JPH03260061A - Formation of boron nitride thin film-coated substrate - Google Patents

Abstract

PURPOSE:To form a thin film of C-BN or W-BN at low temp. without being affected by a substrate by forming a BN thin film on the substrate surface through an intermediate layer of a specified element. CONSTITUTION:A thin film 12 of the cubic sphalerite-type boron nitride C-BN having extremely high hardness and thermal and chemical stability or the hexagonal wurtzite-type boron nitride W-BN having excellent chemical stability and resistance to thermal shock and wear is formed on the surface of a substrate 1 of high-speed steel, etc. In this case, the substrate 1 is supported by a holder 2, Si, for example, among groups 3a, 4a and 4b elements as the vaporization source 10 is vapor-deposited from a vaporization source 4 opposite to the substrate on the substrate 1 surface by an electron beam, etc., and the surface is irradiated by N ion 5' from an ion source 5 to form an Si-contg. intermediate layer 11 on the substrate 1. A B-based vaporization material 9 in a vaporization source 3 is vaporized by an ion beam and deposited on the intermediate layer 11, and the substrate is irradiated by N ion from the vaporization source 5. As a result, the thin film 12 of C-BN or W-BN is deposited with high adhesion without damaging the material of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for forming a substrate coated with a boron nitride thin film.

[Conventional technology]

Depending on its crystal structure, boron nitride (hereinafter referred to as "rBN") has three types: cubic zinc blende type (hereinafter referred to as rc-BNJ), hexagonal graphite type (hereinafter referred to as 'h-BNJ).
That's what it means. ) and hexagonal wurtzite type (rw-BN
It's called J. ) are broadly classified into three types.

Among these, c-BN has a hardness second only to diamond and excellent thermal and chemical stability, so it is used in tools that require wear resistance, and it also has insulation and high heat resistance. It is also expected to be applied to heat sink materials that require conductivity. Also, w-BN is also
- Like BN, it has excellent chemical stability, thermal shock resistance, and high hardness, so it is applied to fields that require wear resistance.

Currently, methods of forming thin films mainly composed of c-BN and w-BN using physical vapor deposition (CVD) or chemical vapor deposition (PVD) are being actively researched.

For example, in the CVD method, a substrate on which a film is to be formed is stored in a reaction chamber, and a gas containing a boron element such as diborane (B, H, Introducing a gas containing nitrogen element,
This method forms a boron nitride thin film on a substrate by thermally decomposing and reacting this raw material gas on a substrate heated to a high temperature of about 1000'C.

However, this CVD method has a problem in that the types of substrates on which a boron nitride thin film can be formed are limited. In other words, in the CVD method, it is necessary to heat the substrate to a high temperature of about 1000'C, but since high-speed steel, for example, has the property of deteriorating at a temperature of about 600'C, the above-mentioned CVD method It is not possible to form boron nitride thin films on high speed steel.

Furthermore, the boron nitride thin film formed by the CVD method tends to be a soft h-BN-based film, and the excellent properties of c-BN and w-BN are not fully utilized.

In addition, PVD methods include reactive sputtering methods that form a boron nitride thin film on a substrate by sputtering a target composed of boron atoms in a nitrogen atmosphere, but this method also uses soft h-BN. Only the main film can be obtained.

As described above, it is difficult to make thin films of c-BN and w-BN, and at present, they are limited to those that can be synthesized artificially at high temperatures and pressures, resulting in high manufacturing costs. Moreover, since it can only be synthesized in powder or granular form, its scope of application is currently limited. It is clear that if c-BN and w-BN can be formed into thin films at low temperatures, the range of their applications will be further expanded.

Therefore, in recent years, high temperature has been developed using ions and plasma.

Attempts to form phases that are stable under high pressure and at low temperatures are becoming more active.

For example, Jikai No. 60-63372 discloses a method of forming a boron nitride thin film on a substrate by irradiating nitrogen ions simultaneously or alternately with vacuum evaporation of boron.

According to this method, c-
BN and w-BN can be synthesized, and the ions and vapor deposited atoms are injected into the inside of the substrate due to the collision and counteraction between the irradiating ions and the vapor deposited atoms, and the nitride formed on the substrate and the nitride formed on the substrate By forming a new mixed layer at the interface with the boron thin film, the adhesion between the substrate and the boron nitride thin film can be improved.

[Problem to be solved by the invention]

However, c-BN and w-BN have a property that they have particularly poor wettability with metals, and therefore, when metals are used as substrates, it is said that it is not possible to obtain adhesion that can withstand sufficiently for practical use. There was a problem.

Furthermore, when a substrate coated with a boron nitride thin film by the above method is exposed to high temperatures, the film tends to peel off due to the difference in thermal expansion coefficient between the substrate and the boron nitride thin film.
Further, due to this difference in coefficient of thermal expansion, internal stress generated within the film acts to promote peeling of the film. Also, due to the difference in lattice constant between the substrate and the boron nitride thin film, c-BN and w-B
There are problems in that the growth of N is hindered or the internal stress within the film increases, making the film more likely to peel off.

In view of the above problems, an object of the present invention is to form c-BN and w-BN on a substrate at low temperature without being affected by the substrate.
Boron nitride which can form the main boron nitride film
The present invention provides a method for manufacturing an il film-coated substrate.

[Means to solve the problem]

The method for forming a substrate coated with a boron nitride thin film according to claim (1) provides a method for forming a substrate coated with a boron nitride thin film.
Simultaneously or alternately with vacuum deposition of a substance containing at least one of group B elements, or after deposition, ions containing at least one of inert gas ions and nitrogen ions are accelerated at an energy range of 1 keV or more and 40 keV or less. to form a thin film containing at least one of group IIIb, group IVa, and group IVb elements, and on this thin film, nitrogen is irradiated simultaneously or alternately with the vacuum deposition of a substance containing boron. A boron nitride thin film is formed by irradiating ions containing at least ions at an acceleration energy of 40 keV or less, and the ratio of the number of particles of boron atoms to nitrogen atoms contained in this boron nitride thin film is in the range of 1 or more and 60 or less. The method for forming a substrate coated with a boron nitride thin film according to claim (2) is characterized in that, in the method for forming a substrate coated with a boron nitride thin film according to claim (1), irradiation is performed during formation of the boron nitride thin film. When the acceleration energy of the ions is less than 2 keV, the ratio of the number of particles of boron atoms to nitrogen atoms contained in the boron nitride thin film is 1 or more.
6 or less, and the acceleration energy of the ions irradiated when forming the boron nitride thin film is 2 keV or more.
In the case of less than 5 keV, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is constant in the range of 1 or more and 10 or less, and the acceleration energy of the ions irradiated when forming the boron nitride thin film is is 5 keV or more, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is kept constant in the range of 1 or more and 20 or less.

The method for forming a substrate coated with a thin boron nitride film according to claim (3) is the method for forming a substrate coated with a thin boron nitride film according to claim (1), in which: Rather, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is determined by comparing the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film to the thin film containing at least one of the group IIIb, group IVa, and group IVb elements. At the interface, the number of particles is in the range of 4 or more and 60 or less, and on the surface of the boron nitride thin film, the ratio of the number of particles between boron atoms and nitrogen atoms contained in the boron nitride thin film is in the range of 1 or more and 10 or less. In the boron thin film, the ratio of the number of particles of boron atoms to nitrogen atoms is decreased continuously or stepwise in the direction of the surface.

FIG. 1 is a conceptual diagram showing an example of a thin film forming apparatus used in the method of forming a boron nitride thin film coated substrate of the present invention.

As shown in FIG. 1, a substrate 1 on which a film is to be formed is held in a substrate holder 2. As shown in FIG. At a position facing the base 1, there is a power source 3.
．． An evaporation source 4 and an ion source 5 are arranged. Further, near the substrate 1, a film thickness meter 6 and an ion current measuring device 7 are arranged.

Note that the base 1, the base holder 2. Flower origin 3. Evaporation source 4, ion #5. The film thickness meter 6 and the ion current measuring device 7 are housed in a vacuum device (not shown).

Evaporation s3.4 is the evaporation substance 9. - 10 is evaporated by, for example, an electron beam, a laser beam, a high frequency wave, etc., and is not particularly limited.

Further, the ion source 5 is, for example, a Karasman type or a bucket type using a Kaps magnetic field for plasma confinement, and is not particularly limited.

Further, the film thickness gauge 6 indicates the evaporated material 9.10 that is deposited on the substrate 1.
The film thickness and number of particles are measured using, for example, a vibrating film thickness meter using a crystal oscillator.

The ion current measuring device 7 measures the number of ions irradiated onto the substrate 1, and has a cup-shaped structure such as a Faraday cup having a secondary electron suppressing electrode.

Further, the evaporation substance 9 evaporated by the evaporation fi3 is a substance containing the element boron, such as elemental boron, boron oxide, or boron nitride.

Further, the evaporation substance 10 evaporated from the evaporation source 4 is
A substance containing at least one of group b, group rVa, and group IVb elements, for example, each element,
These include oxides, nitrides, mixtures thereof, alloys, etc. Further, as group IIIb elements, for example, B, AP
Examples of group IVa elements include Ti and Zr, and examples of group IVb elements include Si.

The ions 5' are, for example, nitrogen ions, nitrogen ions and inert gas ions, or ion species consisting of nitrogen ions, inert gas, and hydrogen ions.

Using such a thin film forming apparatus, as shown in FIG. A boron nitride thin film 12 is formed on the intermediate layer 11.

Further, at the interface between the base body 1 and the intermediate layer 11, the base body 1 and the intermediate layer F
At the interface between the intermediate layer 11 and the boron nitride thin film 12, the intermediate layer 11 and the boron nitride W! A mixed layer 14 consisting of constituent atoms of i12 is formed.

The method of forming intermediate layer 11 and boron nitride thin film 12 will be explained below.

Using the thin film forming apparatus shown in Figure 1, the inside of the vacuum apparatus is lXl.
0-' (Torr) or less, on the substrate 1 simultaneously or alternately with the deposition of an evaporation substance IO containing at least one of Group IIIb, Group IVa, and Group IVb elements by the evaporation source 4. After vapor deposition, the ion source 5 irradiates ions containing at least one of inert gas ions and nitrogen ions at an acceleration energy of 1 keV or more to 40 keV to form a film with a thickness of 10 to 5,000 keV.
A middle class 11 of people is formed.

At this time, the constituent atoms of the substrate 1 are formed at the interface between the substrate 1 and the intermediate layer 11 by collisions and counterattacks between the irradiated ions and the vapor-deposited atoms, causing the ions and the deposited atoms to enter the inside of the substrate 1. and the constituent atoms of the intermediate layer 11.
is formed.

However, when boron alone, which is a group IIIb element, is used as the evaporative substance 10, only inert gas ions are irradiated with ions t1.5.

By forming this intermediate layer 11, the atoms constituting the base 1 and the boron nitride thin film 12 that will be formed later on the surface of the intermediate layer 11 are removed.
It is possible to prevent deterioration of the adhesion between the substrate 1 and the boron nitride thin film 12 due to the difference in thermal expansion coefficient and lattice constant between the c-BN and the boron nitride thin film 12 when forming the boron nitride thin film 12.

Obstacles to the growth of w-BN can be eliminated. Furthermore, at the interface between the base body 1 and the intermediate layer 11, a γ-combined layer 1 is formed.
3, the adhesion between the base 1 and the intermediate layer 11 can be improved.

Note that the thickness of the intermediate layer 11 is preferably in the range of 10 to 5,000. If you deviate from this range and become thinner than 10 people,
If the effect of the intermediate layer 11 described above does not clearly appear and the thickness exceeds 5,000, when the substrate 1 is exposed to high temperatures, the heat between the intermediate layer 11 and the boron nitride thin film 12 that will be formed on the intermediate layer 11 later will be reduced. The difference in conductivity creates a thermal gradient within the membrane,
The film will peel off easily.

Further, the acceleration energy of ions including one of inert gas ions and nitrogen ions irradiated onto the substrate 1 by the ion source 5 is preferably in the range of 1 keV or more and 40 keV or less. If it deviates from this range and becomes smaller than 1 keV, the formation of the mixed layer 13 at the interface between the substrate 1 and the intermediate layer 11 will be insufficient, and if it becomes larger than 40 keV, a large number of defects will occur in the intermediate layer 11. Become.

Next, ions containing at least nitrogen ions are irradiated onto the intermediate layer 11 by the ion source 5 at an acceleration energy of 40 keV or less, simultaneously or alternately with the evaporation material 7 containing boron, by evaporation 2114, A boron nitride thin film 12 is formed.

At this time, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film 12 to be formed (rB/N!u
(referred to as "tc ratio") is in the range of 1 or more and 60 or less.

This B/Ntlltc ratio may be constant throughout the boron nitride thin film 12 or within the boron nitride thin film 12.
The B/N composition ratio may be decreased from the substrate 1 toward the surface (that is, the boron atomic density in the boron nitride thin film 12 is decreased stepwise or continuously from the substrate 1 toward the surface).

When the B/N ratio is determined for the entire boron nitride thin film 12, if the acceleration energy of the ions irradiated during the formation of the boron nitride thin film 12 is less than 2 keV, the B/N ratio will be between 6 and below. Similarly, acceleration energy −2
At keV or higher to 5 keV, it is preferable to keep the B/N&lI power ratio constant in the range of 1 or higher and 10 or lower, and at acceleration energy of -5 keV or higher, it is preferable to keep the B/N pair ratio constant in the range of 1 or higher and 20 or lower. .

Outside this range, the c-BN or w-BN content on the surface of the boron nitride thin film 12 decreases, and the c-B
This may have an adverse effect on the excellent properties of N and w-BN, such as high hardness and chemical stability.

In addition, when decreasing the B/N composition ratio in the boron nitride thin film 12 stepwise or continuously, the surface of the boron nitride thin film 12 should have a B/N & u composition ratio in the range of 1 acid ratio to 10 or less, and the intermediate layer 11 and the boron nitride thin film 12, B/
It is preferable that the Nu composition ratio is in the range from the acid ratio to 60 or less.

If the B/N&[l acid ratio on the surface of the boron nitride fj1 film 12 deviates from the range of 1 or more and 10 or less, c-
The content of BN or w-BN decreases, and this c-B
The excellent properties of N and w-BN, such as high hardness and chemical stability, are adversely affected, and the B/N ratio at the interface between the intermediate layer 11 and the boron nitride thin film 12 ranges from more than 60 to less than 60. Outside the range, the effect of the intermediate layer 11 to alleviate the difference in thermal expansion coefficient and lattice constant between the boron nitride thin film 12 and the substrate 1 will be insufficient.

In this way, the method for forming the boron nitride thin film 12 in which the B/Nl ratio is decreased stepwise or continuously from the substrate 1 toward the surface is as follows: By controlling the number of particles of atoms and nitrogen atoms, the B/N composition ratio at the interface between the intermediate Jifll and the boron nitride thin film 12 is set in the range of 4 or more and 60 or less, and the B/N composition ratio of the boron nitride thin film 12 to be deposited thereafter is controlled. The number of boron atoms and nitrogen atoms that reach the film is controlled so as to reduce the ratio of B/N and nitrogen atoms, and the final B/N composition ratio near the surface of the boron nitride thin film 12 is 1 or more. It should be within the range of 10 or less.

Further, the acceleration energy of the ions irradiated at this time may be constant or may be changed at any time. For example, in order to improve the adhesion with the substrate 1, a relatively high acceleration energy is applied near the surface of the substrate 1. After forming a boron nitride thin film with a certain thickness by irradiating ions in the range of -2 kev or more to 40 keV or less, irradiation is performed near the surface of the film in order to form a boron nitride thin film with few internal defects. The acceleration energy of the ions may be lowered to 2 keV or less.

Note that the base 1 can be made of any material such as various metals, ceramics, glass, or substances made of polymers.

[Effect]

According to the configuration of the present invention, the thin film containing at least one of Group IIIb, Group IVa, and Group IVb formed between the substrate and the boron nitride thin film allows the thin film to be bonded between the substrate and the boron nitride thin film. Deterioration of the adhesion of boron nitride thin films caused by differences in thermal expansion coefficients and lattice constants of c-BN and w-BN during formation of boron nitride thin films.
(D. Obstacles to growth can be eliminated.

[Example] Using the thin film forming apparatus shown in FIG.
Above, the evaporated substance 10 is evaporated by the evaporation of the electron beam
At the same time as the vapor deposition of silicon atoms (Si) having a purity of 99.999% as a simple substance of group IVb element, nitrogen gas is introduced into the ion source 5 to irradiate nitrogen ions with an acceleration energy of 2 keV, thereby forming an intermediate layer. 11 was formed. Further, the number of particles of Si atoms and nitrogen atoms reaching the substrate 1 was controlled so that the ratio of the number of particles of Si atoms and nitrogen atoms in the intermediate JITll (Si/N ratio) was achieved.

Further, the thickness of this middle class 11 was set to 500 people.

Next, the surface of this intermediate layer 11 is coated with purity 9.
Simultaneously with the vapor deposition of 9.7% boron atoms (B), nitrogen gas was introduced into the ion source 5, and nitrogen ions were irradiated with an acceleration energy of 2 keV to form a boron nitride thin film 12. Further, the ratio of the number of particles of boron atoms to nitrogen atoms (B/N composition ratio) in the boron nitride thin film 12 was set to be constant 3 throughout the film.

Further, the thickness of the boron nitride thin film I2 was set to 5000 mm.

Note that the base body 1 is made of high speed steel (high speed steel: 5KHIO1).
The dimensions are 20 mm x 20 mm x 1 mm. ) was used.

Further, the evaporated material 110 during the formation of intermediate Nll in Example 1. The irradiation ion species, the acceleration energy of the irradiation ions (in the range from keV to 40keV), the &[l acid ratio of the intermediate layer, and the irradiation ion species, acceleration energy of the irradiation ions, and B during the formation of the boron nitride YT film 12.
A boron nitride thin film coated substrate was formed by changing the /N&[l acid ratio (in the range from 1 to 60) and using the same conditions and formation process as in Example 1, and from Examples 2 to 1 day. did.

Table 1 shows the conditions of Examples 2 to 18 and Example 1.

In Examples 1 to 18, the B/N&fl ratio of the formed boron nitride thin film 12 was constant within the film.

Further, in Table 1, the mixing ratio of Ar ions and nitrogen ions in Example 18 (number ratio of Ar ions/number ratio of nitrogen ions) is 30%.
It is.

a is the evaporated substance, C is the irradiated ion species, C is the composition ratio of the intermediate layer, is the acceleration energy of the irradiated ions (keV), and e is B/N.
The composition ratio f is the irradiated ion species g is the acceleration energy of the irradiated ions [k e V] (Table 1
: When the B/N ratio is constant) Next, after forming the intermediate layer 11 on the substrate 1 in the same formation process as in Example 1, when forming the boron nitride thin film 12 on this intermediate layer 11, In order to increase the hardness and adhesion of the boron nitride thin film 12, the number of nitrogen atoms and boron atoms is controlled to increase the B/N from the substrate 1 toward the surface.
The boron nitride thin film 12 is formed by reducing the &I ratio stepwise or continuously (the B/N composition ratio is not constant), and the other formation processes are the same as in Example 1, and further an intermediate layer is formed. The evaporated substance, the irradiated ion species, and the acceleration energy of the irradiated ions during the formation of No. 11, as well as the boron nitride thin Wi! , 12
B/N group weight group acid specific ionic species at the time of formation.

The acceleration energy of the irradiated ions and the B/N&ll ratio were changed to different acid ratios, and Examples 19 to 24 were used.

Table 2 shows the conditions of Examples 19 to 24.

In Table 2, in the B/N composition area ratio in the boron nitride thin film shown in item e of Table 2, the upper layer is the surface of the boron nitride 'Fji film, and the lower layer is the B/N ratio near the interface between the intermediate layer and the boron nitride thin film. Nil
Power ratio to acid ratio.

In addition, the mixing ratio of Ar ions and nitrogen ions in Example 24 (number ratio of Ar ions/number ratio of nitrogen ions) was 3.
It is 0%.

(Table 2: When the ratio of BlNMi to mono-acid is not equal to that of mono-acid)> Next, when forming the intermediate layer, the acceleration energy of the ions irradiated onto the substrate 1 is set to 1 keV or more, and ions that deviate from the range of 40 keV. A boron nitride thin film-coated substrate was formed using the same conditions and formation process as in Example 1, and the evaporation substance, irradiated ion species, and acceleration energy of the irradiated ions during the formation of the intermediate layer, as well as the nitridation Comparative Examples 1 to 5 were obtained by changing the B/NM power ratio, acid ratio ion species, acceleration energy of irradiated ions, and B/N string area ratio during formation of the boron thin film, and without forming an intermediate layer. Comparative Examples 6 to 8 were those in which a boron nitride thin film was directly formed on the substrate.

Table 3 shows the conditions of Comparative Examples 1 to 8.

In addition, in Table 3, the combined mixing ratio of Ar ions and nitrogen ions in Comparative Example 8 (number ratio of Ar ions/number ratio of nitrogen ions) is 30%.
It is.

(Margin below C) (Table 37 B/N combination acid ratio) a is the evaporated substance, irradiated ion species C is the composition of the intermediate layer d is the acceleration energy of the irradiated ion (keV) e is B/N
The ratio of the irradiated ion species g to the acid ratio is the acceleration energy (keV) of the irradiated ions. a boron nitride thin film-coated substrate is formed by changing the ratio (prevention ratio) stepwise or continuously, and departing from the scope of claim (3), with other conditions and formation process being the same as in Example 1, In addition, it is an effervescent substance during the formation of the intermediate layer.

The irradiation ion species, the acceleration energy of the irradiation ions, the B/N composition ratio during formation of the boron nitride FIM, the irradiation ion species, the acceleration energy of the irradiation ions, and the B/N composition ratio were varied, and Comparative Examples 9 to 13.15 were prepared. Comparative Example 14 was prepared in which a boron nitride thin film was directly formed on the substrate without forming an intermediate layer.

Table 4 shows the conditions of Comparative Examples 9 to 15.

In addition, in Table 4, the mixing ratio of Ar ions and nitrogen ions in Comparative Example 13 (number ratio of Ar ions/number ratio of nitrogen ions) is 30%.
It is.

(Left below) Tables 5 and 6 show the results of measuring the adhesion and hardness of the films of Examples 1 to 24 and Comparative Examples 1 to 15.

The adhesion strength is determined by using an automatic scratch/punch tester equipped with an AE sensor, applying a continuous load of 1 to 5 ON at a constant speed, and then performing a scrubbing process.The critical load is the load that causes the AE double signal to suddenly rise. The adhesion was evaluated by compressing the size of
It was determined from the size of the indentation when a diamond indenter was pressed under f load.

(Space below) (Table 4: When B/N & [l acid ratio is not constant) (Table 5) (Table 6) (Space below) In Examples 1 to 24 shown in Table 5 above, in all Examples, The value of the critical load Lc (N) is 25 or more, which means that the intermediate layer 11 of the embodiment (group IIIb group Na and group I
It can be seen that high adhesion between the substrate 1 and the boron nitride thin film 12 can be obtained by forming a thin film containing at least one type of Vb group. Also, hardness (Kg/c
+fl), values of 4000 Kg/cJ or more were obtained in all cases, and due to the formation of the intermediate layer 11, the boron nitride thin film 12 is free from the c It can be seen that the growth of -BN and w-BN is no longer hindered.

On the other hand, in Comparative Examples 1 to 5, the hardness was 4000 (Kg/c
rA, ) or more was obtained, but since the acceleration energy of the ions irradiated when forming the intermediate layer was made larger than 40 keV, the irradiation of these ions caused more defects to be generated in the intermediate layer, and as a result, It is considered that the critical load LcO value was smaller than in Examples 1 to 25, and the adhesion of the film was inferior.

Moreover, in Comparative Examples 6 to 8, the boron nitride thin film was directly formed on the substrate without forming an intermediate layer, so that
It is thought that the hardness decreased because the value of the critical load Lc decreased and the amount of c-BNN bone decreased.

Further, in Comparative Examples 9 to 13, the value of critical load Lc was 25 [N3
However, since the B/N combination ratio in the boron nitride thin film deviated from the range stated in claim (3), Example 1
It is considered that the hardness was smaller than ~25.

In addition, in Comparative Example 14, the boron nitride thin film was formed directly on the substrate without forming an intermediate layer, so the critical load Lc value and hardness value were smaller than those in Examples 1 to 24, and both adhesion and hardness were inferior. It is thought that

In Comparative Example 15, the thickness of the intermediate layer deviated from the range of 10 to 5,000 layers, so the critical load and hardness values were smaller than those of Examples 1 to 24, and both adhesion and hardness were inferior. Conceivable.

〔Effect of the invention〕

According to the configuration of the present invention, the thin film containing at least one of Group IIIb, Va, and rVb formed between the base and the boron nitride thin film allows the thin film to be formed between the base and the boron nitride thin film. It is possible to eliminate deterioration in the adhesion of a boron nitride thin film and hindrance to the growth of c-BN and w-BH during formation of a boron nitride thin film caused by differences in thermal expansion coefficients and lattice constants. As a result, a boron nitride thin film mainly composed of c-BN and w-BN can be formed at low temperatures without being affected by the substrate.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an example of a thin film forming apparatus used in the method for forming a boron nitride thin film coated substrate of the present invention, and FIG. FIG. 2 is a conceptual diagram showing an example of a membrane-coated substrate.

Claims (3)

[Claims] (1) At least one of inert gas ions and nitrogen ions is applied to the substrate simultaneously or alternately with or after the vacuum deposition of a substance containing at least one of Group IIIb, Group IVa, and Group IVb elements. A thin film containing at least one of the group IIIb, group IVa, and group IVb elements is formed by irradiating ions containing one of the elements at an acceleration energy of 1 keV or more and 40 keV or less, and on this thin film. Simultaneously or alternately with the vacuum deposition of a substance containing boron, ions containing at least nitrogen ions are irradiated at an acceleration energy of 40 keV or less to form a boron nitride thin film, and the boron atoms and nitrogen contained in this boron nitride thin film are A method for forming a substrate coated with a boron nitride thin film, characterized in that the ratio of the number of particles to atoms is in the range of 1 or more and 60 or less. (2) When the acceleration energy of the ions irradiated during the formation of the boron nitride thin film is less than 2 keV, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is set to a range of 1 to 6. and when the acceleration energy of the ions irradiated during the formation of the boron nitride thin film is 2 keV or more and less than 5 keV,
The ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is constant in the range of 1 or more and 10 or less, and the acceleration energy of the ions irradiated when forming the boron nitride thin film is 5 keV or more. In the case of (1), the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film is constant in the range of 1 or more and 20 or less.
A method of forming a boron nitride thin film coated substrate as described. (3) Regardless of the acceleration energy of ions irradiated during the formation of the boron nitride thin film, the ratio of the number of particles of boron atoms and nitrogen atoms contained in the boron nitride thin film to the boron nitride thin film and the Chapter I
At the interface with the thin film containing at least one of group IIb, group IVa, and group IVb elements, the range is from 4 to 60, and on the surface of the boron nitride thin film, the boron nitride thin film contains The ratio of the number of particles of boron atoms and nitrogen atoms contained is in the range of 1 to 10, and the ratio of the number of particles of boron atoms and nitrogen atoms is adjusted continuously or stepwise in the surface direction in the boron nitride thin film. The method for forming a substrate coated with a boron nitride thin film according to claim 1, wherein the substrate is coated with a boron nitride thin film.