KR100846718B1 - Method of depositing films using bias - Google Patents

Abstract

Provided are a film deposition apparatus and a film deposition method capable of controlling deposition rates and film characteristics. The film deposition apparatus according to the present invention can apply a chamber into which a substrate is loaded, a gas supply system for introducing a reaction gas into the chamber, a filament for dissipating heat to dissociate the introduced reaction gas, and a constant alternating current and direct current voltage. And a bias introduction portion separate from the substrate, the bias being applied to at least one of the top, side, and bottom of the substrate using a voltage applied from the power source during deposition of the film on the substrate from the dissociated reactant gas. . The film deposition method according to the present invention may use such a film deposition apparatus or another film deposition apparatus, and the method of dissociating the reaction gas and applying a bias to the substrate during the deposition of the film on the substrate from the dissociated reaction gas. Include. According to the present invention, the generation behavior of charged nanoparticles from the reaction gas can be changed by the reaction conditions of the reaction gas, and at the same time, the charge characteristics of the charged particles once produced in the gas phase can be utilized. By applying a bias, the deposition behavior is also adjusted individually, thereby allowing the deposition rate and the film properties to be adjusted accordingly.

Description

Method of depositing films using bias

1 is a schematic diagram of a film deposition apparatus according to the present invention.

2A and 2B are diagrams illustrating a bias introduction portion for applying an electrical bias to a substrate during a film deposition process according to the present invention.

3 is a view showing a method of applying a bias on the substrate during the film deposition process according to the present invention.

4 is a flowchart showing a film deposition method according to the present invention.

5 is a schematic diagram showing the difference in deposition behavior due to the interaction between the polarity of the bias applied to the substrate and the polarity of the charged nanoparticles in the film deposition method according to the present invention.

6 is an experimental view showing the deposition behavior according to the concentration of the reaction gas and the bias applied to the bottom of the substrate in the film deposition method according to the invention when the substrate is an electrical conductor.

FIG. 7 is an experimental view illustrating deposition behavior according to a concentration of a reaction gas and a bias applied to a lower portion of a substrate in the method of depositing a film according to the present invention when the substrate is an electrical nonconductor.

FIG. 8 is a Raman spectroscopy measurement result showing the properties of the film as a result of the difference in deposition behavior in the samples of FIG.

9 is an experimental view showing the deposition behavior according to the concentration of the reaction gas and the bias applied on the substrate in the film deposition method according to the invention when the substrate is an electrical non-conductor.

* Description of the symbols for the main parts of the drawings *

10 ... HFCVD unit 15 ... Chamber 20 ... Gas supply system

30 ... filament 40 ... substrate 50 ... water cooling system

60 ... substrate holder 70 ... power 80 ... bias introduction

The present invention relates to a method for depositing a film by a hot filament chemical vapor deposition (HFCVD) or a hot wire chemical vapor deposition (HWCVD) apparatus and an HFCVD method, and more particularly, a film capable of controlling deposition rates and film properties. A deposition apparatus and a film deposition method.

The deposition of a thin film using the HFCVD method has the advantage of effectively dissociating the reaction gas to improve the properties of the film compared to the film deposition method using a plasma. However, there are limitations in terms of deposition applications with increasing reaction temperature.

Therefore, there is a need for a method that can deposit a film at a high temperature as well as a low substrate temperature while using the HFCVD method, and at the same time can further improve the film deposition rate and characteristics of the film, and a film deposition apparatus that can be used to implement such a method. Do.

The technical problem to be achieved by the present invention is to provide a film deposition apparatus capable of controlling the deposition rate and the characteristics of the film.

Another object of the present invention is to provide a film deposition method capable of controlling the deposition rate and the characteristics of the film.

The film deposition apparatus according to the present invention for achieving the above technical problem, the chamber is filled with a substrate therein; A gas supply system for introducing a reaction gas into the chamber; Filaments that release heat to dissociate the reactant gas introduced; A power source capable of applying constant AC and DC voltages; And applying a bias to at least one of a top, a side, and a bottom of the substrate using a voltage applied from the power source while depositing a film on the substrate from the dissociated reactant gas and separating the bias introduction portion from the substrate. Include.

One of the film deposition methods according to the present invention for achieving the above another technical problem is using the film deposition apparatus, dissociating the reaction gas using a filament; And applying a bias to the substrate using a bias introduction portion while depositing a film on the substrate from the dissociated reaction gas.

Furthermore, another of the film deposition methods according to the present invention can be carried out using another film deposition apparatus having means for dissociating the reaction gas and applying a bias to the substrate even without using the film deposition apparatus described above. The method comprises dissociating the reactant gas; And applying a bias to at least one of the top, sides, and bottom of the substrate while depositing a film on the substrate from the dissociated reaction gas. The film deposition apparatus that may be used to practice this method may be an HFCVD apparatus or may be a plasma CVD apparatus.

In the film deposition methods according to the present invention, by controlling the degree of dissociation of the reaction gas to generate charged nanoparticles in the gas phase, it is possible to control the electrical polarity ratio of (+) and (-) of the nanoparticles. . In addition, a mixed gas of silane and hydrogen is used as the reaction gas, and at least one selected from the temperature of the filament, the fraction of the silane in the mixed gas, and the pressure of the mixed gas increases charge in the gas phase. At least one of the fraction and the size of the nanoparticles may be changed. In this case, the bias may be applied on the upper portion of the substrate to change the electrical polarity ratio of the deposited nanoparticles by changing the charge amount of the nanoparticles before the nanoparticles are deposited on the substrate. In addition, the film deposition step is divided into a nucleation step and a growth step to change at least one of the fraction and size of charged nanoparticles in the gas phase within each step and before the nanoparticles are deposited on the substrate. By changing the charge amount of the particles, it is possible to change the electrical polarity ratio of the deposited nanoparticles.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape and the like of the elements in the drawings are exaggerated to emphasize a more clear description, and the elements denoted by the same reference numerals in the drawings means the same elements.

Example

A preferred example of an HFCVD apparatus according to the present invention that can be used to practice the film deposition method according to the present invention is shown in FIG. 1.

Referring to FIG. 1, the HFCVD apparatus 10 according to the present invention includes a gas supply system (consisting of a gas pipe and a gas flow meter) for introducing a source gas such as a reaction gas into the chamber 15 of the HFCVD apparatus 10. ), A filament 30 for releasing heat to dissociate the reaction gas introduced into the chamber 15, a substrate 40 for forming a thin film on the surface thereof, a water cooling device 50 for cooling the substrate 40, and The distance between the substrate 40 and the filament 30 can be adjusted, for example, by means of a substrate holder 60, a power supply 70 capable of applying constant alternating and direct current voltages, and an upper side or bottom of the substrate 40. A bias introduction portion 80 for applying a bias to the. The bias introduction portion 80 is separated from the substrate 40 and applies an electrical bias around the substrate 40 during the deposition process. FIG. 1 illustrates a bias introduction portion 80 for applying a bias to a lower portion of the substrate 40.

Using the HFCVD apparatus 10, in the film deposition method according to the present invention, any one of silicon film, carbon nanotube and nanowire can be deposited, and in the case of silicon film, epitaxial growth or other kinds Can be grown and deposited by any one of a single crystal silicon film, an amorphous silicon film and a polycrystalline silicon film.

In the HFCVD apparatus 10, the filament 30 used to dissociate the reaction gas at a high temperature is graphite or a metal heating element, specifically tungsten (W), rhenium (Re), molybdenum (Mo), or rhodium ( Rh), platinum (Pt), tantalum (Ta), iridium (Ir), or an alloy thereof, and a heating element of various materials is possible. The filament 30 may be in the form of a single line, twisted form or any form. In addition, the number of filaments 30 may be one or more.

The reaction gas introduced to dissociate into the hot filament 30 is a gas mainly composed of a silane compound represented by the general formula Si _n H _{2n + 2} (where n is a natural number) when the silicon film is deposited. , Monosilane, disilane, trisilane, tetrasilane and the like. In terms of handling, monosilane, disilane, trisilane, or a mixed gas thereof is preferable. Of course, the reaction gas is not limited to these, but a fluorinated silane represented by the general formula Si _n H _{2n + 2-m} F _m (n, m is a natural number m <2n + 2, and m is also 0). For example, SiH ₃ F, SiH ₂ F ₂ , SiHF ₃ , SiF ₄ , Si ₂ F ₆ , Si ₂ HF ₅ , Si ₃ F ₈ ; Si _n H _{2n + 2-m} Cl _m (n, m is a natural number m <2n + 2, m is also 0), for example SiH ₃ Cl, SiH ₂ Cl ₂ , SiHCl ₃ , SiCl ₄ , Si ₂ Cl ₆ , Si ₂ HCl ₅ , Si ₃ Cl ₈ ; Organosilanes represented by the general formula Si _n R _{2n + 2-m} H _m , for example Si (CH ₃ ) H ₃ , Si (CH ₃ ) ₂ H ₂ , Si (CH ₃ ) ₃ H; When depositing a low maenyum film, low maenyum represented by Ge _n H _{2n + 2} , for example, GeH ₄ , Ge ₂ H ₆ ; Germanium fluoride represented by the general formula Ge _n H _{2n + 2-m} F _m , for example GeF ₄ ; When depositing carbon nanotubes and nanowires, hydrocarbon gases such as CH ₄ (methane), C ₂ H ₆ (ethane), C ₃ H ₈ (propane), C ₂ H ₄ (ethylene), C ₂ H All hydrocarbon compounds may be used in addition to ₂ (acetylene) and the like.

Although these reaction gas may be used independently, Reactive gas, such as hydrogen, fluorine, and chlorine; Gases containing group III elements that are dopants, for example B ₂ H ₆ (diborane), B (CH ₃ ) ₃ (trimethylboron) or gases containing group V elements, for example PH ₃ (Phosphine); Inert gases such as helium, argon and neon; A support gas such as nitrogen may be added and introduced to dilute and use the silane compound gas. Dilution addition rate may be in the range of about 0.1 to 100% (volume ratio) when expressed as the ratio of the silane compound to the addition gas. In consideration of the actual formation rate of the semiconductor thin film, a concentration of 1% or more of dilution rate is preferably used.

The reaction gas flow rate may be 1 to 1000 sccm, and the pressure inside the chamber 15 may range from 5 mtorr to 760 tor, but depending on the film formation rate, the reaction gas flow rate and the pressure inside the chamber 15 may be arbitrarily selected.

When carrying out the film deposition method according to the present invention, the voltage of the power supply 70 is in the range of + 1000V to -1000V, and an alternating current in the range of DC or frequency of 0.01Hz to 10KHz can be applied.

In performing the film deposition method according to the present invention, the bias introduction portion 80 for applying a bias to the substrate 40 may use a conductive material, in particular a metal material, the electrical conductivity is 1000 ~ 10000000 (Ωcm) ^- Metals of ¹ are preferred. The area of the substrate 40 and the bias introduction portion 80 may be 1 to 120000 cm ² . The size of the bias introduction unit 80 is larger than the area of the substrate 40 to be deposited, and of course, the size may be changed according to the purpose of the deposition.

The bias introduction portion 80 may be in the form of a plate structure as shown in FIG. 2A or in the form of a mesh structure as shown in FIG. 2B. Alternatively, a tubular structure may be used. As shown in FIG. 1, in order to apply a bias to the lower portion of the substrate 40 to be deposited, the bias introduction portion 80 is preferably in the form of a plate as shown in FIG. 2A. In addition, as shown in FIG. 3, the bias may be applied to the upper portion of the substrate 40. In this case, the bias introducing portion 80 uses a mesh form as shown in FIG. 2B and the upper portion of the substrate 40. Position it. Depending on the purpose of the deposition, it is preferable to change the hole size, shape and installation position of the mesh. As described above, in the film deposition apparatus and the method according to the present invention, the bias introduction unit 80 for applying the electrical bias is separated from the substrate 40 so as to be positioned above the substrate 40 as well as under the substrate 40. Can be applied. In addition, a bias can be applied to the side of the substrate 40. During deposition, the polarity of the bias may be kept constant, or may be applied alternately or periodically.

The temperature of the substrate 40 at the time of deposition may be 20 ~ 1000 ℃, the temperature considered from the heat resistance of the substrate 40, the resulting film properties is preferably 25 ~ 500 ℃.

The substrate 40 used in the film deposition method according to the present invention may be any one of a conductive material, a non-conductive material, and a plastic. As a light-transmissive substrate, glass substrate materials conventionally used, such as blue plate glass, borosilicate glass, and quartz glass, as well as polyethylene terephthalate (shortened PET, or polyterephthalate in other words), polycarbonate (polycarbonate in other words), polyimide (shortened PI) ) Or a transparent polymer film substrate such as polyethylene naphthalate. Polymer resins, such as cloth cloth, as well as substrates and ceramics of a metal component having electrical conductivity are possible. As mentioned earlier, this separation of the bias inlet 80 from the substrate 40 allows the electrical bias to penetrate, as well as electrically conductive substrates, as well as plastic substrates that are electrically nonconductive and require low reaction temperatures. It is also possible to control the deposition behavior of the film by applying a bias even on non-conductors such as ceramics.

Specifically, a metal substrate such as stainless steel, molybdenum, titanium, silver or aluminum is formed on a metal substrate such as stainless steel, titanium, aluminum or molybdenum, a glass substrate such as borosilicate glass, blue plate glass or quartz glass or a polymer film surface. It can be used as 40. Moreover, the board | substrate which provided the transparent electrode on the said glass substrate, the polymer film, and the board | substrate of a metal component can also be used preferably. As a transparent electrode at this time, metal oxides, such as tin oxide, indium oxide, and a zinc oxide, a translucent metal, etc. can be used effectively. In addition, the thickness of the substrate 40 may be 0.5 to 10 mm in the case of a glass substrate, 10 to 500 μm in the case of a polymer film, and 50 to 50,000 mm in the case of a substrate of a metal layer or a metal component. In addition, in the case of the amorphous semiconductor thin film, the film formed on the substrate 40 according to the present invention has a thickness of about 10 kPa to 10 m (100,000 kPa), and the thin film formation rate is 0.1 to 1000 kPa / sec, preferably 5 It is about 30 microseconds / sec.

A method of depositing a film according to the present invention with such an HFCVD apparatus 10 will be described with reference to FIGS. 4 and 5 as follows.

First, referring to step s1 of FIG. 4, the reaction gas is dissociated using the filament 30.

The present invention is based on our new theory of thin film deposition. Until now, it has been believed that the growth of thin films is mainly atomic or molecular. Since most thin film processes have been developed based on these assumptions, the conditions that cause vapor phase nucleation have been the limit of deposition rate. In order to overcome the limitation of the deposition rate, it is necessary to create a condition in which a good quality thin film can grow even under the conditions of nucleation in the gas phase. To this end, if the generated nuclei or nanoparticles are charged, a charged cluster is formed. It has been shown that high quality thin films can be manufactured at high deposition rates. (Nong-Moon Hwang, Doh-Yeon Kim, J. Appl. Phys, 79 234. 2003)

On the other hand, Yamada and Tagaki developed a technique called "ionized cluster beam deposition (ICBD)" to intentionally generate charged clusters and accelerate them to deposit thin films. In this method, however, adiabatic expansion was used to make clusters and electron guns were used to ionize them. This method is not only complicated, but also has low ionization rate of the resulting clusters, making it difficult to exceed 30%. This method also used a high vacuum of ˜0.000001 Torr because it accelerated and deposited these clusters.

However, according to the present invention, by simply dissociating the reaction gas with the filament 30, a charged deposition source (nanoparticles or nanoclusters) without the use of additional devices for producing nanoparticles (or nanoclusters) is produced. ) May be spontaneously generated in the chamber 15.

In the present invention, the degree of dissociation of the reaction gas may also be adjusted to control the (+) or (−) charge characteristics of the charged nanoparticles generated in the gas phase. That is, the amount of charge and polarity ratio of the nanoparticles can be adjusted as intended. By varying the relative proportions of the (+) or (-) charged particles in this way, the deposition rate and the film properties can be controlled by controlling the correlation with the charge properties of the charged nanoparticles affected.

Specifically, a mixed gas of silane and hydrogen is used as the reaction gas, and at least one selected from the filament 30 temperature, the fraction of the silane in the mixed gas, and the pressure of the chamber 15 due to the mixed gas is increased in the gas phase. At least one of the fraction and the size of the charged nanoparticles may be varied.

For example, the degree of dissociation of the reactant gas depends in particular on the temperature of the filament 30. As the temperature of the filament 30 increases, the degree of dissociation of the reaction gas increases. This increase in temperature of the filament 30 changes the degree of dissociation of the reactant gas, which in turn changes the electrostatic properties of the deposition unit particles based on our deposition theory. In the case of silicon thin film deposition, as the temperature of the filament 30 increases, the relative ratio of the negatively charged particles increases as compared to the positively charged nanoparticles. The increase in dissociation degree of the reaction gas and the improvement of the thin film characteristics according to the temperature control of the filament 30 have a difference in the reaction gas dissociation degree in the conventional method using plasma.

In addition, according to the difference in electrical conductivity of the substrate 40 to be deposited, the electrostatic characteristic resulting from the amount of charge possessed by the charged nanoparticles is removed from the surface of the substrate 40 or continuously accumulated on the surface of the substrate 40 to continuously The behavior of the interaction between the substrate 40 and the charged nanoparticles changes depending on the polarity of the charged nanoparticles being deposited. If the electrical conductivity of the substrate 40 is large, the electrostatic properties due to the amount of charge possessed by the charged nanoparticles are removed from the surface of the substrate 40 and thus do not affect the subsequently charged nanoparticles. However, in the case where the electrical conductivity of the substrate 40 is small or insulator, since the electrostatic property due to the amount of charge possessed by the charged nanoparticles is accumulated on the surface of the substrate 40, the polarity of the charged nanoparticles deposited thereafter. Depending on the attraction or repulsive force. The electrical conductivity difference of the substrate 40 will be described in detail in the following experimental examples.

Next, referring to step s2 of FIG. 4, after dissociating the reactant gas or dissociating the reactant gas, the power supply 70 is used to move around the substrate 40 or the substrate 40 through the bias introduction unit 80. Deposition behavior is controlled by applying an electrical bias of +) or (-) polarity continuously or alternately. That is, the deposition rate of the charged nanoparticles and the structural characteristics of the thin film can be determined by selectively selecting a part having any polarity among the (+) or (-) polarity in the deposition process with respect to the charged nanoparticles that have already been produced. To adjust.

For example, a bias may be applied on top of the substrate 40 to alter the electrical polarity ratio of the deposited nanoparticles by changing the charge amount of the nanoparticles before they are deposited on the substrate 40. Control of the deposition behavior of the charged nanoparticles according to the position of the bias introduction portion 80 will be described in detail in the following experimental examples. In addition, the film deposition step is divided into a nucleation step and a growth step to change at least one of the fraction and size of charged nanoparticles in the gas phase within each step and before the nanoparticles are deposited on the substrate 40. The electrical polarity ratio of the nanoparticles deposited may be changed by changing the charge amount of the nanoparticles. For example, it is possible to reduce the fraction and size of the nanoparticles in the nucleation stage, which is the initial stage of film deposition, and to reduce the fraction and size of the nanoparticles in the growth stage, or vice versa. In addition, in the nucleation step, the electrical polarity ratio of the deposited nanoparticles may be predominantly negative, and in the growth phase, the electrical polarity ratio of the deposited nanoparticles may be positively reversed, or vice versa. Do.

5 is a schematic diagram showing the difference in deposition behavior due to the interaction between the polarity of the bias applied to the substrate and the polarity of the charged nanoparticles according to the present invention.

As shown in FIG. 5A, when the polarity of the charged nanoparticle 90 is negative, applying a positive bias (for example, + 150V) to the conductive substrate 40 causes the nanoparticle 90 to be attracted. ) Is directed to the substrate 40, the deposition rate is high. As shown in (b), if the polarity of the charged nanoparticles 90 is negative or positive, no bias is applied to the conductive substrate 40 to show a normal deposition rate. However, as shown in (c), when the polarity of the charged nanoparticle 90 is negative, applying a negative bias (for example, -150V) to the conductive substrate 40 causes the nanoparticle 90 to be repulsed. Is bounced off the substrate 40 so that the deposition rate is very low. The deposition rate can be controlled by applying a bias to the charged nanoparticles, thereby controlling the structural properties of the deposited thin film.

As such, the present invention can change the generation behavior of charged nanoparticles from the reaction gas by the reaction conditions of the reaction gas and at the same time separate the charge characteristics of the charged particles once produced in the gas phase, apart from this production behavior. By applying bias, the deposition behavior is also adjusted individually. In addition, the present invention separates the bias introduction portion 80 for applying the electrical bias from the substrate 40, thereby lowering the substrate 40, as well as the upper or side of the substrate 40 to apply the bias to the deposition behavior It can be controlled effectively. The deposition behavior of thin films and thick films can be controlled on electrically conductive substrates as well as on non-conductors such as ceramics that are electrically nonconductive and require low reaction temperatures, and ceramics that are not penetrated by electrical bias. In addition, there is an effect of reducing haze, void generation, surface roughness, and crystallinity of the thin film due to the deposition of a film having a uniform structure according to the deposition behavior.

On the other hand, even without using the above HFCVD apparatus 10 may be configured to have a means for dissociating the reaction gas to another film deposition apparatus and a means for applying a bias to the substrate to perform the film deposition method according to the present invention, The film deposition apparatus that may be used to practice this method may be an HFCVD apparatus or may be a plasma CVD apparatus.

Experimental Example 1

The CVD apparatus 10 shown in FIG. 1 was used.

The temperature of the filament 30 for dissociating the reaction gas was 1833 (K), and the substrate 40 was a stainless steel material having a size of 2 x 2 cm and 1 mm (thickness), and the temperature of the substrate 40 was 393. It was set to (K). As a reaction gas, a mixed gas of hydrogen (H ₂ ) and silane (SiH ₄ ) was used, and the concentration of silane was 20% and 10%, respectively. DC bias of + 150V and -150V was applied using the power supply 70, and a copper plate was used as the bias introduction unit 80, and was installed below the substrate 40 as shown in FIG. 1. The chamber 15 pressure was 0.7 Torr, and deposition proceeded for 30 minutes each. The mass of the substrate 40 before and after the reaction was measured to show the deposition amount per unit area according to the bias effect as a difference in the mass change value of the comparative substrate deposited under the same conditions except for the bias application. (Increase the mass of the deposited film by applying a bias-increase the mass of the substrate deposited without applying a bias under the same conditions = deposition amount by the bias effect)

FIG. 6 is an experimental view showing deposition behavior according to a concentration of a reaction gas and a bias applied to a lower portion of a substrate in the deposition method according to the present invention when the substrate is an electrical conductor (stainless steel).

Referring to Figure 6, (a) shows the increase in mass of the silicon thin film obtained by depositing at 20% silane concentration, bias + 150V, (b) is deposited under the condition of 20% silane concentration, bias -150V Shows the mass increase of the silicon thin film obtained by (c), and (c) shows the mass increase of the silicon thin film obtained by depositing on conditions of 10% of a silane concentration and a bias of + 150V. And (d) shows the mass increase of the silicon thin film obtained by depositing on 10% of silane concentration and the bias of -150V.

As shown in Fig. 6, from the increase in the mass of the silicon thin film obtained by the bias application method to the conductive substrate, the deposition rate of the silicon thin film is (a) is the largest, (b) is the next largest, (c ) Is next big. In the case of (d), the deposition rate was reduced compared with the case where no bias was applied. These results can be interpreted as the generation behavior of the charged nanoparticles produced under the conditions of 20% silane concentration and 10% silane concentration.

That is, under conditions of 20% silane, i.e., (a) and (b), the negatively charged particles are mainly generated, and the negatively charged nanoparticles are also partially generated and applied to the opposite polarity bias. Thereby increasing the deposition rate. On the other hand, under conditions of 10% silane, i.e., (c) and (d), when negatively charged particles are generated as compared with the conditions of 20% silane, -150V is applied (in case of (d)) This is because negatively charged particles, which occupy most of the nanoparticles produced, are difficult to deposit and are easily deposited, and the positively charged nanoparticles are very small in amount, which contributes to an increase in deposition rate.

As such, when the charge characteristics of the charged nanoparticles generated according to the dissociation conditions of the reactant gas (here, the concentration of the silane as the reactant gas) are changed, the charged charges generated when stainless steel having high electrical conductivity is used as the substrate The deposition rate could be increased by applying a bias in which the relative proportion of the polarity of the nanoparticles is opposite to the largest polarity. In addition, the relative ratios of the produced (+) or (-) charged nanoparticles increased with increasing reaction gas concentration.

Experimental Example 2

As in Experimental Example 1, the CVD apparatus 10 shown in FIG. 1 was used.

The temperature of the filament 30 for dissociating the reaction gas was 1833 (K), and the substrate 40 was a polyethylene terephthalate material having a size of 3 x 6 cm and 0.5 mm (thickness). The temperature was 353 (K).

As a reaction gas, a mixed gas of hydrogen (H ₂ ) and silane (SiH ₄ ) was used, and the concentration of silane was 20% and 10%, respectively. DC bias of + 150V and -150V was applied using the power supply 70, and a copper plate was used as the bias introduction unit 80, and was installed below the substrate 40 as shown in FIG. 1. The chamber 15 pressure was 0.7 Torr, and deposition proceeded for 30 minutes each. The mass of the substrate 40 before and after the reaction was measured to show the deposition amount per unit area according to the bias effect as a difference in the mass change value of the comparative substrate deposited under the same conditions except for the bias application. (Increase the mass of the deposited film by applying a bias-increase the mass of the substrate deposited without applying a bias under the same conditions = deposition amount by the bias effect)

FIG. 7 is an experimental view showing deposition behavior according to a concentration of a reaction gas and a bias applied to a lower part of a substrate in the deposition method according to the present invention when the substrate is an electrical insulator (polyethylene terephthalate).

Referring to FIG. 7, (a) shows an increase in mass of a silicon thin film obtained by depositing at a silane concentration of 20% and a bias of + 150V, and (b) shows depositing at a silane concentration of 20% and a bias of -150V. Shows the mass increase of the silicon thin film obtained by (c), and (c) shows the mass increase of the silicon thin film obtained by depositing on conditions of 10% of a silane concentration and a bias of + 150V. And (d) shows the mass increase of the silicon thin film obtained by depositing on 10% of silane concentration and the bias of -150V.

As shown in Fig. 7, the deposition rate of the silicon thin film obtained by the bias application method to the non-conductive substrate is (b) is the largest, (d) is the next largest, ( a) is next In the case of (a) and (c), the deposition rate decreased compared with the case where no bias was applied.

This result is because, unlike Experimental Example 1, polyethylene terephthalate having low electrical conductivity was used as the substrate 40. The charges possessed by the deposited nanoparticles do not escape from the polyethylene terephthalate substrate 40, which is an electrical insulator, and accumulate on the substrate 40, thereby reducing the deposition rate due to the repulsive force resulting from the same polarity with the subsequently deposited nanoparticles. do. Therefore, in the case of (c), which is mainly composed of negatively charged nanoparticles, the deposition rate is the smallest, and in the case of (a) in which the positively charged nanoparticles are increased, the deposition rate is smaller than that in which no bias is applied. . In the case of applying a bias of -150V as in (b) and (d), the deposition step of the deposition rate of the positively charged nanoparticles having a relatively low production rate compared to the negatively-charged nanoparticles determines the deposition rate. By increasing the deposition rate by a negative bias.

In addition, in the case of the silane (b) having a high relative generation rate of the (+) charged particles to the (-) charged particles and having a relatively high decomposition decomposition amount of gas, the deposition rate is higher than that of (d). .

8 is a Raman spectroscopic measurement result showing the characteristics of the film as a result of the difference in deposition behavior for the samples of FIG.

As shown in FIG. 8, the case of (d) has the largest crystallinity because the mutually repulsive effect of the same charged nanoparticles is the greatest during the thin film deposition process, as shown in (c) and (d). This is because the ratio of the negatively charged nanoparticles to the positively charged nanoparticles is greater than that of the 20% silane concentration, such as (a) and (b), for the phosphorus concentration of 10%.

As such, when the charge characteristics of the charged nanoparticles generated according to the dissociation conditions of the reaction gas (here, the concentration of the silane as the reaction gas) are changed, the generated charges are used when the polyethylene terephthalate, which is an electrical insulator, is used as the substrate. The deposition rate could be increased by applying a bias having the same polarity as that of the largest polarized nanoparticles. In addition, it was clarified that the higher the dissociation degree of the reaction gas under the same conditions, the greater the difference in formation ratio between the two polarities of the produced nanoparticles could increase the crystallinity of the thin film.

Experimental Example 3

As in Experimental Example 2, the CVD apparatus 10 shown in FIG. 1 was used.

The temperature of the filament 30 for dissociating the reaction gas was 1833 (K), and the substrate 40 was a polyethylene terephthalate material having a size of 3 x 6 cm and 0.5 mm (thickness). The temperature was 353 (K). As a reaction gas, a mixed gas of hydrogen (H ₂ ) and silane (SiH ₄ ) was used, and the concentration of silane was 20% and 10%, respectively. DC bias of + 150V and -150V was applied using the power supply 70, respectively. It is the same as Experimental example 2 so far.

Instead, a copper mesh was used as the bias introduction portion 80 and was installed on the polyethylene terephthalate substrate 40. The wire diameter of the copper mesh is 0.4 mm and the holes between the wires are 64 holes / cm ² . The chamber 15 pressure was 0.7 Torr, and deposition proceeded for 30 minutes each. The mass of the substrate 40 before and after the reaction was measured to show the deposition amount per unit area according to the bias effect as a difference in the mass change value of the comparative substrate deposited under the same conditions except for the bias application. (Increase the mass of the deposited film by applying a bias-increase the mass of the substrate deposited without applying a bias under the same conditions = deposition amount by the bias effect)

9 is an experimental view showing the deposition behavior according to the concentration of the reaction gas and the bias applied on the substrate in the deposition method according to the present invention when the substrate is an electrical insulator (polyethylene terephthalate).

Referring to FIG. 9, (a) shows the mass increase of the silicon thin film obtained by depositing at a silane concentration of 20% and a bias of + 150V, and (b) shows depositing at a condition of 20% of silane concentration and a bias of -150V. The increase in mass of the obtained silicon thin film is shown.

As shown in FIG. 9, both (a) and (b) have a lower deposition rate than when no bias is applied, and a case of applying (+) bias (that is, (a)) is a case of (-) bias. The deposition rate was smaller than when added (ie, (b)). This result is apparent because the basic unit of silicon thin film deposition was that most of the charged nanoparticles were trapped in the biased copper network before being deposited on the substrate, and the deposition rate could be controlled by this bias application method.

Experimental Example 4

As in Experimental Example 1, the CVD apparatus 10 shown in FIG. 1 was used.

The temperature of the filament 30 for dissociating the reaction gas was set to 2173 (K), and the substrate 40 was selected from a stainless steel material having a size of 2 x 2 cm, 1.0 mm (thickness), and the temperature of the substrate 40. Was 523 (K).

As a reaction gas, a mixed gas of hydrogen (H ₂ ) and methane (CH ₄ ) was used, and the concentration of methane was 20%. DC biases of + 25V, 0V, and -200V were applied using the power supply 70, respectively, and a copper plate was used as the bias introduction unit 80, and was installed below the substrate 40 as shown in FIG. The chamber 15 pressure was 170 Torr, and the deposition proceeded for 30 minutes each.

As a result of the deposition, carbon nanotube growth was more active than + 25V when -200V was applied, which is interpreted to be due to the fact that most of the nanoparticles produced in the gas phase were negatively charged.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

According to the present invention, the generation behavior of charged nanoparticles from the reaction gas can be changed by the reaction conditions of the reaction gas, and at the same time, the charge characteristics of the charged particles once produced in the gas phase can be utilized. By applying bias, the deposition behavior is also adjusted individually. As a result, the film growth rate can be controlled and the structure of the film can be improved.

That is, according to the present invention, the control of the electrostatic properties of the deposition sources dissociated in the gas phase, the control of mutual attraction or repulsive force according to the bias applied around the substrate, and the control of deposition behavior according to the electrical conductivity difference of the substrate are controlled. Through this, the deposition rate of the film as well as the characteristic change of the film structure can be controlled.

In addition, the present invention separates the bias introduction portion for applying an electrical bias from the substrate, the substrate is not only electrically conductive, but also a plastic substrate that is electrically insulator and requires a low reaction temperature, as well as a ceramic that does not penetrate the electrical bias The deposition behavior of the thin film and the thick film can also be controlled on the same insulator. In this way, the improvement of the bias application method can control the effective deposition of the thin film.

In addition, there is an effect of reducing haze, void formation, surface roughness, and crystallinity of the thin film due to the deposition of a film having a uniform structure according to the deposition behavior.

Claims (19)

delete delete delete delete delete Dissociating the reaction gas; And Applying a bias to the substrate while depositing a film on the substrate from the dissociated reactant gas, Controlling the degree of dissociation of the reaction gas to generate charged nanoparticles in a gaseous phase, and controlling the electrical polarity ratios of (+) and (-) of the nanoparticles. The method of claim 6, wherein the substrate is made of a conductive material, and the deposition rate is increased by applying a bias of a polarity in which the electrical polarity ratio of the nanoparticles generated in the gas phase is opposite to the polarity of the largest. A film vapor deposition method. The method of claim 6, wherein the substrate is formed of any one of a non-conductive material and a plastic, and a deposition rate is increased by applying a bias having a polarity equal to a polarity in which the electrical polarity ratio of the nanoparticles generated in the gas phase is the largest. A film deposition method characterized by increasing. The method of claim 6, wherein the substrate is made of one of a non-conductive material and a plastic, and the crystallinity of the film is increased by increasing the electrical polarity ratio of the nanoparticles. A chamber into which a substrate is charged; A gas supply system for introducing a reaction gas into the chamber; Filaments that release heat to dissociate the reactant gas introduced; A power source capable of applying constant AC and DC voltages; And A bias introduction portion that applies a bias to at least one of the top, side, and bottom of the substrate and separates the substrate using a voltage applied from the power source while depositing a film on the substrate from the dissociated reactant gas; Using a film deposition apparatus, characterized in that Dissociating a reaction gas using the filament; And Applying a bias to the substrate using the bias introduction portion while depositing a film on the substrate from the dissociated reactant gas, Nanoparticles charged in the gas phase by using a mixed gas of silane and hydrogen as the reaction gas, and increasing at least one selected from the temperature of the filament, the fraction of silane in the mixed gas, and the pressure of the mixed gas. Changing at least one of the fraction and the size of the film. The method of claim 10, wherein the bias is applied at the top of the substrate to change the electrical polarity ratio of the deposited nanoparticles by changing the charge amount of the nanoparticles before the nanoparticles are deposited on the substrate. Film deposition method. The method of claim 10, wherein the film deposition step is divided into a production step and a growth step to change at least one of the fraction and size of charged nanoparticles in the gas phase within each step and before the nanoparticles are deposited on the substrate. And changing the electrical polarity ratio of the nanoparticles deposited by changing the charged amount of the nanoparticles. The method of claim 6 or 10, wherein any one of a silicon film, a carbon nanotube and a nanowire is deposited by the above method, and the silicon film is any one of a single crystal silicon film, an amorphous silicon film, and a polycrystalline silicon film. Film deposition method. The method of claim 6 or 10, wherein the substrate is any one of a conductive material, a non-conductive material, and a plastic. The film deposition method according to claim 6 or 10, wherein the voltage for applying the bias is in the range of + 1000V to -1000V, and an alternating current in the range of DC or a frequency of 0.01Hz to 10KHz is applied. delete The film deposition method according to claim 10, wherein the substrate and the bias introduction portion have an area of 1 to 120000 cm ² . The method of claim 10, wherein the bias introduction portion is made of a metal material. The film deposition method of claim 10, wherein the bias introducing portion has an electrical conductivity of 1000 to 10000000 (Ωcm) ⁻¹ .

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