CN105200397B - The antihunt means and chlorine-resistant bilayer nozzle and production method of head-type MOCVD original states - Google Patents

Abstract

The invention discloses a method for stabilizing the initial state of a nozzle-type MOCVD, a chlorine-resistant double-layer nozzle and a manufacturing method. The nozzle uses electric sparks to directly punch nozzle holes of Group III sources and Group V sources, and these nozzle holes replace those with rough inner surfaces. The stainless steel capillary nozzle greatly reduces the inner surface area of the jet hole, thereby reducing the memory effect of the extension; the vacuum brazing process of the stainless steel capillary tube that is not resistant to chlorine corrosion is abandoned during the production of the nozzle, so the nozzle can withstand chlorine gas online cleaning, thus ensuring The initial state of each furnace epitaxial growth is constant and controllable, so that the close-coupled nozzle MOCVD can be perfectly used in the mass production of the third-generation semiconductor optoelectronic devices with high aluminum components; the cooling water channel of the nozzle and the group III source and V source The air jet holes are all processed by EDM, which eliminates the hidden danger of water leakage due to thin capillary walls, and can meet the strict sealing requirements of the semiconductor industry.

Description

Method for stabilizing the initial state of nozzle-type MOCVD and its production of chlorine-resistant double-layer nozzles method

technical field

The invention relates to a metal organic chemical vapor deposition (MOCVD) method and equipment, in particular to a method for stabilizing the initial state of a nozzle-type MOCVD, a chlorine-resistant double-layer nozzle and a manufacturing method.

Background technique

Metal-organic compound vapor deposition growth equipment (MOCVD) has been widely used to grow nitride semiconductor materials. This type of material belongs to the third-generation semiconductor material. At present, light-emitting diodes (LEDs) based on this type of material have been widely used in human society. It has brought high-efficiency, long-life, mercury-free semiconductor lighting, and will open up a new and broader world in energy conversion and wireless high-speed interconnection in the future.

Nozzle-type MOCVD is classified as vertical airflow type in the industry. At present, there are mainly two types of commercial MOCVD in this form. One is the close-coupled nozzle-type MOCVD produced by AIXTRON (Aixtron) in Germany. The distance between the nozzle and the epitaxial substrate is Usually about 11mm is selected. One is the remote-coupled nozzle type MOCVD produced by VEECO in the United States. The distance between the nozzle and the epitaxial substrate is usually about 70mm. The common feature of these two models is that the Group III organic source and the Group V source are transported separately from the two-layer gas chamber into the nozzle of the reaction tube, and then sprayed vertically to the epitaxial substrate, so it is called a vertical airflow type reaction tube in the industry. These two vertical air flow reaction tubes currently do not have an online cleaning function for chlorine (referring to chlorine or hydrogen chloride, the same below). Compared with the vertical airflow type, AIXTRON also produces a horizontal airflow type MOCVD reaction tube, which has a chlorine online cleaning function, which will be mentioned later.

Since MOCVD grows crystal materials one by one and arranges atoms layer by layer, the state of the reaction tube before the growth of each furnace is particularly important. Generally speaking, growing semiconductor materials is like cooking, at least the "pot" should be washed before each cooking! However, due to crystal growth, according to industry habits, the seed before starting to grow is very important, that is, the "seed crystal" is very important; in order to obtain some specific "seed crystals", some nitride material epitaxy engineers deliberately do not wash the "pot" , making the nitride epitaxy process very mysterious, turning a "technology" into an "art"; So closed. It can be seen that this way of thinking of not washing the "pot" is far from the advanced concept of keeping the initial state of the reaction tube constant in the present invention.

In the close-coupled shower head type MOCVD, since the shower head is very close to the epitaxial substrate, there will be deposits on the lower surface of the shower head after growth. Of course, there will be more deposits on the surface of the graphite disk carrying the epitaxial substrate. At present, the production steps between the epitaxial process furnace and the furnace are usually as follows: (1) Remove the graphite plate with the grown epitaxial sheet with a manipulator, and the heater is exposed at this time; (2) Manually use a dust cover to cover the heating Then use a brush to clean the surface of the nozzle mechanically; (3) remove the protective cover, and use a manipulator to replace the clean graphite plate with the substrate to be grown; (4) start the next furnace growth, and put The "dirty" graphite disk should be sent to a high-temperature furnace other than MOCVD to be baked and cleaned for later use; (5) The heat insulation ring on the reaction tube wall should be cleaned every 20 furnaces grown.

Some epitaxy engineers who advocate the concept of "seed crystal" even take off the epitaxial wafer after each furnace, put a new substrate on it, and then adjust some parameters based on experience to start growth again. If the growth is really not good, let the MOCVD reaction tube heat up Clean it up once. In short, even if the equipment models are the same, the process steps are "subtly" different, but after one year, there is no increase in the pass rate. Although this close-coupled MOCVD has many variables, it has the following irreplaceable advantages: (1) The nozzle is close to the epitaxial substrate, so there is less pre-reaction, which is advantageous for growing materials such as aluminum nitride; (2) The distance between the nozzle and the epitaxy The substrate is close, so when the nano-dust in the exhaust gas diffuses to the surface of the epitaxial substrate, it is easy to be collided back by the carrier gas molecules, that is, the closer the nozzle surface is to the epitaxial substrate, the smaller the impact of the dust in the exhaust gas on the epitaxy; (3) The rotating speed of the graphite disk is slow (100 rpm), so the ash on the side wall of the reaction tube will not be stirred to the surface of the epitaxial substrate.

VEECO's remote-coupled shower head MOCVD has very little deposits on the lower surface of the grown shower head because the shower head is very close to the epitaxial substrate. Of course, there will still be deposits on the surface of the graphite disk. The current production steps between furnaces are usually as follows: (1) Use a manipulator to remove the graphite disk with grown epitaxial wafers; (2) Use a manipulator to replace the clean graphite disk with the substrate to be grown; (3) Start the growth of the next furnace, and send the "dirty" graphite disk to a high-temperature furnace other than MOCVD to be baked and cleaned for later use; (4) The reaction tube must be disassembled and cleaned once every 100 furnaces are grown. The growth mode of VEECO is simple and has completely abandoned the concept of "seed crystal", and has achieved great success so far. But this kind of MOCVD also has the following weaknesses: (1) The nozzle is far away from the epitaxial substrate, so the pre-reaction is large, and there is no advantage in growing materials such as aluminum nitride. (2) The nozzle is far away from the epitaxial substrate, so the nano Dust is easy to spread to the surface of the epitaxial substrate, and it is not easy to be blocked by the carrier gas molecules, that is, the exhaust gas has a great influence, and the initial state of the reaction tube cannot be kept constant in principle; (3) The graphite disk rotates fast (700 rpm), so it will Stirring the ash on the side wall of the reaction tube to the epitaxial substrate cannot keep the initial state of the reaction tube constant in principle.

When the above two kinds of MOCVD grow high-aluminum component materials such as aluminum gallium nitrogen, the common problem encountered is that due to the high melting point of this material, the grown graphite disk cannot be cleaned even if it is baked in a vacuum high-temperature furnace. When these graphite disks are used to grow again, the initial state of the reaction tube has changed. Therefore, when using vertical gas flow MOCVD growth, the current mass production of nitride electronic devices is always unstable.

To sum up the above two types of vertical gas flow MOCVD, whether it is close-coupled or far-coupled, they have not fundamentally solved the problem of constant initial state of the reaction tube (even if it is VEECO, it needs to be cleaned once every 100 furnaces, and the 100 furnaces The initial state of the reaction tube is gradually changing!), some epitaxy engineers have not realized the importance of this problem, and are even doing the opposite, pursuing some kind of uncertain "seed crystal" effect.

So, how to ensure that the initial state of the vertical airflow reactor tube is constant? The answer is to introduce chlorine gas or hydrogen chloride online cleaning (hereinafter referred to as chlorine cleaning) after each furnace growth like AIXTRON's horizontal flow MOCVD! At this time, the production steps between the furnaces are usually as follows: (1) Use the manipulator to remove the graphite disc with the grown epitaxial sheet; (2) Use the manipulator to replace another set of "dirty" empty graphite discs, And raise the temperature of MOCVD to 860 degrees, and clean the reaction tube and this set of graphite discs with chlorine; (3) After cooling down, use the manipulator to send another set of clean graphite discs filled with substrates into the reaction tube for the next furnace growth (4 ) after starting the next furnace, manually place the substrate to be grown on the set of graphite disks that have just been cleaned with chlorine for later use. In principle, the MOCVD of AIXTRON can ensure the initial state of the reaction tube is constant, and it can also clean up the refractory substances on the graphite plate after the growth of high-alumina component materials in time. However, due to the large pre-reaction, this horizontal flow MOCVD is not suitable for growth. High alumina component material. Speaking of this, people can't help asking, why doesn't AIXTRON's close-coupled nozzle type MOCVD not add chlorine cleaning function? The reason is: similar to that shown in Figure 1-3, the nozzle is brazed by a stainless steel capillary with a wall thickness of only 0.5mm and three circular plates to form group III organic source nozzles (9) and group V source nozzles (10) (Please also note that these capillaries are submerged in pressurized cooling water, which is prone to leakage and hidden dangers!), although stainless steel materials are resistant to chlorine corrosion, brazing materials cannot resist chlorine corrosion, so they cannot be cleaned with chlorine.

Although the remote-coupled nozzle type MOCVD produced by VEECO does not use the brazing process in the processing of the nozzle, that is to say, this nozzle can be cleaned with chlorine in principle, but because of the following reasons: (1) The nozzle is not easy Dirty, already the tallest of the dwarves, users are relatively satisfied; (2) When growing aluminum-containing component materials, the pre-reaction is large, and people are not willing to choose this kind of MOCVD, so the problem is not fully exposed; ( 3) The temperature of the nozzle and pipe wall is low, and the cleaning effect with chlorine will not be good. These reasons together determine that VEECO may not realize the importance of keeping the initial state of the reaction tube constant.

It can be seen from the above description of the relevant background technology that the understanding level of the present invention no longer stays on the question of whether the reaction tube is clean or not, but rises to the physical essence of how to ensure that the initial state of the reaction tube is constant; The process of dust diffusion is analyzed, and it is considered that even VEECO's remote-coupled MOCVD nozzle has the problem that the initial state of the reaction tube is not constant. Chlorine online cleaning method is common in the semiconductor industry. In order to enhance the chlorine cleaning effect, the temperature of chlorine corrosion needs to be increased. The disadvantage is that the vertical air flow type nozzle is water-cooled, which is a cold wall, and the heat conduction to the surface of the nozzle is mainly gas convection , Unlike AIXTRON horizontal flow MOCVD, the "ceiling" to be cleaned is not water-cooled, but a hot wall, so it is much more difficult to clean the vertical air flow nozzle. In addition, when cleaning with chlorine in the semiconductor industry, there are also lamps used to heat the graphite base. Of course, the light from the lamps will also shine on the surface to be cleaned, so chlorine cleaning is relatively easy.

Contents of the invention

The first object of the present invention is to provide a method for stabilizing the initial state of the nozzle-type MOCVD reaction tube, which can fundamentally improve the repeatability between epitaxial growth furnaces and furnaces by stabilizing the initial state of the reaction tube.

The second object of the present invention is to provide a kind of chlorine-resistant double-layer sprinkler nozzle of stable nozzle type MOCVD reaction tube initial state, it can really make the initial state of reaction tube obtain stable control, thereby greatly improve near coupling nozzle type MOCVD at high Competitiveness of aluminum components during growth of nitride materials.

The third object of the present invention is to provide a method for manufacturing a chlorine-resistant double-layer nozzle that stabilizes the initial state of the nozzle-type MOCVD reaction tube.

First purpose of the present invention is achieved like this:

A method for stabilizing the initial state of a nozzle type MOCVD reaction tube, the specific steps are as follows:

A. After completing a furnace of epitaxial growth each time, open the reaction tube, and use the caliper to take out the graphite disk filled with the epitaxial substrate;

B is replaced with the "dirty" graphite disc that was not cleaned in the previous furnace;

C. Place a porous heat-conducting plate on the surface of the "dirty" graphite disk. Chlorine can diffuse downwards to the surface of the graphite disk through multiple small holes on the porous heat-conducting plate, thereby ensuring that the surface of the graphite disk is cleaned, and the heat passes through the heat-conducting plate upwards. Conducted to the lower surface of the nozzle to be cleaned; if the porous heat conduction plate is not used, the distance between the surface of the nozzle and the graphite surface must be mechanically shortened to increase the temperature of chlorine corrosion on the surface of the nozzle;

D. Fill the reaction tube with 1%--100% dry chlorine from the chlorine channel for online cleaning. When cleaning, the temperature on the surface of the graphite disc is set at 700-1000°C, and the chlorine filling time is 1-60 minutes; Group III Both the organic source and the V-group source nozzles spray nitrogen, argon or hydrogen to prevent the inside of the nozzle from being polluted by chlorine; the cleaning process also cleans the reaction tube tail gas system under the graphite disk, that is, not only the nozzle is cleaned The lower surface of the main body and the upper surface of the graphite disk also clean the exhaust gas path from the surface of the graphite disk to the exhaust gas main valve, thereby essentially stabilizing the initial state of the nozzle-type MOCVD reaction tube;

E. After chlorine cleaning, replace with a graphite disk filled with epitaxial substrates, and perform a new batch of epitaxial growth.

Second purpose of the present invention is achieved like this:

A chlorine-resistant double-layer nozzle with a stable nozzle type MOCVD reaction tube in the initial state, including: a group III organic source chamber, a V group source chamber, a cooling water layer, a nozzle body, an optical channel, a group III organic source nozzle hole, and a V group source Nozzle hole, upper cover of nozzle, partition between Group III source and Group V source, upper flange of nozzle, two water baffles, side plate of nozzle, lower flange of nozzle, main water inlet channel, main water outlet channel;Ⅲ Family source quick connector, optical window purge gas quick connector, V family source quick connector, chlorine quick connector; it is characterized in that: a chlorine channel and chlorine quick connector are added; the main body of the nozzle is machined from a whole piece of blank by EDM The main body of the nozzle, especially the lower surface in contact with chlorine, is made of chlorine-resistant materials; the nozzle holes of group III organic sources and the nozzle holes of group V sources are directly perforated by electric sparks; The integrally processed small column replaces the stainless steel nozzle of the prior art; the cooling water layer is composed of many parallel and straight-through small water channels, and the water flow direction in each small water channel is parallel to each other and perpendicular to the group III organic source nozzle hole and the V group Direction of gas flow in the source orifice.

The nozzle is made of chlorine-resistant materials; in terms of structure, the four parts of the group III organic source nozzle, the V group source nozzle, the cooling water layer, and the V group source chamber are integrated into a porous, multi-layered part. The main body of the sprinkler head is processed by sparks. The main body of the sprinkler head is made of a whole piece of chlorine-resistant blank, unlike the nozzle head of the prior art, which is composed of three stainless steel discs and multiple stainless steel capillaries of two lengths connected by vacuum brazing to form a double-layer nozzle; Chlorine channels are added to the main body of the EDM nozzle; specifically, this chlorine-resistant double-layer nozzle includes: III group organic source chamber, V group source chamber, cooling water layer, EDM nozzle body, chlorine channel , optical channel, group III organic source nozzle hole, group V source nozzle hole, nozzle upper cover, partition between group III source and group V source, nozzle upper flange, two water retaining plates, nozzle side plate, nozzle Lower flange, main water inlet channel, main water outlet channel, group III source quick connector, optical window purge gas quick connector, V group source quick connector, chlorine quick connector; sprinkler head cover, between group III source and V group source The partition boards form the Group III organic source chamber; the partition between the Group III source and the Group V source, the flange on the nozzle, and the main body of the nozzle processed by EDM constitute the Group V source chamber; the two water retaining The plate divides the circumferential water channel into two semicircles, forming the total water inlet channel and the total water outlet channel; the upper flange of the nozzle, the side plate of the nozzle, the lower flange of the nozzle, and the main body of the nozzle processed by EDM form the water channel on the circumference ;The reaction tube flange and the lower flange of the nozzle are sealed with a "○" ring. After the two are separated, the graphite disk and epitaxial substrate in the reaction chamber are exposed, so that materials can be loaded and unloaded and components in the reaction chamber can be maintained; The joint is responsible for leading the group III gas from the flange of the reaction tube, through the lower flange of the nozzle, the circumferential water channel and the upper flange of the nozzle to the organic source room of the group III. When the flange of the reaction tube and the lower flange of the nozzle are opened/closed, the The source quick connector is automatically turned on/off; the optical window purge gas quick connector is responsible for leading the optical window purge gas from the reaction tube flange, through the lower flange of the nozzle, the circumferential water channel and the upper flange of the nozzle to the optical channel. The reaction tube method When the blue and the lower flange of the nozzle are opened/closed, the optical window purge gas quick connector is automatically turned on/off; the V group source quick connector is responsible for passing the V group source gas from the reaction tube flange through the lower flange of the nozzle, the circumferential water channel and The upper flange of the nozzle leads to the V family source chamber. When the reaction tube flange and the lower flange of the nozzle are opened/closed, the V family source quick connector is automatically turned on/off; the chlorine quick connector is responsible for transferring chlorine from the reaction tube flange to the nozzle. The lower flange, the circumferential water channel and the upper flange of the nozzle lead to the chlorine channel. When the reaction tube flange and the lower flange of the nozzle are opened/closed, the chlorine quick connector is automatically turned on/off; the chlorine channel is located in the center of the nozzle, passing through the pipe and the chlorine quick connector It is connected above the upper cover of the nozzle; the group III organic source chamber, the V group source chamber, and the cooling water layer are independent of each other and do not communicate with each other; the optical channel is used for online optical monitoring, and the top is equipped with a quartz glass sealing window. The detector is installed above the upper cover of the nozzle, and monitors the growth of the epitaxial substrate through the quartz window of the optical channel; the cooling water of the nozzle flows in from the main water inlet, and then the cooling water is evenly distributed to the cooling water layer through the main water inlet, Then pass through the main water outlet channel and flow out from the main water outlet; the lower surface of the main body of the nozzle that is in contact with chlorine is prohibited The brazing process that is not resistant to chlorine, and then use the electric spark piercer to pierce multiple group III organic source nozzle holes and group V source nozzle holes with a diameter of 0.3-1.0mm; in order to seal the water channel, use argon arc Welding plugging; the partition between the group III source and the group V source with many square holes is welded on the small pillars of the main body of the EDM nozzle, thereby separating two independent group III organic source chambers and group V sources. For the source chamber, argon arc welding is preferred for welding; since this position is not in direct contact with chlorine, brazing connection is also the correct choice; bounded by the surface of the lower flange of the nozzle, the flange of the reaction tube under the lower flange of the nozzle, Porous heat conduction plates, epitaxial substrates, side walls of reaction tubes, graphite discs, and heaters are reaction tube components other than nozzles, wherein the reaction tube flanges are welded on the side walls of reaction tubes, and the heaters heat the graphite discs; The epitaxial substrate is placed on the surface of the graphite disk, and the porous heat conduction plate is placed on the surface of the graphite disk during online cleaning; the graphite disk rotates around the central axis during growth and cleaning.

The material of the nozzle body is chlorine-resistant and can be welded by argon arc welding. The grade is 316L stainless steel or Hastelloy. The selection condition is chlorine-resistant and suitable for argon arc welding.

The third purpose of the present invention is achieved like this:

A method for making a chlorine-resistant double-layer nozzle for stabilizing the initial state of the nozzle type MOCVD reaction tube, the specific steps are as follows:

A. The blank is processed into a square, the thickness is the thickness of the nozzle, and the side length is the diameter of the nozzle;

B. One side of the square blank (that is, one side of the square) is finished with a positioning surface (called a surface);

C. Drop the positioning surface, place the billet vertically, and complete all the cuttings in one direction according to the trajectory (30) of electric wire cutting, so as to obtain the rectangular water channels of the cooling water layer; then use wire cutting to cut out the perpendicular to the positioning surface a Another locating surface (called b locating surface);

D. The blank is rotated 90 degrees and placed vertically, the b positioning surface is dropped, and wire electric discharge is used again. This time, only the blank part corresponding to the source chamber of the V family is processed; in this way, through two vertical wire cutting, it is It can form many small square columns in the source chamber of the V family (these small square columns are equivalent to the numerous stainless steel capillaries on the nozzle of AIXTRON company, those capillaries are fixed by vacuum brazing, and the brazing material is not resistant to chlorine corrosion);

E. Lay the billet flat, and perforate with electric spark along the central axis of many small square pillars to obtain many group V source nozzle holes; also use electric spark perforation to obtain many group III organic source nozzle holes;

F. Use argon arc welding or laser welding to block the process seams of each water channel, so that the surroundings of each water channel are closed. In order to reduce welding deformation, equal thickness and thin metal sheets should be inserted into the seam before welding, and its material is equal to the blank material;

G. Punch and weld the chlorine channel and optical channel; the welding and connection method of the optical channel is the same as the current AIXTRON vertical air flow MOCVD equipment, which is a common method in the industry; the welding connection method of the added chlorine channel is the same as the optical channel;

H. Weld the partition between the group III source and the group V source with many square holes processed in advance and the many square columns located in the V group source room one by one. The welding method is argon arc welding; if the square column is processed If the column is formed into a cylindrical column, the many holes on the partition between the III group source and the V group source are correspondingly circular holes, and can be inserted into the circular column. In short, no matter what the shape of the column is, it should be able to One-to-one pair welding;

The partition between the I, III group source and the V group source is welded to the upper flange of the nozzle on the circumference, and then the water baffle, the lower flange of the nozzle, and the side plate of the nozzle are welded by argon arc welding to make it a total inlet. The water channel and the total water outlet channel, and the main water inlet is welded on the total water inlet channel, and the main water outlet is welded on the total water outlet channel; thereby obtaining a chlorine-resistant double-layer nozzle that stabilizes the initial state of the nozzle-type MOCVD reaction tube.

Working principle of the present invention:

The epitaxial substrate is located on the graphite disk, and the heater heats the graphite disk; before the epitaxial growth, the nozzle of the reaction tube is raised, that is, the lower flange of the nozzle is separated from the flange of the reaction tube, and the four quick connectors are also separated to expose the inside of the reaction tube graphite disk, etc.; take out the porous heat conduction plate, place the epitaxial substrate, and then start epitaxial growth; during epitaxial growth, organic sources such as trimethylgallium are sprayed from the group III organic source chamber to the epitaxial substrate through the group III organic source nozzle hole On the surface of the bottom, V-group sources such as ammonia gas are also sprayed to the surface of the epitaxial substrate through the V-group source holes, so that the crystal growth of third-generation semiconductor materials such as gallium nitride is carried out on the surface of the epitaxial substrate; the growth process In the process, the growth temperature, the thickness of the epitaxial layer and the stress of the epitaxial layer are monitored in real time through the optical channel; Some particles will be deposited on the surface of each furnace. If these particles are not cleaned up, the initial state of the next furnace growth will change, thus causing the crystal quality of the epitaxial wafers grown in each furnace to be unstable; for this reason, the present invention is completed. After the first furnace grows, the porous heat conduction plate is placed on the surface of the graphite disk; the function of the porous heat conduction plate is to guide the heat of the graphite disk to the surface of the porous heat conduction plate in the form of heat conduction, and then transfer the heat to the surface of the graphite plate through thermal radiation and convection. The lower surface of the main body of the EDM nozzle, at this time, the high-temperature gas chlorine can clean the lower surface of the EDM nozzle main body; chlorine is introduced from the chlorine channel, and then flows according to the chlorine streamline, and the chlorine can pass through the porous heat conduction plate The densely distributed small holes spread to the surface of the graphite disc. Since the temperature on the surface of the graphite disc can reach the set chlorine corrosion temperature, the surface of the graphite disc is easy to clean; the channel of the chlorine streamline is compressed by means of a porous heat conduction plate, thereby enhancing the chlorine resistance to corrosion. The cleaning effect of the lower surface of the shower head main body of electric discharge machining; because the lower surface of the shower head main body of electric discharge machining has contacted with chlorine, the lower surface must be resistant to chlorine corrosion; The source nozzle holes are formed by electric spark perforation on the whole plate, so they have the same chlorine corrosion resistance as the nozzle body material; the body material should be a chlorine corrosion resistant material, the grade is 316L stainless steel or Hastelloy alloy Or other chlorine-resistant metal materials, another screening condition is that it can be welded by argon arc welding.

In order to abandon the vacuum brazing process that is not resistant to chlorine, the main body of the shower head machined by electric discharge is the core of the present invention. During processing, place the blank of the main body of the EDM nozzle vertically, and complete all cutting in one direction according to the trajectory 30 of EDM, so as to obtain the rectangular water channels of the cooling water layer; then place the blank of the EDM main body of the nozzle Rotate 90 degrees and place it vertically, and use wire electric discharge cutting again. This time, only the blank part corresponding to the V family source chamber is processed; in this way, through two vertical wire cutting, many of the V family source chambers can be formed. (These square columns are equivalent to the many stainless steel capillaries on the nozzle of AIXTRON company. Those capillaries are fixed by vacuum brazing, but the brazing material is not resistant to chlorine corrosion); then, the main body of the EDM nozzle is laid flat, along the The central axis of these small square pillars is perforated with electric sparks to obtain many group V source nozzles; similarly, many group III organic source nozzles are obtained by electric spark drilling; in order to ensure that the cooling water layer is isolated from the V group source chamber, the process The many water channel cutting seams that have to be added must be welded and plugged after the mission is completed; then the perforation and welding of the chlorine channel and the optical channel are completed; The clapboard between them is welded with many small square columns located in the V family source chamber, and the solder joints are argon arc welding spots 31, thus forming an airtight V family source chamber; the partition plate between the III group source and the V group source The shape and position of the small hole should match the shape and position of the many small pillars in the source chamber of the V family; the small pillars are either square, circular, or polygonal.

The thicker the entire thickness of the nozzle body of the electric discharge machining of the present invention, the longer the length of the nozzle hole, the more uniform the gas distribution of each hole, and the more uniform the epitaxial growth material obtained; only the deeper the nozzle hole, the more uniform the EDM perforation. slower.

In order to enhance the chlorine cleaning effect, the chlorine cleaning method of the present invention will add an intermediate ----- a porous heat conduction plate, or mechanically shorten the distance between the nozzle and the graphite, in order to increase heat conduction. Of course, the nozzle must be resistant to chlorine corrosion, and to be resistant to chlorine, it needs to be skillfully processed.

The advantages of the present invention are:

The applicant also applied for another single-layer sub-region nozzle that can be cleaned online with chlorine a year ago. The name is "non-brazed MOCVD nozzle that can be cleaned online with chlorine gas" (application number is 201410189925.5), which is completely different from AIXTRON In the form of nozzles, there is one less layer than AIXTRON, but one more area. The concept of that kind of nozzle is more advanced, flexible and powerful, but because it is too advanced, it is not easy to promote. The number of gas chamber layers of the nozzle of the present invention is the same as that of AIXTRON's vertical air flow MOCVD, which is two layers of gas chambers, so it is easier to be accepted by the market. The nozzle of the present invention is also a near-coupled vertical airflow type in the industry, but because the nozzle structure does not use the vacuum-brazed stainless steel capillary nozzle, the nozzle has added an online cleaning function that is crucial to industrialization; of course , and the AIXTRON nozzle is obviously different: (1) The chlorine (or hydrogen chloride) gas path is also added to the nozzle. (2) The original wall thickness of AIXTRON's stainless steel capillary is only 0.5mm. During the brazing process, the wall thickness will "eat" a thickness of the brazing material and become thinner; the outer wall of thousands of such capillaries The entire cylindrical surface is surrounded by pressurized cooling water. During actual use, it is often found that individual capillaries have water leakage, which makes it difficult to grow good materials, and it is even more difficult to find small leaks. There is only the thinnest thickness on one geometric line between the water channel and the air channel of the present invention, and this thickness is designed to be greater than 0.8 mm and can be detected, so the nozzle of the present invention is reliable and durable.

The present invention completely solves the fatal problem of near-coupled vertical air flow MOCVD reaction tubes. Through the fundamental innovation of the manufacturing method, the nozzles of the reaction tubes can resist chlorine corrosion, thereby realizing online cleaning of the reaction tubes and ensuring the initial state of each furnace growth constant, improve the pass rate, and enhance the competitiveness of this reaction tube when it comes to high-aluminum component semiconductor materials; it clears the way for the mass production of GaN-on-Si devices and third-generation semiconductor devices; adopting this Nozzle, MOCVD technology becomes controllable and becomes "fool".

The hole of EDM has naturally removed the burr on the inner wall of the hole, and the inner hole surface area is much smaller than the mechanically drawn stainless steel capillary inner hole surface area. Therefore, according to the professional terminology in the industry, the memory effect of the MOCVD reaction tube of the present invention is used. Small, can make the interface of each layer of epitaxial material steeper, thereby improving the performance of the third-generation semiconductor material device.

Recently, the industry expert group stated in the drafting report of the national development plan: It is estimated that by 2030, the third-generation semiconductor material industry can drive the device and module industry to exceed 780 billion yuan. In turn, it will drive semiconductor lighting, power electronics, mobile communication equipment, consumer electronics and other related application industries to exceed 7 trillion yuan. Therefore, the present invention is significant.

Description of drawings:

Fig. 1 is the sectional view of the embodiment of the present invention;

Fig. 2 is the A-A cross-sectional view of the embodiment of the present invention;

Fig. 3 is the partially enlarged view of part B of the embodiment of the present invention;

Among them: 1—group III organic source chamber (such as trimethylgallium), 2—group V source chamber (such as ammonia gas), 3—cooling water layer, 4—the main body of the nozzle for EDM, 5—porous heat conduction plate, 6—Epitaxy substrate, 7—Chlorine channel, 8—Optical channel, 9—Organic source injection hole III, 10—Group V source injection hole, 11—Nozzle head cover, 12—The gap between Group III source and Group V source Separator, 13—the upper flange of the nozzle, 14—the water retaining plate, 15—the side plate of the nozzle, 16—the lower flange of the nozzle, 17—the reaction tube flange, 18—the group III source quick connector, 19—the optical window purge Gas quick connector, 20—V group source quick connector, 21—chlorine quick connector, 22—chlorine flow line, 23—reaction tube side wall, 24—graphite plate, 25—heater, 26—general water inlet, 27—general Water inlet channel, 28—main water outlet channel, 29—general water outlet, 30—wire electric discharge cutting track, 31—argon arc welding spot, 32—water channel slit, 33—exhaust gas equalizing ring, 34—graphite disk rotating frame , 35—reaction tube bottom plate, 36—Y-shaped tail gas pipe, 37—main tail gas valve, 38—main exhaust gas filter, 39—chlorine-resistant pump, 40—chlorine cleaning tail gas valve, 41—main pump.

Detailed ways

Embodiment 1: The method for stabilizing the initial state of the near-coupled nozzle type MOCVD reaction tube and the chlorine-resistant double-layer nozzle and its production method

A method for stabilizing the initial state of a close-coupled nozzle-type MOCVD reaction tube is as follows (taking manual operation as an example):

A. After completing a furnace of epitaxial growth each time, open the reaction tube, that is, the lower flange 16 of the nozzle is disengaged from the reaction tube flange 17, and take out the graphite disk 24 filled with the epitaxial substrate 6 with randomly configured calipers;

B. Replace the "dirty" graphite disc 24 that was not cleaned in the previous furnace; place a porous heat conducting plate 5 on the surface of the "dirty" graphite disc 24. In this embodiment, the material of the plate is graphite, and chlorine can pass through multiple holes Diffusion to the surface of the graphite disc 24, thereby ensuring that the surface of the graphite disc 24 is cleaned up;

C. Fill the dry chlorine with 5% concentration from the chlorine channel 7 into the reaction tube for online cleaning. The total molar amount charged depends on the thickness and area of the deposition layer, and of course the cleaning temperature; to achieve clean but slightly overdone. Accurate; The temperature of graphite disc 24 surface is about 860 ℃ during cleaning, and the chlorine charging time is 15 minutes altogether, if calculate together with reaction tube heating and cooling time, this step is about 45 minutes altogether; During chlorine cleaning, tail gas main valve 37 is closed, III Group V organic source nozzle holes 9 and V group source nozzle holes 10 all eject nitrogen or hydrogen gas, so as to prevent the inside of the nozzle, tail gas filter 38 and main pump 41 from being polluted by chlorine; chlorine cleans tail gas valve 40 and chlorine-resistant pump 39 through chlorine This cleaning tail gas channel flows, and the chlorine flow trajectory is shown in the chlorine flow line 22; chlorine passes through the tail gas equalizer 32 and enters the Y-shaped tail gas pipe 36, and this process also affects the reaction tube tail gas system under the graphite disk 24. Chlorine cleaning was carried out, that is, not only the lower surface of the nozzle main body 4 and the upper surface of the graphite disc 24 were cleaned, but also the exhaust gas path from the surface of the graphite disc 24 to the exhaust gas master valve 37 was cleaned, thereby stabilizing the near The initial state of the coupling nozzle type MOCVD reaction tube; when cleaning, the graphite disk rotating frame 34 drives the graphite disk 24 to rotate, thereby ensuring uniform and clean cleaning.

D, after cleaning with chlorine, replace a graphite disk 24 full of epitaxial substrate 6 to carry out a new batch of epitaxial growth. Therefore, from the perspective of improving production efficiency, at least three graphite disks 24 are required for normal production: one The epitaxial wafer has just been taken out but has not yet been taken out (it takes man-hours and machine time to install and unload the epitaxial wafer), one dirty one is sent to the reaction tube for dechlorination cleaning, and the other one is slowly loaded with a new substrate for standby; At this time, only one graphite disc can be used for normal production, that is, after the graphite is installed, it will not be removed, and it will be cleaned online and loaded and unloaded online;

The above is the chlorine online cleaning process proposed to stabilize the initial state of the close-coupled nozzle type MOCVD. Obviously, this nozzle must resist chlorine corrosion. The structure and manufacturing method of this nozzle are as follows:

A double-layer chlorine-resistant nozzle for an MOCVD reaction tube that can be cleaned online with chlorine, including:

Group III organic source chamber 1, Group V source chamber 2, cooling water layer 3, EDM nozzle body 4, chlorine channel 7, optical channel 8, Group III organic source nozzle hole 9, Group V source nozzle hole 10, nozzle Upper cover 11, partition 12 between Group III source and Group V source, nozzle upper flange 13, two water retaining plates 14, nozzle side plate 15, nozzle lower flange 16, main water inlet channel 27, main water outlet Water channel 28; Group III source quick connector 18, optical window purge gas quick connector 19, V group source quick connector 20, chlorine quick connector 21; nozzle upper cover 11 and partition 12 between III group source and V group source The group III organic source chamber 1 is formed; the partition plate 12 between the III group source and the V group source, the upper flange 13 of the nozzle, and the nozzle body 4 processed by EDM are composed of the V group source chamber 2; the two water retaining The plate 14 divides the circumferential water channel into two semicircles, forming the total water inlet channel 27 and the total water outlet channel 28; the nozzle upper flange 13, the nozzle side plate 15, the nozzle lower flange 16, and the nozzle main body 4 processed by EDM. It forms a water channel on the circumference; the reaction tube flange 17 and the nozzle lower flange 16 are sealed with a "○" ring, and after the two are separated, the graphite disc 24 and the epitaxial substrate 6 in the reaction chamber are exposed, so that loading and unloading and Maintain the components in the reaction chamber; the group III source quick connector 18 is responsible for leading the group III gas from the reaction tube flange 17, through the lower flange 16 of the nozzle, the circumferential water channel 27 and the upper flange 13 of the nozzle to the group III organic source chamber 1 When the reaction tube flange 17 and the lower flange 16 are opened/closed, the Group III source quick connector 18 is automatically turned on/off; the optical window purge gas quick connector 19 is responsible for passing the optical window purge gas from the reaction tube flange 17 to the Lead to the optical channel 8 through the lower flange 16 of the nozzle, the circumferential water channel 28 and the upper flange 13 of the nozzle. When the reaction tube flange 17 and the lower flange 16 of the nozzle are opened/closed, the optical window purge gas quick joint 19 is automatically turned on/off V group source quick connector 20 is responsible for leading the V group source gas from the reaction tube flange 17 through the nozzle lower flange 16, the circumferential water channel 27 and the nozzle upper flange 13 to the V group source chamber 2, the reaction tube flange 17 When opening/closing with the lower flange 16, the V family source quick connector 20 is automatically turned on/off; the chlorine quick connector 21 is responsible for transferring chlorine from the reaction tube flange 17, through the lower flange 16 of the nozzle, the circumferential water channel 28 and the upper method of the nozzle. The flange 13 leads to the chlorine channel 7, and when the reaction pipe flange 17 and the lower flange 16 of the nozzle are opened/closed, the chlorine quick connector 21 is automatically turned on/off; The top of the cover 11 is connected; the group III organic source chamber 1, the group V source chamber 2, and the cooling water layer 3 are independent of each other and not connected to each other; the optical channel 8 is used for online optical monitoring, and a quartz glass sealing window is set on the top , the optical detector is installed on the top of the nozzle upper cover 11, and monitors the growth of the epitaxial substrate 6 through the quartz window of the optical channel 8; It is evenly distributed to the cooling water layer 3, and then passes through the main water outlet channel 28 and flows out from the main water outlet 29; the main body of the nozzle 4 is cut as a whole according to the wire electric discharge cutting track 30, and then perforated by electric sparks A plurality of group III organic source nozzle holes 9 and V group source nozzle holes 10 with a diameter of 0.7mm are pierced by the machine respectively; in order to seal the water channels, each water channel slit 32 is plugged with argon arc welding; several group III group holes with square holes are processed. The partition plate 12 between the source and the V group source is welded on each small column of the nozzle main body 4 of the electric discharge machining, thereby separating into two independent group III organic source chambers 1 and V group source chambers 2, and the welding points are like argon arc As shown in the solder joint 31; with the lower surface of the lower flange 16 of the nozzle as the boundary, the reaction tube flange 17, the porous heat conducting plate 5, the epitaxial substrate 6, the reaction tube side wall 23, the graphite disc 24, and the heater located below it 25 belong to the reaction tube parts other than the nozzle, and are listed here to illustrate the positional relationship and functional relationship of the nozzle in the reaction tube, wherein the flange 17 is welded on the side wall 23 of the reaction tube, and the heater 25 is connected to the graphite disc 24 Heating; the epitaxial substrate is placed on the surface of the graphite disc 24 during growth, and the porous heat conducting plate 5 is placed on the surface of the graphite disc 24 during online cleaning; during growth and cleaning, the graphite disc 24 rotates around the central axis.

The material of the nozzle main body 4 is a material that is resistant to chlorine corrosion and can be welded by argon arc welding, and the grade is 316L stainless steel or Hastelloy.

The working principle of this embodiment:

The epitaxial substrate 6 is located on the graphite disc 24, and the heater 25 heats the graphite disc 24. Before the epitaxial growth, the reaction tube nozzle is raised, that is, the lower flange 16 of the nozzle is separated from the reaction tube flange 17, and the four quick connectors 18, 19, 20, and 21 are also separately separated, exposing the graphite disc 24 etc. inside the reaction tube, taking out the porous heat conducting plate 5, placing the epitaxial substrate 6, and then starting epitaxial growth; during epitaxial growth, organic sources such as trimethylgallium from The group III organic source chamber 1 sprays to the surface of the epitaxial substrate 6 through the group III organic source injection hole 9, and the V group source such as ammonia gas is also sprayed to the surface of the epitaxial substrate 6 through the V group source hole 10, so that in the epitaxial substrate 6 for crystal growth of third-generation semiconductor materials such as gallium nitride; during the growth process, the growth temperature, the thickness of the epitaxial layer and the stress of the epitaxial layer are monitored in real time through the optical channel 8; the growth is completed and the epitaxial wafer is taken out Finally, some particles will be deposited on the surface of the graphite disk 24, the lower surface of the shower head main body 4 of EDM and the surface of the reaction tube side wall 23. If these particles are not cleaned up, the initial state of the next furnace growth will be reduced. change, thereby causing the crystal quality of the epitaxial wafers grown in each furnace to be unable to be stable; for this reason, in this embodiment, after completing a furnace growth, the porous heat conducting plate 5 is placed on the surface of the graphite disk 24; the effect of the porous heat conducting plate 5 is In order to guide the heat of the graphite disk 24 to the surface of the porous heat-conducting plate 5 in the form of heat conduction, and then conduct the heat to the lower surface of the shower head main body 4 of the electric discharge machining through the mode of heat radiation and convection, at this time, the high-temperature gas chlorine can The lower surface of the shower head main body 4 of electric discharge machining is cleaned up; Chlorine is introduced from chlorine channel 7, then flows by chlorine flow line 22, and chlorine can diffuse to the surface of graphite disc 24 through the densely distributed small holes of porous heat conducting plate 5, due to graphite The temperature on the surface of the disc 24 can reach the set chlorine corrosion temperature, so the surface of the graphite disc 24 is easy to clean; the channel of the chlorine flow line 22 is compressed by means of the porous heat conducting plate 5, thereby enhancing the impact of chlorine on the nozzle body 4 of the electric discharge machining. The cleaning effect of the surface; because the lower surface of the nozzle main body 4 of EDM has contacted with chlorine, therefore, the lower surface must be resistant to chlorine corrosion; the organic source injection holes 9 of the III group and the source injection holes 10 of the V group of the present embodiment are all It is perforated by electric sparks on the whole board, so it has the same anti-chlorine corrosion ability as the material of the nozzle body; the material of the body should be a material that is resistant to chlorine corrosion, and the stainless steel material of grade 316L and Hastelloy, etc. are selected. One screening condition is the ability to weld with argon arc welding.

In order to abandon the vacuum brazing process which is not resistant to chlorine, the shower head main body 4 of electric discharge machining is the core of this embodiment. During processing, the blank of the spray head body 4 processed by EDM is placed vertically, and all cuttings in one direction are completed according to the trajectory 30 of EDM, so that the rectangular water channels of the cooling water layer 3 can be obtained. Then the blank of the shower head main body 4 of the electric discharge machining is rotated 90 degrees and placed vertically, and is cut by wire electric discharge again. This time, only the blank part corresponding to the V family source chamber 2 is processed; Wire cutting can form many small square columns in the source chamber 2 of the V family (these small square columns are equivalent to the many stainless steel capillaries on the nozzle of AIXTRON company, and those capillaries are fixed by vacuum brazing, but the brazing material is not resistant to chlorine corrosion!) ; Subsequently, the nozzle main body 4 processed by electric discharge is laid flat, and the central axis of these small square pillars is perforated with electric sparks to obtain many V group source nozzle holes 10; similarly, many group III organic source nozzle holes are obtained by electric spark perforation 9. In order to ensure that the cooling water layer 3 is isolated from the V family source chamber 2, the many water channel cutting seams 32 that had to be added in the process must be welded and plugged after completing the mission; then the perforation welding of the chlorine channel 7 and the optical channel 8 is completed After these operations are completed, the partition plate 12 between the porous III group source and the V group source is welded with many square small pillars located in the V group source chamber 2 areas, and the welding point is the argon arc welding point 31, so that An airtight family V source chamber 2 is formed.

The entire thickness of the nozzle main body 4 of the electric discharge machining of the present embodiment is preferably 30 mm, that is, the length of the Group III organic source nozzle hole 9 is 30 mm; the longer the nozzle hole is, the more uniform the gas distribution of each hole is, and the obtained epitaxy The more uniform the growth material is; the spacing of the group III organic source injection holes 9 in this embodiment is preferably 9mm × 6mm, and the spacing of the V group source injection holes 10 is also preferably 9mm × 6mm. The gas is mixed evenly, but the processing is more difficult; the distance between the lower surface of the shower head body 4 and the epitaxial substrate 6 is between 2-24mm, preferably 12mm, which is called "close coupling" in the industry in this distance range; the organic source of group III The preferred diameter of nozzle hole 9 and group V source nozzle hole 10 is 0.7 mm; because during growth, graphite disc 24 carries epitaxial substrate 6 and rotates around the center of graphite disc 24, so uniform crystal growth can be obtained on the surface of epitaxial substrate 6; chlorine The position of the channel 7 is preferably arranged at the center of the shower head, so that the sprayed chlorine can diffuse from the center evenly along the radial direction from the inside to the outside; in order to reduce the impact of residual chlorine on the quality of semiconductor materials, the chlorine channel 7 is preferably independent of the V family source chamber 2 Separately set; for compactness, the four quick connectors of group III source quick connector 18, optical window purge gas quick connector 19, V group source quick connector 20, and chlorine gas quick connector 21 are all preferably set through the cooling water channel 27 or 28; for Ensure that the water in the cooling water layer 3 does not leak into the group III organic source orifice 9 or the V group source orifice 10, and the thinnest wall thickness between water and air is preferably designed to be 0.85mm, which is much thicker than the stainless steel capillary in the prior art 0.5mm initial wall thickness.

Example 2:

The structure of embodiment 2 is basically the same as that of embodiment 1, the difference lies in:

A method for stabilizing the initial state of a close-coupled nozzle-type MOCVD reaction tube, using a manipulator to operate:

(1) After each batch of epitaxial growth is completed, the manipulator takes out the graphite disk 24 filled with the epitaxial substrate 6;

(2) The manipulator is replaced with the "dirty" graphite disk 24 that has not been cleaned from the previous furnace, and the porous heat conducting plate 5 of the graphite disk has been placed on the surface;

(3) Charge dry hydrogen chloride with a concentration of 5% from the chlorine channel 7 into the reaction tube for online cleaning. The total charge depends on the molar concentration of chlorine, the thickness and area of the deposited layer, and of course the cleaning temperature to achieve clean But slightly over the head shall prevail; the temperature of graphite disk 24 surface is about 700-1000 ℃ during cleaning; Cleaning; in order to protect the main pump 41, it must be equipped with a dry tail gas treatment device for harmless treatment of the tail gas. At the same time, it must also ensure that the water vapor in the atmosphere does not diffuse into the main pump 41, thereby ensuring the life of the main pump; for To keep the entire exhaust system dry, the pipe wall of the exhaust system needs to be heated above 60°C.

(4) After chlorine cleaning, the manipulator is replaced with a graphite disk 24 filled with epitaxial substrates 6 to carry out a new batch of epitaxial growth.

For convenience, the group III source quick connector 18, the optical window purge gas quick connector 19, the V group source quick connector 20, and the chlorine gas quick connector 21 form a quick connector module, preferably independently arranged on the reaction tube flange 17 The four output heads of the four quick connectors are connected to the corresponding pipes/chambers of the shower head, and the four input heads of the four quick connectors are fixed on the outside of the reaction tube flange 17; When the blue 17 was closed, the four quick connectors were connected, otherwise the sides were separated.

Example 3:

The structure of embodiment 3 is basically the same as that of embodiment 1, the difference lies in:

Before chlorine filling and cleaning, the porous heat conduction plate 5 is canceled; at this time, the working principle is to directly shorten the distance between the graphite disc base 24 and the lower surface of the nozzle main body 4 by mechanical means, and reset it to the lower surface by mechanical means after cleaning. growth state;

The welding between the partition plate 12 between the III group source and the V group source and the many square small columns in the V group source chamber 2 adopts brazing, because these brazing materials do not directly contact with chlorine, so brazing is allowed; The slit 32 is selected to be located on the lower surface opening of the shower head body 4 processed by EDM. At this time, the advantage is that the argon arc welding method is used to block these slits without being hindered by many small square columns in the V family source chamber 2, and the welding is more convenient. The disadvantage is that Insufficient weld depth will affect the long-term chlorine corrosion resistance of the nozzle.

It should be noted that the above-mentioned embodiments are only descriptions of the present invention rather than limitations of the present invention, and any non-essential replacement or modified inventions that do not exceed the spirit of the present invention fall within the protection scope of the present invention.

Claims (1)

1. It is 1. a kind of to realize the stable production method of chlorine-resistant bilayer nozzle made of head-type MOCVD original states, feature It is：Using the linear cutter of two vertical direction, the rectangular pillar for making numerous group V source spray orifices is engraved in synthesis, so as to completely The vacuum brazing technique of not chlorine-resistant is abandoned, during processing：

   A, blank is processed into a square, and thickness is the thickness of nozzle, and the length of side is the diameter of nozzle；

   B, datum level, referred to as first datum level are processed into a side of stock of square；

   C, first datum level is cast, and blank is placed vertically, and all cuttings in a direction are completed by the track of electrical fire wire cutting, so as to Obtain each rectangle water channel of cooling water layer；Another datum level vertical with first datum level, referred to as second are then cut out with wire cutting Datum level；

   D, blank, which is rotated by 90 °, places vertically, and second datum level is cast, and again with Wire EDM, this time processes, only to group V source room institute Corresponding green part is processed；It is numerous in group V source room with regard to that can be formed in this way by the wire cutting of two vertical direction Rectangular pillar；

   E, blank is kept flat, along the central axis electric-spark drilling of each rectangular duckpin, obtains group V source spray orifice；Equally Numerous III race organic source spray orifices are obtained with integrated electric-spark drilling；

   F, the process seam for blocking up each water channel is welded with argon arc welding, makes each water channel all round closure, deformation is welded to reduce, should be inserted in seam before welding Enter uniform thickness foil, the same blank material of sheet material model；

   G, punching welding is carried out to chloride channel and optical channel；Welding uses argon arc welding；

   H, by the partition board between III clan source and group V source of prior processing a lot of square hole and side numerous in group V source room Shape pillar matches welding one by one, and welding method is argon arc welding；

   I, the partition board between III clan source and group V source is circumferentially welded with nozzle upper flange again, is welded and is kept off followed in turn by argon arc welding Water plate, nozzle lower flange, nozzle side plate make total inlet channel and are always discharged water channel, and welded on total inlet channel Total water inlet welds total water outlet on always water outlet water channel；So as to obtain a kind of stable head-type MOCVD reaction tube original states Chlorine-resistant bilayer nozzle.