JPH0827577A - Electron beam-excited plasma film forming device - Google Patents

Abstract

PURPOSE:To provide an electron beam-excited plasma film forming device in which deterioration in the film forming rate is prevented and the compsn. of the formed film can be homogenized even in the case where the kinds of gaseous starting material change and a gaseous mixture is used. CONSTITUTION:This electron beam-excited plasma film forming device 1 is provided with an electron beam generating device 2a generating electron beams having a high energy, an electron beam generating device 2b generating electron beams having a low energy and a plasma reaction device 3 generating plasma by the excitement with electron beams. In the case where electron beams having a high energy are made incident thereon, plasma PBa constituted of gaseous molecules requiring activation energy for their ionization or dissociation is efficiently generated. In the case where electron beams having a low energy are made incident thereon, plasma PBb constituted of gaseous molecules having a low activation energy is efficiently generated. Each plasma PBa and PBb carries out chemical vapor growth on a sample S to form a multi-element thin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample by using plasma excited by an electron beam.

[0002]

2. Description of the Related Art In a conventional plasma CVD (chemical vapor deposition) apparatus, a raw material gas such as monosilane is introduced into a vacuum container and plasma is generated by discharge or the like to activate the raw material gas into ions and radicals. Then, chemical vapor deposition is performed on the surface of the sample such as a silicon wafer to deposit a desired thin film.

On the other hand, a high melting point metal ion plating apparatus using electron acceleration type plasma is disclosed in Japanese Patent Laid-Open No. 59-47380. A plasma CVD apparatus using pressure gradient type discharge is disclosed in Japanese Patent Application Laid-Open No. 1-252781.

[0004]

[Problems to be Solved by the Invention] Conventional plasma CVD
In the device, it is difficult to control the energy of electrons, and the ion density in the plasma of the source gas cannot be controlled to an arbitrary value. That is, since electrons are generated and accelerated at the same place where plasma is generated, a gas with low activation energy is preferentially ionized in the process of accelerating electrons, and the activation energy is reduced. High gas tends to be difficult to be ionized.

Further, when the type of the raw material gas introduced into the CVD apparatus changes, the activation energy of gas molecules also changes, so it is necessary to change the electron energy correspondingly. Also, when the source gas is a mixed gas composed of multiple types of molecules, gas molecules that match the electron energy are efficiently decomposed, but the decomposition rate of gas molecules that do not match is slowed down, and the film formation composition is It does not match the gas composition.

An object of the present invention is to form an electron beam excited plasma film which can prevent the film forming rate from being lowered and can homogenize the film forming composition even when the kinds of source gases are changed or a mixed gas is used. It is to provide a device.

[0007]

According to the present invention, in an electron beam excited plasma film forming apparatus for performing chemical vapor deposition on a sample by utilizing plasma excited by an electron beam, a plurality of different energy sources are used. An electron beam excitation plasma film forming apparatus comprising a plurality of electron beam generating means for generating an electron beam.

Further, the present invention is characterized in that gas supply means for supplying a gas having activation energy corresponding to the energy of each electron beam is provided in the vicinity of the beam exit of each electron beam generation means.

Further, the present invention uses a plurality of electron beams for generating electron beams in an electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample by utilizing plasma excited by the electron beams. Equipped with generating means,
Further, each electron beam generating means is an electron beam excitation plasma film forming apparatus characterized in that it is provided with an accelerating electrode for accelerating the electron beam, and arranged so that the distance from each accelerating electrode to the sample is different from each other. .

Further, the present invention uses a plurality of electron beams for generating electron beams in an electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam. Equipped with generating means,
Furthermore, each electron beam generating means is provided with an accelerating electrode for accelerating the electron beam, and further an orifice for adjusting gas pressure is provided between each accelerating electrode and the sample, so that the gas pressure from each accelerating electrode to each orifice is The electron beam excited plasma film forming apparatus is characterized in that a mechanism for adjusting the orifice opening is arranged so as to be different from each other.

The present invention also provides an electron beam generating means for generating an electron beam in an electron beam excited plasma film forming apparatus for performing chemical vapor deposition on a sample by utilizing plasma excited by an electron beam. Is provided with an acceleration electrode for applying an electric field to the electron beam to accelerate it.
The electron beam excitation plasma film forming apparatus is characterized in that the intensity of the electric field changes in a pulsating manner or in a pulsed manner with time.

Further, the present invention is an electron beam excitation plasma film forming apparatus for exciting a mixed gas by an electron beam to generate plasma for chemical vapor deposition on a sample,
The electron beam generating means for generating an electron beam is provided with an accelerating electrode for applying an electric field to the electron beam to accelerate the electron beam, and the strength of the electric field changes with time in a pulsed manner, and the electric field strength changes the mixed gas. The electron beam excitation plasma film forming apparatus is characterized in that the electron energy is set to correspond to the maximum value of the electron collision cross-sectional area of each of the constituent gases.

Further, according to the present invention, an electron beam generating means for generating an electron beam in an electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam. Is provided with an acceleration electrode for applying an electric field to the electron beam to accelerate it.
Further, the electron beam excitation plasma film forming apparatus is characterized in that a voltage switching means for switching the voltage applied to the acceleration electrode is provided.

[0014]

According to the present invention, the electron beam generating means generate electron beams having different energies, so that even if the type of the source gas is changed or the mixed gas is used, the source material to be film-formed. It becomes possible to match the activation energy required for ionizing or radicalizing the gas with the energy of the electron beam, and it is possible to improve the film formation rate and homogenize the film formation composition.

Further, by providing a gas supply means for supplying a gas having activation energy corresponding to the energy of each electron beam in the vicinity of the beam emission port of each electron beam generation means, the gas decomposition efficiency is further improved. improves.

According to the invention, each electron beam generating means is provided with an accelerating electrode for accelerating the electron beam, and the accelerating electrodes are arranged so that the distance from each accelerating electrode to the sample is different. In the region where the distance from the sample to the sample is long, only the radicals having a long life among the radicals excited by the electron beam reach the sample, and the radicals having a short life are eliminated on the way. Therefore, it becomes possible to select the film-forming component according to the length of the radical lifetime.

Further, according to the present invention, each electron beam generating means is provided with an accelerating electrode for accelerating the electron beam, and further an orifice for adjusting gas pressure is provided between each accelerating electrode and the sample, and each accelerating electrode is provided. By arranging the mechanism for adjusting the orifice opening so that the gas pressure from the electrode to each orifice is different, the same effect as changing the distance from the accelerating electrode to the sample is exhibited. That is, in the region where the gas pressure from the acceleration electrode to the orifice is high,
Of the radicals excited by the electron beam, only those with a long life pass through the orifice, reach the sample, and those with a short life cannot pass through and are culled on the way. Therefore, it becomes possible to select the film-forming component according to the length of the radical lifetime.

According to the invention, the electron beam generating means is provided with an accelerating electrode for applying an electric field to the electron beam to accelerate the electron beam, and the intensity of the electric field changes with time in a pulsating or pulsed manner. This makes it possible to change the energy of the electron beam with time. Therefore, even if the type of raw material gas changes or a mixed gas is used,
It becomes possible to match the activation energy of the source gas to be film-formed with the energy of the electron beam in a wide range, so that the film-forming speed can be improved and the film-forming composition can be homogenized.

According to the invention, the electron beam generating means is provided with an accelerating electrode for applying an electric field to the electron beam to accelerate the electron beam, and further a voltage switching for switching the voltage applied to the accelerating electrode. By providing the means, the energy of the electron beam can be arbitrarily set. Therefore, it becomes possible to optimize the material gas to be film-formed, and further, by switching the voltage applied to the accelerating electrode in accordance with the switching of the material gas, a multilayer film can be formed on the sample.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing the principle of an electron beam excited plasma film forming apparatus according to the present invention. The electron beam excitation plasma film forming apparatus 1 includes an electron beam generator 2 for generating an electron beam and a plasma reaction apparatus 3 for generating plasma by electron beam excitation.

The electron beam generator 2 includes a cathode 5, an auxiliary electrode 6, and a discharge electrode 7 in a cylindrical vacuum container 4.
And an accelerating electrode 8. A cathode region 20 is formed between the cathode 5 and the auxiliary electrode 6, a discharge region 21 is formed between the auxiliary electrode 6 and the discharge electrode 7, and acceleration is performed between the discharge electrode 7 and the acceleration electrode 8. Region 22 is formed.
The auxiliary electrode 6, the discharge electrode 7, and the accelerating electrode 8 have a disc shape perpendicular to the axial direction, and a communication hole for communicating adjacent regions is formed in the center of each electrode.

A power source 11 is connected to both ends of the cathode 5, and the filament of the cathode 5 is energized to emit thermoelectrons to the surroundings. A discharge power source 13 is connected between one end of the cathode 5 and the discharge electrode 7, and plasma PA is generated when a discharge is made between the cathode 5 and the discharge electrode 7 in the vacuum container 4. A switch 12 is connected between the connection line between the discharge power source 13 and the discharge electrode 7 and the auxiliary electrode 6 to assist the start of discharge. An acceleration power supply 14 is connected between the discharge electrode 7 and the acceleration electrode 8, and by applying a positive potential to the discharge electrode 7 to the acceleration electrode 8, only electrons are extracted from the plasma PA and accelerated, Electron beam E
B is generated.

A gas supply port 9 is formed in the vacuum container 4, and an inert gas such as argon gas is supplied to the cathode region 20 as plasma species at a predetermined flow rate. The inert gas supplied to the cathode region 20 flows into the discharge region 21 through the communication hole of the auxiliary electrode 6, further flows into the acceleration region 22 through the communication hole of the discharge electrode 7, and further accelerates region 2.
It is discharged to an external exhaust device through the exhaust port 10 formed in 2.

Around the discharge electrode 7 and the acceleration electrode 8,
Coils 15 and 16 for generating a magnetic field along the axial direction of the vacuum container 4 are arranged and play a role of converging the electron beam EB.

On the other hand, the plasma reaction device 3 is provided with a cylindrical vacuum container 31 and a sample table 35 which is provided so as to face the electron beam generator 2 and supports the sample S. The vacuum container 31 is provided with a supply port 32 for supplying a raw material gas such as monosilane and an exhaust port 33 for exhausting the gas in the container. The sample table 35 is rotatably driven at a predetermined angular velocity by a rotary shaft 36 as needed, and the reaction variations on the sample S are made uniform. A plurality of multi-pole magnets 34 are installed near the inner peripheral surface of the vacuum container 31. Further, in the vicinity of the outer peripheral surface of the vacuum container 31, a reverse magnetic field coil 37 that generates a magnetic field along the container axial direction is installed.

When the electron beam EB generated by the electron beam generator 2 is introduced into the plasma reactor 3, it collides with gas molecules introduced into the vacuum chamber 31 and plasma PB.
Generate If the reaction gas is decomposable such as monosilane, it is decomposed into atoms or molecules by the plasma PB, and when reaching the sample S, a film is deposited on the surface. In this case, if different kinds of raw material gases are alternately supplied from the supply ports 32, films of different materials are alternately deposited.

In this way, the plasma PB is generated by the electron beam EB and the reaction gas is activated, whereby chemical vapor deposition can be performed on the sample S.

FIG. 2 is a view taken along the line AA in FIG. A plurality of multi-pole magnets 34 are installed at equal intervals in the circumferential direction in the vicinity of the inner peripheral surface of the cylindrical vacuum container 31, and the N and S poles of the multi-pole magnet 34 are arranged along the radial direction of the container. , The polarities of the adjacent multi-pole magnets 34 are alternately inverted. With such an arrangement, the plasma PB generated near the center of the vacuum container 31 can be confined inside.

FIG. 3 is a distribution diagram of a magnetic field formed by the coils 15 and 16 and the inverse magnetic field coil 37. The coils 15 and 16 form a magnetic field in the right direction in the figure along the axial direction. The electrons passing near the centers of the coils 15 and 16 travel in the axial direction while being guided in a spiral motion so as to be wound around the magnetic lines of force, so that they are diffused and are less likely to collide with and lose on the wall surface, and are efficiently transported. .

On the other hand, the reverse magnetic field coil 37 forms a magnetic field in the left direction in the figure along the axial direction. Therefore coil 1
The magnetic field lines 5 and 16 and the magnetic field line of the reverse magnetic field coil 37 repel each other, and the magnetic field line immediately after leaving the coil 16 spreads rapidly. Therefore, the electron beams converged by the coils 15 and 16 rapidly expand along the lines of magnetic force, and the electrons are diffused substantially uniformly in the plasma reaction device 3, so that the plasma PB is generated in a wide space. Will be possible.

FIG. 4 is a schematic block diagram showing the first embodiment of the present invention. This electron beam excited plasma film forming apparatus 1
Is an electron beam generator 2a for generating an electron beam having high energy, an electron beam generator 2b for generating an electron beam having low energy, and a plasma reaction for generating plasma by electron beam excitation. And a device 3.

Each electron beam generator 2a, 2b is shown in FIG.
Similarly, the cathodes 5a and 5b and the auxiliary electrodes 6a and 6b
The discharge electrodes 7a and 7b and the acceleration electrodes 8a and 8b are provided, and plasma is generated by discharge in each region between the cathodes 5a and 5b and the discharge electrodes 7a and 7b. In the electron beam generator 2a, the acceleration electrode 8a with respect to the discharge electrode 7a
An electron beam having high energy is generated by setting a high applied voltage to the electron beam. The electron beam generator 2b generates an electron beam having low energy by setting the voltage applied to the accelerating electrode 8b to the discharge electrode 7b low.

On the other hand, the plasma reactor 3 has a cylindrical vacuum chamber 31 and the respective electron beam generators 2 as in FIG.
a sample table 35 for supporting the sample S, which is provided so as to face the a and 2b. The vacuum container 31 is provided with a supply port 32 for supplying a source gas such as monosilane SiH ₄ or monogermane GeH ₄ and an exhaust port 33 for exhausting the gas in the container.

When an electron beam having a high energy is incident from the electron beam generator 2a, it collides with gas molecules introduced into the vacuum chamber 31, and gas molecules having a high activation energy, for example, monogermane, are ionized. Alternatively, radicalized plasma PBa is efficiently generated. When an electron beam having a low energy is incident from the electron beam generator 2b, it collides with a gas molecule introduced into the vacuum chamber 31, and a gas molecule having a low activation energy, such as monosilane, is ionized or radicals. The converted plasma PBb is efficiently generated. Each of the plasmas PBa and PBb undergoes chemical vapor deposition on the sample S to form, for example, amorphous SiGe.

In this way, a plurality of types of plasma PBa having different compositions are produced by a plurality of electron beams having different energies.
PBb can be efficiently generated, a multi-element thin film can be generated at high speed by using a mixed gas, and the composition ratio of film formation can be controlled by changing the composition ratio of the mixed gas. In addition, plasma PB
In order to eliminate the uneven distribution of a and PBb, it is preferable to slightly incline the electron beam generators 2a and 2b so that the electron beams are directed to the vicinity of the center of the sample S.

In the present embodiment and the following embodiments, the power supply circuit connecting each electrode, the magnetic field generating mechanism, the sample rotating mechanism and the like are the same as those in FIG.

In the above description, an example in which two electron beam generating means are installed has been shown, but it is also possible to provide three or more electron beam generating means.

FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention. This electron beam excited plasma film forming apparatus 1
4, as in FIG. 4, an electron beam generator 2a for generating an electron beam having high energy, an electron beam generator 2b for generating an electron beam having low energy, and plasma generated by electron beam excitation. And a plasma reactor 3 for generating.

Each electron beam generator 2a, 2b is shown in FIG.
Similarly, the cathodes 5a and 5b and the auxiliary electrodes 6a and 6b
The discharge electrodes 7a and 7b and the acceleration electrodes 8a and 8b are provided, and plasma is generated by discharge in each region between the cathodes 5a and 5b and the discharge electrodes 7a and 7b. In the electron beam generator 2a, the acceleration electrode 8a with respect to the discharge electrode 7a
An electron beam having high energy is generated by setting a high applied voltage to the electron beam. The electron beam generator 2b generates an electron beam having low energy by setting the voltage applied to the accelerating electrode 8b to the discharge electrode 7b low.

On the other hand, the plasma reactor 3 has a cylindrical vacuum container 31 and each electron beam generator 2 as in FIG.
a sample table 35 for supporting the sample S, which is provided so as to face the a and 2b. A supply port 32a for supplying a raw material gas having a high activation energy is provided in the vacuum container 31 in the vicinity of the beam emission port of the electron beam generator 2a to supply a raw material gas having a low activation energy. The supply port 32b is provided near the beam emission port of the electron beam generator 2b. Also, sample table 3
An exhaust port 33 for exhausting the gas in the container is formed immediately below the container 5.

When an electron beam having a high energy is made incident from the electron beam generator 2a, it collides with gas molecules introduced from the supply port 32a to generate an ionized or radicalized plasma PBa with a high activation energy. Further, when an electron beam having a low energy is incident from the electron beam generator 2b, it collides with gas molecules introduced from the supply port 32b to generate an ionized or radicalized plasma PBb with a low activation energy. In order to prevent the plasmas PBa and PBb from being mixed with each other, the partition wall 38 is provided so as to divide the inside of the vacuum container 31 into two parts. Each of the plasmas PBa and PBb undergoes chemical vapor deposition on the sample S to form, for example, amorphous SiGe.

In this way, a plurality of types of plasma PBa having different compositions are produced by a plurality of electron beams having different energies.
Since PBb can be generated and a gas having an activation energy that matches the electron energy is supplied near the emission port of each electron beam, the ionization efficiency of the gas can be further improved. Further, a multi-element thin film can be formed by using a mixed gas, and the composition ratio of film formation can be controlled by changing the composition ratio of the mixed gas.

In the above description, an example in which two electron beam generating means are installed is shown, but it is also possible to provide three or more electron beam generating means.

FIG. 6 is a schematic block diagram showing a third embodiment of the present invention. This electron beam excited plasma film forming apparatus 1
5, as in FIG. 5, an electron beam generator 2a for generating an electron beam having a predetermined energy, an electron beam generator 2b for generating an electron beam having a predetermined energy, and a plasma by electron beam excitation. And a plasma reactor 3 for generating.

Each electron beam generator 2a, 2b is shown in FIG.
Similarly, the cathodes 5a and 5b and the auxiliary electrodes 6a and 6b
The discharge electrodes 7a and 7b and the acceleration electrodes 8a and 8b are provided, and plasma is generated by discharge in each region between the cathodes 5a and 5b and the discharge electrodes 7a and 7b. In each of the electron beam generators 2a and 2b, an electron beam having a desired energy can be generated by controlling the voltage applied to the acceleration electrodes 8a and 8b with respect to the discharge electrodes 7a and 7b.
Further, the distance from the acceleration electrode 8a of the electron beam generator 2a to the sample S in the plasma reaction apparatus 3 is set to be longer than the distance from the acceleration electrode 8b of the electron beam generator 2b to the sample S. .

On the other hand, the plasma reactor 3 has a cylindrical vacuum chamber 31 and each electron beam generator 2 as in FIG.
a sample table 35 for supporting the sample S, which is provided so as to face the a and 2b. The vacuum container 31 is provided with a supply port 32a for supplying a raw material gas having a predetermined activation energy in the vicinity of the beam emission port of the electron beam generator 2a, and supplies a raw material gas having a predetermined activation energy. The supply port 32b for the electron beam generator 2
It is provided near the beam exit of b. An exhaust port 33 for exhausting the gas in the container is formed directly below the sample table 35.

When an electron beam having a predetermined energy is incident from the electron beam generator 2a, it collides with gas molecules introduced from the supply port 32a to generate ionized or radicalized plasma PBa. Further, when an electron beam having a predetermined energy is incident from the electron beam generator 2b, it collides with gas molecules introduced from the supply port 32b and is ionized or radicalized plasma PBb.
Generate In addition, in order to prevent the plasmas PBa and PBb from being mixed with each other, the partition wall 3 is divided so as to divide the inside of the vacuum container 31 into two.
8 are provided.

Since the distance from the accelerating electrode 8b of the electron beam generator 2b to the sample S is long, the generation position of the plasma PBb is far from the sample S, and only the radicals having a long life among the radicals excited by the electron beam are sampled. Those that have reached S and have a short lifespan are eliminated on the way. On the other hand, since the generation position of the plasma PBa is close to the sample S, radicals having a short life can also reach the sample S. Therefore, it becomes possible to select the film-forming component according to the length of the radical lifetime.

In the above description, an example in which two electron beam generating means are installed is shown, but it is also possible to provide three or more electron beam generating means.

FIG. 7 is a schematic diagram showing a fourth embodiment of the present invention. This electron beam excitation plasma film forming apparatus 1 is shown in FIG.
Similarly, an electron beam generator 2a for generating an electron beam having a predetermined energy and an electron beam generator 2b for generating an electron beam having a predetermined energy
And a plasma reactor 3 for generating plasma by electron beam excitation.

Each electron beam generator 2a, 2b is shown in FIG.
Similarly to, the cathodes 5a and 5b and the auxiliary electrodes 6a and 6b
Each of the electron beam generators 2a and 2b, which includes the discharge electrodes 7a and 7b, and the acceleration electrodes 8a and 8b, and generates plasma due to discharge in each region between the cathodes 5a and 5b and the discharge electrodes 7a and 7b. Then, an electron beam having a desired energy can be generated by controlling the voltage applied to the acceleration electrodes 8a and 8b with respect to the discharge electrodes 7a and 7b.

On the other hand, the plasma reactor 3 has a cylindrical vacuum chamber 31 and each electron beam generator 2 as in FIG.
and a material table 35 for supporting the sample S, which is provided so as to face a and 2b. The vacuum container 31 is provided with a supply port 32a for supplying a source gas having a predetermined activation energy in the vicinity of the beam emission port of the electron beam generator 2a, and supplies a source gas having a predetermined activation energy. The supply port 32b for the electron beam generator 2
It is provided near the beam exit of b.

Further, orifices 11a and 11b whose opening can be adjusted are provided between each source gas supply port and the sample table, and the gas pressure between each beam emission port and the orifice and the gas pressure near the sample table are set to different values. It can be set to.

That is, if the flow rates of the source gases 12a and 12b are equal, the conductance of the orifice 11b is set to 11
By setting it smaller than the conductance of a,
The gas pressure between the acceleration electrode 8b and the orifice 11b is higher than the gas pressure between the acceleration electrode 8a and the orifice 11a.

Of course, the opening of the orifice can be set from the outside according to the amount of gas, and the gas pressure measuring system in the above space,
It is also possible to perform feedback control of the opening of the orifice so as to obtain a desired gas pressure in conjunction with the gas amount control system.

Further, an exhaust port 33 for exhausting the gas in the container is formed directly below the sample table 35.

When an electron beam having a predetermined energy is incident from the electron beam generator 2a, it collides with gas molecules introduced from the supply port 32a to generate ionized or radicalized plasma PBa. When an electron beam having a predetermined energy enters from the electron beam generator 2b, it collides with gas molecules introduced from the supply port 32b to generate ionized or radicalized plasma PBb.

Since the gas pressure from the accelerating electrode 8b to the orifice 11b of the electron beam generator 2b is high, the generation position of the plasma PBb is far from the sample S, and it is excited by the electron beam because it collides with many gas molecules. Of the radicals, only those having a long life reach the sample S, and those having a short life are removed on the way. On the other hand, the generation position of the plasma PBa is close to the sample S, and since the number of collisions with gas molecules is small, radicals having a short life can reach the sample S. Therefore, depending on the length of the radical life,
It becomes possible to select the film forming component. Since this method does not need to change the distance between the accelerating electrode and the sample, it leads to downsizing of the device, and because the gas pressure control range can be widened,
Wide selection range of radicals.

In the above description, an example in which two electron beam generating means are installed is shown, but it is also possible to provide three or more electron beam generating means.

FIG. 8 is a schematic block diagram showing the fifth embodiment of the present invention. This electron beam excited plasma film forming apparatus 1
Includes an electron beam generator 2 for generating an electron beam having a predetermined energy, and a plasma reaction device 3 for generating plasma by electron beam excitation.

The electron beam generator 2 is similar to that shown in FIG.
Cathode 5, auxiliary electrode 6, discharge electrode, and acceleration electrode 8
And plasma is generated by electric discharge in each region between the cathode 5 and the discharge electrode 7.

In this embodiment, the DC power source 14a and the AC power source 14b are connected in series between the discharge electrode 7 and the accelerating electrode 8, and the voltage applied to the accelerating electrode 8 with respect to the discharge electrode 7 is pulsating or pulsed. Is changing over time. Therefore, the electric field applied to the electron beam extracted from the plasma due to the discharge also changes with time in a pulsating manner or a pulse shape, and the energy of the electron beam also changes with time.

On the other hand, the plasma reaction apparatus 3 is provided with a cylindrical vacuum container 31 and a sample table 35 which is provided so as to face the electron beam generator 2 and supports the sample S, as in FIG. . The vacuum container 31 contains monosilane Si.
H ₄ and monogerman supply port 32 for supplying GeH ₄ or the like of the raw material gas, an exhaust port 33 for exhausting the gas in the container
Is formed.

When an electron beam whose energy changes with time is incident from the electron beam generator 2, it collides with gas molecules introduced into the vacuum chamber 31 and gas molecules having activation energy matching the energy fluctuation range are generated. It is ionized or radicalized to generate plasma PB. For example, when the energy of the electron beam is high, gas molecules that require high activation energy such as monogermane are efficiently activated, and when the energy of the electron beam is low, low activation energy such as monosilane is required. The gas molecules to be activated are efficiently activated. Therefore, the plasma PB generated by the gas molecules having various activation energies efficiently performs the chemical vapor deposition on the sample S, for example, amorphous SiGe.
Etc. are formed into a film.

By thus changing the energy of the electron beam with time, it becomes possible to efficiently ionize or radicalize gas molecules having various activation energies. Therefore, even when the type of source gas is changed or a mixed gas is used, the activation energy of the source gas to be film-formed and the energy of the electron beam can be matched in a wide range, and the film formation rate It is possible to improve and homogenize the film forming composition.

FIG. 9 is a schematic diagram showing a sixth embodiment of the present invention. FIG. 9A shows an ionization collision dissociation cross section of the source gases A and B. Further, (b) shows an example of a pulse waveform applied between the discharge electrode and the acceleration electrode. By setting the voltage intensity of the pulse to a value corresponding to the energy value of the electron having the maximum value of the electron impact ionization or dissociation cross section of each raw material gas, the mixed gas is efficiently turned into plasma.

FIG. 10 is a schematic block diagram showing the seventh embodiment of the present invention. This electron beam excited plasma film forming apparatus 1
Includes an electron beam generator 2 for generating an electron beam having a predetermined energy, and a plasma reaction device 3 for generating plasma by electron beam excitation.

The electron beam generator 2 is similar to that shown in FIG.
Cathode 5, auxiliary electrode 6, discharge electrode, and acceleration electrode 8
And plasma is generated by electric discharge in each region between the cathode 5 and the discharge electrode 7.

In this embodiment, the DC power source 14c having the output voltage V1 and the output voltage V are provided between the discharge electrode 7 and the acceleration electrode 8.
Two DC power sources 14d are switchably connected by an operation switch 14e. When the low voltage V1 is applied to the discharge electrode 7 by the operation switch 14e, a low electric field is applied to the electron beam extracted from the plasma due to the discharge, so that the energy of the electron beam becomes low. Further, when a high voltage V2 is applied to the discharge electrode 7 by the operation switch 14e, a high electric field is applied to the electron beam, so that the energy of the electron beam becomes high.

On the other hand, the plasma reactor 3 is provided with a cylindrical vacuum container 31 and a sample table 35 which is provided so as to face the electron beam generator 2 and supports the sample S, as in FIG. . The vacuum container 31 contains monosilane Si.
H ₄ and monogerman supply port 32 for supplying GeH ₄ or the like of the raw material gas, an exhaust port 33 for exhausting the gas in the container
Is formed.

When an electron beam having a predetermined energy is incident from the electron beam generator 2, it collides with gas molecules introduced into the vacuum chamber 31 and gas molecules having an activation energy matching the energy are efficiently generated. It is ionized or radicalized to generate plasma PB. For example, when the electron beam energy is high, gas molecules that require high activation energy such as monogermane are activated, and when the electron beam energy is low, gas molecules with low activation energy such as monosilane are activated. It will be activated efficiently. Therefore, the plasma PB in which the molecule activated by the switch operation is selected
Can perform chemical vapor deposition on the sample S to form, for example, a multilayer film having different film compositions alternately.

In this way, the energy of the electron beam can be arbitrarily switched by the switch operation, and gas molecules having various activation energies can be efficiently ionized or radicalized. Therefore,
It is possible to optimize the raw material gas to be formed, and by switching the applied voltage of the acceleration electrode in accordance with the switching of the raw material gas, a multilayer film can be formed on the sample.

[0073]

As described in detail above, according to the present invention, even when the kind of the source gas is changed or the mixed gas is used, the activity required for ionizing or radicalizing the source gas to be film-formed. It is possible to match the conversion energy with the energy of the electron beam, and it is possible to improve the film forming rate and homogenize the film forming composition.

Further, by providing the gas supply means for supplying the gas having the activation energy corresponding to the energy of each electron beam in the vicinity of the beam emission port of each electron beam generation means, the gas decomposition efficiency is further improved. improves.

Further, according to the present invention, in the region where the distance from the accelerating electrode to the sample is long, only the radicals having a long lifetime among the radicals excited by the electron beam reach the sample, and those having a short lifetime are in the middle. Be culled. Therefore, it becomes possible to select the film-forming component according to the length of the radical lifetime.

Further, according to the present invention, radicals are efficiently selected in a region having a high gas pressure, which is installed between the acceleration electrode and the sample. That is, of the radicals excited by the electron beam, only those with a long life pass through the above-mentioned region and reach the sample, and those with a short life are removed halfway. Therefore, it becomes possible to select the film-forming component according to the length of the radical lifetime.

Further, according to the present invention, since the energy of the electron beam can be changed with time, the activity of the source gas to be film-formed can be changed even when the type of source gas is changed or a mixed gas is used. It is possible to match the activation energy and the energy of the electron beam in a wide range,
The film forming rate can be improved and the film forming composition can be homogenized.

Further, according to the present invention, since the energy of the electron beam can be arbitrarily set, it is possible to optimize the material gas to be a film-forming target, and the applied voltage of the accelerating electrode can be changed in accordance with the switching of the material gas. By switching between, the multilayer film can be formed on the sample.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an electron beam excitation plasma generator to which the present invention is applied.

FIG. 2 is a view taken along the line AA in FIG.

FIG. 3 is a distribution diagram of a magnetic field formed by coils 15 and 16 and a reverse magnetic field coil 37.

FIG. 4 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a third embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a fourth embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a fifth embodiment of the present invention.

FIG. 9 is a schematic view showing a sixth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a seventh embodiment of the present invention.

[Explanation of symbols]

 1 Electron Beam Excited Plasma Film Forming Device 2, 2a, 2b Electron Beam Generating Device 3 Plasma Reactor 4 Vacuum Container 5, 5a, 5b Cathode 6, 6a, 6b Auxiliary Electrode 7, 7a, 7b Discharge Electrode 8, 8a, 8b Acceleration Electrode 9 Supply port 10 Exhaust port 11a, 11b Variable orifice 12a, 12b Raw material gas 15, 16 Coil 31 Vacuum container 32, 32a, 32b Supply port 33 Exhaust port 34 Multipolar magnet 35 Sample table 37 Reverse magnetic field coil 38 Partition wall

Claims (7)

[Claims] 1. An electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample by using plasma excited by an electron beam, wherein a plurality of electron beams having different energies are generated. An electron beam excitation plasma film forming apparatus comprising the electron beam generating means. 2. A gas supply means for supplying a gas having an activation energy corresponding to the energy of each electron beam is provided in the vicinity of the beam exit of each electron beam generation means. Electron beam excited plasma film forming apparatus. 3. An electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam, comprising a plurality of electron beam generating means for generating electron beams. Further, each electron beam generating means is provided with an accelerating electrode for accelerating the electron beam, and the electron beam excitation plasma film forming apparatus is arranged such that the distance from each accelerating electrode to the sample is different from each other. . 4. An electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam, comprising a plurality of electron beam generating means for generating electron beams. Further, each electron beam generating means is provided with an accelerating electrode for accelerating the electron beam, further an orifice for adjusting gas pressure is provided between each accelerating electrode and the sample, and gas from each accelerating electrode to each orifice is provided. An electron beam excitation plasma film forming apparatus, characterized in that a mechanism for adjusting the orifice opening so as to have different pressures is arranged. 5. An electron beam generating means for generating an electron beam in an electron beam excited plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam An electron beam excitation plasma film forming apparatus characterized in that an accelerating electrode for applying an electric field to the beam to accelerate the beam is provided, and the intensity of the electric field changes with time in a pulsating flow or a pulse. 6. Exciting the mixed gas with an electron beam,
In an electron beam excitation plasma film forming apparatus for generating plasma and performing chemical vapor deposition on a sample, an electron beam generating means for generating an electron beam is applied with an electric field to accelerate the electron beam. An accelerating electrode is provided, and the electric field strength changes in a pulsed manner with time, and the electric field strength is set to an electron energy corresponding to the maximum value of the electron collision cross-sectional area of each gas constituting the mixed gas. And an electron beam excitation plasma film forming apparatus. 7. An electron beam generation means for generating an electron beam in an electron beam excitation plasma film forming apparatus for performing chemical vapor deposition on a sample using plasma excited by an electron beam An electron beam excitation plasma film forming apparatus, comprising: an accelerating electrode for applying an electric field to the beam to accelerate the beam, and a voltage switching means for switching a voltage applied to the accelerating electrode.