JPH1174204A - Method and device for manufacturing semiconductor thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high-quantity semiconductor thin film at a low temperature and create the crystallinity of the semiconductor thin film with improved controllability by forming a semiconductor thin film through controlling the heating temperature, when forming it. SOLUTION: A vacuum chamber 11 is evacuated by evacuation vent 12. A plasma generation room 16 is mounted to the vacuum chamber 11, and an induction coil 13 is wound around the plasma generation room 16. A high-frequency power that is generated by a high-frequency transmitter 14 and is set to a specific parameter by a matching equipment 25 applied to the induction coil 13, an induced magnetic field is generated, and an electromagnetic field is applied to the plasma generation room 16. Generated plasma 50 is heated by a heating power supply 18, using a substrate-heating heater 29 and reaches a substrate holder 19, where the temperature is controlled by a temperature monitor 28, and a silicon thin film of polycrystalline silicon or amorphous silicon is deposited on a substrate 20 which is placed on the holder 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor thin film such as polycrystalline silicon (poly-Si) or amorphous silicon, and a manufacturing apparatus for realizing the method. The present invention relates to a method and an apparatus for manufacturing a semiconductor thin film capable of performing thin film growth at low temperature with good controllability.

[0002]

2. Description of the Related Art Conventionally, a thin film of amorphous silicon or polycrystalline silicon is often formed by a chemical vapor deposition (CVD) method of depositing a thin film from a gas phase on a substrate. Specifically, at atmospheric pressure (normal pressure) or under reduced pressure, SiH ₄
A process for thermally decomposing a material gas such as silicon hydride such as (monosilane) or Si ₂ H ₆ (disilane) or a silicon halide such as SiH ₂ Cl ₂ (dichlorosilane), or a DC power to the material gas under reduced pressure Alternatively, the deposition from the gaseous phase as described above is realized through a process of applying high frequency power to plasma-decompose the source gas.

For example, in a typical conventional polycrystalline silicon forming apparatus using a low pressure CVD apparatus, a vacuum vessel is evacuated to a vacuum by a vacuum pump, and then the vacuum vessel and a substrate in the vessel are passed through, for example, an external heating heater. Is heated, and mainly monosilane (S) introduced into the container from the gas inlet is introduced.
A raw material gas such as iH ₄ ) is heated above the decomposition temperature. When the intermediate product obtained by the pyrolysis process reaches the substrate, amorphous silicon is deposited, for example, if the substrate temperature is set to about 600 ° C. or lower, while the substrate temperature is set to about 600 ° C. or higher. Then, polycrystalline silicon is deposited.

However, a conventional low pressure CVD method or a plasma CVD method utilizing the above-described thermal decomposition process or plasma decomposition process.
In the method of manufacturing a silicon thin film by the VD method, when forming polycrystalline silicon, the formation temperature (substrate temperature) is set to about 6
It is necessary to set it to 00 ° C or higher. For this reason, the price of the semiconductor thin film manufacturing apparatus is increased, and the usable substrate material is limited, which is a major problem for realizing the manufacture of an industrially inexpensive device. Further, the size (volume and / or area) of the heating region is limited by the capability of the heater, and the realization of a large-area thin film that is most required for expanding the application of the polycrystalline silicon thin film is required.
Have difficulty.

[0005] One method that can avoid these problems is a plasma CVD method (ECR plasma CVD method) using microwave electron cyclotron resonance (ECR). FIG. 6 schematically shows a typical configuration example of an ECR plasma CVD apparatus.

In an apparatus having a configuration as shown in FIG.
Plasma can be generated even in a low-pressure SiH ₄ atmosphere around Torr. Therefore, using a device having such a configuration, for example, after making SiH ₄ gas into a highly excited state, a microcrystalline silicon film or a polycrystalline silicon film is formed on a substrate at a relatively low substrate heating temperature of about 300 ° C. On the other hand, a method has been proposed in which an amorphous silicon film is deposited on a substrate at a substrate heating temperature lower than this (for example, about 50 ° C.), and a high-quality semiconductor (silicon) thin film is manufactured at a low temperature.

Here, the configuration of the apparatus shown in FIG. 6 will be described in more detail. The vacuum chamber 61 is evacuated to a vacuum through an exhaust hole 62. The plasma generation chamber 65 has a waveguide 63.
At the same time, a microwave is introduced from the microwave power supply 64 through the, and a magnetic field is applied by the electromagnet coil 66. As a source gas, a monosilane (SiH ₄ ) gas is mainly introduced from a source gas container (source gas source) 60 into the vacuum chamber 61 through a gas inlet 67. By setting the strength of the applied magnetic field so as to satisfy the electron cyclotron resonance condition, a plasma 80 having a high degree of dissociation can be obtained in the plasma generation chamber 65. Plasma 80 generated
Passes through the plasma extraction window 68 and passes through the vacuum chamber 61.
Substrate holder 69 heated to about 250 ° C.
And polycrystalline silicon is deposited on the surface of the substrate 70 placed on the holder 69.

[0008]

However, the manufacturing method using the microwave ECR plasma CVD method as described above has some problems to be solved.

First, in the above-mentioned method, although a semiconductor thin film can be formed at a low temperature, a resonance magnetic field is required as shown in the apparatus configuration of FIG.

For example, when a microwave of about 1.25 GHz is introduced into the plasma generation chamber 65, it is necessary to generate a high magnetic field of 875 Gauss which resonates therewith. For that purpose, a large magnetic field generator (such as an electromagnet coil) is required, and the size of the plasma generation chamber (plasma generation source) 65 is limited by the size of the magnet.
For example, in order to generate such a high magnetic field by the electromagnetic coil 66 as illustrated in FIG. 6, it is necessary to flow a large current of the order of several hundreds of A. Weight becomes very large.

More specifically, in the field of VLSI, the diameter of a silicon substrate is increasing, and it is required to deposit a semiconductor thin film on a wafer having a diameter of about 300 mm.
In addition, in a liquid crystal display using a thin film transistor (TFT), whose production has been dramatically increased in recent years, it is required to deposit a semiconductor thin film on a large substrate exceeding 500 mm × 500 mm. Microwave ECR for batch processing of such large areas
When the plasma CVD apparatus is designed, the required weight of the electromagnetic coil 66 is calculated to be several hundred kg. Also,
In order to supply a necessary DC current to these electromagnet coils 66, a power supply having an output of several tens of kW is required. Further, a cooling mechanism such as water cooling is required in order to prevent the operation efficiency from being deteriorated due to heating of the electromagnet coil 66.

As described above, the entire apparatus becomes large and complicated, resulting in a low-efficiency system.

The introduction of the microwave into the plasma generation chamber 65 for generating the ECR plasma 80 is a local power radiation supply using the waveguide 63 or the coil antenna. For this reason, the size (volume / area) of the plasma generation region is limited. In other words, ECR
Since the plasma 80 is spot-ignited, it is difficult to increase the size of the plasma generation region and deposit a semiconductor thin film over a large area.

In view of the above, it has been conventionally determined that it is difficult to form a thin film over a large area, which is expected to be in great demand as an application field of a semiconductor thin film.

The above problems can be overcome by using multiple small ECR plasma sources or by moving and processing the substrate. However, such countermeasures cause a drastic decrease in deposition rate, and the possibility of forming a semiconductor thin film at low temperature and high speed is lost. This has hindered the practical use of such a method for producing a large-area semiconductor thin film.

Further, in the manufacturing method and the manufacturing apparatus using the conventional ECR plasma 80 using a high magnetic field, a relatively large magnetic field also exists near the substrate 70 to be processed. Therefore, the plasma 80 generated in the plasma generation chamber 65 moves along the magnetic field gradient, and both charged particles of ions and electrons enter the surface of the substrate 70 with high energy. As a result, there is a high possibility that the substrate 70 or a film formed on the surface thereof and functioning as a base film may be damaged. Moreover, since the magnetic field near the substrate 70 is often non-uniform, the incidence of charged particles on the substrate 70 and the like also becomes non-uniform, and as a result, non-uniformity or local damage is likely to occur. This point has also been a factor that hinders the practical use of the above manufacturing method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor thin film formed by controlling a substrate temperature by forming a high quality semiconductor thin film at a low temperature. It is an object of the present invention to provide a method of manufacturing a semiconductor thin film and a manufacturing apparatus for the same, which can produce different properties (that is, a polycrystalline thin film or an amorphous thin film) with good controllability.

[0018]

According to the present invention, there is provided a method of manufacturing a semiconductor thin film, comprising: supplying a source gas to a vacuum chamber;
The supplied source gas is converted into a high frequency inductively coupled plasma (ICP) by applying a high frequency power.
ma) decomposing by plasma decomposition using, and forming a predetermined semiconductor thin film on the substrate by a chemical vapor deposition process using the decomposed raw material gas,
The crystal state of the formed semiconductor thin film is controlled by controlling the heating temperature of the substrate during the formation of the semiconductor thin film, thereby achieving the above object.

In one embodiment, the source gas is a gas containing silicon.

In one embodiment, the source gas is a mixed gas obtained by mixing hydrogen with a gas containing silicon.

[0021] Preferably, the heating temperature of the substrate during the formation of the semiconductor thin film is set in a range from about 50 ° C to about 550 ° C.

The frequency of the applied high frequency power is about 5
It can be set from 0 Hz to about 500 MHz.

In one embodiment, the high-frequency inductively-coupled plasma is generated using a means for generating a magnetic field provided in or near the high-frequency inductively-coupled plasma generating region.

The means for generating the magnetic field may be an electromagnetic coil. Alternatively, the means for generating a magnetic field may be a permanent magnet having a predetermined magnetic flux density.

Preferably, the pressure in the generation region of the high frequency inductively coupled plasma at the time of forming the semiconductor thin film is set to about 5 ×
It is set from 10 ⁻⁵ Torr to about 2 × 10 ⁻² Torr.

In one embodiment, a step of measuring an emission spectrum of the high-frequency inductively coupled plasma at least in the vicinity of the substrate, and an emission peak intensity [S
iH], the emission peak intensity from Si atoms [Si], and the relative ratio between the emission peak intensity from H atoms [H] ([S
i] / [SiH] ratio and [H] / [SiH] ratio, and the relative ratio is ([Si] / [SiH])>
Adjusting predetermined process parameters so as to satisfy at least one of 1.0 and ([H] / [SiH])> 2.0.

The predetermined process parameters to be adjusted include at least the pressure in the generation region of the high frequency inductively coupled plasma, the supply flow rate of the source gas, the ratio of the supply flow rate of the source gas, the value of the applied high frequency power, One of the following.

The apparatus for manufacturing a semiconductor thin film according to the present invention comprises a supply means for supplying a raw material gas to a vacuum chamber, and a high frequency inductively coupled plasma (ICP) by applying a high frequency power to the supplied raw material gas. ICP means for decomposing by a plasma decomposition used and forming a predetermined semiconductor thin film on a substrate by a chemical vapor deposition process using the decomposed raw material gas, and a heating temperature of the substrate in the chemical vapor deposition process Substrate temperature control means for controlling the heating temperature of the substrate during the formation of the semiconductor thin film, whereby the crystal state of the semiconductor thin film to be formed is controlled. Thereby, the above-mentioned object is achieved.

In one embodiment, the source gas is a gas containing silicon.

In one embodiment, the source gas is a mixed gas obtained by mixing hydrogen with a gas containing silicon.

Preferably, the heating temperature of the substrate during the formation of the semiconductor thin film is set in a range from about 50 ° C. to about 550 ° C.

The frequency of the high frequency power to be applied is about 5
It can be set from 0 Hz to about 500 MHz.

In one embodiment, the apparatus further comprises a means for generating a magnetic field provided in or near the generation region of the high frequency inductively coupled plasma.

The means for generating the magnetic field may be an electromagnetic coil. Alternatively, the means for generating a magnetic field may be a permanent magnet having a predetermined magnetic flux density.

Preferably, the pressure in the region where the high-frequency inductively coupled plasma is generated at the time of forming the semiconductor thin film is about 5 ×
It is set from 10 ⁻⁵ Torr to about 2 × 10 ⁻² Torr.

In one embodiment, means for measuring an emission spectrum of the high-frequency inductively coupled plasma at least in the vicinity of the substrate, and an emission peak intensity [S] from the SiH molecule in the measured emission spectrum.
iH], the emission peak intensity from Si atoms [Si], and the relative ratio between the emission peak intensity from H atoms [H] ([S
i] / [SiH] ratio and [H] / [SiH] ratio, and the relative ratio is ([Si] / [SiH])>
Means for adjusting predetermined process parameters so as to satisfy at least one of 1.0 and ([H] / [SiH])> 2.0.

The predetermined process parameters to be adjusted include at least the pressure in the generation region of the high frequency inductively coupled plasma, the supply flow rate of the source gas, the ratio of the supply flow rate of the source gas, the value of the applied high frequency power, One of the following.

According to the present invention, the conventional microwave ECR
The formation temperature of semiconductor thin films, especially polycrystalline silicon, which has been realized only by plasma CVD, is reduced by inductive coupling using inductively coupled plasma (ICP) without using a high magnetic field as a plasma source instead of microwave ECR. This is realized by using a plasma CVD (ICPCVD) apparatus. By using an inductively coupled plasma (ICP), the SiH ₄ gas can be plasma-decomposed uniformly over a large deposition area in a low pressure region without requiring a large magnetic field generator.

Specifically, in the conventional method, when the SiH ₄ gas having a high dissociation energy and being hardly decomposed is decomposed into plasma, a resonance phenomenon (EC
R) is used to generate low-pressure plasma with a high electron temperature. For this reason, the size of a magnetic field generator, a microwave waveguide, and the like increases, and it is difficult to reduce the size. Furthermore, it is difficult to deposit a uniform semiconductor thin film on a large area. In contrast, according to the present invention, a high-frequency inductively coupled plasma, which is a plasma source that does not use a high magnetic field and a microwave, creates a low-pressure plasma in a high-density plasma state that is uniformly and sufficiently excited over a large area. Take advantage of what is possible. As a result, it is possible to deposit a high-quality film without causing damage while obtaining a sufficiently high deposition rate.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, typical embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It is the schematic which shows typically the structure of the ICPCVD apparatus in embodiment.

More specifically, the vacuum chamber 11 is evacuated from the exhaust port 12 to a vacuum. A plasma generation chamber 16 is attached to the vacuum chamber 11, and an induction coil 13 is wound around the plasma generation chamber 16. High-frequency power generated by the high-frequency oscillator 14 and set to predetermined parameters (for example, frequency) by the matching unit 25 is applied to the induction coil 13. In the plasma generation chamber 16, at least the vicinity of the place where the induction coil 13 is installed is made of an insulating material such as a quartz tube. By applying high-frequency power to the induction coil 13, an induction magnetic field is generated, and an electromagnetic field is applied to the plasma generation chamber 16.

A source gas containing a silicon element such as a monosilane (SiH ₄ ) gas is supplied to a source gas container (source gas source).
30 is introduced into the vacuum chamber 11 through the gas inlet 17. By setting the number of turns of the induction coil 13 so as to satisfy the inductive coupling condition with the applied high frequency power, a high frequency inductively coupled plasma (ICP) 50 having a high degree of dissociation is obtained in the plasma generation chamber 16. The generated plasma 50 is heated by a heating power supply (temperature control heating power supply) 18 using a substrate heater 29 and the temperature of the substrate holder 1 is controlled by a temperature monitor 28.
9, a silicon thin film (polycrystalline silicon or amorphous silicon) is deposited on the surface of the substrate 20 placed on the holder 19.

The frequency of the high-frequency power applied to the induction coil 13 may be set to a frequency at which coupling by the induction coil 13 is possible and at which the discharge plasma 50 can be generated, for example, in a range of about 50 Hz to about 500 MHz. It is preferable to set The lower limit of about 50 Hz in the above range is a practical AC frequency that does not look like DC when viewed from the plasma 50. In addition, the upper limit of about 500
MHz is the upper limit of the frequency at which an electric field can be applied by a coil antenna without using a waveguide.

Typically, the frequency of the high-frequency power applied to the induction coil 13 is set in a range of about 10 MHz to about 100 MHz, for example, 13.56 MHz. However, the same effect can be obtained if the discharge plasma 50 can be generated in such a wide frequency range.

It should be noted that the applied high frequency was 13.5 above.
When the frequency is set to 6 MHz, the current required to generate the plasma 50 is as small as several mA, and
The number of turns of 3 may be as small as about 2 turns. Therefore, miniaturization of the overall size of the device can be easily achieved.

Although a high-density plasma 50 is generated, unlike the ECR plasma CVD apparatus,
The magnetic field is formed only in the vicinity of the induction coil 13, and is not formed in the vicinity of the substrate 20 to be processed. Therefore,
The problem of charged particles entering the substrate along the magnetic field gradient, which is a problem in the ECR plasma CVD apparatus, does not occur, and substrate damage is suppressed.

Further, in the apparatus configuration of the present invention, the type of the semiconductor thin film to be formed can be appropriately set by appropriately selecting the source gas. For example, in order to form a silicon thin film, a material containing a silicon element such as silicon hydride such as SiH ₄ (monosilane) or Si ₂ H ₆ (disilane) or silicon halide such as SiH ₂ Cl ₂ (dichlorosilane) is used. The gas may be supplied at least. Alternatively, a silicon carbide (SiC) film can be formed by mixing methane (CH ₄ ) with the supplied source gas.

During the formation of the semiconductor thin film, the pressure in the generation region of the plasma (high frequency inductively coupled plasma = ICP) 50 is preferably about 5 × 10 ⁻⁵ Torr to about 2 × 1 Torr.
Set within the range of 0 ^-2 Torr.

Further, the source gas containing silicon (for example, SiH ₄ ) to be supplied is diluted with another suitable gas such as hydrogen, or the high-frequency power applied to the induction coil 13 is increased to thereby increase the polycrystalline silicon film. Can be formed. This point will be further described with reference to FIGS.

FIG. 2 shows 100% Si at a flow rate of 5 sccm.
Si diluted H ₄ gas with hydrogen gas at a flow rate of 20 sccm
When a H ₄ / H ₂ mixed source gas is introduced (“SiH ₄ / H ₂
5% ") and a flow rate of 10 sc without diluting SiH _4.
cm (described as “SiH ₄ 100%”), the pressure in the vacuum chamber 11 is 1 mT
The measured values of the electrical conductivity (photoelectric conductivity and dark electrical conductivity) of the silicon thin film deposited on the surface of the substrate 20 by supplying the source gas so as to obtain the heating temperature of the substrate 20 at the time of formation. Shown as a parameter.

FIG. 2 shows that in both cases, in the substrate temperature range from room temperature to about 150 ° C., a good photoelectric conductivity and a good light-dark ratio (ie, a ratio between the photoelectric conductivity and the dark electrical conductivity) are obtained. This indicates that an amorphous silicon film has been formed. Also, from the results of X-ray diffraction, it was confirmed that hydrogenated amorphous silicon was formed in this region.

On the other hand, at a substrate temperature of about 150 ° C. or higher, the characteristics of the obtained film differ depending on the presence or absence of hydrogen dilution. That is, when hydrogen is diluted, the dark electric conductivity increases with respect to the substrate temperature of about 150 ° C. or more, indicating that a crystallized film is deposited. In fact, crystallization of the deposited film was also confirmed from X-ray diffraction. On the other hand, when hydrogen was not diluted, the change in dark electrical conductivity was small up to a substrate temperature of about 400 ° C., and the result of X-ray diffraction confirmed that the film did not crystallize but remained amorphous. Was done.

As described above, when performing the hydrogen dilution under the above conditions, an amorphous silicon film is deposited up to a substrate temperature of about 150 ° C., and a polycrystalline silicon film is deposited when the substrate temperature exceeds about 150 ° C. You. However, the above-mentioned boundary temperature of around 150 ° C. at which the deposited film shifts from amorphous (amorphous) to polycrystalline (crystalline) depends on the supply amount and type of the raw material gas, the device configuration, the applied power, the discharge frequency, etc. May vary.

On the other hand, FIG. 3 shows a hydrogen dilution of 5% as described above.
When the pressure of the vacuum chamber 11 was kept constant at about 250 ° C. and the applied high-frequency power was changed in the range of about 100 W to about 1000 W when the SiH ₄ gas was supplied, the chamber was formed at room temperature. 4 shows changes in photo-electric conductivity and dark electric conductivity of a silicon thin film. As a result, the dark electric conductivity increased in a relatively high power region of about 500 W to about 1000 W, and crystallization of the deposited film was confirmed in this region.

Although not shown in FIG. 1, actually, a flow rate regulator for adjusting the gas flow rate from the raw material gas container 30 or the amount of exhaust gas from the exhaust port 12 to the pump is adjusted. The apparatus configuration of FIG. 1 may include a pressure regulator for adjusting the pressure in the vacuum chamber 11 and the like. These regulators are depicted in the configuration of FIG. 4 described below.

In order to cope with the hydrogen dilution of the raw material gas as described above, a hydrogen gas (H ₂ ) container 31 and a SiH A gas container 32 containing a silicon element such as ₄ may be provided.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
It is the schematic which shows typically the structure of the ICPCVD apparatus in embodiment.

In the apparatus configuration of FIG. 4, the same reference numerals are given to the components corresponding to the configuration of FIG. 1, and the description is omitted here. Further, the substrate heating power supply (temperature control heating power supply) 18, the substrate heating heater 29, and the temperature monitor 28 illustrated in FIG. 1 are omitted in FIG.

In the apparatus configuration of FIG. 4, during the deposition process,
The generated light from the plasma 50 is introduced into the spectroscopic device 41 through an optical fiber or the like, and emission spectroscopy is performed to detect a change in a predetermined emission peak intensity. Further, the detected light emission peak intensity is monitored by the data processing device 42, and the discharge pressure, the discharge power, and the feedback circuit 43 to the supply flow rate are formed, so that the flow controller 44,
Feedback control is performed on the pressure regulator 45 and the high-frequency oscillator (power supply) 14. Thereby, the plasma 50
Emission peak intensities of Si, SiH, and H (in this specification, [Si], [SiH], and [H], respectively)
) Is controlled to a predetermined value, whereby a high-quality semiconductor thin film can be stably manufactured.

FIG. 5 shows that, while the substrate temperature is kept constant at 250 ° C., the applied high frequency power, the flow rate of the supplied source gas (eg, SiH ₄ ), and the flow rate ratio of the supplied source gas (eg, H ₂ and SiH ₄ ). The ratio (photoelectric conductivity / dark electric conductivity) to various silicon thin films prepared by changing various process parameters such as a flow ratio with ₄ = dilution ratio or a pressure in a region where the plasma 50 is generated. -Dark electrical conductivity ratio). However, the abscissa represents the emission peak intensity of plasma emission spectroscopy near the substrate 20, which is found in the vicinity of about 400 nm to about 420 nm.
Emission peak intensity [SiH] from iH molecule, about 288 n
S centered around m (about 280 nm to about 290 nm)
emission peak intensity [Si] from i atom, and about 618 n
H centered around m (about 610 nm to about 620 nm)
Relative ratios between them ([Si] / [SiH] ratio and [H] / [Si
H] ratio).

From FIG. 5, [Si]> [SiH] is relatively obtained.
Alternatively, when [H]> [SiH], that is, [S
When the [i] / [SiH] ratio or [H] / [SiH] ratio increases, the light-dark electrical conductivity ratio of the produced silicon thin film decreases, and the crystallization of the deposited thin film is likely to occur. You can see that it is.

From this, in order to obtain a crystalline silicon thin film (polycrystalline silicon) while keeping the substrate temperature at the time of thin film formation, the above-mentioned Si, SiH, The relative ratio of the emission peak intensities of H ([Si], [SiH], and [H]) is
Various process parameters such as high-frequency power to be applied, a flow rate of a supplied source gas (for example, SiH ₄ ), and a flow rate ratio of the source gas (for example, so that [Si]> [SiH] or [H]> [SiH] are satisfied. The flow rate ratio between H ₂ and SiH ₄ ) or the pressure in the region where the plasma 50 is generated may be adjusted. More specifically, ([Si] / [SiH])
> 1.0 and ([H] / [SiH])> 2.0 so that at least one of the above process parameters (for example, the applied high-frequency power, the flow rate of the source gas supplied, the flow rate of the source gas, By adjusting the flow rate ratio or the pressure in the region where the plasma 50 is generated, good crystallinity (polycrystal) can be obtained.
A silicon thin film is obtained.

Alternatively, the ratio of the emission peak intensities of the above Si, SiH and H is [Si]> [SiH] or [H]>
When a thin film is formed at a substrate temperature of about 50 ° C. while maintaining various process conditions to obtain [SiH], a high-quality hydrogenated amorphous silicon film can be obtained.

As described above, the above-described analysis of the emission spectrum of plasma (specifically, the [Si] / [SiH] ratio and the [H] / [Si] ratio, which are the relative ratios of the emission peak intensities of Si, SiH and H, are described.
[The analysis of the [SiH] ratio) is effective as a process monitor for realizing the formation of a thin film with excellent controllability as to whether the film is amorphous or crystalline in producing a good semiconductor thin film at a low temperature. It is.

The film formation rate under various conditions during the data measurement shown in FIG. 5 was about 1 A / sec to about 10 A / sec, which was a sufficiently practical film formation rate.

In the device configuration of the first and second embodiments, as shown in FIG. 1 or FIG. 4, the plasma generation as a means for generating a magnetic field for generating the high frequency inductively coupled plasma (ICP) 50 is performed. An inductive coupling device having an external coil arrangement using a solenoid coil type external coil provided near the chamber 16 as the induction coil 13 is used. However, the application of the present invention is not limited to this. For example, an inductive coupling device having a spiral coil arrangement in which a coil is wound in the same plane, an inductive coupling device having an internal coil arrangement in which an induction coil is installed inside a reaction chamber, and further, an auxiliary magnet is provided in various configurations as described above. Even if it has other configurations, such as those having a configuration with added
Exactly the same effect can be obtained. Further, a permanent magnet having a predetermined magnetic flux density may be provided instead of the electromagnet coil.

[0068]

As described above, according to the present invention, a high-frequency inductively coupled plasma which is a plasma source capable of generating a low-pressure plasma over a large area without using a high magnetic field and a microwave. Is used for plasma decomposition of a source gas when a semiconductor thin film is formed by a CVD method. This eliminates the need for a large magnetic field generator,
Uniformly over a large deposition area at low pressure, SiH ₄
Source gas such as gas can be plasma-decomposed. As a result,
To deposit a high-quality semiconductor thin film (amorphous film or polycrystalline film) while obtaining a sufficiently high deposition rate and without damaging the substrate or a film functioning as a base film of the semiconductor thin film formed on the surface thereof. Thus, a high-performance semiconductor device can be manufactured.

[Brief description of the drawings]

FIG. 1 shows ICPCVD according to a first embodiment of the present invention.
It is the schematic which shows the structure of an apparatus typically.

FIG. 2 is a diagram showing the dependence of photo-electric conductivity and dark electric conductivity of a silicon thin film deposited according to the present invention on the substrate temperature during formation.

FIG. 3 is a diagram showing the dependence of photo-electric conductivity and dark electric conductivity of a silicon thin film deposited according to the present invention on applied high-frequency power during formation.

FIG. 4 shows an ICPCVD according to a second embodiment of the present invention.
It is the schematic which shows the structure of an apparatus typically.

FIG. 5: Photoelectric conductivity / dark electric conductivity ratio (light-dark electric conductivity ratio) for various silicon thin films prepared by varying the other process parameters while keeping the substrate temperature constant. It is a figure which shows the measurement data of.

FIG. 6 is a schematic diagram schematically showing a configuration of an ECR plasma CVD apparatus according to a conventional technique.

[Explanation of symbols]

 Reference Signs List 11 vacuum chamber 12 exhaust port 13 induction coil 14 high-frequency oscillator (high-frequency power supply) 16 plasma generation chamber 17 gas inlet 18 heating power supply (power supply for temperature control heating) 19 substrate holder 20 substrate 25 matching device 28 temperature monitor 29 substrate heating heater 30 Source gas container 31 Container for hydrogen gas 32 Container for source gas containing silicon 41 Spectroscopy device 42 Data processing device 43 Feedback circuit 44 Flow rate regulator 45 Pressure regulator 50 High frequency inductively coupled plasma (ICP)

Continuation of front page (72) Inventor Hideo Sugai 2-4-6 Nakashincho, Kasugai-shi, Aichi

Claims (22)

[Claims] A step of supplying a source gas to a vacuum chamber; and a step of applying the supplied source gas to a high frequency inductively coupled plasma (ICP) by applying a high frequency power.
ma) and forming a predetermined semiconductor thin film on a substrate by a chemical vapor deposition process using the decomposed raw material gas. Controlling the heating temperature of the substrate to control the crystalline state of the semiconductor thin film to be formed. 2. The method according to claim 1, wherein the source gas is a gas containing silicon. 3. The method according to claim 1, wherein the source gas is a mixed gas obtained by mixing hydrogen with a gas containing silicon. 4. A heating temperature of the substrate when forming the semiconductor thin film is set in a range from about 50 ° C. to about 550 ° C.
A method for manufacturing a semiconductor thin film according to claim 1. 5. The frequency of the high frequency power to be applied is about 5
The method for producing a semiconductor thin film according to claim 1, wherein the frequency is set to 0 Hz to about 500 MHz. 6. The high frequency inductively coupled plasma is generated using a magnetic field generating means provided at or near the high frequency inductively coupled plasma generating region.
3. The method for producing a semiconductor thin film according to item 1. 7. The method according to claim 6, wherein said means for generating a magnetic field is an electromagnet coil. 8. The method according to claim 6, wherein said means for generating a magnetic field is a permanent magnet having a predetermined magnetic flux density. 9. A pressure in a region where the high-frequency inductively coupled plasma is generated at the time of forming the semiconductor thin film is set to about 5 × 10 ⁻⁵ To
2. The method of manufacturing a semiconductor thin film according to claim 1, wherein the pressure is set to about 2 × 10 ^-2 Torr from rr. 10. A step of measuring an emission spectrum of the high-frequency inductively coupled plasma at least in the vicinity of the substrate; and a step of measuring an emission peak intensity [SiH] from SiH molecules and Si atoms in the measured emission spectrum. Measuring the relative ratio ([Si] / [SiH] ratio and [H] / [SiH] ratio) between the emission peak intensity [Si] and the emission peak intensity [H] from H atoms; Adjusting predetermined process parameters such that the ratio satisfies at least one of the following relationships: ([Si] / [SiH])> 1.0 and ([H] / [SiH])>2.0; The method for producing a semiconductor thin film according to claim 1, further comprising: 11. The predetermined process parameter to be adjusted includes at least a pressure in a generation region of the high frequency inductively coupled plasma, a supply flow rate of the source gas, a ratio of a supply flow rate of the source gas, and a ratio of the applied high frequency power. The method of manufacturing a semiconductor thin film according to claim 10, wherein the value is one of the following values: 12. A supply means for supplying a raw material gas to a vacuum chamber, and supplying the supplied raw material gas to a high-frequency inductively coupled plasma (ICP) by applying high-frequency power.
ICP means for decomposing by a plasma decomposition using ma) and forming a predetermined semiconductor thin film on a substrate by a chemical vapor deposition process using the decomposed raw material gas; Substrate temperature control means for controlling the heating temperature of the semiconductor thin film formed by controlling the heating temperature of the substrate when the semiconductor thin film is formed by the substrate temperature control means. Semiconductor thin film manufacturing equipment. 13. The semiconductor thin film manufacturing apparatus according to claim 12, wherein said source gas is a gas containing silicon. 14. The apparatus according to claim 12, wherein the source gas is a mixed gas obtained by mixing hydrogen with a gas containing silicon. 15. The semiconductor thin film manufacturing apparatus according to claim 12, wherein a heating temperature of said substrate when said semiconductor thin film is formed is set in a range from about 50 ° C. to about 550 ° C. 16. The apparatus for manufacturing a semiconductor thin film according to claim 12, wherein the frequency of the applied high-frequency power is set to about 50 Hz to about 500 MHz. 17. The apparatus for manufacturing a semiconductor thin film according to claim 12, further comprising means for generating a magnetic field provided at or near a region where said high frequency inductively coupled plasma is generated. 18. The apparatus according to claim 17, wherein the means for generating the magnetic field is an electromagnet coil. 19. The apparatus according to claim 17, wherein said means for generating a magnetic field is a permanent magnet having a predetermined magnetic flux density. 20. The pressure in the region where the high-frequency inductively coupled plasma is generated at the time of forming the semiconductor thin film is set to about 5 × 10 ⁻⁵ T
2. The method according to claim 1, wherein the pressure is set to about 2 × 10 ⁻² Torr from orr.
3. The apparatus for manufacturing a semiconductor thin film according to 2. 21. A means for measuring an emission spectrum of the high-frequency inductively coupled plasma at least in the vicinity of the substrate; and an emission peak intensity [SiH] from SiH molecules and an intensity from Si atoms in the measured emission spectrum. Means for measuring the relative ratio ([Si] / [SiH] ratio and [H] / [SiH] ratio) between the emission peak intensity [Si] and the emission peak intensity [H] from H atoms; Means for adjusting predetermined process parameters such that the ratio satisfies at least one of the following relationships: ([Si] / [SiH])> 1.0 and ([H] / [SiH])>2.0; The apparatus for manufacturing a semiconductor thin film according to claim 12, further comprising: 22. The predetermined process parameter to be adjusted includes at least a pressure in a generation region of the high frequency inductively coupled plasma, a supply flow rate of the source gas, a ratio of a supply flow rate of the source gas, and a ratio of the applied high frequency power. 22. The apparatus for manufacturing a semiconductor thin film according to claim 21, wherein the value is one of the following values: