JPH0154430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vapor deposition method using an activated nozzle, which is advantageously used to form compound films, single films, and the like.

[Conventional technology]

Conventionally, compound films such as carbides and nitrides, or SiC
Activated reactive deposition methods are used to form films and the like. This activated reactive vapor deposition method is a method in which a reaction gas is ionized to perform compound vapor deposition in order to increase reaction efficiency. Conventional examples thereof include JP-A-48-60088 and JP-A-49-52186. Examples include those described in Japanese Patent Publication No. 57-2271 and Japanese Patent Publication No. 58-41351.

For example, JP-A No. 49-52186 discloses that a carbide coating is formed by reactively depositing activated metal vapor and hydrocarbon gas atoms in the vapor phase in the space between the substrate and the metal source. A source metal is heated by an electron beam and vaporized in a vacuum chamber, providing metal vapor electrons to a reaction zone. Then, a hydrocarbon gas is introduced into the reaction zone, and some electrons of the metal heating electron beam are deflected into the reaction zone by a low voltage electric field from a deflection electrode provided in the reaction zone, and the atoms of the metal vapor and gas are heated. is activating. Activation of the reactants increases the probability of reaction, allowing the reaction between metal vapor and hydrocarbon gas to occur with high efficiency.

Furthermore, the above-mentioned Japanese Patent Publication No. 58-41351 describes an activated reaction vapor deposition method for forming a nitride film of metal carbide on a substrate, and in this case, a hollow hot cathode type electron gun is used. An electron gun is used to control the temperature of the substrate and the pressure of the reaction gas to obtain a stoichiometrically stable coating with high efficiency.

Furthermore, Japanese Patent Publication No. 57-2271 describes an activated reaction vapor deposition apparatus for forming a metal carbide or nitride film on a substrate, and in this case, separate atmospheric gas and reactive gas are used. In order to avoid the complexity of supply control, the reaction gas is introduced into the processing chamber via a hollow hot cathode type electron gun.

[Problem that the invention seeks to solve]

This method of using plasma to activate evaporated substances and reaction gases in order to accelerate the reaction to form a compound film has little effect unless it is carried out under conditions that increase the plasma density. The gas pressure in the reaction system is a high value (5×
10 ^-1 Pa or higher). If vapor deposition is performed in this state, scattering by gas molecules and atoms will increase, resulting in a decrease in film quality and a decrease in deposition rate. Furthermore, with the conventional methods described above, it is very difficult to obtain a stoichiometric composition ratio for films of compounds that are difficult to react with, such as boron nitride and silicon nitride.

Therefore, an object of the present invention is to provide a vapor deposition method using an activated nozzle that can form a high-density plasma state at low pressure and form a high-quality film at high speed.

[Means for solving problems]

In order to achieve the above object, a vapor deposition method using an activated nozzle according to the present invention uses a high-voltage electron beam,
Introducing a gas that activates thermoelectrons emitted from an evaporation source and a hot cathode using laser, resistance heating, high-frequency heating, etc. to heat and evaporate the evaporated substance by applying a positive DC or AC voltage. A discharge is caused at the tip of the activation nozzle to ionize and excite the gas introduced through the activation nozzle and the evaporated substance from the evaporation source,
The method is characterized in that a negative direct current or high frequency voltage is applied to the object to be vapor-deposited, and ions generated by discharge are drawn into the object to efficiently carry out a reaction.

[Effect]

In the method of the present invention configured as described above,
The required material is stably evaporated by an evaporation source that heats and evaporates the evaporation substance using a high-pressure electron beam, laser, resistance heating, high-frequency heat, etc., and the film to be formed is generated from the activation nozzle. A suitable discharge substrate gas is introduced along with the necessary reactive gases. Further, thermoelectrons are emitted from the hot cathode by direct current application or indirect heating. By applying a positive DC or AC voltage to the activation nozzle, thermionic electrons emitted from the hot cathode and evaporation source are drawn into the activation nozzle, and the vicinity of the tip of the activation nozzle creates pressure (molecules/atomic Since the plasma density is high, a high-density plasma can be generated near the tip of the activation nozzle without increasing the pressure of the entire system. Therefore, the frequency with which the ON species and excited species generated in the plasma are scattered by neutral gas species, etc., decreases, and at the same time, due to the direct current negative or high frequency voltage bias applied to the workpiece to be vapor-deposited, Ions from the density plasma efficiently enter the object to be vapor-deposited. This allows ionic or excited species to react with the evaporated material to form the desired film.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows an example of a reactive vapor deposition apparatus implementing the method according to the present invention, in which numeral 1 is a vacuum vessel, and an evaporation source 2 containing an evaporative substance is arranged in the vacuum vessel 1. The evaporation source 2 is configured to heat and evaporate the evaporation substance using a high-pressure electron beam, laser, resistance heating, high frequency heating, etc. The heating means is configured to heat and evaporate the evaporation substance depending on the substance to be evaporated and other conditions. can be selected appropriately. At a position facing the evaporation source 2, there is a substrate 3 which is a workpiece to be vapor-deposited.
is located. Also shown in the vacuum container 1 are a hot cathode 4, an activation nozzle 5, and a substrate heating heater 6, and the hot cathode 4 is connected to a DC or AC power source 7.
The activation nozzle 5 is connected to a DC or AC power source 8 for applying a DC positive or AC voltage, and the substrate 3 is connected to a high frequency power source 9 or a DC power source 9' for applying a DC negative or high frequency voltage. be done.

A case will be described in which a boron nitride film is formed using the illustrated apparatus configured as described above.

A high-pressure electron beam evaporation source was used as the evaporation source 2 to evaporate boron, and nitrogen was introduced from the activation nozzle 5 to form a boron nitride film on the substrate 3.
In this case, other film forming conditions are as follows.

Nitrogen partial pressure...0.1Pa Activation nozzle voltage/current...0V to 70V, 0A to 5A Electron beam power...1.5KW Substrate bias voltage...-100V Substrate temperature...300℃ Activation nozzle 5 FIG. 2 shows the change in film composition when the discharge current is changed. As is clear from Fig. 2, when no current flows through the activation nozzle 5, that is, when normal field evaporation is performed, the composition ratio (N/B) is about 0.03; As the current of the activation nozzle 5 is increased, the composition ratio increases and a stoichiometric composition (N/B=1) is obtained. In this case, the composition was determined using an X-ray microanalyzer.

In the illustrated embodiment, whether the bias applied to the object to be vapor-deposited is a negative DC voltage or a high-frequency voltage can be appropriately selected depending on the substance to be deposited.

〔Effect of the invention〕

As explained above, according to the method of the present invention, heat is emitted from the evaporation source and the hot cathode, which heat and evaporate the evaporation substance using a high-voltage electron beam, laser, resistance heating, high-frequency heating, etc. Electrons are drawn into the gas outlet of an activation nozzle for gas introduction which has an activation effect by applying a direct current or alternating current voltage, causing a discharge at the tip of the activation nozzle, and passing through the activation nozzle. In addition to ionizing and exciting the gas introduced by the evaporation source and the evaporated substance from the evaporation source, a negative DC or high frequency voltage is applied to the object to be vapor-deposited, and the ions generated by the discharge are drawn into the object to undergo a reaction. Because it is configured to perform efficiently,
Because the pressure at the tip of the activation nozzle is higher than that of the entire system, it is easy to obtain a high-density plasma, and the system as a whole can maintain a low pressure. The density of ion species and excited species incident on the object to be processed increases, and a high-quality film can be formed over a large area. Therefore, by applying the method of the present invention,
A stoichiometric composition can be easily obtained even when forming a film of a compound that is difficult to react with, such as boron nitride or silicon nitride.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a reactive vapor deposition apparatus implementing the method of the present invention, and Fig. 2 shows the composition of silicon nitride films formed using the apparatus shown in Fig. 1 under various film formation conditions. This is a graph showing. In the figure, 1: vacuum container, 2: evaporation source, 3: substrate,
4: hot cathode, 5: activation nozzle, 6: heater for heating the substrate, 7: DC or AC power supply, 8: DC or AC power supply, 9: high frequency power supply, 9': DC power supply.

Claims (1)

[Claims] 1. Thermionic electrons emitted from the evaporation source and hot cathode are heated and evaporated by using high-voltage electron beams, lasers, resistance heating, high-frequency heating, etc., and are activated by applying a positive DC or AC voltage. ionizes the gas introduced through the activation nozzle and the evaporated substance from the evaporation source by causing a discharge at the tip of the activation nozzle, which has a An activation nozzle characterized by applying a negative direct current or high frequency voltage to the object to be vapor-deposited to draw ions generated by discharge into the object to efficiently carry out a reaction. Vapor deposition method using