  146  and  149 , respectively. 
     In the process gas supplier  140  according to the embodiment, since three types of process gases g 1 , g 3 , and g 4  are injected through the first, second, and third gas injectors  146 ,  148 , and  149 , respectively, deposition of a deposition material on the inner wall of the process gas supplier  140  due to reaction of the process gases g 1 , g 3 , and g 4  in the process gas supplier  140  before reaching the substrates  1  may be prevented. Furthermore, since three types of process gases g 1 , g 3 , and g 4  are suppliable using a single process gas supplier  140 , three separate process gas supply tubes are not necessary. 
     Referring further to  FIG. 4 , the gas reactor  160  may be located at an upper side of the outer tube  141 . The halogen-containing gas supplied through the first inner tube  142  may react with the metal source  163  (e.g., a Ga source) and thus one of the process gases g, e.g., the third process gas g 3 , may be generated in the gas reactor  160 . Accordingly, the third process gas g 3  generated in the gas reactor  160  may be supplied downward through the second inner tubes  143  from an upper part of the process gas supplier  140 . 
     The gas reactor  160  may include an inlet passage  161  for passing therethrough the second process gas g 2  supplied from the first inner tube  142 , a first connection passage  162   a  for passing therethrough the second process gas g 2  supplied from the inlet passage  161 , a second connection passage  162   b  connected to the first connection passage  162   a,  a metal source storage  166  for accommodating therein the metal source  163  reacting with the second process gas g 2  passed through the second connection passage  162   b,  and an outlet passage  164  for supplying the third process gas g 3  generated due to reaction between the metal source  163  and the second process gas g 2 , to the second inner tubes  143 . 
     The second process gas g 2  supplied upward through the first inner tube  142  of the supply gas supplier  140  may be supplied through the inlet passage  161  into the gas reactor  160 . The second process gas g 2  supplied into the gas reactor  160  may be supplied through the first and second connection passages  162   a  and  162   b  to the metal source  163 . The gas reactor  160  may have a cylindrical shape, and the first and second connection passages  162   a  and  162   b  may be provided in such a manner that the second process gas g 2  supplied from the inlet passage  161  located at the center of the supply gas generator  160  flows along outer edges of the supply gas generator  160  and reaches the metal source  163 . Due to this configuration, compared to a case in which the second process gas g 2  contacts the metal source  163  immediately after passing through the inlet passage  161 , a contact area and time of the second process gas g 2  on the metal source  163  may be increased. Therefore, according to the current embodiment of the present invention, the possibility that the second process gas g 2  reacts with metal included in the metal source  163  to generate the third process gas g 3  may be increased. In addition, since the metal source  163  is located in the chamber  110  which is maintained at a high temperature by the heater  120 , an additional heater for maintaining a temperature for reaction between the second process gas g 2  and the metal is not necessary, and the reaction temperature may be easily controlled. 
     The second process gas g 2  supplied to the metal source  163  may react with the metal included in the metal source  163  to generate the third process gas g 3 , and the generated third process gas g 3  may be supplied through the outlet passage  164  to the second inner tubes  143 . The outlet passage  164  may be provided in the gas reactor  160  to allow the generated third process gas g 3  to flow toward the second inner tubes  143 . Since the outlet passage  164  is located in the chamber  110 , liquefaction or condensation of the third process gas g 3  in the outlet passage  164  may be prevented. The third process gas g 3  may flow downward through the second inner tubes  143  and may be injected through the second gas injectors  148  onto the substrates  1 . 
     Meanwhile, the gas reactor  160  may include a block  165  to provide the inlet passage  161 , the first connection passage  162   a,  the second connection passage  162   b,  and the outlet passage  164 . That is, the block  165  may be provided in the gas reactor  160  to form gaps between the inner surface of the gas reactor  160  and the block  165 , and the gaps may serve as the inlet passage  161 , the first connection passage  162   a,  the second connection passage  162   b,  and the outlet passage  164  based on the locations thereof. 
     According to the embodiment, the metal source  163  for generating the third process gas g 3  and the outlet passage  164  for supplying the third process gas g 3  to the process gas supplier  140  may be located in the chamber  110 . Therefore, unlike the conventional deposition layer forming apparatus  10  (see  FIG. 1 ) in which the additional metal halogen gas generator  60  is located outside the chamber  20 , an additional heater for maintaining a reaction temperature of the metal source  163  is not necessary, the reaction temperature of the metal source  163  may be easily controlled, and liquefaction or condensation of the third process gas g 3  flowing through the outlet passage  164  due to a low temperature may be prevented. Therefore, the third process gas g 3  may be stably supplied from the process gas supplier  140 . Furthermore, since the additional metal halogen gas generator  60  (see  FIG. 1 ) is not necessary, an apparatus size may be reduced. 
     As described above, according to the embodiments, epitaxial layers may be uniformly formed on a plurality of substrates. 
     Furthermore, process gases may be stably supplied and an apparatus size may be reduced. 
     In addition, three types of gases may be simultaneously supplied. 
     Besides, process gases may be supplied to achieve a uniform reaction rate. 
     While the present invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.