KR100779082B1 - Plasma enhanced chemical vapor deposition apparatus, and manufacturing method of nano-structured particles - Google Patents

Abstract

The present invention discloses a plasma enhanced chemical vapor deposition apparatus (PECVD) and a method for producing nanoparticles using the same. The plasma enhanced chemical vapor deposition apparatus includes a reaction chamber having an internal space having a predetermined volume, an upper electrode and a lower electrode mounted on the reaction chamber to generate plasma, a gas inlet for introducing a reaction gas into the reaction chamber, and the reaction chamber. It is mounted on and includes a filament that emits electrons. The filament is mounted outside the electric field region applied by the upper and lower electrodes so that a separate power is applied. Therefore, the plasma can be easily generated by the filament to efficiently produce nanoparticles.

Plasma Enhanced Chemical Vapor Deposition Apparatus, PECVD, Filament, Nanoparticles, Carbon Nanotubes

Description

Plasma enhanced chemical vapor deposition apparatus, and manufacturing method of nano-structured particles

1 is a diagram illustrating a conventional plasma enhanced chemical vapor deposition apparatus (PECVD).

2 is a view showing a plasma enhanced chemical vapor deposition apparatus according to the present invention.

FIG. 3 is a diagram illustrating various types of filaments of the plasma enhanced chemical vapor deposition apparatus of FIG. 2.

4 and 5 are photographs showing silicon nanoparticles prepared using the plasma enhanced chemical vapor deposition apparatus of the present invention.

The present invention relates to a plasma enhanced chemical vapor deposition apparatus (PECVD) and a nanoparticle manufacturing method using the same.

Carbon nanotubes (CNTs) have had the power to be selected as one of the 10 new technologies that will change the future since they were first discovered in 1991. Although it is referred to as a panacea in the field of materials, it is currently about $ 500 per gram, so it has not reached the practical stage yet. In addition, there is a problem that the relevant application market is not activated.

Generally, there are 5 to 6 CNT manufacturing methods, such as electric discharge, laser deposition, thermochemical vapor deposition, and plasma vapor deposition. The electric discharge type is a method of obtaining CNTs by electric discharge in a state where the distance between the anode / cathode carbon rods is increased. However, the electric discharge is not suitable for industrial mass production. The laser deposition method is a method of obtaining CNTs by vaporizing carbon using a laser, but the quality is excellent, but the productivity is extremely low. The thermochemical vapor deposition method is a method of naturally generating CNTs by flowing gas into a high temperature furnace at 600 ° C. to 1000 ° C., and a large amount of metal seed is required initially, and mass production is possible, but there is a problem of low quality. . The plasma vapor deposition method is similar to the thermochemical vapor deposition method, there is an advantage that can be produced CNT even at a low temperature of 400 ℃ ~ 500 ℃.

1 is a view showing a conventional plasma enhanced chemical vapor deposition apparatus. Referring to FIG. 1, the reaction gas is introduced into the chamber by the gas inlet 10. A high frequency power is applied to the upper electrode 7 and the lower electrode 8 is grounded to form an electric field between the electrodes. The introduced reactant gases enter the electric field region to produce a plasma region 5. The lower electrode 8 may serve as a substrate holder by being grounded. The substrate 3 is placed on the lower electrode 8, and the CNTs 6 may be formed on the substrate by the generated plasma. The gas after the reaction is discharged through the outlet 4.

Such a conventional chemical vapor deposition apparatus has the advantage of producing nanoparticles at a relatively low temperature, but the problem of low productivity still remains.

An object of the present invention is to provide a plasma enhanced chemical vapor deposition apparatus (PECVD) that can improve the productivity of nanoparticles.

In addition, another object of the present invention is to provide a method for efficiently producing nanoparticles using a plasma enhanced chemical vapor deposition apparatus that can improve the productivity of the nanoparticles.

In order to achieve the above object, the present invention includes a plasma enhanced chemical vapor deposition apparatus (PECVD).

The plasma enhanced chemical vapor deposition apparatus includes a reaction chamber having an internal space of a predetermined volume, and an upper electrode and a lower electrode mounted to the reaction chamber to generate plasma. And a gas inlet for introducing a reaction gas into the reaction chamber and a filament mounted in the reaction chamber to emit electrons.

In particular, the filament is mounted outside the electric field region applied by the upper and lower electrodes so that a separate power source is applied. This is to prevent unwanted spikes from being applied to the filament by the electric field applied by the upper and lower electrodes.

The filament is preferably made of a material having excellent thermal stability and excellent electron emission. For example, the filament may be made of a tungsten-based metal, or may be coated with toria or carbon nanotubes.

In addition, it may further include a quartz tube covering the filament. Therefore, it is possible to prevent the filament and the reaction gas from reacting.

In addition, the filament may have a plurality of metal lines arranged horizontally or vertically with each other. It is preferable that the metal lines are arranged vertically for structural stability. Therefore, the bending of the metal wires can be prevented even at a high temperature.

The plasma enhanced chemical vapor deposition apparatus may further include a first power source applied to the filament and a second power source applied to the upper and lower electrodes.

The second power may be applied only to the upper electrode, and the lower electrode may be grounded. Thus, the lower electrode may be used as a substrate holder on which the substrate is placed.

The plasma enhanced chemical vapor deposition apparatus may further include a heating device for adjusting the temperature of the substrate. The heating device is preferably mounted to the lower portion of the substrate holder. Therefore, the temperature of the substrate can be easily adjusted.

The present invention also provides a method for producing nanoparticles using the plasma enhanced chemical vapor deposition apparatus.

In detail, the reaction gas is introduced into the reaction chamber through the gas inlet, and electrons are emitted by the filament to which the first power is applied in the reaction chamber. According to the electron emission amount as described above, the size of the nanoparticles may be changed. The introduced reaction gas and the emitted electrons are introduced between the upper and lower electrodes to which the second power is applied to form a plasma. Electrons emitted by the filaments can easily form a plasma by exciting the reaction gas. And the nanoparticles are deposited on the substrate using the plasma.

In order to effectively deposit nanoparticles on the substrate using the plasma, the substrate may be maintained at a temperature of 200 ° C to 600 ° C. Therefore, the method may further include heating the substrate to the temperature.

The filament can easily emit electrons, for example, may be made of a tungsten-based metal, or may be coated with toria, carbon nanotubes, or the like.

In addition, the filament preferably emits electrons without reacting with the reaction gas. Therefore, the filament may be sealed with a quartz tube to prevent or inhibit the reaction between the filament and the reaction gas. Alternatively, in order to prevent the filament from reacting with the reaction gas, an inert gas such as argon, helium, and nitrogen may be introduced into the filament.

Carbon nanotubes, silicon nanoparticles, metal oxide nanoparticles, and the like may be prepared by using a suitable reaction gas and a power source, respectively, by the nanoparticle manufacturing method.

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention described below may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more fully illustrate the present invention. In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

2 is a view showing a plasma enhanced chemical vapor deposition apparatus according to the present invention.

Referring to FIG. 2, a reaction chamber having a predetermined volume of internal space is provided. The reaction chamber may be divided into two zones depending on the function.

A gas inlet 10 and a filament 20 are mounted in the reaction chamber in one of the two zones. Reaction gas is introduced into the reaction chamber by the gas inlet 10. Voltage is applied to the filament 20 by the first power source 100 to emit electrons from the filament 20. In order to suppress the reaction between the surface of the filament 20 and the reaction gas, an inert gas such as argon, helium, or nitrogen may be flowed around the filament 20.

An upper electrode 70 and a lower electrode 80 are mounted in the reaction chamber of the remaining ones of the two regions. Voltage may be applied to the upper and lower electrodes 70 and 80, respectively, and in this embodiment, a second power source 110, for example, a high frequency power source, is applied to the upper electrode 70, and the lower electrode 80 is applied to the upper electrode 70. The ground voltage is applied. The grounded lower electrode 80 may serve as a substrate holder by placing a substrate 30 on the lower electrode 80. A heating device 90 may be mounted below the lower electrode 80. Therefore, the temperature of the substrate 30 placed on the lower electrode 80 can be easily adjusted. The temperature of the substrate is preferably maintained at a temperature of 200 ℃ to 600 ℃.

The reaction gas and electrons are introduced into the electric field region formed between the upper and lower electrodes 70 and 80 by the second power supply 110 to form a plasma 50. Nanoparticles 60 are deposited on the substrate 30 by the plasma 50.

The filament 20 is mounted in a reaction chamber other than the electric field region applied by the upper and lower electrodes 70 and 80 so that a separate power is applied. That is, the filament 20 is preferably not affected by the electric field by the second power source 110. Accordingly, unwanted current flows due to the electric field generated by the second power supply 110, thereby preventing spikes. For example, the filament 20 may be located between the gas inlet 10 and the upper and lower electrodes 70 and 80. In addition, the filament 20 is preferably spaced apart from the electric field region between the upper and lower electrodes 70 and 80 by a predetermined interval. More preferably, it is preferably located 5 to 10cm apart.

A gas outlet 40 is mounted in the reaction chamber so as to face the gas inlet 10. Therefore, the gas remaining after the nanoparticles 60 are formed by the gas outlet 40 may be discharged to the outside.

FIG. 3 is a diagram illustrating various types of filaments of the plasma enhanced chemical vapor deposition apparatus of FIG. 2.

The filament may be a filament 20 in which a plurality of metal lines are horizontally arranged with each other, or a filament 25 arranged vertically. Preferably vertically arranged filaments 25 may be used. Therefore, it may be structurally more stable, such as not bending at high temperatures.

The filament is preferably made of a material having excellent thermal stability and excellent electron emission. For example, the filament may be coated with tungsten-based metal, toria or carbon nanotubes.

In addition, the filament may be sealed by a quartz tube. Therefore, by preventing the reaction of the filament and the reaction gas, it is possible to more easily emit electrons from the filament.

4 and 5 are photographs showing silicon nanoparticles prepared using the plasma enhanced chemical vapor deposition apparatus of the present invention.

The gas mixed in SiH ₄ : HCl: H ₂ = 1: 1: 98 ratio flowed through the gas inlet (10 in FIG. 2) of the plasma enhanced chemical vapor deposition apparatus of FIG. 2. The gas was introduced through the filament 20 between the upper and lower electrodes 70 and 80. The gas passing through the filament 20 is excited by the electrons emitted from the filament 20 and flows into the upper and lower electrodes 70 and 80 to easily generate plasma.

The filament 20 was adjusted to a temperature of 1800 ° C. to 2200 ° C., and RF power was applied to the upper and lower electrodes 70 and 80.

Silicon nanoparticles prepared using the plasma enhanced chemical vapor deposition apparatus can be seen in FIGS. 4 and 5.

4 and 5, it can be seen that silicon nanoparticles can be easily generated using the plasma enhanced chemical vapor deposition apparatus. In addition, it can be seen that the size of the silicon nanoparticles varies according to deposition conditions, that is, depending on the degree of supersaturation or the amount of electrons emitted from the filament 20 by controlling the temperature of the filament 20. When the supersaturation is high or the filament temperature is high, the silicon nanoparticle 200 of FIG. 4 generates particles having a size of 3 to 4 nm, and when the supersaturation is low or the filament temperature is low, the silicon nanoparticles 250 of FIG. 5 are 10 nm in size. Particles were produced.

Therefore, plasma can be easily generated by the electrons generated by the filament 20, and thus silicon nanoparticles can be effectively produced. In particular, it can be seen that as the temperature of the filament 20 is increased, the amount of electrons emitted from the filament 20 increases, so that silicon nanoparticles having a smaller size can be manufactured.

As discussed above, the present invention provides a plasma enhanced chemical vapor deposition apparatus comprising a filament. The filament is not affected by the electric field by the upper and lower electrodes, and a separate power source is applied alone to emit electrons. Therefore, the plasma enhanced chemical vapor deposition apparatus can be safely operated. In addition, the electrons emitted by the filament may contribute to the productivity of the nanoparticles by exciting the gas introduced into the plasma enhanced chemical vapor deposition apparatus to easily generate a plasma.

In addition, the present invention provides a method for producing nanoparticles using the plasma enhanced chemical vapor deposition apparatus. By using the plasma-enhanced chemical vapor deposition apparatus, plasma can be easily generated and thus nanoparticles can be produced easily and effectively. Therefore, it is possible to reduce the amount of impurities contained in the prepared nanoparticles by reducing the amount of metal catalyst used, it is possible to solve the difficulty of removing the impurities. In addition, by controlling the filament temperature of the plasma enhanced chemical vapor deposition apparatus can obtain the nanoparticles of the desired size can contribute to the productivity of the nanoparticles.

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes by those skilled in the art within the spirit and scope of the present invention. This is possible.

Claims (14)

A reaction chamber having a predetermined volume of internal space; An upper electrode and a lower electrode mounted in the reaction chamber to generate plasma; A filament mounted in the reaction chamber outside of an electric field region caught by the upper and lower electrodes to emit electrons; And Plasma enhanced chemical vapor deposition apparatus comprising a; gas inlet toward the filament and the upper and lower electrodes to pass through the filament and the reaction gas between the upper and lower electrodes in the reaction chamber; PECVD). delete The power supply of claim 1, further comprising: a first power source applied to the filament; And a second power source applied to the upper and lower electrodes as a separate power source different from the first power source. The plasma enhanced chemical vapor deposition apparatus as claimed in claim 1, wherein the filament is made of a tungsten-based metal. The apparatus of claim 4, wherein the filament is coated with toria or carbon nanotubes. The apparatus of claim 1, wherein the filaments are arranged in a plurality of metal lines horizontally or vertically. The apparatus of claim 1, further comprising a quartz tube covering the filament. The apparatus of claim 1, wherein a substrate is placed on the lower electrode. 9. The plasma enhanced chemical vapor deposition apparatus as recited in claim 8, further comprising a heating device for controlling the temperature of the substrate. Introducing a reaction gas through the gas inlet toward the filaments of the reaction chamber and the upper and lower electrodes; Emitting electrons by the filaments, The introduced reaction gas and the emitted electrons are introduced between the upper and lower electrodes to form a plasma, and Forming nanoparticles on the substrate using the plasma nanoparticles manufacturing method. The method of claim 10, further comprising heating the substrate to have a temperature of 200 ° C. to 600 ° C. 12. The method of claim 10, further comprising introducing an inert gas into the filament. The method of claim 12, wherein the inert gas is any one selected from the group consisting of argon, helium, and nitrogen. The method of claim 10, wherein the nanoparticles are any one selected from the group consisting of carbon nanotubes, silicon nanoparticles, and metal oxide nanoparticles.

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