JPS59195531A - Apparatus for continuously growing sno2 film - Google Patents

Abstract

PURPOSE:To grow SnO2 films on substrates in two steps of temp. in large quantities by installing the 1st growing chamber kept at the 1st temp. and the 2nd growing chamber kept at the 2nd temp. in parallel and by successively passing the substrates through both the chambers by means of a transferring mechanism. CONSTITUTION:The SnO2 film growing chamber of an apparatus 1 for continuously growing SnO2 films is composed of the 1st growing chamber 2 heated to the 1st temp. with a heating coil 7 and the 2nd growing chamber 3 heated to the 2nd temp., and both the chambers 2, 3 are installed in parallel with a separation chamber 4 in-between. Samples S are introduced into the chamber 2 with the surfaces downward through an inlet side chamber 5 filled with an atmosphere of a clean gas by means of a sample transferring mechanism 18 consisting of a driving wheel 20D, a following wheel 20I, and a sample transferring member 19 stretched between the wheels 20D, 20I such as a chain. The samples S are successively passed through the chambers 2, 4, 3, and they are taken out through an outlet side chamber 6 filled with an atmosphere of a clean gas. During this time, the 1st and the 2nd gaseous starting materials are fed to the chambers 2, 3 from feeding inlets 8, 9 and exhausted from exhaust ports 10, 11, respectively to grow SnO2 films on the samples S in two steps.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of 5I102/Si photoelectric conversion elements - the production of 5N02 films as transparent electrodes on glass substrates, the growth of Sl2O3 films on Si, etc. This invention relates to a continuous 5nOz film growth apparatus that is effective for forming 5nOz films.

N-type 5N02 is a solar cell that is attracting attention these days.
and S+102/S consisting of a heterojunction of n-type S1
There is an i-photoelectric conversion element. And 5 in this element
It has also been found that it is desirable to grow the n02 film on the 81 substrate not by the spray method but by the CVD method under a two-step temperature environment. In other words, the region near the junction is grown at a relatively low temperature of about 300°C, even though the crystallinity is somewhat poor, with many minority carrier recombination levels, and the region near the light incident surface is grown with good crystallinity and low resistance. 350 areas
It is said that a high open circuit voltage and a good fill factor can be obtained by growing at a relatively high temperature of about 'C' (Japanese Unexamined Patent Publication No. 18994/1983). In any case, this 5nOz/Si photoelectric conversion element is extremely promising in the future, and although it is rare that mass production technology will be established, so far, it has not been possible to get on the production base. (← Such a method is not disclosed, −νJ.

゛-The only conventional manufacturing method for this type of 5n02/Si photoelectric conversion element is the so-called batch method.
,':: Before and after the growth of the 5nOz film, the apparatus was opened and samples were taken out and put in. Although this method is fine for small-scale experiments, it cannot be used for mass production. Furthermore, the process of growing a film by changing the temperature in two stages as described above, which relied on such a patch method, would be time consuming and unreasonable.

As a solution to these conventional drawbacks, the present applicant first attempted to make a step towards the continuous growth of 5n021 prior to the present invention, and first, the temperature of the wide furnace or Sn02 film growth chamber was changed over time. I thought of a device that automatically changes the temperature, but if you use such a device and continuously transport or take out samples,
Depending on the sample, the thickness ratio of the low-temperature grown film and the high-temperature grown film may differ, or worse, even the growth order may become inconsistent, making it difficult to put it to practical use.

The present invention is aimed at mass production without the two disadvantages by using a new idea in the situation described in 2.
We are trying to provide a continuous film growth device.

Before explaining the 1#lil example, the main structure of the present invention will be summarized. In the present invention, the heating furnace or growth chamber for growing the SnO2 film is replaced by It consists of two growth chambers: a first growth chamber with a first temperature or a relatively low temperature, and a second growth chamber with a second temperature or a relatively high temperature for growing a relatively high temperature film. They are arranged side by side in the horizontal direction, and the sample is transported from the first growth chamber to the second growth chamber by a sample transport mechanism. As a result, the sample entered from the sample insertion 11 of the first growth chamber is taken out from the outlet of the second growth chamber, and a product in which two layers of Sn02 films with different crystal properties are grown as desired is produced on the substrate 81. You will be able to obtain it continuously. In addition, each thickness in each growth chamber or the film thickness ratio between the low-temperature grown film and the high-temperature grown film is determined by the transport speed,
If the growth rate is constant, it can be controlled by the physical length ratio of both growth chambers in the transport direction.

Hereinafter, preferred embodiments of the present invention will be described as shown in the accompanying drawings.

FIG. 1 shows a 51102 film continuous growth apparatus according to an embodiment of the present invention. The 5n02 film continuous growth apparatus 1 of this embodiment first has a first growth chamber 2 and a second growth chamber 3 arranged in parallel in the length direction. The second feed gases Gl and G2 are introduced into the first growth chamber 2 from the first raw material gas supply port 8 and into the second growth chamber 3 from the first raw material gas supply port 9, respectively. First raw material gas exhaust: Exhausted through air ports 10 and 11. The first and second raw material gases Gl and G2 may have the same components and compositions, but generally they have mutually different components and compositions. In principle, even if the components and compositions differ in this way, if the sending direction and speed of each waste are appropriately arranged, both raw material gases can be exchanged between the first growth chamber 2 and the second growth chamber 3. The first growth chamber 2 and the second growth chamber 3 may be directly adjacent to each other, or there may be cases where mixing of both source gases is unavoidable in the process of practical application by the applicant. Therefore, in order to avoid any inconvenience in such cases,
In the preferred embodiment shown, a separation chamber 4 is provided between the first growth chamber 2 and the second growth chamber 3, and a suitable separation gas 11, such as high-purity Ar gas, is separated into this separation chamber 4. After the separation chamber 4 is filled with the separation gas from the separation gas supply 1112, the separation gas is exhausted from the separation gas exhaust port 3.

The sample S is transported by the sample transport member 19 in the sample transport mechanism 18, and is transferred from the insertion opening of the first growth chamber 2 to the large separation chamber into the first growth chamber 2, as shown by arrow F in the figure. 4, it passes through this separation chamber 4, enters the clean gas atmosphere chamber 5 on the inlet side, is sent out from the outlet of the clean gas atmosphere chamber 5 on the inlet side, and is taken up as a Sn'0211!2 product. It will be done. A detailed explanation of each room will be given later.

In this way, when the sample IS is transported by the sample transport member 19 of the sample transport mechanism 18 and inserted into the wood Sn02 film continuous growth apparatus l, the sample S must be inserted from the dusty air. Therefore, an i-side clean waste atmosphere chamber 5 is installed in front of the insertion port of the first growth chamber 2, and an appropriate inert waste and food clean gas is supplied from the clean gas supply port 14 to fill this chamber. It is desirable to maintain a clean atmosphere and to bleed air from the 1.'J clean gas υF air port 15.

Similarly, since the sample S on which SnO2 film growth has been completed will be taken out into dusty air, the second growth issue -! 3
(1 side 111) clean scum atmosphere chamber 6
It is desirable to sink one day. This exit is 1-1 side 4+! j
? 'f+gas z1 is also supplied to the enclosed air chamber 6, and a suitable inert gas or other circulating waste is supplied 1. ++6 and 4+'j n+cus υ1ki1=+17 should be provided.

For people, i side clean gas atmosphere chamber 5, output side clean n1 gas atmosphere'
As a result of each lpi+"'% chamber 6 being provided, the sample insertion 11 of the pigeon □ 1021 model continuous growth apparatus l becomes the first person in the clean atmosphere chamber 5 on the person 11 side, and the extraction port becomes the outlet (
- I side becomes the outlet of the clean and clean scum atmosphere chamber 6.

More characteristic features of this embodiment include the first raw material gas supply 1"8, the second raw material gas supply 1"9, and the pair of first raw material gas exhaust gas 1 and second raw material gas υ. Qi +-+1
The first point is that there is a plurality of numbers 1, and the second point is that the sample is held downward relative to the sample transport member 19.

Before explaining this characteristic point, it should be stated in advance that the specific configuration of the sample transport mechanism 18 is not directly defined by the present invention, and the sample is transported between the lengths of the 5I102 film continuous growth apparatus 1. Any configuration may be used as long as it is possible, and although it is extremely easy for those skilled in the art to configure such a sample transport mechanism 18 using existing technology, this In the applicant's practical example, a chain 25 is used as the sample transport member 19 as shown in the third figure, and a normal endless drive method is used, that is, the drive wheel 20D
A sample transport mechanism 18 drives this chain 25 by a following wheel 20I.

Also, as mentioned earlier, such a sample transport mechanism 18
However, even if the wing part 1j structure that holds the sample downward can be easily constructed using existing technology! Although the present invention does not directly define this, similarly, in the practical example of the present applicant, as shown in the third figure, the chain 25 is made of stainless steel or other suitable material. This purpose is achieved by placing an appropriate number of sample holding pins 27 on the lower surface of this □ tray 26 so as to sandwich the side surfaces of the sample wafer in a suitable recessed manner. Of course, this means that the downward surface of sample S is
This is a constant plane of nOz film growth, and along with this, as shown in qS1, the primary orcus supply 118,
The first raw material waste supply 119 and other waste supplies 1-1 are also
It is provided at the bottom of each chamber, and the waste passes through each chamber from C to G. In addition, the tray 26 is provided with an appropriate number of vents 1-128 in an appropriate arrangement so as not to cause a major hindrance to the flow of raw material waste. A detailed explanation of the constructors and the meanings of other characteristic configurations of this embodiment will be given below.

5n (Jz I sample growth first raw material gas G1 is Motoyama%
In practical use by humans, SnCl 4 is used in Ar or N2 gas.
A gas containing vapor of
2 or N2, or t120 vapor in Ar gas
Adding gas containing ml+l1tr-. Also, secondary acid 44N! The second raw material waste G2 sent to 3 is the 2? , 9 and 5bCI as an n-type dopant.
A gas component containing air in Ar or N2 is also suitable. If there is such a waste relationship and the separation chamber 4 is not provided, the first growth chamber 2 and the second growth chamber 3
A 4-1 mixture was produced between both races. However, when the separation chamber 4 is provided as in this embodiment and Ar gas, which is an inert gas with a purity of 1"11J, is supplied to this separation chamber 4 as the separation gas 1, the inner thickness Fl gas is separated. In the case of the illustrated embodiment, the separation scum 11 was ejected from below at right angles to -L from the main surface of the sample, and was removed from the separation gas bleed port 13 at the top by 71 pages. However, in order to effectively perform this separation, although not shown in the figure, the separation gas 11 is ejected from the side to the - surface of the sample in the 41st line, and similarly, the main surface and 111 : It is also good to remove the gas from the separation gas exhaust port I3 on the opposite side.The same thing can be done with the external gas system depending on the situation.

The first growth chamber 2 and the second growth chamber 3 are heated to their respective predetermined temperatures by the growth chamber heating coil 7, as mentioned above. Introducing S into the first growth chamber 2 taking into account s j + h'L'# may be undesirable.
In the two-film continuous growth apparatus 1, there is an inlet-side clean gas atmosphere chamber 5 in front of the first and second growth chambers, and this inlet-side clean gas atmosphere chamber 5 is used to keep the sample at room temperature in addition to its original state. to the first growth temperature], which is extremely convenient because it also serves as a preheating region for preliminary heating.

On the other hand, the exit-side clean gas atmosphere chamber 6 adjacent to the sample take-out port of the second growth chamber 3 has a cooling function that gradually cools the sample, which was at a high temperature, to near room temperature, in addition to its original function. It also performs the functions of the room, which is also very convenient.

Although the gist of the present invention can be achieved even if the sample S is placed upward on the sample transport member 18 and the respective gases are supplied from above accordingly, the conditions such as the flow rate of the supplied gases are poor. This may cause the film thickness to become non-uniform, or the adhesion force S of particles on the film surface to increase.
In some cases, pinholes were formed on the film surface. On the other hand, as described above in this example, when the sample S is arranged downward using the configuration shown in the third figure, and each gas is supplied from the bottom to the top, the film thickness distribution The properties were improved, and the result was that there was almost no adhesion of particles.

・On the Ki side, the respective sources for the first growth chamber 2 and the second growth chamber 3.
b) Even if the gas supply and exhaust are performed at one place, the principle structure of the present invention is satisfied, but as in the illustrated embodiment, by using a plurality of each in appropriate numbers, the uniformity of the film thickness can be improved. has further improved. In addition, the first raw material gas supply port 8 and the second raw material gas supply port 9 are equipped with flow rate regulating valves 21 and 22 such as 21-dol valves or butterfly valves to adjust the flow rate. By adjusting the exhaust pressure by using the D1 pressure regulating valves 23 and 24, which consist of similar suitable valve means or orifice configurations, etc., at the gas exhaust port 10 and the second raw material gas exhaust port 11, the film thickness uniformity can be further improved. In addition to further improvement, we were also able to adjust the growth rate.

In the illustrated case, the growth chamber heating coils 2 and 7 are in the first growth chamber 2.
Although shown as being common to the second growth chamber 3, it goes without saying that they may be dedicated to each. However, even if the heating energy is common, the heating energy received by each chamber is proportional to the volume of each chamber or the size of the magnetic induction part, so it ultimately depends on the design of the length of each chamber. It is not difficult to set a suitable temperature.

'leaf along the transport direction of the first growth chamber 2 and the second growth chamber 3
The ratio of 'n is the -th - growth pt if the outside conditions do not change.
It can also be used to set or control the growth film thickness of the 51102 film in the second growth chamber 2 and the second growth chamber 3.

Other resistance properties will be disclosed separately by the applicant. The uniformity of the thickness of the grown film can be further improved by making the tray 26 rotate instead of advancing in the transport direction, or by making it advance in a meandering manner.

As shown in the second diagram, wood SnO2 is
Take out the film from the insertion port of the continuous film growth apparatus (1).
The substrate temperature in C1 second growth chamber 3 is 350±20°C)
The 5n02/Si photoelectric conversion device produced according to the method showed a photoelectric conversion efficiency about 25% higher than that of a device produced using a conventional manufacturing apparatus having only one growth chamber. To give concrete numerical values, the incident light AM1.5, 10
0mW/cm2. Element temperature 28°C 9 element area 2
At 3.0 cm2, the photoelectric conversion efficiency is 9.57%, the fill factor (FF) is 78.3%, and the open circuit voltage is 0.425V.

An excellent short circuit current of 681 mA was obtained.

In the above embodiments, the explanation was limited to the growth of a 5N02 film on a Si substrate as a photoelectric conversion part, or in general, in a similar solar cell, a glass as a light entrance window was explained. A transparent electrode is formed on the substrate 2, and a photoelectric conversion element part made of a semiconductor material such as the 5N02/Si photoelectric conversion element part mentioned above is formed in the second part. A 5nOz film is often used for the transparent electrode. The present invention can be applied to the case where a 5n02 film as a transparent electrode is continuously grown on a glass veneer as described above, and can similarly contribute to labor saving and rationalization.

In the end, according to the present invention, a device suitable for continuous growth of 5n02 films by two-step temperature growth CVD method can be obtained.
This not only contributes to improving the performance and lowering the cost of 5nOz/Si photoelectric conversion elements, but also provides an apparatus that can be used when forming transparent electrodes as other components of solar cells. Even if you think about it, it will make a significant contribution to the advancement of optical energy utilization technology in the future.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an embodiment of the 5nOz film continuous growth apparatus δ of the present invention, and Fig. 2 is a trial diagram of the embodiment shown in Fig. 1. FIG. 3 is a schematic diagram of a main part of an example of a sample transport mechanism. , inside, l is the 5n0211 continuous growth device, 2 is the second growth chamber, 4 is the separation chamber, and 5 is the artificial side growth>x! 6 is a clean gas atmosphere on the outlet side, 7 is a coil for heating the growth chamber, 8 is a first raw material gas 1 supply jJ, 9 is a first raw material scum supply port, 1o is a first raw material -゛Gas grab 1-
1.11 is the second raw material waste gas "", 12 is separation: jii
)A': gas supply port, 13 is a separation gas exhaust; 1.18 is a sample transport mechanism; 19 is a sample transport member; 20D is a driving wheel; 21I is a slave shaft; 21.22 is a flow rate adjustment valve; 23.
24 is an exhaust pressure adjustment go, 26 is an I-ray, 27 is a sample holding claw, and S is a sample.

Claims (1)

[Claims] A 5n62 film growth apparatus for growing a 5n02 film on a substrate in a heated growth chamber, comprising:
It is composed of a first growth chamber heated to a first temperature and a second growth chamber heated to a second temperature, and the second growth chamber is arranged in parallel, and the second growth chamber is arranged in parallel. Insert the sample from the sample insertion port of the chamber, transport it to the second growth chamber through the second growth chamber, and complete the growth of the 5nOz film from the sample takeout port of the second growth chamber. A 5nOz film continuous growth apparatus characterized by having a sample transport mechanism for sending out 5nOz film.