JP2002280588A - Inline type cvd device and method for forming film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost inline type CVD device capable of effectively film-forming for both an amorphous silicon photoelectric transfer unit and a polysilicon photoelectric transfer unit by one device, and also to provide a method for forming a film using the same. SOLUTION: The inline type CVD device for forming the pin-type amorphous silicon photoelectric transfer unit and the pin-type polysilicon photoelectric transfer unit comprises a p-layer film formation chamber (23) for common use in the amorphous silicon photoelectric transfer unit and the polysilicon photoelectric transfer unit, an i-layer film formation chamber (24) for the amorphous silicon photoelectric transfer unit, an i-layer film formation chamber (25) for the polysilicon photoelectric transfer unit, and an n-layer film formation chamber (26) for common use in the amorphous silicon photoelectric transfer unit and the polysilicon photoelectric transfer unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an in-line type CVD.
The present invention relates to an apparatus and a film forming method using the apparatus.

[0002]

2. Description of the Related Art A photoelectric conversion device, for example, a thin-film solar cell module, has a plurality of string-shaped solar cells formed of a transparent electrode layer, a photoelectric conversion semiconductor layer, and a back electrode layer laminated on a transparent substrate in series. It has a connected structure. The above photoelectric conversion semiconductor layer is most inexpensive to be formed of amorphous silicon, but has a problem of low photoelectric conversion efficiency. To improve photoelectric conversion efficiency,
For example, a pin-type amorphous silicon (a-Si) photoelectric conversion unit and a pin-type polysilicon (Poly-S)
i) A tandem type in which a photoelectric conversion unit is stacked is advantageous.

FIG. 1 is a sectional view of a tandem type thin film solar cell module. A transparent electrode layer 2 made of a transparent conductive oxide (TCO) such as SnO ₂ on a glass substrate 1
The transparent electrode layer 2 is provided with a scribe line (not shown) and is separated for each unit cell.

On the transparent electrode layer 2, an amorphous silicon photoelectric conversion unit comprising a p-layer silicon-based thin film (for example, p-layer amorphous SiC) 3p, an i-layer amorphous silicon 3i, and an n-layer silicon (for example, n-layer microcrystalline silicon) 3n 3, and p-layer silicon (eg, p-layer polycrystalline or microcrystalline silicon) 4p, i-layer polysilicon 4i
And polysilicon photoelectric conversion unit 4 made of n-layer silicon (for example, n-layer polycrystalline or microcrystalline silicon) 4n
Are formed. The total film thickness of the amorphous silicon photoelectric conversion unit 3 is set to, for example, about 0.25 to 0.3 μm, and the thickness of each of the p layer and the n layer is about several tens nm. The total thickness of the polysilicon photoelectric conversion unit 4 is set to, for example, about 1.5 to 2 μm, and the thicknesses of the p-layer and the n-layer are about several tens nm,
The thickness of the i-layer accounts for the majority. The reason why the thickness of the polysilicon photoelectric conversion unit 4 is increased is that the light absorption of polysilicon is low. The amorphous silicon photoelectric conversion unit 3 and the polysilicon photoelectric conversion unit 4 are provided with scribe lines (not shown) serving as connection grooves.

[0005] On the photoelectric conversion unit, a back electrode layer 5 composed of, for example, a laminated film of ZnO and Ag is formed. A scribe line (not shown) is provided in the back electrode layer 5 and the photoelectric conversion unit, and is separated for each unit cell. In this way, a plurality of unit cells are connected in series.

Conventionally, an amorphous silicon photoelectric conversion unit and a polysilicon photoelectric conversion unit have been formed using separate in-line CVD apparatuses having a p-layer film forming chamber, an i-layer film forming chamber, and an n-layer film forming chamber, respectively. ing. For this reason, the cost of the CVD apparatus has been increased.

Therefore, a p-layer film forming chamber, an i-layer film forming chamber, and n layer
It has been considered that both an amorphous silicon photoelectric conversion unit and a polysilicon photoelectric conversion unit are sequentially formed by using one in-line type CVD apparatus having a layer forming chamber and changing the film forming conditions. However, in consideration of increasing the film forming speed in order to increase the productivity of the thick i-layer polysilicon as described above, the film forming conditions and the apparatus configuration of the film forming chamber are different from those of the i-layer amorphous silicon. You have to change a lot. Specifically, when forming the i-layer polysilicon, it is necessary to increase the pressure of the reaction gas and to reduce the distance between the discharge electrode and the substrate accordingly. Therefore, in reality, it is extremely difficult to cope with the same i-layer deposition chamber when depositing the i-layer amorphous silicon and the i-layer polysilicon by simply changing the deposition conditions. .

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-cost in-line type CVD apparatus capable of effectively forming both an amorphous silicon photoelectric conversion unit and a polysilicon photoelectric conversion unit by one unit, and an apparatus therefor. It is to provide a film forming method used.

[0009]

An in-line type CVD apparatus according to the present invention is an in-line type CVD apparatus for forming a pin type amorphous silicon photoelectric conversion unit and a pin type polysilicon photoelectric conversion unit on a substrate. A p-layer deposition chamber shared for the photoelectric conversion unit and the polysilicon photoelectric conversion unit;
An i-layer deposition chamber for an amorphous silicon photoelectric conversion unit, an i-layer deposition chamber for a polysilicon photoelectric conversion unit,
An n-layer film forming chamber shared by the amorphous silicon photoelectric conversion unit and the polysilicon photoelectric conversion unit is provided.

In the in-line type CVD apparatus according to the present invention, it is preferable to provide a return device for returning the substrate from the n-layer deposition chamber to the p-layer deposition chamber.

A film forming method according to the present invention is a method for forming a pin type amorphous silicon photoelectric conversion unit and a pin type polysilicon photoelectric conversion unit on a substrate by using the above-described in-line type CVD apparatus. Forming a p-layer silicon-based thin film on a substrate in a layer-forming chamber; forming an i-layer amorphous silicon on a substrate in an i-layer forming chamber for an amorphous silicon photoelectric conversion unit; A step of passing a substrate without film formation in an i-layer film forming chamber for a conversion unit, a step of forming n-layer silicon on a substrate in an n-layer film forming chamber, and a step of forming a film on a substrate in a p-layer film forming chamber a step of forming a p-layer silicon film, a step of passing a substrate without forming a film in an i-layer film forming chamber for an amorphous silicon photoelectric conversion unit, and a step of forming a film on a substrate in an i-layer film forming chamber for a polysilicon photoelectric conversion unit. I layer A step of forming a film of Rishirikon, characterized by comprising a step of deposition of the n-layer silicon on the substrate in the n-layer deposition chamber.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a vertical in-line type C according to the present invention.
FIG. 2 is a diagram illustrating a configuration of a VD device. As shown in FIG. 2, this in-line type CVD apparatus has a load / unload chamber 2
1. Preheating chamber 22, p-layer film forming chamber 23 shared for amorphous silicon photoelectric conversion unit and polysilicon photoelectric conversion unit, i-layer film forming chamber 24 for amorphous silicon photoelectric conversion unit, for polysilicon photoelectric conversion unit , An n-layer film forming chamber 26 shared by the amorphous silicon photoelectric conversion unit and the polysilicon photoelectric conversion unit, and a cooling chamber 27. Elevating devices 2 are provided above the preheating chamber 22 and the cooling chamber 27, respectively.
8 and 29 are provided, and a transfer chamber 30 in which a conveyor is disposed is provided between them. These mechanisms constitute a return device.

The i-layer film forming chamber 24 for the amorphous silicon photoelectric conversion unit and the i-layer film forming chamber 25 for the polysilicon photoelectric conversion unit may be provided one by one or may be provided in multiple chambers.

As shown in FIG. 3, in this vertical in-line type CVD apparatus, a pair of glass substrates 1a and 1b are placed in a load / unload chamber 21 by anodes 11a and 11b, respectively.
b, and supported vertically and transported in the direction of the film forming chamber.
Then, for example, the anodes 11a and 1
The glass substrates 1a and 1b supported by 1b are held facing the cathodes 12a and 12b, respectively. In each of the other film forming chambers, each member is arranged in the same manner as in FIG. In addition, each film forming chamber is heated to a predetermined temperature, a reaction gas is introduced, and the pressure is set at a predetermined pressure. Further, high-frequency power is supplied between the cathode and the anode from the high-frequency power supplies 13a and 13b to generate plasma, and a desired silicon layer is formed on the substrates 1a and 1b.

The reaction gas pressure (P) and the electrode-substrate distance (E / S) in each film forming chamber are set, for example, as follows.

Shared p-layer deposition chamber 23: P = 133 Pa (1 Torr), E / S = 24 mm i-layer amorphous silicon deposition chamber 24: P = 40 Pa (0.3 Torr), E / S = 17 mm i-layer polysilicon Film forming chamber 25: P = 800 Pa (7 Torr), E / S = 10 to 12 m
m Shared n-layer film forming chamber 26: P = 133 Pa (1 Torr), E / S = 24 mm.

As described above, the i-layer polysilicon film forming chamber 2
In No. 5, the reaction gas pressure (P) must be considerably higher than that of the i-layer amorphous silicon film forming chamber 24 in order to increase the film forming speed, and the electrode-substrate distance (E / S) must be reduced accordingly. . Therefore, it is not realistic to share the same i-layer film forming chamber, and the configuration as shown in FIG. 2 is realistic.

Using the in-line type CVD apparatus shown in FIG.
The film formation of the pin type amorphous silicon photoelectric conversion unit and the pin type polysilicon photoelectric conversion unit is performed as follows.

First, the glass substrate placed on the anode is transported in the load / unload chamber 21 and preheated in the preheating chamber 22. Next, a p-layer silicon-based thin film is formed on the substrate in the shared p-layer deposition chamber 23, and i-layer amorphous silicon is deposited on the substrate in the i-layer deposition chamber 24 for the amorphous silicon photoelectric conversion unit. In the i-layer film forming chamber 25 for the polysilicon photoelectric conversion unit, the film is not formed by passing the substrate in a vacuum, and the n-layer silicon is formed on the substrate in the shared n-layer film forming chamber 26. In this way, the pin is formed on the substrate in the first film forming process.
Forming an amorphous silicon photoelectric conversion unit.
Thereafter, the substrate is taken out to the cooling chamber 27, lifted by the elevating device 29, transported in the transport chamber 30 in which the conveyor is arranged, lowered by the elevating device 28, and returned to the preheating chamber 22.

Next, p-layer silicon is formed on the substrate in the common p-layer film forming chamber 23, and the substrate is passed through the substrate in vacuum in the i-layer film forming chamber 24 for the amorphous silicon photoelectric conversion unit. First, an i-layer polysilicon is formed on a substrate in an i-layer film forming chamber 25 for a polysilicon photoelectric conversion unit, and an n-layer silicon is formed on a substrate in a shared n-layer film forming chamber 26.
In this way, the pin-type polysilicon photoelectric conversion unit is formed on the pin-type amorphous silicon photoelectric conversion unit by the second film forming process. Then, the substrate is placed in the cooling chamber 2
7, is raised by an elevating device 29, transported in a transport chamber 30 in which a conveyor is arranged, lowered by an elevating device 28, returned to the load / unload chamber 21 via the preheating chamber 22, and taken out of the substrate. .

As described above, when continuously forming the pin type amorphous silicon photoelectric conversion unit and the pin type polysilicon photoelectric conversion unit, the number of the i-layer film forming chambers 24 and the i-layer film forming chambers 25 is limited. Is preferably adjusted so that the tact time in each film forming chamber is adjusted.

As described above, the pin is not always required.
Type amorphous silicon photoelectric conversion unit and pin
It is not necessary to continuously form the mold-type polysilicon photoelectric conversion unit. For example, only a first film forming process is performed using a large number of substrates, a substrate on which a pin type amorphous silicon photoelectric conversion unit is formed is stored, and a second round is performed using the stored many substrates. Only the film forming process is performed and p
An in-type polysilicon photoelectric conversion unit may be formed. In this method, it is preferable to prevent deterioration of the amorphous silicon photoelectric conversion unit during storage by using various means.

In the CVD apparatus shown in FIG.
8, 29 and a transfer chamber 30 in which a conveyor is arranged
A return device comprising a common p-layer film forming chamber 23, an amorphous silicon i-layer film forming chamber 24, a polysilicon i-layer film forming chamber 25, and a common n-layer film forming chamber 26. , N-layer film forming chamber 26 to i-layer film forming chamber 25, i
The inside of the layer forming chamber 24 and the inside of the p-layer forming chamber 23 may be reversed.

[0025]

As described above in detail, according to the present invention, 1
It is possible to provide a low-cost in-line type CVD apparatus capable of effectively forming both an amorphous silicon photoelectric conversion unit and a polysilicon photoelectric conversion unit on a stand, and to provide an efficient film forming method using this apparatus. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tandem type thin-film solar cell module.

FIG. 2 is a diagram showing a configuration of an in-line type CVD apparatus according to the present invention.

FIG. 3 is a sectional view showing an arrangement of a substrate and electrodes in each film forming chamber of the in-line type CVD apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Transparent electrode layer 3 ... Amorphous silicon photoelectric conversion unit 4 ... Polysilicon photoelectric conversion unit 5 ... Backside electrode layer 11a, 11b ... Anode 12a, 12b ... Cathode 13a, 13b ... High frequency power supply 21 ... Load / unload Room 22: Preheating chamber 23: Shared p-layer film forming chamber 24: i-layer film forming chamber for amorphous silicon photoelectric conversion unit 25: i-layer film forming chamber for polysilicon photoelectric conversion unit 26: Shared n-layer film forming chamber 27 ... Cooling chambers 28 and 29 ... Elevating device 30 ... Transfer chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 BA30 BB12 CA06 GA14 HA01 KA01 LA16 5F045 AA08 AB03 AB04 AF07 BB08 CA13 DP11 EB08 EH13 EN04 HA24 5F051 AA05 CA02 CA03 CA04 CA16 CB12 DA15

Claims (3)

[Claims] 1. An in-line CVD apparatus for forming a pin type amorphous silicon photoelectric conversion unit and a pin type polysilicon photoelectric conversion unit on a substrate, wherein the inline type CVD apparatus is shared by the amorphous silicon photoelectric conversion unit and the polysilicon photoelectric conversion unit. A p-layer deposition chamber, an i-layer deposition chamber for an amorphous silicon photoelectric conversion unit, an i-layer deposition chamber for a polysilicon photoelectric conversion unit,
An in-line type CVD apparatus comprising: an n-layer film forming chamber shared by an amorphous silicon photoelectric conversion unit and a polysilicon photoelectric conversion unit. 2. The in-line type CVD apparatus according to claim 1, further comprising a return device for returning the substrate from the n-layer deposition chamber to the p-layer deposition chamber. 3. A method for forming a pin-type amorphous silicon photoelectric conversion unit and a pin-type polysilicon photoelectric conversion unit on a substrate using the in-line type CVD apparatus according to claim 1, wherein the p-type film forming chamber is provided. Forming a p-layer silicon-based thin film on a substrate by using the above method; forming an i-layer amorphous silicon film on the substrate in an i-layer film forming chamber for an amorphous silicon photoelectric conversion unit; a step of passing a substrate without forming a film in an i-layer film forming chamber, a step of forming n-layer silicon on a substrate in an n-layer film forming chamber, and a step of forming p-layer silicon on a substrate in a p-layer film forming chamber. A step of forming a film, a step of passing a substrate without forming a film in an i-layer film forming chamber for an amorphous silicon photoelectric conversion unit, and a step of forming i on a substrate in an i-layer film forming chamber for a polysilicon photoelectric conversion unit.
A film forming method comprising: a step of forming a layer polysilicon; and a step of forming an n-layer silicon on a substrate in an n-layer film forming chamber.