JPH047033A - Active molecule producing apparatus - Google Patents

Abstract

PURPOSE:To produce active molecules efficiently by installing a pulse molecular- beam source to generate pulse molecular beam and discharging a raw material gas lead as pulses to a vacuum container in a microwave resonator which can discharge at a high pressure. CONSTITUTION:A pulse molecular beam source is composed of an electromagnetic valve 13 which works pulse-wise to lead a raw material gas as pulse molecular beam to a vacuum container 1 and a driving apparatus 12 for the valve. The pulse molecular beam source and the vacuum containers are connected each other through a small hole. Then active molecules are generated in the vacuum container 1 using a resonator-type microwave discharge tube 14 which can discharge in atmospheric pressure. As a result, active molecules with high controllability and few impurities are produced efficiently. The apparatus is thus applicable for thin film growth such as thin films for semiconductor devices, surface reformation of adsorbents, etc., amorphous thin films, plasma etching, and excitation apparatus for superfine particle production and analysis of component elements.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing active molecules using microwaves,
The active molecules generated by this device can be used for thin film growth and as an atomization device for analysis.

[Conventional technology]

BACKGROUND ART Conventionally, as a method for generating a beam of active molecules, such as radicals or ions, a method is known in which a gas sample is dissociated by electric discharge. The first method is to blow out the source gas from a sample introduction nozzle to create a nozzle-like gas flow, and apply high pressure to an electrode installed downstream of the nozzle to cause discharge. This conventional method will be explained with reference to FIG. A sample introduction nozzle 2 and an exhaust pump 3 are installed in a vacuum container 1. The sample is introduced into the vacuum vessel 1 through the sample introduction nozzle 2 via the electromagnetic valve 6 controlled by the electromagnetic valve drive device 5 . At this time,
A high voltage is applied between the electrodes 8a and 8b by the high voltage generator 4, causing discharge and generating radical molecules, which are exhausted by the exhaust pump 3. The timing of the electromagnetic valve drive device 5 and the high voltage generator 4 is adjusted by a pulse control device 7.

As a second method, there is a method in which a raw material gas is made into a continuous flow under reduced pressure, an electrodeless discharge such as a microwave discharge is performed, and a continuous flow of radicals is introduced into a vacuum container downstream of the discharge. Fourth
This method will be explained with reference to the drawings. A sample introduction nozzle 2 and an exhaust pump 3 are installed in a vacuum container 1. A sample is introduced into a vacuum container 1 through a sample introduction nozzle 2, and is evacuated by an exhaust pump 3. At this time, the pressure inside the nozzle 2 is reduced, microwaves are applied to the resonator 10 by the microwave power source 9, a discharge occurs, and active molecules are generated.

[Problem that the invention seeks to solve]

However, with conventional technology, when obtaining a highly controllable pulsed active molecular beam, electrodes are required, and the electrodes are worn out due to discharge, and furthermore, impurities are mixed in due to the wear of the electrodes. . In addition, in discharges that do not require electrodes, in order to obtain stable discharges, it is necessary to flow gas continuously and at low pressure, resulting in poor controllability and difficulty in obtaining active molecular beams with few collisions. there were. The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a method for generating an active molecular beam with good controllability and with few impurities.

[Means for solving problems]

The present invention has a pulsed molecular beam source for guiding raw material gas into a vacuum container via a solenoid valve and generating pulsed molecular beams, and the raw material gas is introduced in the form of a nozzle into the vacuum container. This active molecule generating device is characterized in that gas is discharged in a microwave resonator capable of discharging at high pressure to efficiently generate active molecules.

The microwave used here uses a microwave resonator capable of discharging even at atmospheric pressure, making it possible to discharge pulsed molecular beams that were previously difficult to discharge.

[For production]

According to the invention, a gas sample at 1 atm is applied from 10-6 to I
The pulsed molecular beam source is introduced into the vacuum vessel through a pulsed molecular beam source installed at the entrance of the vacuum vessel maintained at Q-''I'orr.
Opens and closes with a pulse width of 1 to 10 μs, diameter 01 to 1
Gas is introduced through the mm hole. Under this condition, the introduced gas sample is transported as a supersonic molecular beam without collisions.

At this time, active molecules such as radicals can be generated by discharging at the gas inlet using a resonator-type microwave discharge tube with an output of 10 to 500 W capable of discharging at atmospheric pressure. Since the generated active molecules are transported without collision, they can be used downstream for film formation, etc., without being recombined. The pulsed molecular beam source is
Fine control is possible by setting the number of pulse repetitions and pulse width.

Further, by performing electrodeless discharge using microwaves, consumption of electrodes and contamination of impurities can be suppressed.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing an active molecule production apparatus as a first embodiment of the present invention. Reference numeral 12 in the figure is a pulse-operated electromagnetic valve driving device, which drives the electromagnetic valve 13 and sends out the sample in a pulsed manner. Reference numeral 14 denotes a cylindrical microwave resonator, which is tuned to a frequency of 2450 MHz, and is set so that the microwave electric field is strongest at the center.

Next, a method for producing active molecules will be explained using the above-described production apparatus shown in FIG.

First, a sample is supplied from a gas cylinder 1, and the inlet pressure of the solenoid valve is set to 1 to 2 atmospheres.

The pulse repetition rate from the electromagnetic valve drive device 12 is 10 to 1.
When a pulse current with a pulse width of 1 to 10 μs flows at 00H2, the solenoid valve 13 opens intermittently, and the pressure increases from 10-6 to 1
A sample is blown out into the microwave resonator 14 and the vacuum container 1 set at 0-' Torr. A microwave power source 9 is connected to a microwave resonator installed near the air outlet.
A microwave with a frequency of 2450 MHz is applied with an output of 1o to soow to cause discharge. Here, the frequency of the applied high frequency does not need to be limited to 2450 MH2, but the shape of the resonator is determined depending on the frequency. Under the above conditions, the gas becomes a supersonic molecular beam and flows several centimeters downstream without collisions. Therefore, the active molecules generated by the microwave discharge near the outlet can be transported to the target location without reacting again because there is no collision.

Note that 16 is an O-ring provided at the lower end of the valve body 17 for opening and closing a small hole between the pulsed radiation source 2 and the vacuum vessel 1.

FIG. 2 is a schematic diagram showing an active molecule generating apparatus as a second embodiment of the present invention. 12 in the figure is a pulse-operated electromagnetic valve drive device, which drives the electromagnetic valve 13 and sends out the sample in a pulsed manner.

14' is a cylindrical microwave resonator with a frequency of 24
It is tuned to 50MHz and set so that the microwave electric field is strongest at the center.

In this embodiment, a discharge tube 15 made of a material with low absorption of microwaves, such as quartz or alumina, is installed between the nozzle 2 and the vacuum vessel 1 to minimize the incorporation of impurities due to discharge. is possible.

Next, a method for producing active molecules will be explained using the active molecule producing apparatus of the second embodiment described above.

First, a sample is supplied from the sample container 11, and the inlet force of the solenoid valve is set to 1 to 2 atmospheres.

Solenoid valve drive device Toki et al. Pulse repetition is 1 to 100
When a pulse current with a pulse width of 1 to 10 microseconds flows at Hz, the solenoid valve 13 opens and the pressure increases to 10-6 to 1O-9 Torr.
The sample is blown out into the microwave resonator 14' and the vacuum container 1, which are set at r. Output 10 to 5 from microwave power supply 9 to the microwave resonator installed near the air outlet.
Microwaves of 00 W and a frequency of 2450 MHz are applied to cause discharge inside the discharge tube 15. Under the above conditions, the gas becomes a supersonic molecular beam, and several cm downstream,
It becomes a flow without collision. Therefore, near the air outlet,
Active molecules generated by microwave discharge can be transported to the desired location without reacting again because there is no collision.

〔Effect of the invention〕

As described in detail above, according to the active molecule generating device of the present invention, it is possible to generate target active molecules with high controllability and high efficiency. Therefore, it is suitable for use in the growth of thin films such as semiconductor thin films, gas separation films, and oxide films, surface modification of adsorbents and catalysts, amorphous thin films, plasma etching, ultrafine particle generation, and excitation equipment for analysis of constituent elements. It has remarkable effects such as being able to be used as a.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an active molecule generating apparatus as a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing an active molecule generating apparatus as a second embodiment of the present invention. Figures 3 and 4
The figure is a schematic diagram showing a conventional active molecule generation device. 1... Vacuum container, 2... Sample introduction nozzle, 3...
Exhaust pump, 4... High voltage generator, 5... Solenoid valve drive device, 6... Solenoid valve, 7... Pulse control device, 8
... Electrode, 9 ... Micropower source, 10 ... Microwave resonator, 11 ... Sample container, 12 ... Solenoid valve driving pulse generator, 13 ... Solenoid pulp, 14
...Atmospheric pressure compatible microwave resonator, 15...Discharge tube.

Claims (1)

[Claims] A pulsed molecular beam source consisting of a pulse-operated electromagnetic valve and its driving device for guiding source gas as a pulsed molecular beam into a vacuum vessel; a vacuum vessel coupled to the pulsed molecular beam source through a small hole; An active molecule generation device comprising a resonator-type microwave discharge tube capable of discharging at atmospheric pressure for generating active molecules within the vacuum container.