JPS63288997A - Formation of thin diamond film - Google Patents

Abstract

PURPOSE:To efficiently form a thin diamond film at room temp. by changing the angle formed with both the surface of a substrate and high-velocity corpuscular beams while carbon is condensed on the surface of the substrate. CONSTITUTION:While projecting high-velocity corpuscular beams 10 on the surface of a substrate 6, carbon 7 is fed on the surface of the substrate 6 to condense carbon 7 on the surface of the substrate 6 and also while changing the angle theta formed by both the surface of the substrate 6 and the high-velocity corpuscular beams 10 during this condensation, a thin film is formed. In this method, the following operation is preferably adopted. In other words, the high- velocity corpuscular beams are projected on the substrate by regulating the angle theta formed by both the substrate and the high-velocity corpuscular beams to 0-5 deg. and while the high-velocity corpuscular beams give shock at a shallow angle on the surface of the substrate, carbon is condensed on the substrate to form the thin film and the angle theta is intermittently regulated to theta is 0-5 deg. and the film is continuously formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a hard coating film with excellent environmental resistance that can be applied in all fields, and is particularly useful in the semiconductor industry by taking advantage of its high insulation and high thermal conductivity. Reliable target rIII
Alternatively, the present invention relates to a method for forming a diamond thin film that is applied as a heat sink film and further converted into a semiconductor to be used as a semiconductor element that can be used at high temperatures.

Conventional technology In recent years, much research has been conducted on the formation technology of diamond thin films, including the hot filament CVD method (chemical vapor deposition method).
A diamond crystal film is obtained by a method such as a plasma CVD method or a plasma CVD method.

A method for forming a diamond thin film using the conventional hot filament CVD method will be explained with reference to FIG. FIG. 3 is a schematic diagram of an apparatus used in the hot filament CVD method. In Fig. 3, 1 is a vacuum chamber, and a vacuum pump (not shown)
A gas introduction section 2 for introducing a mixed gas of hydrocarbon such as methane and hydrogen is connected to the substrate 3, and a substrate 3 on which a diamond thin film is formed on the upper surface thereof faces the gas introduction section 2. The substrate 3 is attached to a substrate holder 4 which can adjust the temperature of the substrate 3. A hot filament 5 is provided between the gas introduction section 2 of the vacuum chamber 1 and the substrate 3 as means for activating the mixed gas.

Next, a method for forming a diamond thin film using the above apparatus will be explained. First, a mixed gas of hydrocarbon and hydrogen is introduced into the vacuum chamber 1 from the gas introduction part 2, and the inside of the vacuum chamber 1 is maintained at the required pressure (1 to several hundred Torr) by exhausting, and the substrate is 3 to the required temperature (
700-1000°C). The introduced mixed gas is activated by thermal decomposition by the hot filament 5 to produce excited carbon such as ions and radicals, thereby forming a diamond thin film on the substrate 3.

Problems to be Solved by the Invention However, in the conventional manufacturing method, it is necessary to maintain the temperature of the substrate 3 on which the diamond thin film is formed at a high temperature of about 700 to 1000°C, and it is difficult to form the diamond film on the substrate incorporating the semiconductor element. could not be formed.

The present invention solves the above-mentioned problems, and aims to provide a method for forming a diamond thin film that can efficiently form a diamond thin film at room temperature.

Means for Solving the Problems In order to solve the above problems, the present invention provides a method of condensing carbon on the surface of the substrate by supplying carbon to the surface of the substrate while irradiating the surface of the substrate with a high-speed particle beam. At the same time, a thin film is formed while changing the angle between the surface of the substrate and the high-speed particle beam during this condensation.

Effect: According to the method described above, the angle between the surface of the substrate and the high-speed particle beam is changed while carbon is condensing on the surface of the substrate, so that a diamond thin film can be efficiently formed on the surface of the substrate even at room temperature. At the time of condensation, carbon is supplied to the surface of the substrate while irradiating the surface of the substrate with a high-speed particle beam to form a film, so the film becomes hard and becomes a diamond-like carbon film with an amorphous structure.

When the surface of the substrate is irradiated with a high-speed particle beam so that the angle 0 between the surface of the substrate and the high-speed particle beam is 0 to 5 degrees, diamond crystal grains are formed in the film obtained on the surface of the substrate kept at room temperature. will now include. However, these diamond crystal grains are surrounded by an amorphous structure and cannot grow large. Therefore, next, by setting the angle θ between the surface of the substrate and the high-speed particle beam to 10 degrees or more, and applying a larger impact to the surface of the substrate than when the angle 0 is 0 to 5, the diamond crystal grains are surrounded. Sputtering the amorphous structure. Amorphous structures are more unstable than diamond crystals, so they are selectively etched. If this state continues for a long time, diamond crystal grains will also be sputtered, so it is necessary to choose a time to remove them. When only diamond crystal grains are left and the angle 0 between the surface of the substrate and the high-speed particle beam is returned to 0 to 5 degrees, diamond crystal growth occurs.

By alternately repeating changing the angle 0 to 0 to 5 degrees and 10 degrees or more, diamond crystals grow efficiently at room temperature.

EXAMPLE The method for forming a diamond thin film of the present invention will be explained below with reference to the drawings.

As shown in FIG.
A high-speed particle beam 10 containing hydrogen 8 and an inert gas (or carbon) 9 is irradiated onto the surface of the substrate 6 so that the angle θ with the surface of the substrate 6 is 0 to 5 degrees. The carbon of the carbon-containing particles 7 is condensed to form a thin film while impacting the surface at a shallow angle, and the angle θ between the surface of the substrate 6 and the high-speed particle beam 10 is intermittently set to 10 degrees or more to form a high-speed particle beam. 1
0 applies a larger impact to the surface of the substrate 6.

It has been confirmed that a diamond thin film can be efficiently formed at room temperature by continuously forming a film while changing the angle 0 alternately from 0 to 5 degrees and 10 degrees or more. Here, the energy of the fast particle beam 10 is 100 eV ~
The present inventors also confirmed that it is particularly effective in the range of 10,000 eV.

The above will be specifically explained based on FIG. 2. Second
The figure is a schematic diagram of an apparatus used to carry out the method of forming a diamond thin film of the present invention. In FIG. 2, reference numeral 11 denotes an ion beam sputtering device, in which hydrogen and argon are introduced into an ion source 12 through a gas inlet 13, a discharge is caused using a hot filament 14, and mixed ions, which are high-speed particle beams, are emitted from a grid 15. beam a to chamber 1
Accelerate into the interior of 6 and take it out. The mixed ion beam a
The light passes straight through the chamber 16 and is irradiated onto a graphite plate target 17 provided inside the chamber 16 and a silicon substrate 18 polished with diamond grains (1 μII).

Next, a method for forming a diamond thin film using the above apparatus will be explained. The inside of chamber 16 is connected to chamber 1.
IX by a vacuum pump (not shown) connected to 6
A mixed ion beam a with a pressure of about 10-' Torr and a pressure ratio of argon and hydrogen of 1=3 was applied to the target 17 and the substrate 18 at a voltage of about 1200eV (target 17
The density is about 0.5 mA/d).

First, irradiation is performed with the angle θ between the mixed ion beam a and the surface of the substrate 18 set to 0 degrees. Then, mixed ion beam a
The high-velocity particles collide with the target 17, and due to the impact carbon and carbon-containing particles such as hydrocarbons fly out and condense on the surface of the substrate 18 to form a diamond-like carbon film with an amorphous structure.

By irradiating the substrate 18 with the mixed ion beam a at an angle θ of 0 degrees, the diamond-like carbon film contains diamond crystal grains. However, these diamond crystal grains are surrounded by an amorphous structure and cannot grow large. After forming a film containing diamond crystal grains on the substrate 18 for 5 minutes under the above conditions,
Next, the substrate 18 is rotated so that the angle θ between the surface of the substrate 18 and the mixed ion beam a is 1 as shown by the two-dot chain line in FIG.
Mixed ion beam a was irradiated for 2 minutes at 0 degrees. During this time, the amorphous structure surrounding the diamond crystal grains was more unstable than the diamond crystal grains, so it was selectively sputtered and etched, reducing the film thickness. Next, when the angle 0 was returned to 0 degrees, diamond crystal grains grew on the substrate 18. As a result of repeating this cycle of 0 degrees and 10 degrees alternately 30 times,
Diamond crystals could be efficiently formed on the substrate 18 with a density five times higher than in the conventional case where the angle θ is not changed. Here, the mixed ion beam a has a diameter of 2.51 mm at the exit of the ion source I2, and since the mixed ion beam a has a spread, the direction of the mixed ion beam a is the direction of each of its constituent ions. The motion of each ion always has a component perpendicular to the direction of the mixed ion beam a.

Therefore, even if the angle O between the mixed ion beam a and the surface of the substrate 18 is 0 degrees, the surface of the substrate 18 is bombarded by the mixed ion beam a.

Furthermore, if the energy of the mixed ion beam a is 1000V or less, the impact given to the surface of the substrate 18 will be insufficient, and especially when the angle θ is set to 10 degrees or more, the etching will be insufficient, and the mixed ion beam a Energy of 100aV or more is required. Moreover, when the energy of the mixed ion beam a becomes 100OOe V or more, the substrate 1
The impact on the surface of the substrate 18 increases, and some particles are driven into the surface of the substrate 18, and the etching selectivity for the amorphous structure and the diamond crystal decreases, so that the diamond crystal is also etched.

Therefore, the energy of mixed ion beam a is 100e
It is preferable to take the value between V and 10,000 eV.

Furthermore, if the mixed ion beam a continues to be irradiated with the mixed ion beam a for a long time with the angle O being 10 degrees, even diamond crystal grains will be sputtered. It is better to make it shorter than the state time.

In the example, a mixed ion beam (high-speed particle beam) a of hydrogen and argon was used, but the same effect can be obtained by using an ion beam of hydrogen and another inert gas. Furthermore, if the gas introduced into the ion source 12 from the gas inlet 13 is a hydrocarbon gas such as methane, an ion beam (high-speed particle beam) containing hydrogen and carbon can be obtained, and the same effect can be obtained using this. Obtained. It was also effective even when the ion beam was neutralized to become a neutral molecular beam.

In addition, by first setting the angle 0 between the substrate 18 and the mixed ion beam a to 10 degrees or more and roughening the surface of the substrate 18 by etching, the roughened portion becomes a nucleus for diamond formation, and the diamond crystal formation density is increases. It was effective whether the angle θ was initially 0 to 5 degrees or 10 degrees or more.

In addition, sputtered particles from the target 17 were used as carbon-containing particles forming the film, but examples include thermally evaporated carbon, hydrocarbon-decomposed carbon, and ionized and accelerated carbon-containing particles (for example, CH It was also effective for hydrocarbons such as , etc.

Effects of the Invention As described above, according to the present invention, carbon is supplied to the surface of a substrate, and the surface of the substrate is irradiated with a high-speed particle beam while changing the angle formed between the high-speed particle beam and the surface of the substrate. As a result, a diamond thin film can be formed with high efficiency on the surface of a substrate at room temperature, and its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the basic configuration of the method for forming a diamond thin film of the present invention, FIG. 2 is a schematic diagram of an apparatus used to carry out the method for forming a diamond thin film of the present invention, and FIG. 1 is a schematic configuration diagram of an apparatus used to carry out a method for forming a thin film. 6... Substrate, 7... Particles containing carbon, 10...
High-speed particle beam. Agent Yoshihiro Morimoto Figure 1 6 - Board Figure 2

Claims (1)

[Claims] 1. While irradiating the surface of the substrate with a high-speed particle beam, carbon is supplied to the surface of the substrate to condense carbon on the surface of the substrate, and during this condensation, the surface of the substrate is A method of forming a diamond thin film that forms a thin film by changing the angle between the diamond and the high-speed particle beam. 2. The substrate is irradiated with a high-speed particle beam such that the angle between the substrate and the high-speed particle beam is 0 to 5 degrees, and the high-speed particles impact the surface of the substrate at a shallow angle while discharging carbon. forming a thin film by condensing on the substrate, and intermittently setting an angle between the surface of the substrate and the high-speed particle beam of 10 degrees or more, which is larger than when the angle is 0 to 5 degrees on the surface of the substrate. The method for forming a diamond thin film according to claim 1, wherein the film is formed continuously by applying an impact. 3. The method for forming a diamond thin film according to claim 1, wherein the high-speed particle beam irradiated onto the substrate contains hydrogen and an inert gas or hydrogen and carbon. 4. The method for forming a diamond thin film according to claim 3, in which the energy of the high-speed particle beam containing hydrogen and inert gas or hydrogen and carbon is irradiated onto the surface of the substrate on which carbon is to be condensed, from 100 eV to 10,000 eV. . 5. A claim in which the time during which the angle between the surface of the substrate and the high-speed particle beam is maintained at 0 to 5 degrees is longer than the time during which the angle is maintained at 10 degrees or more. The method for forming a diamond thin film according to item 2.