JPH01298094A - Production of diamondlike carbon film - Google Patents

Abstract

PURPOSE:To form a carbon film sufficiently provided with practicability as a diamond at low temp. by exciting gas contg. carbon with high-frequency plasma under the irradiation of ion beams generated from gaseous hydrogen or rare gas and forming the diamondlike carbon film on a substrate. CONSTITUTION:A diamondlike carbon film is formed on a substrate 5 under the irradiation of ion beams (a generator 2 and an ion-source gas introduction port 3) by exciting gas 4 contg. carbon with high-frequency plasma (a high frequency generation source 7). In the above-mentioned stage, the acceleration voltage of the irradiating ion beams is regulated to 100-5000V and the ion beams formed from one or more kinds of gases selected from hydrogen and rare gas (He, Ar and Ne, etc.), are utilized as the above-mentioned ion beams. The substrate 5 may be heated in accordance with necessity but the excellent diamondlike carbon film can be obtained without heating the substrate.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a diamond-like carbon film.

[Conventional technology]

Diamond has the highest hardness and thermal conductivity of all materials, and its thin film applications are being widely studied.

A method for manufacturing a diamond-like carbon film is disclosed in JP-A-58
Thermal filament C described in Publication No. 91100, in which a mixed gas of hydrogen and hydrocarbons is decomposed by a hot filament to obtain diamond crystals on a substrate heated to around 800°C.
Manufacturing methods using CVD methods are known, such as the VD method and the microwave plasma CVD method using microwave plasma instead of a hot filament described in Japanese Patent Publication No. 61-3320.

In addition, as another method, ion beam evaporation method (JP-A-53-106391, JP-A-59-17450)
These methods involve forming a film on a substrate by ionizing raw material gas or atoms and drawing them out using an electric field. A film containing diamond microcrystals can be obtained as a product.

[Problem to be solved by the invention]

However, films formed by conventional methods such as the above-mentioned thermal filament CVD method and microwave plasma CVD method are
Since the film contains aggregates of crystals with a grain size of ~10 μm, its surface is extremely uneven.

stomach. Furthermore, it is necessary to heat the substrate to 800° C. for film formation, which is a major drawback in terms of application.

Furthermore, although the ion beam evaporation method described above has a flat film surface and can be synthesized at low temperatures, the formed film is far inferior to diamond in its transparency to visible light, hardness, insulation, etc. However, it has hardly been put into practical use.

An object of the present invention is to provide a method for forming a diamond-like carbon film that can be formed at low temperatures and has sufficient practicality as diamond.

[Means to solve the problem]

In the method of the present invention, a diamond-like carbon film is formed on a substrate while irradiating the substrate with an ion beam.

According to the method of the present invention, without requiring high substrate temperature,
A diamond-like carbon film with diamond-like properties and no surface irregularities can be obtained.

The diamond-like carbon film referred to here is a film having properties similar to diamond, having a hardness of ~2000 g/mm2 on the Vickers scale, and high insulation properties of around 1010 Ωcm.

In other words, in the conventional high-frequency plasma CVD method in which hydrocarbon gas is decomposed by high-frequency plasma to deposit a carbon film on a substrate, when the substrate temperature is lowered, a large amount of hydrogen is mixed in and only a film with low hardness can be obtained. There wasn't.

In contrast, in the method of the present invention, by irradiating the substrate with an ion beam, impurities such as hydrogen contained in the deposited film are effectively removed, and the deposited film is further crystallized. The degree of oxidation is sufficiently increased, and even weakly bound amorphous and graphite phases are effectively removed from the film.

Hereinafter, the method of the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows an example of a diamond-like carbon film manufacturing apparatus that can be used in the method of the present invention.

This apparatus basically consists of a vacuum chamber 1 and an ion beam generator 2.

The vacuum chamber 1 is provided with a carbon-containing gas inlet 4, a gas exhaust port 10, and a substrate holder 6 in which a substrate 5 is set. A high frequency generation source 7 is connected to the substrate holder 6, and the substrate holder 6 can be further cooled with cooling water 9.

The ion beam generator 2 generates a beam of ions obtained from the gas introduced from the ion source gas inlet 3, and a Kauffman type ion beam generator is used in this apparatus. Note that the ion beam generator is not limited to the Kauffman type.

In order to manufacture a diamond-like carbon film using this apparatus, first, the inside of the vacuum chamber 1 is evacuated to a degree of vacuum of about 1X10-6 Torr using an exhaust system (not shown) through the gas exhaust port 10.

Next, a gas for forming an ion beam, such as hydrogen gas, is introduced into the ion source gas inlet 3, and the ion beam generator 2 generates an ion beam so that the substrate 5 can be irradiated with the ion beam.

In this state, the raw material gas (carbon-containing gas) for the diamond-like carbon film is introduced from the carbon-containing gas inlet 4, and the high-frequency generation source 7 is energized to generate high-frequency waves.

Here, the inside of the vacuum chamber 1 is controlled to the degree of vacuum necessary for film formation, and the diamond-like carbon film can be formed on the substrate 5 while irradiating the substrate 5 with the ion beam.

The pressure inside the vacuum chamber 1 during film formation must be such that the ion beam can sufficiently irradiate the substrate.
Desirably, it is about 0-' to 10-2 Torr.

Note that high-frequency plasma is generally difficult to generate at such a low pressure, but in the present invention, by irradiating with an ion beam, stable high-frequency plasma can be obtained, and a film with good adhesion can be obtained with less contamination of impurities. be able to.

Although the substrate 5 may be heated if necessary, in the method of the present invention, a good diamond-like carbon film can be formed without heating the substrate.

As the ion beam used in the method of the present invention, any beam can be used as long as the above-mentioned effects can be obtained, but hydrogen is particularly suitable for removing impurities in the film and promoting crystallization. Ions and rare gases (He, Ar, N
A beam containing ions (e.g.) is suitable.

Note that the acceleration voltage of the ion beam is 1oov to 5000
V, more preferably 20oV~
It is 1000V.

That is, if the accelerating voltage is 5000 V or more, the carbon film being formed will be etched significantly by accelerated ions, and a practically necessary film forming rate cannot be obtained. Moreover, the film is likely to deteriorate due to etching.

Furthermore, if it is less than 100V, the ion beam current will not be sufficient and the film formation rate required for practical use will not be obtained, and the energy of accelerated ions will also be low, resulting in decreased crystallinity, amorphous phase, etc. Removal of carbon, etc. containing double bonds becomes insufficient.

Further, the frequency and output of the high frequency from the high frequency generation source 7 are appropriately selected from within a range that provides the high frequency necessary for decomposing the carbon-containing gas, for example, 13.56 MHz, 3.
It may be set to about 00W.

As the carbon-containing gas, hydrocarbon gases such as methane and ethane, and halogenated carbons and halogenated hydrocarbons such as CCl1a and (:HCft8) can be used.

〔Example〕

The present invention will be specifically explained below using Examples.

Example 1 A quartz plate as the substrate 5 was placed in the substrate holder 6 of the apparatus shown in FIG. 1, and a diamond-like carbon film was formed as follows.

First, the inside of the vacuum chamber 1 was evacuated to a degree of vacuum of about I x 10-6 Torr using an evacuation system (not shown) through the gas exhaust port IO.

Next, 205 CC of hydrogen gas is supplied from the ion source gas inlet 3.
Introduce it into the Kauffman type ion beam generator 2 with M,
Acceleration voltage 500v, beam current 0.5111A/C [l
At +2, a hydrogen ion beam was generated.

Furthermore, the 0114 gas is introduced from the carbon-containing gas inlet 4 into the 205
At the same time, the high frequency generation source 7 was energized to generate high frequency (13.56 MHz, 300 W).

In this state, the inside of the vacuum chamber 1 is 2 x 10-'
A film was formed on the quartz substrate while controlling the degree of vacuum to Torr and irradiating the quartz substrate with an ion beam.

Note that the quartz substrate was heated to 250° C. with a heater (not shown).

The film (thickness: 3 μm) obtained on the quartz substrate was found to be a carbon film containing diamond crystals by X-ray diffraction. Further, when the film was observed with a scanning electron microscope, it was found to be a smooth film with almost no irregularities observed on the surface.

The electrical conductivity of the obtained membrane is lXl0−”Ω−1cm
-+ It had very high insulation properties. Also, the film formation speed is 3 μm.
/h was there.

Examples 2 to 5 Films were formed in the same manner as in Example 1, except that He gas was used as the ion source and the operating conditions shown in Table 1 were individually used.

Table 1 Table 2 shows the analysis results of the carbon film under each operating condition.

Table 2 Examples 6-8. Comparative Examples 1 and 2 Films were formed in the same manner as in Example 1, except that the operating conditions were changed individually as shown in Table 3. Table 4 shows the analysis results of the obtained carbon film.

〔Effect of the invention〕

According to the method of the present invention, it is possible to produce It using high frequency plasma.
s! By using an ion beam in combination with this method, a practical diamond-like carbon film with high crystallinity, insulating properties, and good flatness can be produced at low temperatures.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of a diamond-like carbon film manufacturing apparatus that can be used in the present invention. 1... Vacuum chamber, 2... Ion beam generator, 3...
Ion beam source gas inlet, 4---carbon-containing gas inlet, 5...substrate, 6...substrate holder, 7...high frequency generation power source, 8...Ion beam, 9...Substrate holder cooling water, 10...Gas exhaust port, 11...Insulating insulator.

Claims (1)

[Claims] 1) It includes a process of exciting a carbon-containing gas with high-frequency plasma and forming a diamond-like carbon film on a substrate under ion beam irradiation, and the acceleration voltage of the irradiation ion beam in this process is 100V to 5000V, Furthermore, the method for producing a diamond-like carbon film, wherein the ion beam contains one or more types of ions selected from hydrogen ions and rare gas ions.