JPH0760797B2 - Amorphous thin film forming equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for producing an amorphous thin film used in various electronic devices such as a solar cell, a thin film semiconductor, an electrophotographic photosensitive member and an optical sensor. Is.

[Prior Art] FIG. 2 shows a conventional semiconductor thin film manufacturing apparatus.

In the figure, electrodes 02, 03 for forming a discharge space are provided vertically in an airtight reaction vessel 01.
03 is electrically connected to the high frequency power supply 04. A coil 05 for generating a magnetic field parallel to the electric field direction in the discharge space is horizontally arranged on the outer periphery of the reaction vessel 01, and is electrically connected to an AC power source 06. The exhaust hole 07 communicates with a vacuum pump (not shown), and a reaction gas introduction pipe
08 communicates with the monosilane and hydrogen gas cylinders, respectively. A heater 09 heats the substrate 010.

Now, place the substrate 010 on the electrode 03, and set the inside of the reaction vessel 01 to 1 mmHg.
After reducing the pressure to a certain degree, while supplying a mixed gas of monosilane and hydrogen gas from the reaction gas introduction pipe 08, the pressure between the electrodes 02 and 03 was 13.
Apply high frequency voltage of 5MHz.

On the other hand, a commercial AC voltage of 50 or 60 Hz is applied to the coil 05 to generate a magnetic field of about 100 gauss between the electrodes 02 and 03. The substrate 010 is heated to about 300 ° C. by the heater 09.

The gas such as monosilane introduced from the reaction gas introduction pipe 08 is decomposed in the discharge space between the electrodes 02 and 03, and is adhered to the surface of the substrate 010 while being stirred by the magnetic field generated by the coil 05. To form.

[Problems to be solved by the invention]

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

However, the place where the substrate 010 is placed is on the electrode 03, and is located in the discharge space between the electrodes 02 and 03. Therefore, basically, it is directly hit by ions having high energy.

That is, due to the electric field between the electrodes, Coulomb force ₁ = q acts on the ions of charge q, and the ion particles directly hit the substrate to damage the amorphous thin film that is being formed.

Since the substrate is placed on one of the electrodes, the size of the substrate to be processed at one time is limited, and the amorphous thin film cannot be formed on the substrate having a larger area than the electrode.

[Means for solving problems]

The apparatus of the present invention supplies a glow-tube-shaped reaction container, a long discharge electrode housed in the reaction container in parallel with and parallel to the axis, and a glow discharge voltage to the discharge electrode. An AC power supply, a coil that surrounds the reaction vessel and generates a magnetic field in the axial direction, and a power supply that supplies a current for generating a magnetic field to the coil, and the discharge electrode is provided outside the space between the discharge electrodes. An amorphous thin film is formed on a substrate placed at a right angle.

[Action]

In the present invention, the magnetic field is generated in the direction orthogonal to the electric field for discharge between the electrodes for generating glow discharge plasma.

The charged particles drift in the direction orthogonal to the electric field in a form in which the initial velocity is given to the Coulomb force given by the discharge electric field and the Lorentz force given by the magnetic field, but the Coulomb force weakens when leaving the electric field space and the Lorentz force is exerted. Draw a Larmor orbit by the cyclotron motion by and fly.

On the other hand, electrically neutral radical particles deviate from the orbits of the charged particle group and try to go straight.

Therefore, if the substrate is supported outside the discharge electric field space in parallel with the electric field, an amorphous thin film without damage of charged particles is formed on the surface of the substrate.

Moreover, since the electrodes are long and arranged in parallel with the axis in the tubular reaction vessel, an amorphous thin film can be formed on a long substrate.

〔Example〕

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

Reference numeral 1 denotes a cylindrical reaction vessel in which long electrodes 2 and 3 for generating glow discharge plasma are arranged so as to face each other in parallel with the axis. 4 is an AC power supply, the electrodes 2 and 3 above
It is connected to the. The coil 5 surrounds the reaction vessel 1 and is connected to the power source 6. Reference numeral 7 denotes a reaction gas introduction pipe, which is connected to a cylinder (not shown) and supplies a mixed gas of monosilane and argon to the reaction container 1. The exhaust hole 8 communicates with the vacuum pump 9 and exhausts the gas in the reaction vessel 1.

Now, the substrate 10 is supported by an appropriate means in a direction orthogonal to the surface of the electrodes 2 and 3 and outside the discharge space formed by the electrodes 2 and 3 as shown in the figure. After the vacuum pump 9 is driven to exhaust the inside of the reaction vessel 1, 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 to keep the pressure at 0.05 to 0.5 Torr,
When a voltage is applied from the low frequency power source 4 to the electrodes 2 and 3, glow discharge plasma is generated between the electrodes 2 and 3.

On the other hand, the coil 5 generates a magnetic field in a direction orthogonal to the electric field generated between the electrodes 2 and 3. The magnetic flux density may be about 10 gauss.

Of the gas supplied from the reaction gas introduction pipe 7, monosilane gas is decomposed into radical Si by glow discharge plasma generated between 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 will be absorbed by the electrodes 2 and 3.
Coulomb force ₁ = q and Lorentz force due to electric field E between
₂ = q (x) causes a so-called x drift motion.

Note that is the velocity of the charged particles.

That is, in the form in which the initial velocity is given by the x drift, it jumps out in the direction orthogonal to the electrodes 2 and 3 and flies toward the substrate 10. However, outside the discharge space where the influence of the electric field generated between the electrodes 2 and 3 is small, the magnetic field generated by the coil 5 causes a cyclotron motion to fly along a Larmor trajectory.

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

On the other hand, the electrically neutral radicals Si are not affected by the magnetic field and reach the substrate 10 from the orbits of the charged particle groups, forming an amorphous thin film on the surface thereof.

〔The invention's effect〕

According to the present invention, a large-area amorphous thin film is formed in the production of various devices such as solar cells and electrophotographic photoconductors, which is extremely valuable in industry.

[Brief description of drawings]

 FIG. 1 is a lateral sectional view of an apparatus showing an embodiment of the present invention, and FIG. 2 is a side sectional view of a conventional apparatus. 1 ... Reaction vessel, 2, 3 ... Electrode, 4 ... AC power supply, 5 ... Coil, 6 ... Power supply, 7 ... Reaction gas introduction pipe, 8 ... Exhaust hole, 9 ... Vacuum pump, 10 ……substrate.

Claims (1)

[Claims] 1. A cylindrical reaction vessel, a long discharge electrode housed in the reaction vessel in parallel with and parallel to an axis, and an AC power supply for supplying a glow discharge voltage to the discharge electrode. And a coil that surrounds the reaction container and generates a magnetic field in the axial direction, and a power supply that supplies a current for generating a magnetic field to the coil, and is perpendicular to the discharge electrode outside the discharge electrode space. An amorphous thin film forming apparatus characterized by forming an amorphous thin film on a substrate placed on a substrate.