JPH02174223A - Plasma vapor growth device, usage thereof and formation of film - Google Patents

Abstract

PURPOSE:To perform the formation of plasma in a plasma discharge tube by disposing a plasma discharge tube in a resonance chamber in such a manner that one end of the plasma discharge tube is equipped with an opening at the side of a sample chamber while maintaining an airtight state to the resonance chamber; besides by forming the plasma discharge tube with a material having the transmission of microwaves. CONSTITUTION:A plasma discharge tube 7 is formed with materials such as silica glass and the like having the property of transmission of microwaves so that the microwaves may penetrate its tube and its tube is composed of a mainframe 32 of the plasma discharge tube, one end of which is formed in the shape of an opening and a plasma hood 33 connecting to the mainframe 32. One junction face between a partition 17 and the mainframe 32 and the other junction face between a flange 34 and the discharge tube 32 are sealed by O-rings and the like so that the pressure of a sample chamber 2 does not leak out to a resonance chamber 1. Then internal and external parts of the discharge tube 7 are intercepted and it is constructed that plasma is formed just only in the plasma discharge tube 7.

Description

[Detailed Description of the Invention] The present invention relates to a plasma vapor phase method using electron cyclotron resonance (hereinafter abbreviated as rECRJ) applied to the formation of films such as semiconductor devices, especially films by epitaxial growth method. The present invention relates to a growth device, a method of manufacturing the device, a method of using the device, and a method of forming a film.

When several types of specific gases are placed in a container and heated to high temperatures, they react within the container and produce substances with low vapor pressure that precipitate. This thin film growth process is called vapor phase growth, and of this vapor phase growth, the process in which a single crystal is used as a substrate and a single crystal is further grown thereon is called epitaxial growth.

Incidentally, trace impurities (dopants) such as As, P, Sb, and B are generally added to a single crystal of semiconductor silicon in order to control the electrical characteristics of the semiconductor. In addition, semiconductors are sometimes formed by locally increasing dopant concentration by ion implantation or the like in order to locally control their electrical properties.

A thin film is formed on the surface of semiconductor silicon to electrically protect the semiconductor silicon containing such dopants, and the epitaxial growth method is currently used as a method for forming a single crystal film on the surface of semiconductor silicon. It is widely used industrially.

FIG. 3 is a schematic cross-sectional view of a plasma vapor phase growth apparatus that has been commonly used as a semiconductor device manufacturing apparatus using such an epitaxial growth method.

That is, the plasma vapor phase growth apparatus includes a plasma generation chamber 71, a sample chamber 72 connected to the lower part of the plasma generation chamber 71 and communicating with the plasma generation chamber 71, and a sample chamber 72 arranged around the plasma generation chamber 71. The main parts are an excitation coil 73 to which DC power is supplied, and a waveguide 74 that introduces microwaves into the plasma generation chamber 71.

In the above-mentioned plasma vapor phase growth apparatus, first, a DC power is applied to the excitation 6n coil 73 to form a predetermined magnetic field, and the microwave is passed from the waveguide 74 through the introduction window 79 as shown by arrow Z to generate plasma. A first reaction gas such as H2 is introduced into the plasma generation chamber 71 from the direction of the arrow Y to generate an ECR plasma. is generated. Thereafter, the plasma is accelerated from the extraction window 75 to form a divergent magnetic field, and reacts with a second reaction gas such as SiH introduced into the sample chamber 72 from the direction of the arrow X, and is placed on the sample stage 76. An epitaxial film 80 was formed on the surface of a substrate 77 made of semiconductor silicon or the like.

However, in the above-mentioned conventional plasma vapor phase epitaxy apparatus, since the inner circumferential surface 78 of the plasma generation chamber 71 is made of stainless steel, F, which is a component of stainless steel, is
Metal elements such as e, Cr, and Ni form the epitaxial film 8.
There was a problem in that the oxides were mixed into the 0 and impaired the electrical characteristics of the semiconductor element.

As a means to solve this problem, a method has been proposed in which the plasma generation chamber 71 is made of an insulator that does not contain metal (Japanese Patent Laid-Open No. 51-21099).

However, in this method, oxygen, carbon, etc., which are constituent elements of the insulator, may be mixed into the film, and the problem of impairing the electrical characteristics as a semiconductor, as in the above-mentioned conventional example, remains unsolved.

Furthermore, a method has been proposed in which the inner circumferential surface 78 of the plasma generation chamber 71 is formed using silicon contained in an epitaxial film (Japanese Patent Laid-Open No. 52-52099).

However, silicon has a problem in machinability, and it is extremely difficult to manufacture the plasma generation chamber 71 by processing a silicon ingot.

Furthermore, a plasma discharge tube made of a non-conductive, non-magnetic material is disposed in the apparatus in a state of protruding into a discharge region (plasma generation chamber), and plasma is generated within the plasma discharge tube. has also been proposed (Japanese Unexamined Patent Publication No. 1983-
202532).

However, the plasma apparatus described in the publication does not disclose a means for both film formation and etching, and when the apparatus is used for film formation, the film formation process and the etching process can be switched freely. Therefore, there was a problem in that the process for obtaining a suitable film became complicated.

The present invention has been made in view of the above-mentioned problems, and includes:
A plasma vapor phase epitaxy apparatus which is suitable for forming a film with a low concentration of harmful impurities, especially an epitaxial film, and which can be used for both film formation and etching, and which can improve productivity, and the apparatus. An object of the present invention is to provide a method for manufacturing a method, a method for using the device, and a method for forming a film.

・In order to achieve the above object, the plasma vapor phase growth apparatus according to the present invention includes a main body of the apparatus consisting of a resonance chamber and a sample chamber, and a DC power source arranged around the resonance chamber. A supply mechanism for supplying a film forming gas or an etching gas is connected to the sample chamber, and has one end connected to the sample chamber. The first feature is that a plasma discharge tube opening to the side is disposed within the resonance chamber in an airtight state with respect to the resonance chamber, and the plasma discharge tube is formed of a microwave-transparent material. There is.

A second feature is that after a film-forming gas is introduced into the sample chamber to form a film on the inner circumferential surface of the plasma discharge tube, a film is formed on the substrate placed in the sample chamber.

Furthermore, it is also one of the useful forms of the plasma vapor phase epitaxy apparatus according to the present invention that the inner circumferential surface of the plasma discharge tube is coated with an element or compound contained in the film-forming gas.

Further, after forming a film on the inner circumferential surface of the plasma discharge tube, an etching gas is introduced into the sample chamber to adjust the film thickness of the film, thereby providing a plasma vapor deposition apparatus having a more preferable form. Can be done.

Another preferred method of using the apparatus is to introduce an etching gas into the sample chamber to etch the inner peripheral surface of the plasma discharge tube.

Furthermore, the outside of the plasma discharge tube is maintained in a low pressure range where plasma is not generated, or the outside of the plasma discharge tube is maintained in a high pressure range where plasma is not generated while maintaining a gas atmosphere that is harmless to the film quality. It is also a better way to use the device to generate plasma only within the plasma discharge tube.

Furthermore, in the plasma vapor deposition apparatus according to the present invention, the waveguide and the wall of the resonant chamber are integrally formed, and an airtight space is formed from the resonant chamber to the inside of the waveguide. It is also characterized by

In this device, as described above, either the outside of the plasma discharge tube is maintained at a low pressure range where plasma does not occur, or the outside of the plasma discharge tube is maintained at a high pressure range where plasma is not generated while maintaining a gas atmosphere that is harmless to the film quality. The method of using the device is also characterized by maintaining the pressure within the range and generating plasma only within the plasma discharge tube.

The above-mentioned apparatus is provided with a main body consisting of a resonance chamber and a sample chamber, and a plasma discharge tube formed with an open end is disposed inside the resonance chamber while maintaining an airtight state with respect to the resonance chamber. After that, the plasma discharge tube can be manufactured by introducing a film-forming gas into the sample chamber to form a film on the inner circumferential surface of the plasma discharge tube.

Furthermore, it is desirable that the gas supply mechanism is provided with a switching means capable of switching between the film forming gas and the etching gas.

According to the above configuration, ECR motion can be performed within the resonant chamber, and when a film forming gas or an etching gas is supplied to the sample chamber during the ECR motion, plasma is generated only within the plasma discharge tube. Since the plasma detonator is made of a microwave-transparent material such as quartz, metal elements are not mixed into the film.

Furthermore, the outside of the plasma discharge tube is maintained in a low pressure range where plasma does not occur, or the outside of the plasma discharge tube is maintained in a high pressure range where plasma is not generated while maintaining a gas atmosphere that is harmless to the membrane. Generating plasma only within the plasma discharge tube also prevents oxygen from entering the film.

In addition, if a film is formed on the substrate after forming a film on the inner peripheral surface of the plasma discharge tube, the film contains only the elements or compounds contained in the film-forming gas, and harmful impurities are excluded. , has the effect of giving better results to the electrical characteristics of the semiconductor device.

The film may be formed on the inner circumferential surface of the plasma discharge tube in advance, or may be formed during the film forming process. In the former case, the device can be easily manufactured using the film.

Furthermore, by providing the gas supply mechanism with the switching means as described above, it becomes possible to perform both film formation and etching.

By introducing the etching gas into the sample chamber, the film thickness can be set to an optimum thickness, and deposits on the inner peripheral surface of the plasma discharge tube can also be removed.

Furthermore, by integrally forming the resonant chamber wall and the waveguide, and creating an airtight space from the resonant chamber to the inside of the waveguide, the conventional introduction window can be omitted. Therefore, so-called induction loss due to the introduction window can be eliminated.

In this device, as described above, either the outside of the plasma discharge tube is maintained at a low pressure range where plasma does not occur, or the outside of the plasma discharge tube is maintained at a high pressure range where plasma is not generated while maintaining a gas atmosphere that is harmless to the film quality. By maintaining the pressure within the range and generating plasma only within the plasma discharge tube, incorporation of oxygen into the film is prevented.

躙亘舅 Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1(A) is a cross-sectional view schematically showing an ECR plasma vapor phase growth apparatus as an example of the plasma vapor phase growth apparatus according to the present invention, and the plasma vapor phase growth apparatus includes a resonance chamber l and a An apparatus main body 3 consisting of a sample chamber 2, an excitation coil 4 disposed around the resonance chamber 1 and supplied with DC power (not shown), and a microwave irradiated from the direction of arrow A into the resonance chamber 1. A waveguide 5 for introducing a gas, a gas supply mechanism 6 for supplying a film forming gas or an etching gas to the sample chamber 2, and a plasma gas supply mechanism 6 having an open end and disposed in the apparatus main body 3. The main parts are a discharge tube 7, a load rotor chamber 8 provided on one side wall of the sample chamber 2, and a composite turbomolecular pump 10 provided on the other side wall of the sample chamber 2 via a first gate valve 9. It is configured. 11 is an introduction window formed of quartz glass sandwiched between the resonance chamber l and the waveguide 5;
is an injection pipe for injecting an inert gas such as a door or a gas harmless to the film quality such as H2 into the resonance chamber l. Further, 13 is a vacuum pump, which is connected to the resonance chamber 1 via an exhaust pipe 14. 15 is a conductance valve that controls the flow rate of the composite turbomolecular pump 10.

Specifically, the apparatus main body 3 is constructed by integrally forming a resonance chamber l formed in a substantially cylindrical shape and a sample chamber 2 having a larger diameter than the resonance chamber 1. The sample chamber 2 and the resonance chamber 1 have a first
It is partitioned off by a partition plate 17 in which a hole 16 is formed. That is, the partition plate 17 is fixed to the device main body 3 via fixing devices such as screws (not shown).

Further, a second hole 18 for introducing microwaves is formed approximately at the center of the upper wall of the resonance chamber l.

Further, in the sample chamber 2, a sample stage 19 is arranged at a position facing the first hole 16, and on this sample stage 19, a susceptor 21 formed in a donut shape in plan view is arranged.

This susceptor 21 is made of transparent quartz on which a sample 20 such as a semiconductor substrate is placed, and the sample stage 19 is made of transparent quartz.
A heater 22 and a rotation support mechanism (not shown) for rotationally driving the sample stage 19 are provided inside. In addition, sample chamber 2
An optical pyrometer (not shown) for measuring the temperature of the sample 20 is provided at a suitable location on the wall.

Specifically, the heater 22 includes a heat transfer section 23 whose wires are made of W-Re (tungsten-rhenium) alloy or Ta (tantalum), which is folded and meandered into a disk shape in a plan view, and a heat transfer section 23 that is made of wires made of W-Re (tungsten-rhenium) alloy or Ta (tantalum). It is composed of a thermocouple 24 for measuring temperature.

The heater 22 has a heat transfer section 23 that passes through the susceptor 21.
The sample 20 is irradiated and heated by the heat, the temperature is measured by a thermocouple 24, and the thermocouple detection pattern is controlled by negative feedback based on this output.

Further, when the excitation coil 4 is supplied with DC power, a predetermined magnetic field is generated, and the angular frequency ω of the microwave and the angular frequency ω of the electron cyclotron are resonated from the six directions of the arrows. The structure is such that a magnetic field is created such that the two are equal, causing the electrons to perform resonant motion. The conditions for causing this resonance, that is, the ECR conditions, can be easily obtained by solving classical mechanical equations and are expressed by the following equation.

ω=ω. = e B / m...-... ■Here, e is the charge of the electron (=1.6 xlo-"C), B is the magnetic flux density (T), and m is the mass of the electron (=9. 1x10-”
In this example, the frequency ω of the microwave, which is 0 kg), is set to 2.45 GHz, and from the above equation 0, 8.
A magnetic flux density B of 75×1O−2T is given.

The supply mechanism 6 is equipped with a switching means 25 that can appropriately switch to a film forming gas, an etching gas, or the like. That is, the supply mechanism 6 includes a first transport pipe 26 for transporting an etching gas such as Ar, a second transport pipe 27 for transporting a film forming gas such as SiO□, and a diluting gas such as H2. A third transport pipe 28 for transporting (carrier) gas is provided, and these transport pipes 26, 27, 28 are merged into one transport pipe 29 at point B and connected to the sample chamber 2. The gas selected automatically or manually by the switching means 25 is supplied to the sample chamber 2 from a nozzle 30 provided at the tip of the transport tube 29. In this case, the gas flow rate supplied to the sample chamber 2 is controlled by a flow rate control mechanism (not shown).
It is controlled in the range of ~503 CCU.

The plasma discharge tube 7 is made of a microwave-transparent material such as quartz glass so that microwaves can pass therethrough, and includes a plasma discharge tube body 32 having an open end at one end, and a plasma discharge tube main body 32 having an open end. The plasma hood 33 is connected to the main body 32.

A brim-like flange is formed around the open end of the plasma discharge tube main body 32, and a female screw portion is formed on the inner surface of this open end. In addition, the plasma discharge tube main body 32
The other end is formed into a hemispherical shape for pressure resistance.

The plasma hood 33 has a straight portion 35 having approximately the same diameter as the inner diameter of the plasma discharge tube 7, and the tip of the straight portion 35 is widened into a trumpet shape. Further, a male threaded portion is formed on the outer periphery of the straight portion 35.

In the plasma discharge tube 7 formed in this way, the plasma discharge tube main body 32 is fixed with screws or the like (not shown) through the annular flange 34 having an appropriate number of holes. The plasma hood 33 is fixed to the partition plate 17 with a tool, and then the plasma hood 33 is screwed onto the plasma discharge tube main body 32 to assemble the plasma discharge tube. In this case, the joint surfaces between the partition plate 17 and the plasma discharge tube body 32 and the joint surfaces between the flange 34 and the plasma discharge tube 32 are sealed with an O-ring or the like so that the pressure in the sample chamber 2 does not leak into the resonance chamber 1. (Fig. 1 (b)), that is, the plasma discharge tube 7
The inside and outside of the plasma discharge tube 7 are cut off, and plasma is generated only within the plasma discharge tube 7.

In addition, the load lock chamber 8 has a sample loading window 37 at its upper part.
A transport arm 38 for transporting the sample 20 and placing it on the susceptor 21 is provided inside.

In addition to the screw holes, the flange 34 is provided with gas vent holes in its radial direction so that residual gas between the flange 34 and the plasma discharge tube 32 flows into the resonance chamber.

Next, a method for forming a film on the inner circumferential surface of the plasma discharge tube 7 in the plasma vapor deposition apparatus configured as described above will be explained.

First, the composite turbomolecular pump 10 is driven to fill the sample chamber 2.
The pressure inside the container is reduced to about 1×10”-'Pa.

Next, the first valve 12a is closed, and the second valve 14 is closed.
a is opened and the vacuum pump 13 is driven to prevent plasma from being generated in the area surrounded by the resonance chamber l and the plasma discharge tube 7 (hereinafter, this enclosed area will be referred to as the "cavity resonance part 39"). This cavity resonator 39 is set to a sufficiently low pressure (approximately vacuum state) of IX1O-3Pa or less. Next, the second gate valve 8a is opened and nitrogen gas is injected into the load lock chamber 8 from the direction of arrow C. The sample chamber 2 and load lock chamber 8 are brought to atmospheric pressure. Thereafter, the sample 20 is supplied from the sample loading window 37 onto the transport arm 38, and the sample 20 is transported and placed on the susceptor 21 by a transport mechanism (not shown).

Note that this sample 20 is not for product use, but for susceptor 2.
1. This is to prevent a film from being formed on the sample stage 19, heater 22, etc. After the sample 20 is placed on the susceptor 21 in this manner, the second gate valve 8a is closed, and the pressure inside the load lock chamber 8 is increased to l x 10-'' by an oil rotary pump, a cryopump (not shown), or the like. After exhausting the air until the temperature reaches about Pa, the gate valve 8a of the cylinder 2 is opened (.

At this time, the pressure inside the sample chamber 2 is I x 10''-'Pa
The transfer arm 38 maintains the reduced pressure state below.
is returned to the load-lock chamber 8, the second gate valve 8a is closed, and the inside of the sample chamber 2 is evacuated again by the composite turbo-molecular pump 10 until the pressure reaches about I x 10''-'Pa.

Next, while flowing 5 SCCM of SiH4 from the second transport pipe 27 and 20 SCCM of H2 gas from the third transport pipe 28 into the sample chamber 2, the conductance valve 15
is adjusted to set the pressure inside the plasma discharge tube 7 and the sample chamber 2 to 7×10''-''Pa to IPa. This pressure is set so that plasma can be generated within the plasma discharge tube 7.

Next, microwaves of 00 W output are supplied from the direction of the arrow, and DC power is supplied to the excitation coil 4.

Since the plasma discharge tube 7 is made of a microwave transparent material, the microwave propagates inside the plasma discharge tube 7. On the other hand, the inside of the plasma discharge tube 7 is set at a pressure that allows generation of plasma as described above, and the ECR plasma 60 is generated in this plasma discharge tube 7, and this plasma 60 passes through the plasma hood 33 and hits the sample 20. While a silicon film is formed on the sample 20, an amorphous silicon (a-3i) film 40 having a dielectric effect is formed on the inner peripheral surface of the plasma discharge tube 7. This film 4
After forming 0, the sample 20 is carried out of the apparatus and discarded in the reverse order of the introduction procedure. This is because there is a possibility that this sample 20 contains impurities inside, so it is not used as a product.

In this way, a film 40 having the same composition as the film is formed on the inner circumferential surface of the plasma discharge tube 7. In this state, it may be used as a plasma vapor deposition apparatus, and the film may be formed each time during the film forming process.

Here, the thickness of the coating 40 is such that it does not hinder the generation of plasma 60 within the plasma discharge tube 7 and does not cause the coating 40 to peel off from the inner circumferential surface of the plasma discharge tube 7 and adversely affect the sample 20. It needs to be 1μm, specifically
degree is preferred. Hereinafter, a method for adjusting the film thickness of this film 40 will be explained.

That is, an etching gas such as Ch, Hz, a mixture thereof, or HCI gas is supplied from the first transport pipe 26 to the sample chamber 2, and as described above, under ECR conditions.
Plasma 60 is generated within the blaster discharge tube 7. As a result, excessively deposited film 40 can be removed by etching, and this film 40 can be adjusted to a predetermined thickness. This state may be used as a plasma vapor deposition apparatus as a finished product.

Next, after forming the desired film 40 on the inner circumferential surface of the plasma discharge tube 7, the sample 20 is placed on the susceptor 21 of the sample chamber 2 again through the same process as described above, and a predetermined film is formed. (
Before this film formation process, a natural oxide film formed on the surface of the sample 20 and residual gas adhering to the inside of the plasma discharge tube 7 during the previous film formation are removed. etching, that is, pretreatment.

This preprocessing will be explained below.

First, a rotation support mechanism (not shown) installed in the sample stage 19 is activated to rotate the sample 20 in a horizontal plane. Next, the heater 22 is energized to raise the temperature of the sample 20. During this time, the first gate valve 9 is opened and the combined turbomolecular pump 10 continues to operate. Further, the temperature increase is stopped when the temperature of the sample reaches a predetermined value. The predetermined value is suitable for thermally desorbing residual gas molecules adhering to the inner circumferential surface of the plasma discharge tube 7, and also increases the rate of gas desorption from the inner wall surface of the sample chamber 2 to lower the degree of vacuum. A temperature of about 700° C. is preferable as a temperature that does not cause deterioration, and the pressure in the sample chamber 2 at this time is set to 7×10″-′Pa or less.

Next, while supplying 50 SCCM of Ar as an etching gas to the sample chamber 2 from the first conveying pipe 26, the conductance valve 15 is adjusted to reduce the pressure inside the sample chamber 2 to lX
Set to 10””Pa-10Pa. This pressure is set within a preferable range to prevent etching effects and damage to the crystal structure of the sample 20 due to excessive ion energy (argon ion irradiation).

Thereafter, microwaves with an output of 1 kW are introduced into the resonance chamber 1 from the direction of arrow A to generate plasma 60 in the plasma discharge tube 7 under ECR conditions, and thermally desorb deposits on the inner peripheral surface of the plasma discharge tube 7. At the same time, a diverging magnetic field is formed near the plasma hood 33 to irradiate the sample 20 with argon ions, thereby etching and removing the natural oxide film formed on the surface of the sample 20. The time required for this etching is desirably 3 minutes or more in order to obtain a sufficient etching effect.

In this process, the only solid boundary in contact with the plasma is the film 40 formed on the inner peripheral surface of the plasma discharge tube 7, and the sputtering effect of argon ions (argon ions scattering into the gas and colliding with nearby object surfaces) However, due to this effect of knocking out atoms on the object surface, only Si is mixed into the plasma. Therefore, elements other than Ar and Si do not reach the surface of the sample 20, and metal elements, oxygen, etc. The sample 20 does not contain any impurities.

After such pretreatment is completed, an epitaxial film is formed on the sample 20.

That is, the second conveying pipe 27 is used instead of the etching gas.
7.5 SCCM of SiH4 was supplied as a film forming raw material gas, and 42.5 SCCM of SiH4 was supplied as a dilution gas from the third conveying pipe 28.
CCM H2 is supplied to the sample chamber 2, and epitaxial growth is performed on the surface of the sample 20 under the same conditions and principle as in the pretreatment process described above to form an epitaxial film 41, which is a single silicon black film. Even in this process, the solid boundary in contact with the plasma 60 is only the film 40 formed on the inner peripheral surface of the plasma discharge tube 7, and due to the etching effect of hydrogen ions and hydrogen radicals, the components mixed into the plasma are silicon. Only. Therefore, only silicon that is reduced and isolated according to the following reaction formula is contained in the epitaxial film 41 formed on the surface of the sample 20.

SiH4→Si+2Hz In the above manner, an epitaxial film 41 that does not contain impurities such as metal elements and oxygen is formed, and the intended purpose is achieved.

In the above embodiment, in order to prevent plasma from being generated in the cavity resonator 39, the inside of the cavity resonator 39 is
Although the pressure was set at a sufficiently low level (approximately a vacuum state) of 10-"Pa or less to prevent oxygen from entering the membrane, the cavity resonator 39
It is also possible to prevent oxygen from entering the membrane 41 by setting the pressure inside the cavity resonator 39 to a high pressure that does not generate plasma while keeping the interior surrounded by a gas that is harmless to the llI 41.

Specifically, the first valve 12a is opened, and an inert gas such as Ne or He or H2, which is harmless to the membrane 41, is supplied to the resonance chamber 1 from the injection pipe 12, while the atmosphere is released from the exhaust pipe 14. replacing the inside of the cavity resonator 39 with the inert gas, etc. 9;
Furthermore, a gauge pressure of 0.1 kg/
crn'' fl, l x By setting the pressure to 10'Pa or higher, the incorporation of trace amounts of oxygen into the film is prevented, and as in the previous embodiment, the epitaxial film 41 does not contain impurities such as metal elements and oxygen. can be formed and the intended purpose can be achieved.

FIG. 2 is a cross-sectional view schematically showing an ECR plasma vapor deposition apparatus according to a second embodiment, in which the waveguide 5 and the resonant chamber wall 1a are integrally formed, and the resonant chamber 1 to the inside of the waveguide 5 is an airtight space.

That is, this plasma vapor phase apparatus connects the resonance chamber wall 1a via the microwave conversion joint 42 formed in a substantially conical shape.
and waveguide 5 are integrally formed, and furthermore, this waveguide 5
is bent as appropriate, and the exhaust pipe 14 and pressure regulating valve 43 are connected to its tip.

A microwave oscillator 44, a first stub 46 for adjusting the phase of the microwave radiated from the antenna 45 of the microwave oscillator 44, a vacuum pump 13, and a plasma discharge tube are disposed on the wall of the waveguide 5. An appropriate number of probes 47 detect the incident power to the plasma discharge tube 7 and the reflected power from the plasma discharge tube 7.
and an appropriate number of second stubs 48 that adjust the phase of the microwave propagating toward the resonance chamber 1 in order to minimize the reflected power and maximize the incident power, each of which is attached in an airtight state. It is being That is, the first stub 46
The second stub 48 and the probe 47 are hermetically attached to the waveguide 5 by a linear introducer 49 using a metal bellows, and by a current introduction terminal 50, respectively. Further, the vacuum pump 13 is configured such that the microwave
The waveguide 5 is airtightly attached to the waveguide 5 via a mesh 51 whose opening size is smaller than the microwave cutoff wavelength to prevent leakage to the microwave. Note that the pressure regulating valve 43 maintains the pressure inside the waveguide 5 higher than atmospheric pressure, and the airtight connection part, for example, the linear introducer 4
9. Prevents a small amount of air from leaking from the current introduction terminal 50 portion.

In this embodiment, as in the first embodiment, the inside of the resonant chamber 1 is maintained at an appropriate pressure, that is, the cavity resonator 39 is maintained at a low pressure range where no plasma is generated, or a gas atmosphere that is harmless to the membrane is maintained. It is possible to generate plasma only within the plasma discharge tube 7 by maintaining the pressure within a high pressure range in which no plasma is generated, thereby forming a film 41 that does not contain impurities. In this case, it goes without saying that the inside of the waveguide 5 is also maintained at the same pressure as the resonance chamber 1.

In addition, since the introduction window is omitted in this embodiment, it is possible to eliminate microwave induction loss due to this introduction window.
High efficiency of film formation can be achieved.

Table 1 shows the film 41 in the plasma vapor phase apparatus according to the present invention.
The metal concentration in the film 41 and the oxygen concentration in the film 41 are shown in comparison with a conventional example.

In the table, inventions ■ to ■ are all conditions set so that plasma is generated only within the plasma discharge tube, and invention In the case where the inside of the cavity 39 is set to atmospheric pressure: The present invention (2) is the plasma vapor phase growth apparatus shown in FIG. In the plasma vapor deposition apparatus shown in FIG. 1, the inside of the cavity resonator 39 is replaced with H2, and
Gauge pressure inside 0.1 kg/crrr' (1,1x1
When the pressure is set to 0'Pa1 or more; the present invention (■) is the second
In the plasma vapor phase growth apparatus shown in the figure, when the cavity resonant part 39 is set to a low pressure of l x 10-'Pa or less; and a gauge pressure of 0.1 kg/cm' (1.1 x 10'
When the pressure is set to more than Pa): are shown respectively.

Furthermore, in the conventional example, the apparatus shown in FIG.
was heated to 800°C, 50 SCCU of argon was supplied to the plasma generation chamber 71 from the direction of arrow Y, and the pressure inside the plasma generation chamber 71 was set to 4 X 10-'Pa and EC
A film was formed by generating plasma under R conditions. The thickness of the epitaxial film 41 was 3 μm, the analysis position of the sample was set at 1000 points from the surface of the film, and the metal concentration in the film was analyzed using secondary ion mass spectrometry.
゜Table 1 As is clear from this table, metal contamination in the film was found to be significantly reduced in Examples 1 to 2 of the present invention compared to the conventional example. In addition, in the present invention (2), since the cavity resonator 39 is set to atmospheric pressure, a small amount of oxygen leaks into the sample chamber 2 through the attachment part of the plasma discharge tube 7, and oxygen is detected in the film. When the cavity resonator 39 is brought into a vacuum state or when the gas is replaced with a predetermined gas (inventions 1 to 2), no oxygen is detected in the film. That is, the present invention ■～■
In this case, all the impurities were removed and a semiconductor with excellent layer quality could be obtained.6 Furthermore, since the introduction window was omitted in the present inventions There is no induction loss due to absorption of microwaves in the introduction window, and the film growth rate (nm
/m1n) increases, and productivity can be improved.

As described above, the film 41 formed using the plasma vapor deposition apparatus according to the present invention does not contain any impurities, and a semiconductor element with excellent electrical characteristics can be obtained.

Further, the manufacturing of the device and the formation of the film can be performed extremely rationally. Furthermore, by integrally forming the resonant chamber wall 1a and the waveguide 5, the introduction window can be omitted, the growth rate of the film 41 can be increased, productivity can be improved, and the desired result can be achieved. can achieve the objectives of

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that changes can be made without departing from the gist of the invention. The resonance chamber 1 and the sample chamber 2 may be configured as separate bodies, and the plasma discharge tube 7 may be disposed within the apparatus body. The pressure set in the examples is not particularly limited as long as it provides the desired effect.

light! 4. Problems As detailed above, 11. In the plasma vapor deposition apparatus according to the present invention, the supply mechanism for supplying the film forming gas or the etching gas is connected to the sample chamber, and one end is connected to the sample chamber side. Since the plasma discharge tube that opens to the resonance chamber is disposed in the main body of the apparatus in an airtight state, and the plasma discharge tube is made of a microwave-transparent material, it is possible to generate plasma within the plasma discharge tube. can be generated.

Therefore, after a film-forming gas is introduced into the sample chamber to form a film on the inner peripheral surface of the plasma discharge tube, a film may be formed on the sample in the sample chamber, or the inner peripheral surface of the plasma discharge tube may be coated with a film. When a film is formed on the sample in the sample chamber using a device coated with an element or compound contained in the sample gas,
Impurities such as metal elements and carbon are not mixed into the sample, and a semiconductor with excellent electrical properties can be obtained.

Moreover, this device can be manufactured very rationally and easily.

Furthermore, this apparatus is equipped with a switching means for switching between the film-forming gas and the etching gas, so that the film-forming process and the etching process can be switched freely, and the pre-treatment for film formation and the cleaning inside the apparatus can also be performed freely. can be done.

Furthermore, after forming a film on the inner circumferential surface of the plasma discharge tube, the thickness of the film can be adjusted by introducing etching gas into the sample chamber. The thickness can be adjusted.

Furthermore, since an etching gas can be introduced into the sample chamber to etch the inner circumferential surface of the plasma discharge tube, the film raw material components attached to the plasma discharge tube are prevented from peeling off from the plasma discharge tube. There are no negative effects.

Plasma discharge can be achieved by maintaining the outside of the plasma discharge tube in a low pressure range where plasma does not occur, or by maintaining the outside of the plasma discharge tube in a high pressure range where plasma is not generated while maintaining a gas atmosphere that is harmless to film formation. By generating plasma only within the tube, it is also possible to prevent oxygen from entering the film, making it possible to obtain a semiconductor of higher quality.

Furthermore, by integrally communicating the inside of the waveguide and the resonance chamber, and creating an airtight space from the resonance chamber to the inside of the waveguide, it is possible to omit the introduction window, eliminating induction loss. , the growth rate of the film can be increased, and productivity can be improved.

In addition, in this device, as described above, either the outside of the plasma discharge tube is maintained in a low pressure range where plasma is not generated, or the outside of the plasma discharge tube is maintained in a gas atmosphere that is harmless to film formation while plasma is generated. By maintaining the pressure in a high pressure range and generating plasma only within the plasma discharge tube, it is possible to prevent oxygen from entering the film, and it is possible to obtain a semiconductor of excellent quality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing a first embodiment of a plasma vapor phase growth apparatus according to the present invention, (A) is an overall view, and (B)
2 is an enlarged sectional view of a main part, FIG. 2 is a sectional view schematically showing the second embodiment, and FIG. 3 is a sectional view schematically showing a conventional example. l...Resonance chamber, 2...Sample chamber, 3...Device main body,
4... Excitation coil, 5... Waveguide, 6... Supply mechanism, 7... Blasma discharge tube, 20... Sample, 25...
...Switching means, 40... Film, 41... Epitaxial film.

Claims (10)

[Claims] (1) A device main body consisting of a resonance chamber and a sample chamber, an excitation coil arranged around the resonance chamber and supplied with DC power, and a waveguide for introducing microwaves into the resonance chamber. , a supply mechanism for supplying a film forming gas or an etching gas is connected to the sample chamber, and a plasma discharge tube having one end opened toward the sample chamber is kept airtight from the resonance chamber. A plasma vapor phase epitaxy apparatus, characterized in that the plasma discharge tube is disposed within the resonance chamber, and the plasma discharge tube is made of a microwave-transparent material. (2) A film forming method using the plasma vapor phase growth apparatus according to claim (1), which comprises: introducing a film forming gas into the sample chamber to form a film on the inner peripheral surface of the plasma discharge tube; A film forming method comprising forming a film on a substrate placed in the sample chamber. (3) The plasma vapor phase growth apparatus according to claim (1), wherein the inner peripheral surface of the plasma discharge tube is coated with an element or compound contained in the film forming gas. . (4) After forming a film on the inner peripheral surface of the plasma discharge tube, an etching gas is introduced into the sample chamber to adjust the thickness of the film. A method of using the plasma vapor phase growth apparatus according to item (2). (5) A method of using the plasma vapor phase epitaxy apparatus according to claim (1) or claim (3), characterized in that an etching gas is introduced into the sample chamber to etch the inner circumferential surface of the plasma discharge tube. (6) The plasma discharge tube according to claim (1) or claim (3), wherein the outside of the plasma discharge tube is maintained in a low pressure range where no plasma is generated, and plasma is generated only within the plasma discharge tube. How to use a phase growth device. (7) Claim (1) characterized in that plasma is generated only within the plasma discharge tube by maintaining the outside of the plasma discharge tube in a gas atmosphere that is harmless to film quality and in a high pressure range where no plasma is generated. Or a method of using the plasma vapor phase growth apparatus according to claim (3). (8) Claim (1) characterized in that the microwave waveguide and the resonant chamber wall are integrally formed, and an airtight space extends from the resonant chamber to the inside of the microwave waveguide.
) or the plasma vapor phase growth apparatus according to claim (3). (9) A method of using the plasma vapor phase epitaxy apparatus according to claim (8), characterized in that the outside of the plasma discharge tube is maintained in a low pressure range where plasma is not generated, and plasma is generated only within the plasma discharge tube. . (10) According to claim (8), the outside of the plasma discharge tube is maintained in a gas atmosphere that is harmless to film quality and maintained in a high pressure range where plasma is not generated, and plasma is generated only within the plasma discharge tube. How to use plasma vapor phase growth equipment.