JPH03130361A - Formation of compound film - Google Patents

Abstract

PURPOSE:To stably form the compd. film of a stoichiometric compsn. on a substrate surface by making gaseous reactive raw materials and the sputtered particles from a target incident to the substrate surface at the time of forming the thin film of the compd. on the substrate surface by a reactive ion beam sputtering method. CONSTITUTION:A holder 2 mounted with the substrate 3 consisting of a sintered body of SiC, etc., is disposed in a film forming chamber 1 and the target 4 consisting of Cr alone is disposed apart a high frequency coil 11 therein. The inside of the film forming chamber 1 is evacuated to a high vacuum and the gaseous Ar is supplied form a gas cylinder 7a to an ion source 6 and is accelerated as Ar ions by an accelerating electrode 5 to sputter the Cr target 4. The substrate 3 is irradiated with the sputtered particles of the Cr. The N2 of the reactive gas is supplied from a cylinder 7b into the film forming chamber 1 by a nozzle 8 and high frequency electric power is supplied from a power source 9 to the high frequency coil 11 to form the plasma near the substrate 3. The gaseous N2 is brought into reaction with the sputtered particles of the Cr by this plasma, by which the compd. film of CrN having the stoichiometric compsn. on the substrate 3 is stably formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has an ion source outside a film forming chamber, and an ion beam is drawn from there into the film forming chamber by an accelerating electrode to irradiate a target. The present invention relates to a method for forming a compound film by a reactive ion beam sputtering method in which a reactive gas containing constituent elements of the film is introduced into a film forming chamber to deposit the compound film on a substrate.

[Prior Art 1] In the ion beam sputtering method, since the ion source is provided outside the film forming chamber, sputtering can be performed at low pressure to form a film. Since the sputtered particles are not scattered before reaching the substrate from the target, they enter the substrate with high energy, and the film has the advantage of having high adhesion. Further, a compound film can be formed by introducing a reaction gas containing the constituent elements of the film into the film forming chamber.

However, there is a problem in that simply introducing a reactive gas results in poor reactivity, making it impossible to obtain a compound film with a stoichiometric composition. Furthermore, if a large amount of reactive gas is introduced to increase reactivity, sputtered particles will be scattered, making it impossible to take advantage of the advantage of ion beam sputtering in which high-energy particles are incident on the substrate.

Therefore, in order to further improve reactivity while taking advantage of the advantages of conventional ion beam sputtering methods, we have developed
Vol. 55 p. 119.1986 describes a method in which an ion source for ionizing a reactive gas is provided in addition to the ion source used for sputtering, and an ion beam is extracted from this ion source to irradiate the substrate on which a film is to be deposited. Disclosed. Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 124561/1982, although it is a single ion beam, there is also a method in which the ion beam contains a reactive gas and the substrate is placed at a position where the ion beam is irradiated. Proposed.

[Problems to be Solved by the Invention] However, in both conventional reactive ion beam sputtering methods, the substrate is irradiated with a reactive gas in the form of an ion beam in order to improve reactivity. In the case of a body, there is a problem in that the substrate cannot be continuously irradiated with an ion beam due to charge-up in which the electric charge of the ions is accumulated. That is, in the conventional method, it is difficult to form a compound film having a stoichiometric composition on an insulating substrate.

The present invention has been made in view of such conventional problems, and while taking advantage of the ion beam sputtering method in which the film has high adhesion, it is also possible to form a compound film with a stoichiometric composition on an insulating substrate. An object of the present invention is to provide a method for forming a compound film that can form a compound film.

[Means for Solving the Problems] In order to solve the above objects, the present invention provides a method for forming a compound film by reactive ion beam sputtering at a total pressure of I x 10-' to l x 10-'' Torr. In an atmosphere, plasma was formed near the substrate by high-frequency discharge with input power of 10 to 50 W at the same time as sputtering.

In the present invention, the total pressure is
The reason for setting the value to be orr is that if the vacuum is higher than I X 10 Torr, no discharge will occur in the discharge chamber of the ion source, making it impossible to extract the ion beam. "If the pressure is higher than Torr, the sputtered particles will scatter and enter the substrate, making it impossible to maintain high energy. In other words, the mean free path of the sputtered particles in vacuum is
Under a vacuum higher than O-3 Torr, it is about 5 Cffi or more, and the distance between the substrate and the target is usually about that extent.

Therefore, in this case, more than half of the sputtered particles are incident on the substrate without being scattered even once, and high energy can be maintained.

In addition, the reason why the power input to the high frequency coil is set to 10 to 50 W is because if it is less than LOW, a stable plasma cannot be formed because continuous discharge does not occur, whereas if it exceeds 50 W, the ion source will not work. This is because it will not work properly. That is, the ions in the plasma have higher energy as the input power increases, but on the other hand, the plasma region expands and extends into the ion source, causing the ion source to malfunction.

[Function] According to the method for forming a compound film having the above configuration, particles sputtered by an ion beam enter the substrate with high energy. On the other hand, the reactive gas is ionized in the plasma and enters the substrate. On the substrate, since the ions of the reactive gas are very active, the reaction with the sputtered particles is promoted, and a compound film having a stoichiometric composition is formed. Even if the substrate is an insulator, since the discharge is a high-frequency discharge, the highly mobile electrons cancel out the charge accumulated on the substrate. Therefore, ions continue to be incident on the substrate, forming a compound film.

[Example] (First Example) Fig. 1 shows a sputtering apparatus used in this example, in which a substrate holder 2 is fixedly installed in the upper part of a film forming chamber 1, and this substrate A substrate 3 is attached to the holder 2. Further, a target 4 is disposed obliquely at a position facing the substrate 3. On the other hand, deposition chamber 1
An ion source 6 equipped with an accelerating electrode 5 is provided on the side wall of the ion source 6 . The ion source 6 is connected to the gas cylinder 7a, generates ions, and extracts them into the film forming chamber 1 as an ion beam using the accelerating electrode 5, and irradiates the target 4 to perform sputtering. Further, a gas introduction nozzle 8 is connected to the gas cylinder 7b, so that a reaction gas containing elements constituting a desired compound film can be introduced into the film forming chamber 1.

Furthermore, a high frequency power source 9 is provided outside the film forming chamber 1, and a high frequency coil 11 is connected to this high frequency power source 9 via a matching box 10. The tip of the high frequency coil 11 is provided so as to be located near the substrate 3.

In this example, CrN
A film was formed on an SiC sintered body serving as an insulating substrate 3.

That is, Cr alone was used as the target 4, Ar was introduced into the ion source 6 to a level of 2.0 x 10-' Torr, and an ion beam was extracted. Further, N2 was used as a reaction gas so that the total pressure inside the film forming chamber 1 was 1. OXl0-'Torr
It was introduced so that SOW power was applied to the high frequency coil 11 to cause discharge, and plasma was formed near the substrate 3. The ion beam irradiates the target 4 with an accelerating voltage lK'/, and the sputtered particles are transferred from the plasma to the substrate 3.
A CrN film was formed by reacting with the N+ ions incident on the sample.

FIG. 2 shows an X-ray diffraction pattern of the film thus formed, and the formation of CrN was confirmed.

Furthermore, as a result of measuring the adhesion strength by a scratch test, the film formed in this example showed a high value of 1.5 GPa or more.

(Second Example) In this example, an Al2N film was formed on glass, which is an insulating substrate 3, using a sputtering apparatus having the configuration shown in FIG.

That is, Aj2 alone is used as the target 4, and the ion source 6
2. The ion beam was introduced to OX 10-'Torr and extracted. In addition, N H as a reaction gas
s when the total pressure inside the film forming chamber 1 is 8. OXl0-'To
It was introduced so that rr. 50 for the high frequency coil 11
Power of W was applied to cause discharge, and plasma was formed in the vicinity of the substrate J. The ion beam irradiated the target 4 with an accelerating voltage of 1 Kv, and the sputtered particles reacted with ions containing N that entered the substrate 3 from the plasma, forming an Al2N film.

FIG. 3 shows an X-ray diffraction pattern of the film thus formed, and the formation of AffN was confirmed.

Furthermore, the film formed in this example showed a high value of 1.9 GPa as a result of measuring the adhesion strength by a scratch test.

(Third Example) In this example, a Cr5C* film was formed on a SiC sintered body, which is an insulating substrate 3, using a sputtering apparatus having the configuration shown in FIG.

In other words, the target 4 is Cr alone, and the ion source 6 is 1.5% Ar. The ion beam was introduced to OX 10-'Torr and extracted. Further, CH4 is used as a reaction gas so that the total pressure inside the film forming chamber 1 is 1. OXl0-”Torr
It was introduced so that A power of 50 W was applied to the high frequency coil 11 to cause it to discharge, thereby forming plasma near the substrate 3. The ion beam is aimed at target 4 with an accelerating voltage of IKV.
The sputtered particles reacted with C-containing ions incident on the substrate 3 from the plasma, forming a CrxCz film.

The film thus obtained was evaluated in the same manner as in Example 1.2, and it was confirmed that CrxCz was produced and that the film had high adhesion.

[Effects of the Invention] As described above, according to the method for forming a compound film of the present invention,
Because we decided to form plasma near the substrate by high-frequency discharge with an input power of 10 to 50 W at the same time as sputtering in an atmosphere with a total pressure of I x 10-' to I x 10-' Torr, the film had high adhesion. While taking advantage of the advantages of the ion beam sputtering method, it is possible to form a compound film with a stoichiometric composition even on an insulating substrate.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the sputtering apparatus used in each example of the present invention, and Figures 2 and 3 are X-ray diffraction diagrams of compound films obtained in the first and second examples of the present invention, respectively. It is a chart showing the results. l... Film formation chamber 3... Substrate 4... Target 6... Ion source 9... High frequency power supply 1 1... High frequency coil

Claims (1)

[Claims] (1) When forming a compound film by reactive ion beam sputtering, the total pressure is 1 x 10^-^4 to 1 x 10^
- A method for forming a compound film characterized by forming plasma in the vicinity of a substrate by high-frequency discharge with an input power of 10 to 50 W at the same time as sputtering in an atmosphere of 3 Torr.