JPH0366819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a photovoltaic device using amorphous silicon.

FIG. 1 shows a typical structure of a photovoltaic device using amorphous silicon. 1 is a transparent insulating substrate such as glass; 2, 3, and 4 are an oxide transparent conductive film, an amorphous silicon film, and an amorphous silicon film formed sequentially on the substrate 1;
This is a back electrode made of aluminum or the like.

The amorphous silicon film 3 consists of a P-type layer 5 in contact with the transparent conductive film 2, an n-type layer 7 in contact with the back electrode film 4, and an i-type (intrinsic) layer between these two layers.
Layers 6 and 7 are deposited by plasma reaction decomposition of silane gas containing a compound of elements that can serve as suitable impurities.

FIG. 2 shows a conventional plasma reactor for forming this type of amorphous silicon film. 8 is a plasma reaction chamber, 9 and 10 are each inside the reaction chamber,
first and second electrode plates arranged vertically to face each other, 11;
1 is a high-frequency power source for applying a high-frequency electric field to both electrodes to generate plasma, and 12 to 14 are gas cylinders for introducing various reaction gases into the reaction chamber 8, including SiH ₄ , B ₂ H ₆ , and PH ₃ gas, respectively. Contains. 15 is an exhaust port connected to a vacuum pump for evacuating the inside of the reaction chamber.

To form the amorphous silicon film 3 shown in FIG. 1 using this apparatus, first, the substrate 1 with the transparent conductive film 2 coated on the surface is placed on the heatable second electrode plate 10.
Next, the exhaust from the exhaust port 15 and the cylinder 12~
By operating the gas introduction from 14, high frequency power source 1
1 generates plasma between electrodes 9 and 10,
Deposit a silicon film.

FIG. 3 shows an apparatus which forms p-type, i-type, and n-type silicon films in different reaction chambers as an advanced version of the amorphous silicon deposition apparatus described above.

20a to 20c are first to third isolated from each other.
The reaction chambers 21a to 21c are first to third gas introduction plugs for introducing a predetermined reaction gas into each reaction chamber, and B ₂ H ₆ is passed through the first gas introduction plug.
and SiH ₄ gas, SiH ₄ gas through the second stopper, and PH ₃ and SiH ₄ gas through the third stopper, respectively.
22a to 22c are exhaust ports for exhausting each reaction chamber. The inside of each reaction chamber is the same as the apparatus shown in FIG. 2, but a roller conveyor 23 transports the substrate from the first reaction chamber 20a through the second reaction chamber 20b to the third reaction chamber 30c. The structure allows for In addition, shutters 24a to 24d that can be opened and closed from the outside are installed on the wall separating each reaction chamber.
is installed.

Next, a method for manufacturing the element shown in FIG. 1 using the above-mentioned manufacturing apparatus will be explained. First, the substrate 1 coated with the transparent conductive film 2 is placed on the roller conveyor 23 of the first reaction chamber 20a via the shutter 24a. At this time, the shutters 24a to 24d are all closed,
Also, all roller conveyors are stopped. After the shutter 24a is closed, exhaust is exhausted from the exhaust port 22a, and a mixed gas of SiH ₄ and B ₂ H ₆ is introduced from the first plug 21a to plasma deposit p-type amorphous silicon.

After obtaining the required p-type silicon film thickness in this way, the plasma reaction is stopped, the first stopper 21a is closed, and the first reaction chamber 20a and the second reaction chamber 20b are evacuated from the exhaust ports 22a and 22b. 24b is opened, and the roller conveyor 23 transports the substrate 1 from the first reaction chamber 20a to the second reaction chamber 20b. After that, the shutter 24b is closed, and the second plug 21
SiH ₄ gas is introduced from b, and intrinsic amorphous silicon is deposited to a required thickness.

Thereafter, the substrate 1 is transferred to the second reaction chamber 20 using the same procedure as when moving the substrate 1 from the first reaction chamber to the second reaction chamber.
b to the third reaction chamber 20c, and the shutter 24c
After closing, enter the third reaction chamber through the third stopper 21c.
After introducing PH ₃ and SiH ₄ gases, depositing n-type amorphous silicon to a predetermined thickness, stopping the plasma reaction in the third reaction chamber, and closing the third stopper, the substrate 1 is taken out from the shutter 24d. . Through this series of steps, a photovoltaic element is formed in which p-, i-, and n-type amorphous silicon layers are formed on the substrate 1.

In the above conventional method, the substrate 1 is connected to the shutter 24a.
from the first reaction chamber to the second reaction chamber and the third reaction chamber.
The plasma discharge and gas must be intermittent until it is taken out from the shutter 24d through the reaction chamber. In addition, when mass-producing devices by forming devices one after another, if the deposition times of the p-type layer, i-type layer, and n-type layer are exactly the same, the intermittent gas and plasma discharge and the shutters 24a to 24d can be synchronized. It is possible to open and close the board by opening and closing it, and it is possible to feed the boards continuously without wasting any waste. However, in reality, it takes about 30 to 40 minutes to form an i-type layer, and
The time required to form the mold layer is approximately 5 to 8 times, and the substrate on which the p-type layer has been formed in the first reaction chamber 20a is moved to the third reaction chamber after the preceding substrate has finished forming the i-type layer. It is not possible to move to the second reaction chamber until then. It usually takes about 40 minutes for the first substrate to complete element formation and be taken out, but in the above manufacturing method, the first substrate is taken out, the second substrate completes element formation, and is taken out. It will take about 40 minutes for the camera to warm up.

Therefore, the present invention aims to improve the poor productivity described above, and provides a method in which substrates can be processed continuously without interrupting plasma discharge and raw material gas in each reaction chamber. be.

That is, the present invention provides a method for manufacturing a photovoltaic device comprising a plurality of amorphous silicon layers of different conductivity types sequentially formed by a glow discharge method as described above, in which a silicon layer containing a conductivity type determining impurity is formed. A preliminary chamber is provided between the plasma reaction chamber and the plasma reaction chamber in which a silicon layer containing no conductivity type determining impurities is formed, and in this preliminary chamber, the raw material gas containing the conductivity type determining impurities is converted into the raw material gas containing no impurities. It is characterized by replacing it with .

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 4 shows an example of the configuration of an apparatus used in the present invention.

30a to 30g are vacuum chambers isolated from each other, 30a, 30c, 30e, and 30g are preliminary chambers, 30b, 30d, and 30f are first to third reaction chambers, and 31a to 31g are reaction chambers and preliminary chambers, respectively. These are the first to seventh plugs that introduce the reaction gas into the chamber. Furthermore, 32a to 32g are exhaust ports that exhaust air from each chamber. Each reaction chamber is similar to that of FIGS. 2 and 3 and is equipped with parallel plate electrodes 33,34. Further, as in FIG. 3, shutters 35a to 35h that can be opened and closed from the outside are provided, and the roller conveyor 3
6, the substrate 1 can be inserted from the shutter 35a and sent from the preliminary chamber 30a to chamber 35h via chambers 30b to 30g. 37 is a power source that applies a high frequency electric field between the electrodes 33 and 34.

Next, a method for manufacturing the element shown in FIG. 1 using the above manufacturing apparatus will be explained.

First, a substrate coated with only the transparent conductive film 2 is placed on the roller conveyor 36 in the first preliminary chamber 30a via the shutter 35a. At this time, shutter 35b
~35h are all closed, and the first reaction chamber 30
b is immediately exhausted from the exhaust port 32b, and the plug 31b
B ₂ H ₆ and SiH ₄ gases are introduced from p
The amorphous silicon layer is kept in a state of continuous deposition by plasma decomposition. Second reaction chamber 30d
Similarly to the first reaction chamber, the gas is exhausted from the exhaust port 32d, and SiH ₄ gas is introduced from the plug 31d.
The i-type amorphous silicon layer continues to be deposited by plasma decomposition. Furthermore, the third reaction chamber 30f is similarly exhausted from the exhaust port 32f,
PH ₃ and SiH ₄ gas are introduced from the plug 31f,
The n-type amorphous silicon layer continues to be deposited by plasma decomposition.

Here, after exhausting the first preliminary chamber 30a in which the substrate 1 is placed through the exhaust port 32a, the plug 31a is
After introducing B ₂ H ₆ and SiH ₄ gas to create the same atmospheric conditions as in the first reaction chamber, the shutter 35b is opened and the substrate 1 is transported to the first reaction chamber by the roller conveyor 36, where the p-type layer is formed. Deposit on substrate 1. At this time, immediately after the substrate 1 is completely accommodated in the first reaction chamber 30b, the shutter 35b and the stopper 31a are closed, the reaction gas is exhausted from the exhaust port 32b, the exhaust port 32a is closed, and N ₂ gas is released from the stopper 31a. The pressure is returned to atmospheric pressure using an inert gas such as the like, the shutter 35a is opened, and the next substrate is placed on the conveyor 36. From then on,
Repeat this.

While a p-type layer is being deposited to a required thickness in the first reaction chamber 30b, the second preliminary chamber 30c is exhausted from the exhaust port 32c, and B ₂ H ₆ and SiH ₄ gases are introduced from the plug 31c. The atmosphere is adjusted to be the same as that of the chamber 30b, so that even if the shutter 35c is opened, the glow discharge state in the chamber 30b is not affected. In the above state, the shutter 35c is opened, and the substrate 1 on which the p-type layer has been deposited to a required thickness is transported by the roller belt 36 to the second preliminary chamber 30c. At the same time that the substrate 1 is stored in the second preliminary chamber 30c, the next substrate is transported from the first preliminary chamber 30a to the first reaction chamber 30b by opening the shutter 35b. Thereafter, this process is repeated in the first reaction chamber to the second preliminary chamber.

Immediately after the substrate transported from the first reaction chamber 30b is stored in the second preliminary chamber 30c, the shutter 35c is closed, and while exhausting air from the exhaust port 32c, the plug 31c is opened, the same as that used in the second reaction chamber 30d. A raw material gas is introduced to create the same atmosphere in the second reaction chamber and the second preliminary chamber. After that, open the shutter 35d,
The substrate 1 is transported by the roller conveyor 36 to the second reaction chamber 30d, where the intrinsic layer is deposited. Naturally, the length of the second reaction chamber is longer than the first reaction chamber depending on the deposition time. That is, while the intrinsic layer is being deposited on the substrate 1, the shutter 35d is opened and closed several times, and the p-type layer is deposited one after another, and the completed substrate is brought in from the second preliminary chamber. The substrate on which the required thickness of the intrinsic layer has been deposited is transported from the shutter 35e to the third preliminary chamber 30e, but at this time also, the third preliminary chamber 30e is controlled to have the same atmosphere as the second reaction chamber. , there is no effect on the second reaction chamber 30d, and the intrinsic layer continues to be formed on the next substrate. At the same time as the substrate 1 is stored in the third preliminary chamber 30e, the shutter 35e is closed, and SiH ₄ is discharged from the plug 31e while exhausting from the exhaust port 32e.
Introduce PH ₃ gas to make the atmosphere in the third preliminary chamber similar to that of the third reaction chamber, and close the shutter 35f as before.
is opened, the substrate 1 is transported to the third reaction chamber 30f by the roller conveyor 36, and the formation of the n-type layer is started.

At the same time that the substrate 1 is stored in the third reaction chamber 30f, the shutter 35f is closed and the third preliminary chamber 30
e is adjusted to the same atmosphere as the second reaction chamber by the exhaust port 32e and the gas introduction plug 31e, and the next substrate is transported from the second reaction chamber 30d to the third preliminary chamber 30e by opening the shutter 35e. Thereafter, the second reaction chamber 30
This process is repeated in d to third reaction chambers 30f.
The substrate 1 on which the n-type layer of required thickness has been formed in the third reaction chamber 30f is then transported to the fourth preliminary chamber 30g by opening the shutter 35g.
g is previously exhausted from the exhaust port 32g, and the plug 3
1g, PH ₃ and SiH ₄ gases are introduced and adjusted to the same atmosphere as the third reaction chamber 30f, and opening the shutter 35g does not affect the glow discharge in the third reaction chamber at all. Thereafter, the next substrate waiting in the third preliminary chamber is carried into the third reaction chamber in the same manner. The board stored in the fourth preliminary chamber is exhausted from the fourth preliminary chamber through the exhaust port 32g.
is closed, the atmosphere is replaced with an inert gas such as Ar or N ₂ through the gas introduction valve 31g, and the shutter 35h is opened and taken out.

By repeating the above steps, each layer is efficiently deposited in any reaction chamber, and p, i,
Photoelectric conversion elements having n-type silicon layers are sequentially formed.

As described above, according to the present invention, when manufacturing a photovoltaic device by sequentially forming different conductivity type amorphous silicon layers by plasma reaction, plasma discharge in each reaction chamber is not interrupted, and each The reaction chamber is always capable of efficiently depositing each layer on the substrate.
In addition, compared to the case where each reaction chamber is provided consecutively, by providing a preparatory chamber between them, it is possible to further reduce the influence of impurities of different conductivity type, thereby improving the characteristics of the photovoltaic device. be able to.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the configuration of a typical photovoltaic element, Figure 2 is a diagram showing the configuration of a manufacturing apparatus for explaining the conventional method, and Figure 3 is the configuration of an advanced manufacturing apparatus for the conventional method. FIG. 4 is a diagram showing the configuration of a manufacturing apparatus for explaining the present invention. 30a, 30c, 30e, 30g...preparatory room,
30b, 30d, 30f...reaction chamber, 31a-3
1g... Gas inlet plug, 32a to 32g... Exhaust port, 33, 34... Electrode, 35a to 35h... Shutter, 36... Conveyor, 37... High frequency power supply.

Claims (1)

[Claims] 1. In a method for manufacturing a photovoltaic device having a plurality of plasma reaction chambers and a plurality of dissimilar conduction type amorphous silicon layers sequentially formed in each plasma reaction chamber by a glow discharge decomposition method, a substrate preparation chamber and a a first plasma reaction chamber forming an amorphous silicon layer into which impurities having conductivity type 1 are introduced, and an intrinsic amorphous silicon layer into which impurities are not introduced between the first plasma reaction chamber and the first plasma reaction chamber; between the second plasma reaction chamber and a third plasma reaction chamber in which an amorphous silicon layer into which an impurity having a second conductivity type is introduced; A preliminary chamber is provided between the third plasma reaction chamber and the substrate removal chamber, into which gas can be introduced independently from each plasma reaction chamber, and each preliminary chamber is connected from the plasma reaction chamber to the preliminary chamber. When moving the substrate, keep it at the same pressure using the same type of gas as the reaction gas in each plasma reaction chamber, which is the front chamber, and move it without stopping or disturbing the plasma in each plasma reaction chamber, which is the front chamber. When moving from the preliminary chamber to the next plasma reaction chamber, the reaction gas in the next chamber must be kept at the same pressure with the same type of gas, without stopping or disturbing the plasma in the next chamber. A method for manufacturing a photovoltaic element, which comprises moving it.