JPS6314876A - Amorphous thin film forming device - Google Patents

Abstract

PURPOSE:To form uniform thin films on both faces of a substrate by disposing a coil and AC power source which generate a magnetic field in the direction orthogonal with an electric field for discharge generated between two sets of plural sheets of parallel electrodes between which the substrate of an electronic device is held in place. CONSTITUTION:The substrate 10 is supported at an equal spacing between the electrodes 2 and 3. After the inside of a reaction vessel 1 is evacuated by a vacuum pump 9, reactive gases are supplied from a reactive gas pipe 7 into the chamber. A voltage is thereafter impressed from a low-frequency power source 4 to the electrodes 2, 3 to generate glow discharge plasma between the two electrode plates. On the other hand, an AC voltage is impressed to the coil 5 to generate the magnetic field B in the direction orthogonal with the electric field E of the electrode plates. The reactive gases are, therefore, decomposed to radical particles which are electrically neutral by the glow discharge plasma between the respective two electrodes. The radical particles collide against electric charge particles and are corrected of the course thereof; in addition, the magnetic field fluctuates and the radial particles are uniformly splashed to form the uniform amorphous films on both faces of the substrate supported to the outside of the discharge electric field space.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to solar cells, fuel cells, and thin film semiconductors.

This invention relates to an apparatus for dispensing amorphous thin films used in various electronic devices such as electrophotographic photoreceptors and optical sensors.

[Conventional technology]

FIG. 2 shows a conventionally used semiconductor thin film manufacturing apparatus.
This is a well-known technique described in publications such as No.

In the figure, electrodes 02 and 0.9 for forming a discharge space in an airtight reaction vessel 01 are provided downward, and these electrodes 02 and 03 are electrically connected to a high frequency power source 04. On the outer periphery of the reaction vessel 01, J: a coil 0 for generating a magnetic field parallel to the electric field direction in the discharge space.
5 is arranged horizontally and is electrically connected to an AC power source 06. The exhaust hole 07 is connected to a vacuum pump (not shown), and the reaction gas introduction pipe 08 is connected to a vacuum pump (not shown).
3H4) and hydrogen gas (H2) cylinders. Note that 09 is a heater that heats the substrate 010.

Now, place the substrate 010 on the electrode 03.1H, 1 reaction vessel 0.
After reducing the pressure inside 1 to about 1 mm Hg, a mixed gas of monosilane and hydrogen gas was supplied from the reaction gas inlet pipe 08, and then the electric current 102. A high frequency voltage of 13.5 MHz is applied between O3.

On the other hand, a commercial AC voltage of 50 or 6 QHz is applied to the coil 05, and about io is applied between the electrodes 02 and 03.

Generates a magnetic field for Gaunu. Note that the substrate 010 is.

It is heated to about 300°C using heater 09.

The gas such as monosilane introduced from the reaction gas introduction pipe 08 is transferred to the electric fi02. It is decomposed in the discharge space between the coils 03 and attached to the surface of the substrate 010 while being agitated by the fluctuating magnetic field generated by the coil 05.

Forms an amorphous thin film.

[Problem that the invention seeks to solve]

In the conventional device described above, since the variable magnetic field generated by the coil 05 is applied parallel to the direction of the electric field generated between the two electrodes 02 and 03, the silicon existing in the discharge space between the electrodes 02 and 03 is ions are stirred, and a relatively uniform amorphous thin film is formed on the substrate 010.

but.

(2) The location where the substrate 010 is placed is to the north of the electrode 03, and is located within the discharge space between the electrodes 1i02.08. As a result, they are basically directly hit by high-energy ions.

That is, electrode 02. Due to the electric field E between O3, a Coulomb force F, = qE acts on the ions of the stain charge q.

The ion particles will directly hit the substrate O1O and damage the amorphous thin film that is being formed.

■ The direction of the fluctuating magnetic field B generated by coil 05 is
Since it is parallel to the electric field E generated in the discharge space, the ions and electrons in the discharge space are caused to swirl by Larmor motion, but the stirring effect due to the swirling motion is not very large and requires extremely large electric power. Requires.

■ Since the substrate 010 is placed on one pole 03, the size of the substrate 010 that can be processed at one time is limited, and it is difficult to form an amorphous thin film on a substrate with a larger area than the electrode 03. It is not possible to form an amorphous thin film on both sides of the substrate 010 at the same time.

■ Since the substrate 010 is placed on the L of one electrode 03, a uniform film can be formed on a large area j, τ substrate in DC discharge or low frequency discharge where the supply of secondary electrons necessary for sustaining the discharge is woody. Difficult to do.

Therefore, an expensive high frequency power source is absolutely necessary.

[Means for solving problems]

The present invention is an apparatus for forming an amorphous thin film on a substrate using glow discharge plasma. A first discharge electrode is arranged such that its edge faces one surface of the substrate, and a plurality of electrode plates are arranged in parallel in the reaction vessel so that their edges face the lower surface of the substrate. a second discharging electrode disposed in the second discharging electrode; a power supply supplying a discharging voltage between the electrode plates of the first and second discharging electrodes;
．． ), a coil and an AC power supply that surround the reaction vessel and generate a magnetic field orthogonal to the electric field generated between the pair of discharge electrode plates, and a gas that reduces the pressure inside the reaction vessel and supplies a reaction gas. It has a supply device.

[Effect]

In the present invention, 2Mi electrodes for glow discharge plasma generation consisting of a plurality of electrode plates arranged in parallel are prepared,
The substrates are sandwiched and the electrode plates are arranged with their edges facing each other.

Further, a magnetic field was generated by a coil and an AC power source in a direction perpendicular to the electric discharge field generated between each set of electrode plates.

Charged particles drift in a direction perpendicular to the electric field with an initial velocity given by the Coulomb force given by the discharge electric field between the electrode plates and the Lorentz force given by the magnetic field, but when they leave the electric field, That is, the Coulomb force weakens from the edge of the electrode plate toward the surface of the substrate, and the light flies off in a Larmor trajectory due to cyclotron motion due to the Lorentz force.

On the other hand, electrically neutral radical particles deviate from the orbit of the charged particles and try to travel straight.

They collide with charged particles (especially ions) and are forced to modify their course. Moreover, this magnetic field is fluctuating, and the radical particles are scattered uniformly.

Therefore, on both sides of the substrate supported outside the discharge electric field space,
A uniform amorphous thin film will be formed.

〔Example〕

The present invention will be explained below based on an embodiment of the apparatus shown in FIG.

1 is a reaction volume H, in which first and second electrodes 2 and 3 for generating glow discharge plasma are housed facing each other. These electrodes 2 (or 3) are a plurality of long electrode plates arranged in parallel, and are connected to a low frequency power source 4, which will be described later, with adjacent electrodes having different poles.

A low frequency power source 4 and 2 is connected to each electrode plate of the L electrodes 2 and 3 using a commercial frequency of 60 Hz, for example. The carp/I 15 surrounds the reaction vessel 1 and is connected to the AC power source 6. Reference numeral 7 denotes a reaction gas introduction pipe which communicates with a cylinder (not shown) and supplies a mixed gas of monosilane and argon to the reaction vessel 1. Exhaust hole 8
teeth.

It communicates with a vacuum pump 9 to exhaust the gas in the reaction vessel 1.

Now, as shown in the figure, the substrate 10 is supported by appropriate means between the electrodes 2 and 3 so that the edges 2A and 3A face each surface of the substrate 10 and the gaps are equal. After evacuating the inside of the reaction vessel 1 by driving the vacuum pump 9, a mixed gas of monosilane and argon is supplied from the reaction gas introduction pipe 7. The reaction vessel 1 is filled with the above mixed gas and the pressure is reduced to 0.
When the voltage is maintained at 0.05 to 15 Torr and a voltage is applied to the electrodes 2 and 3 from the low frequency power source 4, glow discharge plasma is generated between each electrode plate of the electrodes 2 and 3.

On the other hand, an AC voltage of, for example, 100 Hz is applied to the coil/L 15 to generate a magnetic field B in a direction perpendicular to the electric field E generated between the electrode plates of the electrodes 2 and 3. Note that the magnetic flux density may be about 10 Gauss.

Among the gases supplied from the reaction gas introduction pipe 7, monosilane gas is decomposed into radical Si by glow discharge plasma generated between the electrode plates of the electrodes 2 and 3, and adheres to the surface of the substrate 10 to form a thin film.

At this time, charged particles such as argon ions.

Due to the electric field E between each electrode plate of electrode 2 or 8 -o
The so-called ExB drift movement is caused by the linker F, = qE and the Lorentz force F2 = q (VXB).

Note that ■ is the speed of charged particles.

That is, it flies out in a direction perpendicular to the electrodes 2 and 8 and flies toward the substrate 10 with an initial velocity given by the EXB drift. However, outside the discharge space where the influence of the electric field generated between the electrode plates of electrodes 2 and 8 is small,
Due to the cyclotron movement caused by the magnetic field B generated by the coil 6, it flies in a Larmor orbit.

Therefore, charged particles such as argon ions will not directly hit the substrate 10.

On the other hand, the electrically neutral radicals Si are not affected by the magnetic field B, deviate from the trajectory of the charged particle group, reach the substrate 10, and form an amorphous thin film on its surface. At this time, the radical Si collides with the charged particles traveling in the Larmor orbit, so that an amorphous thin film is formed not only in front of the electrodes 2 and 3 but also spread to the left or right. Moreover, since the magnetic field B is varied, it is possible to uniformly form an amorphous thin film on both sides of the substrate 10.

Furthermore, in this embodiment, since the substrate 10 is arranged vertically, amorphous canals adhering to the inner surfaces of the two reaction vessels gxo and the electrodes 2 and 3 are less likely to fall and contaminate the surfaces thereof.

〔Effect of the invention〕

According to the present invention, uniform amorphous thin films can be formed on both sides of a substrate in the production of various devices such as solar cells, fuel cells, and electrophotographic photoreceptors.

Since large areas will be formed, it is extremely valuable for industry.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an apparatus showing one embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing a conventional device. DESCRIPTION OF SYMBOLS 1... Reaction container, 2, 3... Electrode, 4... Low frequency power supply, 5... Coil, 6... AC power supply, 7... Reaction gas introduction pipe, 8... Exhaust Hole, 9...vacuum pump,
10...Substrate.

Claims (1)

[Claims] A reaction container that houses a substrate on which an amorphous thin film is to be formed, and a first discharge electrode in which a plurality of electrode plates are arranged in parallel with each other in such a manner that an edge thereof faces one surface of the substrate. and,
a second discharge electrode in which a plurality of electrode plates are arranged in parallel in the reaction vessel so that their edges face the other surface of the substrate; and electrode plates of the first and second discharge electrodes. a power source that supplies a discharge voltage between the two; a coil and AC power source that surround the reaction vessel and generate a magnetic field orthogonal to the electric field generated between the pair of discharge electrode plates; An amorphous thin film forming apparatus comprising: a gas supply device that supplies a reaction gas under reduced pressure.