CN101591773A - Vapor Deposition System - Google Patents

Abstract

The present invention provides a vapor deposition system, which comprises: an ion generation area, a reaction chamber, and a porous tube disposed between the generation area and the reaction chamber. The generation area provides a plasma of a first element. The porous tube collects and introduces the plasma of the first element and a second element into the reaction chamber. The plasma of the first element and the second element are subjected to chemical vapor epitaxy with a substrate in the reaction chamber to grow a thin film layer.

Description

Vapor Deposition System

technical field

The invention relates to a vapor deposition system, in particular to a plasma vapor deposition system.

Background technique

In the field of semiconductors, Chemical Vapor Deposition (CVD) technology is one of the most basic and important thin film growth methods. The basic process is to pass the reaction source into the reaction chamber in the form of gas, which uses diffusion The boundary layer reaches the surface of the substrate; and chemical reactions such as oxidation, reduction, or reaction with the substrate are carried out on the surface of the substrate by the energy provided by the surface of the substrate, and the products are deposited on the surface of the substrate due to internal diffusion. Basically, there are many kinds of chemical vapor deposition techniques. At present, Metalorganic Chemical Vapor Deposition (MOCVD) is widely used in the industry, which is widely used in components with various structures, especially III-V family of optoelectronic components. MOCVD can achieve better flatness, and can deposit most ternary compounds and quaternary compounds, such as InGaAs and AlGaInP, and grow aluminum-containing compounds, such as aluminum gallium arsenide (AlGaAs), which is widely used. In some special cases, such as In _x Ga _1-x As _y P _1-y quaternary compound system, which is widely used in infrared, it can only be grown by MOCVD system.

However, the existing MOCVD technology also has many disadvantages, such as high manufacturing cost and difficult control of metering ratio and thickness. Especially in the manufacture of nitride semiconductors, using MOCVD to grow III-V buffer layers on the substrate of light-emitting diodes, it is necessary to use ammonia (NH ₃ ) or hydrazine (N ₂ H ₄ ) gas as the reaction source of V-group elements . However, this type of gas needs to be reacted at a high temperature, and increasing the growth temperature will inevitably increase the demand for the saturated vapor pressure of nitrogen during the growth of the Ga _X Al _1-X N (0<X≤1) buffer layer, which will increase the reaction accordingly. source consumption. Therefore, the effective reactive nitrogen will not increase correspondingly, but will instead increase the consumption of reactive sources. On the other hand, ammonia as a reaction source also leads to hydrogen coverage when growing the III-V semiconductor buffer layer, making the grown III-V nitride buffer layer in a highly insulating state, and additional processing is necessary to obtain a higher Good electrical properties. In addition, ammonia gas has great loss and damage to vacuum pipe fittings, graphite, and vacuum oil, which is easy to cause damage to the system and increase the difficulty and time of maintenance.

To this end, the industry has developed a plasma chemical vapor deposition system, which reduces the temperature of the deposition reaction with the aid of plasma auxiliary energy, and can directly use nitrogen as the reaction source to avoid ammonia damage to the system. Compared with the traditional MOCVD, the plasma chemical vapor deposition system can be operated for a long time, and has the advantages of good reproducibility, low temperature required, and better uniformity and quality of the deposited film. According to different methods of generating plasma, there are mainly microwave plasma CVD (microwave enhanced CVD) and electron cyclotron resonance microwave plasma CVD (electron cyclotron resonance (ECR)). According to the microwave plasma CVD method, the reaction gas is passed into the microwave generator from the top of the reaction tank, and then introduced into the reaction chamber through the waveguide; after proper adjustment, the microwave forms a standing wave above the substrate in the reaction chamber to excite and produce purple spherical plasma. However, the growth rate of the buffer layer in this method is low, the deposition area is small, and the movement of the substrate is quite sensitive to the formation of plasma. Electron rotation resonance microwave plasma CVD method has the same principle as microwave plasma CVD method, the difference is that two sets of electromagnets are placed around the reaction chamber, and the above electromagnets can make electrons rotate, which greatly improves the efficiency of plasma generation. Compared with the microwave plasma CVD method, this method has a larger control space and can expand the growth range. However, it cannot overcome other shortcomings such as the sensitive influence of the movement of the substrate on the formation of plasma.

In this way, there are still some problems in the existing vapor deposition technology, and further improvement and perfection are still needed.

Contents of the invention

The invention provides a vapor deposition system and method, which can directly use nitrogen as a reaction source, and independently control the stress of the deposited film without causing significant impact on its deposition characteristics.

In order to achieve the above object, the present invention provides the following technical solutions: a vapor deposition system comprising: an ion generation area, a reaction chamber, and a porous tube placed between the generation area and the reaction chamber; The generating area provides plasma of a first element, and the porous tube collects the plasma of the first element and a second element into the reaction chamber. The plasma of the first element and the second element perform chemical vapor phase epitaxy with a substrate in the reaction chamber to grow a thin film layer.

The ion generating region dissociates gas molecules having the first element. The reaction chamber is an intermediate frequency heater. The intermediate frequency heater can control the temperature of the substrate and the vapor deposition system between room temperature and 900 degrees Celsius. The first element is a Group V element. The Group V element is selected from ammonia (NH ₃ ) or nitrogen (N ₂ ) or a mixture thereof. The second element is a Group III organometallic. The Group III organometal is an organometallic compound of gallium. The Group III organometallic source is a mixture of an organometallic compound of gallium, an organometallic compound of indium, and a mixture of an organometallic compound of aluminum, such as trimethylgallium (TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl ), triethylgallium (TEGa), triethylindium (TEIn), triethylaluminum (TEAl). The substrate includes at least one material selected from the group consisting of sapphire, GaN, AlN, SiC, GaAs, GaP, Si, ZnO, MgO, MgAl ₂ O ₂ , and glass, or other alternative materials.

Compared with the prior art, the high-frequency plasma chemical deposition system of the present invention has the advantages of the general plasma vapor deposition system, and can independently control the stress of the deposited film without causing significant influence on other deposition characteristics. In addition, because the plasma generation region of group V elements and the organometallic source of group III elements are arranged in a line, the effective utilization rate of the initiator can be improved.

Description of drawings

FIG. 1 shows a high frequency plasma vapor deposition system according to an embodiment of the present invention.

Wherein, the reference signs are explained as follows:

1 ion generation area

2 reaction chamber

3 porous tubes

4 supervisors

5 gas cabinet

6 chip transfer chamber

7 Vacuum pumping system

8 pressure controller

9 gas flow controller

100 high frequency plasma vapor deposition system

Detailed ways

In order to better understand the spirit of the present invention, it will be further described below in conjunction with preferred embodiments of the present invention.

High-frequency plasma CVD uses a coil type and a capacitive type to form a high-frequency electric field to excite the reaction gas in the reaction chamber to generate plasma with high chemical activity. At the same time, the chemical activity of the substrate surface is also improved by the impact of the plasma. Such joint action increases the chemical reaction rate on the surface of the substrate, and can generate high-concentration free radicals near the substrate at a relatively low temperature, allowing thin films to be deposited on it. When the deposition system is used to deposit synthetic diamond-like thin films, it has the advantage of large-area deposition. Its applicable substrate includes at least one material selected from the material group consisting of sapphire, GaN, AlN, SiC, GaAs, GaP, Si, ZnO, MgO, MgAl ₂ O ₂ , and glass, or other alternatives Material.

As shown in FIG. 1 , a high frequency plasma vapor deposition system 100 according to an embodiment of the present invention includes an ion generating area 1 , a reaction chamber 2 , and a porous tube 3 arranged side by side. The ion generation area 1 can be fed with Group V gas through a main pipe 4 and dissociated to generate plasma for providing plasma of Group V elements. The Group V gas is input into the ion generation area 1 through the main pipe 4 . The group V gas is selected from ammonia (NH ₃ ) or nitrogen (N ₂ ) or a mixture thereof, and nitrogen is used in this embodiment. The reaction chamber 2 is used to grow the group V element and one or more group III elements with the substrate in the chemical vapor phase thin film layer, the second element is a group III organic metal, such as an organometallic compound of gallium, Or a mixture thereof with an organometallic compound of indium and an organometallic compound of aluminum. The porous tube 3 is located between the ion generating area 1 and the reaction chamber 2, and is used to introduce one or more sources of group III elements and the plasma gas of group V elements formed by the ion generating area 1 into the reaction chamber 2, so that A film layer is formed on the surface of the substrate. By adjusting the relative positions of the ion generation area 1 , the main tube 4 and the porous tube 3 , the nitrogen gas excited by the high-frequency plasma can be reduced to return to a stable molecular state through free collision. The substrate is transferred from the chip transfer chamber 6 to the reaction chamber 2 and heated to the reaction temperature by an internal intermediate frequency heater to deposit a thin film. The intermediate frequency heater can control the temperature of the substrate and the vapor deposition system between room temperature and 900 degrees Celsius.

Ammonia (NH ₃ ) or nitrogen (N ₂ ) of Group V gas is stored in the gas cabinet 5 , and Group III organometallic sources are also stored in different gas chambers in the gas cabinet 5 . The Group III organometal is an organometallic compound of gallium. The Group III organometallic source is a mixture of an organometallic compound of gallium, an organometallic compound of indium, and a mixture of an organometallic compound of aluminum, such as trimethylgallium (TMGa), trimethylindium (TMIn), trimethylaluminum (TMAl ), triethylgallium (TEGa), triethylindium (TEIn), triethylaluminum (TEAl). The gas flow controller 9 controls the delivery flow of Group V gas and Group III organometallic sources in the gas cabinet 5, and supplies them to the main pipe 4 and the inlet 2 of the porous pipe 3 respectively. In addition, the vacuum degree in the reaction chamber 2 is controlled by the vacuum pumping system 7 , and the pressure of the vacuum pumping system 7 and the gas flow controller 9 is controlled by the pressure controller 8 .

Specifically, according to an embodiment of the present invention, a high-frequency voltage, such as a 13.56 MHz radio-frequency voltage, is applied between the two electrode plates of the high-frequency ion generator in the ion generation area 1 to generate glow radiation between the two electrodes. . Group V gas is introduced from the main pipe 4 and passes through the glow emission area in a radial flow manner. A high-frequency voltage is applied to two corresponding metal electrode plates. When the concentration of gas molecules between the two electrode plates is within a certain range (requirements or standards for a specific range), the surface of the electrode plates is bombarded by ions (Ion Bombardment) The generated secondary electrons (Secondary Electrons) will gain enough energy under the electric field provided by the electrode plate, and the gas molecules between the electrode plate and the electrode plate will undergo so-called dissociation (Dissociation) and ionization (Ionization) due to impact. , and excitation (Excitation) and other reactions, correspondingly generate ions, atoms, atomic groups (Radicals), and more electrons to maintain the concentration balance among the particles in the plasma, and deposit on the surface of the substrate in the reaction chamber. Taking nitrogen in group V elements as an example, its reaction equation can be expressed as:

e ^-- +N→N ⁺ +2e ^--

The high-frequency plasma vapor deposition system has the general advantages of the general plasma vapor deposition system, such as low operating temperature, low cost, low pollution, etc., and can also independently control the stress of the deposited film, and will not have a significant impact on other deposition characteristics , such as deposition rate and film uniformity. In addition, according to an embodiment of the present invention, since the plasma generation region of group V elements and the organometallic source of group III elements are arranged in a line, the effective utilization rate of the sources of group V elements and group III elements can be improved. On the other hand, since the substrate can be heated to the reaction temperature by the intermediate frequency heater, it is beneficial to the crystallinity and quality of the thin film layer. When growing solid-state light-emitting components such as light-emitting diodes or laser diodes, this thin film layer can be used as a buffer layer for the original component to increase the crystal quality of the component.

The technical content and technical features of the present invention have been described above, but those skilled in the art may still make various replacements and modifications based on the content of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to the content described in the embodiments, but should include various replacements and modifications that do not depart from the present invention, and are covered by the claims of this patent application.

Claims (10)

1. gas-phase deposition system, it comprises: an ion produces district, a reaction chamber, and a perforated tube that places between this generation district and this reaction chamber; This ion produces the gas molecule that distinguishing dissociates has first element and the plasma that one first element is provided, and this perforated tube compiles this reaction chamber of importing with the plasma and one second element of this first element; The plasma of this first element and this second element carry out chemical gas phase crystalline substance of heap of stone with a substrate in this reaction chamber makes the thin film layer of growing up.

2. gas-phase deposition system as claimed in claim 1 is characterized in that it is a high frequency ion generator that this ion produces the district; This reaction chamber is an intermediate frequency heater.

3. gas-phase deposition system as claimed in claim 2 is characterized in that this intermediate frequency heater can be controlled at the temperature of this substrate and this gas-phase deposition system room temperature between 900 degree Celsius.

4. gas-phase deposition system as claimed in claim 1 is characterized in that this first element is a V group element.

5. gas-phase deposition system as claimed in claim 4 is characterized in that this V group element is to be selected from one of ammonia or nitrogen or its mixture.

6. gas-phase deposition system as claimed in claim 1 is characterized in that this second element is an III family organo-metallic.

7. gas-phase deposition system as claimed in claim 6 is characterized in that this III family organo-metallic is the organometallic compound of gallium.

8. gas-phase deposition system as claimed in claim 6, it is characterized in that this III family organo-metallic source for the organometallic compound of the organometallic compound of gallium, indium, reach at least a material or its mixture in the organometallic compound of aluminium.

9. gas-phase deposition system as claimed in claim 8, the organometallic compound that it is characterized in that this gallium is TMGa or TEGa, and the organometallic compound of this indium is TMIn or TEIn, and the organometallic compound of this aluminium is TMAl or TEAl.

10. gas-phase deposition system as claimed in claim 1 is characterized in that this substrate comprises to be selected from sapphire, GaN, AlN, SiC, GaAs, GaP, Si, ZnO, MgO, MgAl ₂O ₂, and material cohort that glass constituted at least a material or other replaceable material.