JP3376421B2 - Method of forming diamond-like carbon film - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for forming a diamond-like carbon (hereinafter referred to as DLC) film,
In particular, it relates to a method for producing a DLC film using a liquid phase.

[0002]

2. Description of the Related Art DLC thin films have characteristics such as high hardness, abrasion resistance, low friction coefficient and conductivity. Utilizing such characteristics, the DLC thin film is used for sliding parts of machine parts and electric parts.

The DLC film is currently manufactured by a sputtering method, an ionization vapor deposition method, a high frequency plasma CVD method, or the like. The sputtering method utilizes a phenomenon in which, when a metal in a low-pressure gas is heated or bombarded with ions, atoms are scattered from the metal surface into the gas by vaporization or collision and attached to a nearby object surface.

The ionization vapor deposition method is a method in which a high temperature arc discharge by a hot filament is used to generate plasma and a negative bias is applied to a separately installed electrode. This method is characterized in that the film thickness can be controlled on the order of nanometers and that a film having a relatively high hardness can be obtained.

In the high frequency plasma CVD method, when a raw material gas such as titanium or ethylene is subjected to high frequency and discharged, the electrode becomes a negative potential due to the self-bias effect and DLC is formed on the surface. A major feature of this method is that it is possible to form a film on an insulator.

[0006]

However, the above-mentioned problem is solved.
The DLC manufacturing methods are all vapor deposition methods and require high energy states such as substrate heating and plasma generation.
In particular, a process using a vacuum system requires a large amount of equipment and energy to generate and maintain a vacuum.

That is, in order to form a DLC film, generally, more sophisticated equipment or process is required, and as a result, more resources and energy are consumed and more waste and waste energy are generated. Let The production of such a large amount of waste and waste energy is not desirable when considering the global environment.

Therefore, it does not require high energy,
It is desirable that the DLC film can be formed in a state with less environmental load. It is more desirable that a film can be formed by using the minimum necessary raw materials in the thin film forming step, and the remaining raw materials can be easily recovered and recycled. However, a thin film forming method that has a low environmental load and is low cost has not been known so far. Furthermore, there is no known method that requires a pretreatment such as masking and mask removal even when a patterned film is formed at an arbitrary position.

Therefore, an object of the present invention is to provide a method capable of forming a DLC film by a process having a smaller environmental load and further forming an arbitrary pattern.

[0010]

In order to achieve the above object, the inventors can form a film on a cathode electrode by using a needle-shaped anode electrode and cathode electrode in a liquid phase. I found that.

According to the method for forming a DLC film of the present invention, an anode electrode having a needle-shaped tip and a cathode electrode are arranged in an organic solvent or a nitrogen-containing organic solvent to form the needle-shaped anode electrode and the cathode. By applying a predetermined voltage between the cathode and the electrode, D containing carbon or carbon and nitrogen, which are the constituent elements of the organic solvent, on the cathode electrode.
It is characterized in that an LC film is formed.

In a preferred embodiment of the method for forming a DLC film of the present invention, the organic solvent is acrylonitrile,
At least one selected from the group consisting of methanol, ethanol, acetone, 2-propanol, 1-propanol, tetrahydrofuran, glycol and glycerin
It is a species.

A preferred embodiment of the method for forming a DLC film of the present invention is characterized in that the anode electrode or the cathode electrode is moved to form a patterned DLC film at an arbitrary position.

A preferred embodiment of the method for forming a DLC film of the present invention is characterized in that the organic solvent is a water-containing solvent.

A preferred embodiment of the method for forming a DLC film of the present invention is characterized in that the organic solvent is an aqueous solution containing 0.001 to 10% of water.

A preferred embodiment of the method for forming a DLC film of the present invention is characterized in that a DLC film is formed by applying an electric current between the anode electrode and the cathode electrode.

In a preferred embodiment of the method for forming a DLC film of the present invention, nitrogen gas is introduced into the organic solvent,
It is characterized in that a DLC film is formed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for forming a DLC film of the present invention, an anode electrode having at least a needle-shaped tip and a cathode electrode are arranged in an organic solvent or an organic solvent containing nitrogen to form a DLC film. To do. DLC films are usually
In Raman spectroscopy, 1450 cm ^- was mainly ¹ 1
In the present invention, G (1580 cm) means a material having a very wide peak of 150 to 1650 cm ^−1.
-1 ) and D (1332 cm ^-1 ) having fine peaks (3n
(m or less) means that a portion having a graphite-like structure and a portion in which the portion is disturbed are mixed.

The organic solvent is not particularly limited,
For example, acrylonitrile, methanol, ethanol,
At least one selected from the group consisting of acetone, 2-propanol, 1-propanol, tetrahydrofuran, glycol and glycerin can be mentioned. In the present invention, DLC containing the constituent elements of such an organic solvent
Since a film can be formed, an organic solvent containing the desired components of the DLC film is selected and used.

The organic solvent may be a water-containing organic solvent. When it is a water-containing organic solvent, it preferably contains 0.001 to 10% of water. This range is 0.001
This is because if the amount is less than the above, the effect of adding water cannot be exhibited, and if the amount is 10 or more, the DLC film is not formed or even if it is formed, the characteristics are poor.

With respect to the electrodes, general copper electrodes, tungsten electrodes, platinum electrodes and the like can be used without any particular limitation. However, at least the tip of the anode electrode has a needle shape. This is because the region in which the current flows is limited, and the DLC film can be formed only in that region, and further, when pattern formation is performed,
This is because fine processing becomes easy.

Examples of the material of the needle include tungsten and platinum. The diameter of the needle is not particularly limited, but the tip of the needle is preferably 0.1 μm to 0.1 mm.
Is. This range is set because it is difficult to set the thickness to 0.1 μm or less, and it is difficult to form the pattern due to the concentration of the current when the thickness is 0.1 mm or more.

In the present invention, a DLC film containing the constituent element of the organic solvent is formed on the cathode electrode by applying a predetermined voltage between the anode electrode and the cathode electrode. At this time, the applied voltage varies depending on the film thickness of the DLC film to be synthesized, the form of the pattern and the like and is not particularly limited, but is preferably in the range of 1000 to 3000 volts.

The distance between the anode electrode and the cathode electrode is not particularly limited, but is preferably a distance such that energization occurs. For example, the distance between the anode electrode and the cathode electrode is 0.1 mm to 10 mm, preferably 1 to 3 mm. When the energization can be continued, the distance between the anode electrode and the cathode electrode can be 10 mm or more.

Further, regarding the relationship between the anode electrode and the cathode electrode, it is preferable that at least the tip of the needle at the tip of the anode electrode is arranged so that the tip thereof faces the substrate as the cathode electrode. Preferably, the needle tip is arranged vertically to the substrate as the cathode electrode. The reason why the tip of the needle is perpendicular to the substrate is that the film forming position can be controlled more accurately.

When a film is formed by energizing by applying a high voltage, it is preferable to introduce nitrogen gas into the organic solvent to prevent the organic solvent from burning or exploding due to an arc, and then the reaction is performed. Performed while discharging the oxygen.

In order to accelerate the formation of the DLC film,
The film may be formed by stirring the organic solvent using a magnetic stirrer or the like.

In the method of forming a DLC film of the present invention,
It is also possible to form a DLC film having a pattern formed at an arbitrary position. This is because at least the tip of the anode electrode has a needle shape, and the energy due to the anode discharge is concentrated at the tip portion, and it becomes possible to locally form a film at a more accurate position. The energy due to the anode discharge at this time is comparable to that due to plasma or ionizing radiation. Therefore, according to the present invention, it is possible to create the best film forming environment similar to the environment caused by plasma or ionizing radiation. This environment is preferred to produce more sp3 bound carbon atoms as compared to conventional electrolysis.

In the present invention, the main chemical reaction is anodic discharge in an organic solvent.
It is possible to pattern the DLC film at an arbitrary position, and the present invention can be applied to a microfabrication process such as semiconductor manufacturing. In this case, in the present invention, a pattern is directly formed on the substrate by simply setting the substrate on the cathode electrode and applying a voltage without performing pretreatment such as masking and mask removal, which are essential in fine processing. can do.

[0030]

EXAMPLES One example of the present invention will now be described, but the present invention is not construed as being limited to the following example. Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

Example 1 FIG. 1 shows a schematic view of an example of a method for forming a DLC film of the present invention. Analytically pure acrylonitrile (CH ₂ C
HCN) solvent was used as the electrolytic solvent. The temperature of the organic solvent was 80 ° C or lower. P type with a resistance of 10 to 20 Ω · cm
The Si substrate was attached to a copper rod electrode. The anode was a thin tungsten needle attached to a copper rod (the tip tip diameter was about 5 μm).
m). Bend the tungsten needle
A structure perpendicular to the Si substrate was formed. The distance between the tungsten needle and the plate was set to about 2 mm. The portion of the tungsten needle perpendicular to the organic solvent was protected by a glass tube. Before and during the experiment, nitrogen gas was introduced into the organic solvent to expel air and prevent explosion. A magnetic stirrer was used to facilitate the diffusion of the organic solvent. The voltage applied to the substrate could be varied from 0 to 3000 volts and the current limit was 100mA.

The deposited DLC film was examined by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy.

In this experiment, the arc was even observable with the naked eye when some high voltage was used. It is expected that during the experiment, the energy supply was more well concentrated.

XPS results showed that the deposited film contained only carbon, nitrogen and oxygen elements. It was not possible to remove the presence of oxygen from the surrounding atmosphere. The presence of nitrogen was significant. According to the regions of N1 peak and C1 peak, the content of nitrogen ([N] / [N] + [C]) in this film is about 28.7% (theoretical value of βC ₃ N ₄ is 57%. It is.).

Raman spectroscopy is the most common technique for the properties of carbon materials, and Raman spectroscopy of a typical sample is shown in FIG. In Figure 2, respectively, it includes a broad band located 1590 cm ^-1 and 1380 cm ^-1 are identified called Raman G band and D-band. The G band corresponds to a graphite-like layer in the micro region consisting of sp2 bonds of carbon atoms, while the D band is formed from a portion where the bonds are disturbed because the graphite region consisting of sp2 bonds of carbon is small. Mainly carbon sp3
It is equivalent to bonding, and it can be said that the larger the portion corresponding to this D band, the more diamond-like. In addition, the spectrum of the deposited sample showed high hydrogen levels in this sample when the incident laser beams were superposed. For hydrogenated amorphous films, the most prominent trends are broader linewidths, decreased D intensities, increased optical gaps, and a corresponding increase in the proportion of sp3-bonded carbon in the films. Therefore, this sample is sp2
And hydrogenated amorphous carbon-nitrogen films containing sp3 bonded carbon-carbon or carbon-nitrogen bonds. Tetrahedral C-N and linear C≡ like sp3 bond
There were some features near 1250 and 2250 cm ⁻¹ where N stretch bonds were reported, but they were very weak and noisy and could not be identified.

The FTIR spectrum of a typical sample is shown in FIG.
Shown in. The sharp peak at 2335 cm ⁻¹ is due to atmospheric CO ₂ . Bands at 2988 and 1650 cm ⁻¹ were associated with C—H and N—H vibrational modes, respectively, indicating that hydrogen atoms were also present and bound to nitrogen and carbon.
These results are in agreement with those of Raman spectra.
The characteristic bands at 2245, 1550, 1370 and 1250 cm ^-1 are C
And N atoms are chemically bound in the film. The absorption band at 2245 cm ⁻¹ corresponds to the stretching vibration of the carbon-nitrogen triple bond. Bands at 1370 and 1590 cm ⁻¹ are associated with Raman-active D and G modes, respectively. In graphite single crystals, these modes are Raman-active, while when the symmetry of the graphite ring is broken due to the bonding of nitrogen atoms to the CNx film,
IR forbidden becomes IR active. In particular, the band centered at 1250 cm ⁻¹ is associated with the sp3 bound C—N mode. Crystal C
_{At 3} N ₄ , if carbon is sp3 bonded to nitrogen, the corresponding absorption bond is around 1250 cm ^-1 . When the electrolysis of the solvent is carried out using a fine needle-shaped anode, a local Joule heat is generated in the solvent, and then, under appropriate circumstances of energy loss, if the applied voltage is high enough, a glow discharge will occur. May happen. In this case, it is possible to form a very narrow first reaction region containing a high concentration of radicals in the solvent from the beginning. Therefore, it is possible to create the best environment very close to that caused by plasma and ionizing radiation. That is, some non-equilibrium reactions can occur or some metastable products can be obtained. This is the reason why a high content of sp3-bonded carbon-nitrogen film is formed in the present invention.

The anode discharge technique was used to synthesize carbon nitride films on acrylonitrile (CH ₂ CHCN) at temperatures below 80 ° C. The anode was a thin tungsten needle, while the cathode was a Si substrate. If the applied voltage was sufficient, sparks could be observed during deposition. In this film, the content of nitrogen [N] / [N] + [C] was about 28.7%. It could be predicted by Raman spectroscopy and Fourier transform infrared absorption that this technique could create the best environment for forming sp3-bonded CN.

Example 2 Next, in order to compare the case of forming a film while generating an arc and the case of forming a film without generating an arc, a sample was prepared using the same method as in Example 1. did. When generating an arc, a high voltage of 1300 V was applied to form a film. On the other hand, if no arc is generated, 1200
A film was formed by applying a voltage of volt.

FIGS. 4A and 4B show SEM images of typical films obtained by non-sparking and sparking, respectively. It can be seen that the morphology of the non-spark film is somewhat cone-like and not dense. Spark membranes, on the other hand, consist of small and compact particles.

Raman spectroscopy is the most common and technique for characterizing carbon-related materials. Raman spectra for films A and B shown in FIG. 4 are shown in FIG. FIG. 5 '(A) contains two bands located at 1590 and 1380 cm ^-1 , identified as the G and C bands, respectively. The sharp peak at 1550 cm ^-1 is due to O _{2 in} the atmosphere. The G band corresponds to a graphitic layer in the micro region consisting of carbon sp2 bonds, while the D band is
Since the graphite region consisting of carbon sp2 bond is small, it originates mainly from carbon sp3 bond that emerges from the part where the bond is disturbed. The position, the bandwidth of the G and D bands, and the ratio of intensities from the D to G bands were determined to measure the degree of structural order.

In addition to the broad bands at 1380 and 1590 cm ^-1 , FIG. 3 shows another two bands at about 1293 and 1452 cm ^-1 . Kumar et al. Found that the lower peak at 1300 cm ^-1 does not have perfect cubic symmetry.
This is because of the CC vibration mode of sp3 binding. A band centered at about 1452 cm ^-1 has been reported in some literature. This band is usually due to the tetrahedrally bonded diamond similarity. Therefore, sample B prepared under the conditions of arc generation is believed to have significantly improved diamond properties compared to the non-sparked one produced by sample A.

When the electrolysis of the solvent is carried out using a fine needle-shaped anode, local Joule heat can occur in the solvent, and then under appropriate energy loss conditions, if the applied voltage is If high enough, glow discharge can occur. In this case, it is possible to form a very shallow first reaction zone containing essentially a high concentration of radicals from the solvent. Therefore, it is possible to create the best environment that is similar to that caused by plasma or ionizing radiation. That is, some non-equilibrium reactions occur or some metastable product can be obtained. This environment is preferred to produce more sp3 bound carbon atoms as compared to conventional electrolysis.

In summary, a diamond-like carbon film was discharge-deposited on a silicon substrate under ethanol solvent under high voltage using a fine tungsten needle-shaped anode, and during the deposition, if the applied voltage was sufficient, a spark was applied. Can be observed. It is speculated from Raman spectroscopy that this method can create the best environment favorable for forming more sp3 bonded carbon atoms compared to conventional electrolysis.

Example 3 Next, the same method as in Example 1 was used to pattern the DLC film several times. The results are shown in Fig. 6. 7 and 8 show the result of pattern formation. Figure 7 shows that in ethanol
The pattern was formed at a voltage of 1200 V for 115 minutes at room temperature. The distance from the tip of the needle of the anode electrode to the Si substrate on the cathode electrode was 2 mm or less. Figure 8
The pattern formation was performed at a voltage of 1000 V for 135 minutes, and other conditions were the same as those in FIG. The pattern film thickness was 1 to 5 μm.

The line width of the pattern was about 5-10 μm.
These are difficult to form a sharp pattern because they scan the electrodes manually. However, it is clear that computer controlled equipment can be used to form finer patterns.

Example 4 Raman measurements were carried out on membranes obtained by adding water in an organic solvent of ethanol. The results are shown in FIG. From these Raman spectra, we find that with various trends, both 0 and 4.0 ml of water (about 0.001 to 4.0 ml of water corresponding to the solvent) were added in varying amounts, both the D and G bands. bandwidth is reduced, it is found indicate that the / I _G ratio (intensity of D-band) I _D increases. The increase in D and G bandwidth corresponds to the distortion of the bond angle of the three bonded carbon atoms at the bond angle of 120 ° C. found in graphite. Due to the bond angle hindrance, the bandwidth became very large with the addition of water. Thereafter, the band narrowed as further damage was partially removed by the addition of water.

The increase in ID / IG intensity with the addition of water was consistent with the model predicting growth in number and / or size of crystals. As reported in the literature for annealing amorphous carbon, as the annealing temperature was increased, the size and / or number of crystals grew and began to contribute to the Raman spectrum, increasing the ID / IG ratio.

The addition of water reduced the resistance of the organic solvent. From the Raman results, it is considered that the addition of water partially removes the bond angle obstruction, increases the crystal dominant region, and leads to the deterioration of the quality of the DLC film.

Next, the influence of water on the voltage-current characteristics of the electrolytic solvent was investigated. Using the same method as in Example 1, methanol (CH ₃ OH), ethanol (CH ₃ CH ₂ OH), acetone (H 2
₃ O-CO-CH ₃ ), and 2-propanol (CH ₃ CHOHCH ₃ ),
1-propanol (CH ₃ CH ₂ CH ₂ OH), tetrahydrofuran (C ₄ H ₈ O), glycol (HOCH ₂ —CH ₂ OH), glycerin
A DLC film was formed using an electrolytic solvent of (HOCH ₂ CHCH ₂ OH). Raman measurement was performed on each of the formed DLC films, and it was confirmed that they were DLC films.

These methanol (CH ₃ OH), ethanol
(CH ₃ CH ₂ OH), acetone (H ₃ O-CO-CH ₃ ), and 2-propanol (CH ₃ CHOHCH ₃ ), 1-propanol (CH ₃ CH ₂ C)
H ₂ OH), tetrahydrofuran (C ₄ H ₈ O), glycol (HO
CH ₂ -CH ₂ OH), using the electrolyte solvent of glycerin (HOCH ₂ CHCH ₂ OH), examined the effect of water on the voltage-current characteristics of the electrolyte solvent.

In the case of glycol and glycerin, since they are very viscous and have a high boiling point, the temperature dependence on resistance (R = V / I, V is the applied voltage, and I is the corresponding current). analyzed.

The effect of water on the relationship between current and voltage is
Depends on organic solvent. The results for methanol are shown in FIG.

In the case of methanol, the initial addition of water reduced the resistance exactly as expected. However, the resistance increased with the addition of more water (see Figure 10). In the case of ethanol, the resistance decreases with the addition of water,
The reduction was not so great.

In the case of acetone and 1-propanol, 2-propanol and tetrahydrofuran, the resistance decreased with the addition of water and the degree of increase was dramatic.

Organic solvents for glycols and glycerin are very viscous. At room temperature, we were unable to determine the current, even when applying the maximum voltage of the power supply (3.0 kV). However, the resistance decreased significantly with increasing room temperature.

A log plot of added water volume and resistance of various organic solvents is shown in FIG. The temperature dependence of the resistance when different volumes of water are added to glycol and glycerin are shown in FIGS. 12 and 13.

It can be seen from FIG. 11 that the influence of water on the resistance depends on the organic solvent. This phenomenon should be related to the physical properties of different organic solvents. In Table 1, the physical properties of various organic solvents are listed.

[0058]

[Table 1] From FIG. 11 and Table 1, we can see that when the dielectric constant increases with respect to the organic solvent of methanol, ethanol, 1-propanol, 2-propanol and tetrahydrofuran,
The regularity that those resistances become small was found. It is known that the permittivity of a substance is the polarizability of the substance. If the permittivity is large, the polarization ability becomes strong, and the number of polarized particle types increases. Therefore, the dielectric constant of the electrolytic solvent is a key factor for the current density during discharge deposition.

From Table 1, the dielectric constant of methanol is larger than that of ethanol, acetone, 1-propanol, 2-propanol and tetrahydrofuran, which means that when methanol is used as an electrolytic solvent, the resistance is different from that of other organic solvents (ethanol , Acetone, 1-propanol, 2-propanol, tetrahydrofuran). It is also clear that the dielectric constant of water is higher than the organic solvents of ethanol, acetone, 1-propanol, 2-propanol and tetrahydrofuran, and a small amount of water was added to these 5 organic solvents during discharge deposition. This high permittivity is the reason why the current increases. However, in the case of methanol the phenomenon was slightly different and the resistance was increased by the further addition of water.

On the other hand, in the case of glycol and glycerin, the experimental results showed the opposite of the above regularity.
The dielectric constants of glycol and glycerin are higher than those of methanol and ethanol, while their resistance is higher than that of methanol and the like. Here, the concept of viscosity is applied to explain these phenomena.

All liquids have a definite resistance to change shape. This property, the type of internal friction, is called viscosity. In other words, the more viscous an organic solvent is, the more difficult it is to diffuse. It can be seen from Table 1 that the viscosities of glycol and glycerin are sufficiently higher than those of methanol and ethanol. Thus, even with their dielectric constant, the molecules do not readily diffuse in organic solvents to another part. Therefore, when glycol and glycerin are used as the electrolytic solvent, the resistance is slightly lowered.

It is known that the viscosity decreases with increasing temperature. The temperature dependence of the resistance of glycol and glycerin when different amounts of water are added is shown in FIGS. 12 and 13. They showed that the resistance decreased as the temperature increased. These results are due to a decrease in the viscosity of the organic solvent at high temperatures which facilitates more adequate diffusion.

On the other hand, it should be noted that the effect of water addition in the organic solvents of glycol and glycerin is slightly different. In the case of glycol, water addition was seen in decreasing resistance, while glycerol had less effect. It can be seen from Table 1 that the viscosity of glycerin (10690) is much higher than any other organic solvent. Even when its dielectric constant is sufficiently higher than that of water,
It may form more fully polarized molecules during discharge deposition. In summary, it has been found that there are at least two factors relating to the resistance of organic solvents: dielectric constant and viscosity.

[0064]

According to the method for forming a DLC film of the present invention,
It is possible to form a film from a liquid phase, and by using an organic solvent at room temperature and atmospheric pressure that is as close to the environment as possible, there is an advantageous effect of being environmentally friendly and capable of forming a DLC film.

The method of forming a DLC film according to the present invention has an advantageous effect that it is possible to recycle raw materials not used for film formation. That is, the low temperature process and the recyclable liquid phase process have an advantageous effect that the amount of industrial waste discharged to the environment can be extremely reduced.

According to the method for forming a DLC film of the present invention, thin film formation and pattern formation can be carried out easily and at low cost. That is, since the thin film is directly formed, there is an advantageous effect that some forming steps such as heat treatment for patterning the ceramics can be omitted.

[Brief description of drawings]

FIG. 1 is a schematic view of one embodiment of a method for forming a DLC film of the present invention.

FIG. 2 is a diagram showing Raman spectrum spectroscopy of a sample.

FIG. 3 is a diagram showing an FTIR spectrum of a sample.

FIG. 4 is a diagram showing a SEM image of a sample,
(A) is the SE of the DLC film when it is formed without generating an arc.
M image is shown, (B) is the case of forming a film by generating an arc
The SEM image is shown.

FIG. 5 is a diagram showing a Raman spectrum,
(A) And (B) is a figure which shows the Raman spectrum about the film | membranes (A) and (B) shown in FIG. 4, respectively.

FIG. 6 is a diagram showing a patterned DLC film.

FIG. 7 is a diagram showing a patterned DLC film when a voltage of 1200 V is applied.

FIG. 8 is a diagram showing a patterned DLC film when a voltage of 1000 V is applied.

FIG. 9 is a diagram showing Raman measurement of a film obtained by adding water in an organic solvent of ethanol.

FIG. 10 is a diagram showing the influence of water on the relationship between current and voltage.

FIG. 11 shows the relationship between the volume of added water and the log plot of the resistance of various organic solvents.

FIG. 12 is a diagram showing temperature dependence of resistance when different volumes of water are added to glycol.

FIG. 13 is a diagram showing temperature dependence of resistance when different volumes of water were added to glycerin.

[Explanation of symbols]

1 DC source 2 Cu copper electrode 3 Metal needle 4 Si substrate 5 Magnetic stirrer 6 Thermometer 7 N ₂ gas

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-25896 (JP, A) JP-A-62-54095 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 26/00

Claims (7)

(57) [Claims] 1. An organic solvent is provided with an anode electrode having a needle-shaped tip at least and a substrate as a cathode electrode, and a predetermined voltage is applied between the needle-shaped anode electrode and the cathode electrode. Thus, the method of forming a diamond-like carbon film, which comprises forming a diamond-like carbon film composed of a component containing a constituent element derived from the organic solvent on the cathode electrode. 2. The organic solvent is acrylonitrile, methanol, ethanol, acetone, 2-propanol,
1-propanol, tetrahydrofuran, glycol,
The method according to claim 1, wherein the method is at least one selected from the group consisting of glycerin. 3. The method according to claim 1, wherein the anode electrode or the cathode electrode is moved to synthesize a patterned DLC film at an arbitrary position. 4. The method according to claim 1, wherein the organic solvent is a water-containing solvent. 5. The method according to claim 4, wherein the water-containing solvent is an organic solvent containing 0.001 to 10% water. 6. The method according to claim 1, wherein a DLC film is formed between the anode electrode and the cathode electrode by applying an electric current. 7. The method according to claim 1, wherein nitrogen gas is introduced into the organic solvent to form a diamond-like carbon film.