JPS5916329A - Plasma vapor reaction device - Google Patents

Abstract

PURPOSE:To form junctions at lamination boundaries and then perform continuous production without forming layer insulators by a method wherein the supply is performed by orienting the direction of flow of reactive gas in parallel with the surface to be formed, and a waveguide connected to a reaction vessel for supplying microwave energy is provided. CONSTITUTION:As semiconductor reactive gas, silane is supplied from the port 28, and carrier gas such as hydrogen from the ports 27 and 26 according to necessity, and thus high frequency energy is supplied by a high frequency power source 15 by means of electrodes which compose a pair. A substrate is heated by a heater 12. The reactive gas flows along the surface to be formed of the substrate 2 from upward to downward, and then reaches a vacuum pump 37. A reaction vessel 7 possesses a peep window 8, a copper net for preventing electric wave leakage 49, and a quartz pipe for microwave supply 55, the wave guide 54, and a microwave power source 56 on the back side. They are so provided that electric fields of the reactive gasses 26, 27, 28 and the high frequency 15 are arranged in parallel along the surface to be formed of the substrate 2. In addition to the high frequency, microwave of frequency of 1GHz or more is supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION When forming non-single crystal semiconductors having conductivity types of VcP type, 1 type and N type on a substrate by laminating them in layers, the present invention provides the following steps:
By forming each semiconductor layer in a corresponding plasma vapor phase application reaction vessel, and by connecting the reaction vessels to each other, a plasma vapor phase system that allows semiconductor layers to be formed without exposure to outside air (atmosphere) can be achieved. Relating to a reactor.

The present invention is directed to a non-single crystal semiconductor layer doped with hydrogen or a norogen element, preferably silicon, germanium, silicon carbide (not only EIiO but also 81xO in the present invention).
, -, lO< x≦1), germanium silicide (SiXGJ-a O<X/ 1) tin silicide (
By filling this film with hydrogen or a halogen element in an active state, a semiconductor layer having conductivity types of P type and N type with a small density of recombination centers can be formed. A plurality of layers are formed, and a junction such as a PN junction, a P-type junction, an N-type junction, or a PIN junction is formed at the lamination boundary, and impurities from other adjacent semiconductor layers are mixed into each semiconductor layer, causing the junction characteristics to deteriorate. It is possible to form an interlayer insulator without deteriorating the semiconductor layer by exposing it to the atmosphere, especially oxygen, during the process of forming the semiconductor layer on each of the two layers, which oxidizes a part of the semiconductor. The present invention relates to a plasma gas phase application manufacturing apparatus for continuous production that eliminates the need for production.

In the present invention, the semiconductor film to be formed is not sputtered (damaged), and even non-single crystal semiconductors can be crystallographically grown (GROWTH) on the substrate. and supplying an electric field for plasma generation. Furthermore, the present invention supplies microwaves (IGHz or higher) to the reaction vessel to increase the plasma conversion rate of the reactive gas by 20% compared to 0.1 to 1% using only high frequency waves.
By increasing the size to ~70 cm, the growth rate of the film was increased by 5
It is characterized by improving mass productivity by increasing the capacity by ~8 times.

In order to prevent the formation of such impurities, the present invention provides a reaction vessel for forming a P-type semiconductor layer, a reaction vessel for forming a J-type semiconductor layer, and a reaction vessel for forming an N-type semiconductor layer. According to the stacking order of the semiconductor layers formed by forming 41 layers on the substrate, each reaction vessel is connected to the first preliminary chamber on the substrate ((first semiconductor)
A reaction vessel for forming a second semiconductor layer on the first semiconductor layer is further connected to the reaction vessel for forming a second semiconductor layer on the first semiconductor layer, and thereafter reaction vessels are stacked in the same manner. The present invention relates to a plasma reaction manufacturing apparatus that is connected in series to the number of semiconductor layers.

Conventionally, in the plasma vapor phase reaction of non-single crystal semiconductors such as amorphous silicon, the discharge method of the manufacturing equipment is 13.5
A high frequency such as 6 MHz is supplied to parallel plate electrodes, and a substrate having a surface to be formed is placed on one of the electrodes.Furthermore, a gas flow of reactive gas is simply formed in the responder. A method is known in which the amount of water is supplied without any damage. However, in this conventionally known method, the growth rate of the film is as low as 1 to 2 A/sec. In addition, the substrate is placed only once between the electrodes, and the semiconductor layer is formed only on the main surface of the substrate.For this reason, mass production is not sufficient, and when producing a solar cell, which is a typical application example. Manufacturing cost is 1oan'
The size of the board exceeded 5,000 yen, and more than 4,000 yen of that amount was equipment depreciation costs, which was completely absurd.

Therefore, with a substrate size of 10 cm', 10 to 3
There is a strong need for a manufacturing device that can produce products with 0 times higher productivity using the same size reactor.

The present invention has been made to meet this objective.

The semiconductor layer r cannot be formed by simply using an intrinsic semiconductor, but by superimposing P-type and N-type semiconductor layers and forming a junction, its engineering applications are expanded. Even if manufacturing in a container improves productivity, impurities for each conductivity type will mix with each other within the semiconductor layer due to the sputtering effect. Therefore P
When stacking a plurality of semiconductor layers having at least one N, P-type, N-type, or P-type N junction, when trying to form a sufficient junction at the interface, a reaction vessel for each conductivity type is prepared as described above. Therefore, it is extremely important to allow independent separation.

In addition to such a separate and independent method, the present invention aims to improve the bonding characteristics by eliminating the mixing of impurities. That is, for example, when trying to form one P-N junction by laminating a P-type semiconductor layer as the first semiconductor layer, adsorption of this impurity occurs at the same time as the semiconductor layer is formed. . In the present invention, in order to prevent re-release from the inner wall of the reaction vessel, and to prevent the reactive gas once adsorbed from the supply system and exhaust system from separating and mixing when forming the second semiconductor layer, it is necessary to use only the reaction vessel. Without,
A reactive gas supply system and an exhaust system are also provided independently for each reaction vessel.

However, as a result of further investigation into Lie 17 regarding the mixing of impurities, it became clear that this alone was not sufficient and that the formed first semiconductor layer itself could also be a source of impurity mixing.

Therefore, when a second semiconductor layer is to be formed on the upper surface, the second semiconductor layer is grown on the base layer, and the second semiconductor layer is grown on the surface to be formed so that the reactive gas flows through the base semiconductor layer. It has been found that it is extremely important to avoid sputtering effects as much as possible.

That is, when a high frequency electric field is applied perpendicularly to the surface to be formed, the reactive gas turned into plasma by this electric field strongly collides with the base. For this reason, when the second semiconductor layers were being stacked, they mixed with each other at the interface.

As a result, when the surface to be formed is oriented parallel to one electrode surface of the conventionally known parallel plate electrode (that is, the electric field is perpendicular to the substrate surface), the mixture of β and other impurities can be eliminated using the independent reaction vessel method. However, the mixing part is about 1
It turned out that there are also 000-200OA.

In order to avoid such drawbacks, the present invention uses an independent separation reaction method, and the DC and high frequency electric fields used for the plasma reaction are parallel to the surface to be formed, and the reactive gas is directed parallel to the surface to be formed. By applying these currents, the mixing of impurities is eliminated, and the mixing part is heated to 200 to 300 A+! : It is characterized in that it is approximately 1/1 o to 115 o.

In this way, it was possible to sufficiently reduce the density of recombination centers concentrated at or near the junction. In other words, the recombination center is formed by mixing impurities, and monovalent impurities that do not become donors interact with v-valent impurities to create a deep trap level. The concentration of dangling bonds in the semiconductor can be reduced from 10 to 100% by crystallographic growth.
It is characterized by having a diameter of about 1/100 of 10'' to 10'''am-'.

4 1" t971B Furthermore, the present invention further provides a method in which the reactive gas is
00KHg->50MHz e.g. 13.56MEZ)K
Since the ionization rate is less than 1, most of the reactive gas is not sufficiently converted into plasma.

For example, Si-H, 5i-F, C-,! (,N
-HXGθ-H bond-bearing reactive gas (Eti)%
It has been found that the cause is that the frequency necessary to break hydrogen bonds is not supplied in ,Si, ]I(,,,NmaGe)9, etc. That is, direct current or high-frequency electric current supplies kinetic energy to elements with atomic weights heavier than t, but does not supply sufficient kinetic energy to orange elements such as hydrogen. Therefore, in the present invention, Q, the supply frequency is set to the resonance frequency of Eli-H, etc. or IGHz close to it.
Supplying microwaves with a plasma ionization rate of 40
It is characterized by increasing the temperature up to ~'70%. As a result, since the resonant frequency is sufficiently lower than the heavy element, kinetic energy is not applied to the heavy element, so there is no sputtering effect on the surface to be formed, and since the plasma conversion rate is high, the growth rate of the semi-dielectric film is 3 to 5. It had the great feature of being able to increase the energy by up to twice as much. Also, regarding microwave energy, a patent application filed by the present inventor (Japanese Patent Application No. 53-15288'7 E)
l53.12. (No application) is known.

However, in this method, since the microwave is placed in front of the reaction vessel, a large amount of reaction products adhere to the inner wall of the reaction vessel at this front. For this reason, in the present invention, a waveguide is continuously provided in the reaction container itself through a window made of quartz or alumina so that microwaves are supplied randomly into the reaction container. In this way, microwaves are supplied throughout the reaction vessel, promoting activation and ionization of the reactive gas therein, and forming a film on the substrate of the film disposed in the immediate vicinity. I was able to do that. Therefore, the amount of semiconductor element effectively used in the semiconductor layer formed on the surface on which the supplied reactive gas is formed is conventionally 1 to 3.
%, in the present invention it is 20-40% K
I was able to raise it to

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

Example 1 An example of the plasma vapor phase reactor of the present invention will be described with reference to FIG.

This drawing is for P-work joint, N-work joint, PN joint, P-work N joint, P-work N-work P joint, N-work P-work N joint, or P-work NPIN.
・In order to prevent each semiconductor layer from being influenced by the semiconductor layer formed before it, a semiconductor layer of a different conductivity type or the same conductivity type is added to a semiconductor on a substrate such as an @-PIN junction. A second semiconductor layer is formed in another independent reaction vessel connected to the reaction vessel in which the second semiconductor layer was formed, and is laminated on the previous semiconductor layer to form a bond, and further layers are automatically and continuously formed. It is a device for

The drawings show an example of a plasma vapor phase reactor in which a special KP N-junction is formed by laminating three semiconductor layers.

Each of the three reaction vessels (6), (7), and
, ct→ and exhaust means (a), ni) to prevent reactive gases from flowing backward or mixing from the supply system or the exhaust system.

This device has a first preliminary chamber (5) on the entrance side,
Door 02) Board (4) on top of the boat (not shown)
, (4) were inserted and placed in this preliminary chamber.

Furthermore, this preliminary chamber (5) was evacuated using a vacuum pump (35) Vc. The substrates having the formation surfaces are arranged in a row with their back surfaces in contact with each other with a gap of 3 to 5 cm. After this, the reaction vessels (6), ()), which have been evacuated in advance, are
), the gate valve (44) was opened, the substrates and the boat were transferred to the plasma reaction vessel (6), and then the gate valve (44) was closed).

At this time, the substrate (1) of the reaction vessel (6) is attached to the reaction vessel (1), and the substrate (1) of the reaction vessel (7) is attached to the reaction vessel (8).
K, and the substrate of the reaction vessel (8) is connected to the second outlet side preliminary chamber (9) K at the same time as the gate valve (45) (46) (4″
Q is opened and moved.

After the gate valve 07) is closed, nitrogen is introduced into the substrate transferred to the second preliminary chamber (41), and the pressure is brought to atmospheric pressure (41).
One door is taken outside.

In other words, the movement of the gate valve is the gate valve (44), (45) when the door (42) and (43) are opened at atmospheric pressure.
, (46), ση is closed, and conversely, the door (
42) (43) is closed and the preliminary room (5), (9
) is sufficiently evacuated, the gate valve (4s (45) (
46) (t'1) has an opening mechanism 7 2
The P-type semiconductor in the first reaction vessel (6) in the 2 Ru0 system IK was set to 0.01 to '1 torr.

The reactive gas is silane (si) for silicide gas (c).
n L,, 1% K S i B,) % dichlorosilane (El IHLOQ trichlorosilane (SiH
Cl, ), silicon tetrafluoride (stlS), etc., but silane, which is easy to handle, was used. In terms of price, dichlorosilane is cheaper υ, and it may be used.0 In order to form 5iXOr-JO<X(1) in this example, methane (O)Q , ethane (C
The blade may be a hydrocarbon such as propane<ah~ or a carbon chloride such as carbon tetrachloride (aaQ).

For silicon carbide, boron is replaced with diborane as a P-type impurity, and gallium is replaced with TMG (Ga (a tumor)).
K and I) were added to a concentration of 10-9 x 10 cm. In this example, TMG is used, Ga is used as a P-type impurity, 1, and 01- is 8 i x O1-Jl (0
< xt 1) Supplied from K (c).

did. These reactive gases have their respective flow rates G53)
and a valve (3) to supply K to the reaction vessel (6).The reaction system initially removed oxygen etc. attached to the inner wall surface of the vessel at
It was removed by heating to 0-500°O.

Heat the substrate to 100 to 400°C, for example 200°C, using a heater of 0.
1) Heat in K. After this, the above-mentioned reactive gas is introduced into the container, and the predetermined pressure is set to O, 1 torr, for example.
Further, high frequency energy αl (10 to 50 W) was supplied to cause a plasma reaction.

This P-type semiconductor layer is formed by this reaction system I, and about 1
Although a thin film with a thickness of 0 OA, silicon carbide generally requires more radio frequency energy than silicon alone.

However, in this case, the transparent conductive film, which is the surface on which it is formed, is extremely easily smeared, and the tin oxide is replaced by 14 tin, making it apt to become cloudy instead of transparent.

However, as shown in this example, when the plasma electric field is made parallel to the surface to be formed, the reaction products due to this electric field move along the surface, so the clouding due to the sputtering effect is reduced by 3.
It is not seen even when 0 to 50 W is applied, and 2 to 5 in the case of vertical electric field.
Improved manufacturing yield compared to W, which was at its limit○
Substrates are conductor substrates (stainless steel, titanium, titanium nitride, and other metals), semiconductors (silicon, silicon carbide, germanium), insulators (alumina, glass, organic materials), or composite substrates (tin oxide, engineered, etc. on glass insulating substrates). Those with a single layer of conductive film such as TO or a double layer of KSnOL on ITO, those with conductive electrodes selectively formed on an insulating substrate, and Kl' or N-type semiconductors on an insulating substrate. was formed). These are collectively referred to as a substrate not only in this embodiment but also in all of the present invention. Of course, this substrate may be flexible or a rigid plate.

In the following examples, a transparent conductive film is formed on a glass substrate, and a KP-type half body layer (approximately 100A), a semiconductor layer (approx.
The subcommittees forming A) will be explained in detail.

In the reaction system shown in FIG. 1, a silicon carbide semiconductor was formed and a silicon film was formed in addition to a silicon carbide semiconductor layer in order to make the special KP type semiconductor layer have a wide Kg using the plasma-magnetic discharge method. The substrate (1) is lined with ports (eg quartz) (2) K.

In this example, a substrate having a thickness of 200 μm to 2 mm and a thickness of 1 ocm was used. This substrate was sealed in a reaction container (6)K. This reaction container is 1~20MHK, special K 13.56M
High frequency energy from a high frequency source α of Hz is stored in a pair of electrodes a to a temperature of 6 K so as to excite, react or heat a reactive gas. This electrode 07) serves as an inlet for the reactive gas @(c), and the electrode (a) also serves as an outlet. Furthermore, a heater (heater by heat or infrared imaging KK) is installed on the outside of the exhaust.
30). A large number of 1 mH holes are made below the electrode, and the reactive gas is ejected through the holes of the electrode and turned into υ plasma by high-frequency induction energy with an electric field parallel to the formation surface of the substrate (1). Ru.

In this manner, a plasma reaction was performed for 1 to 5 minutes to produce a silicon carbide film to which gallium was added as a P-type impurity.

Further, the substrate was transferred onto the first semiconductor layer to a second reaction vessel (1) K according to the above-described operating sequence, and an intrinsic semiconductor layer was formed therein to a thickness of about 500 OA.

That is, in the reaction system H in FIG. Similarly to the HK system (2), high frequency energy of 13.56 MH2 was supplied from a high frequency power source αυ.The substrate was heated to 250° by a CK heater (2).

The reactive gas flows upward and downward along the formation surface of the substrate (2), reaching the vacuum pump (3″QK).
Fig. 2 shows a vertical cross-sectional view of 3) from the outlet side.

Figure 2 is outlined.

In Figure 2, the reaction vessel (7) has a viewing window (4B), a copper mesh for preventing radio wave leakage (49), a quartz window for microwave supply on the back side (55), a waveguide (54), and a microwave power source (56).
Equipped with: The arrangement is such that a reactive gas (c), a wire, and a high frequency electric field are arranged parallel to the surface of the substrate (2) to be formed.

Furthermore, in addition to high frequency waves, frequencies higher than hOHZ, such as 2.
45GHz microwave is supplied.

The growth rate of the film is shown in Figure 3. When microwave energy and high-frequency energy are added (61), when microwave energy alone is used (6 points), when high-frequency energy is used alone (61) It was also found that a silicon semiconductor film did not grow if the substrate was simply subjected to resistance heating.

In addition, as is clear from the drawings, excitation by microwave energy was found to be extremely effective in increasing the growth rate.

1. At 250°O in the drawing. OA/sec was obtained from (66), but when only microwaves were applied at 200 W, (65) and when a product frequency electric field was added at 1 OW, (64) was obtained, and the growth rate was 7 times as high. I understand. For this reason, compared to conventional methods, when microwaves are used in combination, mass productivity is extremely high, and even when microwaves are applied at 500 W or more, no ivy effect is observed on the coating. 2~1ox1o-'
(intervention cm)''s leading conductivity (at AM engineering) and 1 0
I am confident that I was able to obtain a conductivity of ~10-' (Ac m)' and create an extremely ideal layer.

In this example, gallium, which contains many P-type impurities and is difficult to re-emit, was used, and in particular, since the present invention does not sputter the substrate surface, the interface was different from the conventional 10
Instead of having a thickness of 00-200OA, it was only 100-20OA thick.
10, and this is the result of an investigation using an MA (ion microphone = -f rope analyzer) to determine the doping in one layer until it reaches lXl0 am K.

Furthermore, after forming the N-type semiconductor layer to a thickness of about 500 OA in System (1), the substrate was transferred to the reaction vessel (8) of System (2) according to the operations described above, and an N-type semiconductor layer was formed thereon.
In this N-type semiconductor layer, phosphine is added to P as shown in FIG.
■/day ta, 1.0% Toshi (31), silane (30) and carrier gas (A) were supplied, and a KN type semiconductor layer with a thickness of 200A was formed in the same manner as in System I. Thus, after forming the second 4-t(9) outer KP-N junction, aluminum electrodes were formed on the resulting substrate by vacuum evaporation to a thickness of approximately 1 μm. Made on a glass substrate (TO + back electrode (PIN semiconductor))
(A1 back electrode) was constructed.

Its characteristics as a photoelectric conversion device are 10 to 12% on average 11
It has AM process (100mW/crn) K, No. 1
Even in the 10 cm hybrid type, it was possible to obtain an intrinsic efficiency of 8 to 9%. This improvement in efficiency is due to the fact that the P-type semiconductor layer on the P-type semiconductor layer is grown and stacked on the P-type semiconductor layer, even in non-single-crystal semiconductors such as thin amorphous semiconductors. This was due to the fact that the open circuit voltage was 0.88 to 0.9v,
The short circuit current is large at 20-22 mA/c mL, and
The FF is also very high at 0.70 to 0.18, and the density of recombination centers inside the PIN type semiconductor layer is 1% compared to the conventional method.
It is presumed that the increase in current due to the change in current from /10 to 1150 led to a large improvement in characteristics.

As described above, the plasma reactor of the present invention is an extremely original device that improves the productivity of formed semiconductors by 10 to 30 times, and also improves the conversion efficiency by 30 times compared to the conventional 5 to 8 inches. It is something.

Many applications such as a photoelectric conversion device with a tandem structure of P/NP/N111...P/N are also possible in the present invention. Even if the crystal structure in the non-single crystal semiconductor film formed in the present invention is amorphous, it Even if it is a crystal, there are no restrictions on its structure. The present invention provides that the plurality of laminated semiconductor films formed are at least P-type, N-type or 1-type.
It is important that the semiconductor has one PN or N-type junction. In order to reduce the leakage characteristics of conductive properties as a semiconductor, a major feature is that they are not mixed at the junction surface.

Furthermore, this dangling bond of silicon or carbon is replaced with hydrogen)
81-01 instead of neutralizing with S i-H, O-HK
．． It goes without saying that the reaction may be carried out using 0-01 and 10 genides, especially chlorinated gases, and the concentration is preferably 10 molar or less, for example 2 to 5 molar.

Regarding the type of semiconductor to be formed, Example IK is shown, but 81, Ge, Elix (3, -, (0<xt
1), 51xae, (6<+c, <1), 5i
Not only XSn, -JOi
It goes without saying that compound semiconductors such as aAa, GaAlAs, BP, and Ode may also be used. P or N type impurities are selectively added to the silicon carbide film formed by the present invention using photoetching technology. It is also possible to partially create a PN junction by mixing or diffusing it, or to create a transistor by using the junction. In particular, in the energy source side of the light incidence side (so-called W-N QFi'T)E TONALLOW which has a beterojunction structure with a large bond width) and in each reaction chamber, not only the conductivity type but also the product is different, and each It is now possible to fabricate and laminate
We believe that it is extremely important industrially.

[Brief explanation of the drawing]

1 and 2 schematically show a manufacturing apparatus for forming a semiconductor film for carrying out the present invention. FIG. 3 shows the characteristics of the silicon semiconductor film obtained by the manufacturing apparatus shown in FIG. 37 Gun 2 Figure I 3rd

Claims (1)

[Claims] ■, A semiconductor in which a junction is formed by laminating non-single crystal semiconductor layers of type 1 and type N (K, P type) on the formation surface of the substrate in a reaction system maintained at a reduced pressure of 1 atmosphere or less. , a reaction vessel for forming a P-type semiconductor layer, a reaction vessel for forming a ■-type semiconductor layer, and a reaction vessel for forming an N-type semiconductor layer are provided. The reaction vessel has a reactive gas introduction system and an exhaust system for evacuating the reaction product, and the reaction vessels are connected to each other, and gas pipes are provided on one side and the other side of the reaction vessel. A first and a second preparatory chamber are arranged in series, and a gate is provided in the continuous part of the reaction chamber and the preparatory chamber to prevent the reactive gases introduced into the respective reaction vessels from mixing with each other during the plasma gas phase reaction. In a plasma gas phase reactor equipped with a valve, the flow direction of the reactive gas is oriented parallel to the formation surface, and a waveguide connected to the reaction vessel for supplying microwave energy is provided. A plasma gas phase reaction device comprising: