JPS609876A - Device for producing thin film - Google Patents

Abstract

PURPOSE:To prevent deposition of a-Si on the wall surface of a vacuum vessel and to produce efficiently a semiconductor element, etc. by providing means for evacuating the entire part of the vessel, ejecting a gaseous raw material through a nozzle and maintaining the degree of vacuum at which a local glow discharge is generated. CONSTITUTION:A nozzle 10 for a gaseous raw material in common use as an electrode for introducing discharge electric power is provided in a vacuum vessel 5 in production of a thin a-Si film, etc. The 3rd electrode 12 which impresses a bias voltage to prevent the generated discharge 11 from contacting with the nozzle 10 is installed near the nozzle 10. The inside of the vacuum 5 is evacuated to about <=5X10<-13>Torr and the gaseous raw material is introduced through the nozzle 10 into the vessel. Electric power is supplied to the nozzle 10 from a discharge power source 4 to generate the discharge and a DC bias is applied to the 3rd electrode 12 to prevent the discharge region 11 from contacting with the nozzle 10. the deposition of a-Si on the wall surface of the vessel 5 is obviated and the need for washing the vessel 5 is eliminated by the above-mentioned device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus and method for manufacturing an amorphous silicon (hereinafter abbreviated as a-3i) thin film.

Conventional configuration and its problems An apparatus for manufacturing this type of thin film is shown in FIG.

1 is a conductive substrate such as a stainless steel plate; 2 is a sample holder including a heater capable of raising the temperature of the substrate 1 to, for example, about 200°C; 3 is a discharge electrode that also serves as an inlet for introducing source gas into the apparatus; 4 5 is a power source that supplies power to the discharge electrode, and 5 is a vacuum chamber. 6 is an exhaust port for exhausting excess raw material gas, etc.;
A rotary pump and an exhaust gas treatment device (not shown) are located at the subsequent stage.

A method for producing an a-8ipin diode using this device will be described below. The temperature of the substrate 1 is raised to about 200°C,
A raw material gas prepared by diluting SiH4 and B2H6 with hydrogen or an inert gas is introduced from introduction 07 at a pressure of about 1 Torr K'fX throughout the vacuum chamber 5. power supply 4
to generate a glow discharge in the vacuum chamber 5,
Decompose S I H4 and B2H6 and deposit a p-type layer. Next, only S I H4 is diluted with hydrogen or the like, and an i-type layer is deposited. The n-type layer is a mixture of 5IH4 and PH3.

An a-Si pin diode is created as described above, but as mentioned above, when depositing each layer, the vacuum chamber 5
The entire interior must be kept at about 1'rorr for glow discharge to occur, and the raw material gas is adsorbed to the wall surface.

The adsorbed gas gradually desorbs from the wall surface and mixes in as impurities when the next thin film layer is deposited. Furthermore, a-8i is deposited on the entire surface of the discharge electrode 3 and on all the walls of the vacuum chamber 5, and gas is also desorbed from the deposited a-3t, resulting in a
-8i was incorporated as an impurity. To prevent this, p-type and i-type.

When depositing different types of thin film layers, such as n-type, there is a conventional method of using a separate vacuum chamber 5, but the manufacturing equipment becomes expensive. Furthermore, I
Because d a -S i accumulates, it is necessary to clean the inside of the device at regular intervals.

OBJECTS OF THE INVENTION The present invention alleviates the drawbacks of the conventional manufacturing apparatuses described above and provides a manufacturing apparatus j''- for manufacturing semiconductor elements using an A-8i thin film with high efficiency.

Structure of the Invention The present invention is capable of evacuating the entire vacuum chamber to a degree of vacuum at which glow discharge does not occur, and ejecting raw material gas from a nozzle to achieve a degree of vacuum at which local glow discharge occurs. Because a-3i is not deposited, cleaning of the vacuum chamber is not necessary. Furthermore, since the vacuum chamber is maintained at a high vacuum, the amount of raw material gas adsorbed on the wall is small, so there is less gas to be desorbed, making it difficult for it to be incorporated into the film as an impurity. When three nozzles are used, one each for p-type, i-type, and n-type raw material gases, pin-type semiconductor devices can be left unaffected by impurities by simply switching the gas without purging the inside of the vacuum chamber. This is a thin film manufacturing device that can produce up to 5 pages.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Since many elements in FIG. 2 are common to those in FIG. 1, the same numbers are given to common elements. In particular, what is different from the conventional example is that
The raw material gas nozzle 1o, which also serves as a discharge power introduction electrode, replaces the electrode 3 in FIG. This is what is being done.

13 is a power source that applies a DC bias to the third electrode 12. The third electrode is fixed to the vacuum chamber 6 by a support 14. 14 is a seal that allows the conductor 15 to penetrate into the container 6.

Next, a method for manufacturing a-3i using the thin film manufacturing apparatus shown in FIG. 2 will be described. The temperature of the substrate 1 is raised to about 20° C. by a heater (not shown) in the substrate holder 2, and the temperature is evacuated from the exhaust port 6 to a degree of vacuum of 5×1 O −3 Torr or less. The raw material gas is introduced from the nozzle 10,
The degree of vacuum in the vacuum chamber 6 is 6 Pa.

The exhaust conditions and raw material gas introduction conditions are set to be 5x10 Torr or less. From discharge power source 4 to nozzle 10
supplies power to generate a discharge. A DC bias is applied to the third electrode 12 so that the discharge region 11 does not come into contact with the nozzle 10.

When changing the type of raw material gas, it may be done using one nozzle, but mutual contamination between gases is reduced if the type is changed for each type. Furthermore, when depositing a thin film on a large-area substrate, it is sufficient to line up several nozzles. In order to prevent variations in the amount of gas emitted from several nozzles arranged in a row, the nozzle openings may be designed to have conductance sufficiently small relative to the amount of gas flowing out. To switch the gas coming out of the nozzle in a short time and reduce impurity contamination due to desorption gas,
This can be done by pushing the needle into the nozzle mouth from inside the nozzle.

Effects of the Invention According to the present invention, as described above, only a part of the vacuum chamber has a degree of vacuum at which glow discharge occurs.
- There is no need to clean the vacuum chamber 7 base as Si is not deposited, and the inside of the vacuum chamber is at a high vacuum of 5×1O-3 Torr or less except for the glow discharge area, so material gas etc. are not adsorbed to the wall surface. This reduces contamination due to these desorptions.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional thin film manufacturing apparatus, and Figure 2
The figure is a configuration diagram of a thin film manufacturing apparatus according to an embodiment of the present invention. 1... Board, 2... Board holder, 3.
...Gas inlet and discharge power supply electrode, 4...
...Discharge power supply, 6...Vacuum chamber, 6...
Exhaust port, 10... Raw material gas introduction nozzle, 11.
...Discharge region, 12...DC bias application third electrode, 13...DC power supply. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (3)

[Claims] (1) A nozzle that spouts raw material gas, a discharge power source arranged to supply power to the nozzle, a substrate holder that can heat the substrate to a certain temperature, and a 5X
At least a vacuum chamber that can be evacuated to a vacuum level of 10 Torr or less is included, and the source gas ejected from the nozzle is arranged in a vacuum range where glow discharge occurs on the surface of the substrate. Features of thin film manufacturing equipment. (2) The thin film manufacturing apparatus according to claim 1, wherein an electrode to which a direct current bias can be applied is arranged near the exit of the nozzle to prevent glow discharge from occurring. (3) There are at least three nozzles, one is a nozzle for spouting a raw material gas that does not contain impurities, and the other is a nozzle for raw material gas containing impurities that exhibits p-type conductivity.
3. The thin film manufacturing apparatus according to claim 1 or 2, wherein the material is a nozzle for a source gas containing impurities 2... exhibiting n-type conductivity.