JPS5864022A - Plasma vapor phase growth device - Google Patents

Abstract

PURPOSE:To prevent adhesion of a reaction product to electrodes and generation of complication in a current of reactive gas (turbulent flow) at a plasma vapor phase growth device by a method wherein a horizontal type reaction cylinder is used, and a pair of electrodes is arranged outside. CONSTITUTION:Substrates 1 are held by square type quartz jigs, the jigs are settled in a separate chamber 29 of a reaction cylinder from an inlet 30, and the chamber is evacuated by a rotary pump 33 through a valve 32. Moreover a closing door 34 is opened, the jigs are introduced into the reaction cylinder by an automatic feeder, and a mixing plate 35 for mixer is also arranged. By closing the closing door 34, the substrates are arranged in space between electrodes 9, 10 interposing the intervals of 10-40mm. between them. A pair of the electrodes 9, 10 are arranged vertically or on both the sides of the reaction cylinder 25 as to apply electric field to the substrate vertically or in parallel, an electric furnace 5 is provided outside, and the substrates 1 are heated at 100-500 deg.C. Reactive gas is introduced into the reaction cylinder 25, a high frequency electric power is applied between the electrodes 9, 10, and presence of voids, etc. in the formed silicon carbide or in silicon is reduced utilizing the flight of reactive gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma vapor phase apparatus that forms a large amount of reaction products on a substrate in a single reaction in a plasma vapor phase method, and a method for manufacturing the same.

The present invention is arranged horizontally for such mass production, and has a reaction tube (10 to 300 m x 1 to 5 m in length), and an electromagnetic energy supply for turning a pair of reactive gases into plasma on the outside of the reaction tube. An electrode and a heating device are provided on the outside of the electrode to surround the reaction tube and the electrode, and a reactive gas is caused to flow forward in the reaction tube, and the substrate □ is placed along the flow of the gas. It is a feature.

Further, in such a device, substrates are arranged perpendicularly or parallel to the electromagnetic field generated by a pair of electrodes, and these are arranged in multiple stages or in multiple rows to form one substrate of 2 to 20 cm, for example, a room.
The purpose of this method is to form a film, particularly a silicon, carbon, or silicon carbide film, on a total of 400 surfaces of 20 rows and 20 rows of substrates at one time.

(2) The present invention furthermore suppresses the plasma in the front direction of the reaction tube and sufficiently mixes reactive gases or a carrier gas such as hydrogen or helium to form a laminar flow.
The reactor is characterized by the provision of a mixer that introduces the nurse (-) into the reaction cylinder that has been turned into plasma.

The present invention uses a reactive gas consisting of a hydride or a halide (carbohydrate silicide gas) having a carbon-silicon bond, a silicide gas such as ylang (Si n LuI n≧1), or a hydrocarbon such as acetylene. A film containing non-single-crystal silicon carbide, silicon, or carbon as a main component is formed on the surface to be formed using a reaction tube pressure of 0.05 to 0.5 torr.
The present invention relates to a plasma vapor phase method in which formation is performed at a temperature of 0.00 to 400"O.

In the present invention, the reactive gas is not nitrogen or argon,
In particular, by diluting with a carrier gas of hydrogen, helium or a mixture thereof, there is less damage to the surface to be formed.
It is an object of the present invention to form a mud-wave film with excellent uniformity in film thickness.・By gradually adding an impurity gas containing a V-valent impurity, such as 7-oshin (PH, ) or arsine (A8Hj) to the shell, a P-type layer is closely formed on the substrate having the surface to be formed, and then a process-type layer and an N-type layer are formed. The purpose is to form layers in the order of P-N.

Conventionally, amorphous (hereinafter simply referred to as As) silicon is known as a typical example of a non-single-crystal semiconductor produced by a plasma vapor phase method. This is expected to be applied to photoelectric conversion devices such as solar cells. However, when attempting to create such a device, or when attempting to obtain a visible light emitting device using a semi-single crystal semiconductor, the reaction occurs in a vertical Pelger type.

At this time, parallel electrodes are placed above and below inside this Pelger,
An electromagnetic field with a frequency of 13.56 MH2 was applied between the electrodes to cause plasma discharge, and a reactive gas was introduced into the Pel jar to cause a reaction. Furthermore, the substrate having the surface to be formed is placed on the lower electrode. However, in such a method, the circumference of the electrode is 0.1 to 10.
Due to the reduced water pressure of torr, the distance between the electrodes cannot be widened, and therefore the distance between the electrodes is only 1 to 4 cm.
It didn't happen. If this was extended beyond 10 cm, Lll- discharge between the electrodes, especially the anode and the Pelger, etc. started, and the discharge between the electrodes also became unstable. Therefore, in reality, it has been impossible to arrange a plurality of substrates in multiple layers between these electrodes and to form a film on several tens of substrates at once.

Furthermore, in the case of a vertical Pel jar, the flow of the reactive gas tends to vary, making it impossible to create a so-called laminar flow.

The present invention is characterized by the use of a horizontal reaction column which avoids the drawbacks of the vertical Pelger.

Another feature is that by arranging a pair of electrodes on the outside of the reaction tube, the electrodes are covered with reaction products.

A further object of the present invention is to use a heat-resistant mesh-like electrode made of stainless steel or the like to uniformly heat all of the reactive gas and substrate inside the reaction tube from the outside.

In this way, the reaction tube contained only the substrate and the substrate holder, resulting in an extremely simple structure.

Furthermore, the present invention is characterized in that when the power of the electromagnetic energy for turning into plasma is increased, the sputtering surface that has been turned into plasma is sputtered by this power, and the semiconductor or insulator that has already been formed is spattered by this sputtering (damage). A part of the ζ1 is released to the outside again, and the formed structure becomes a so-called amorphous (As) which has electrical properties.
, semi-amorphous (semi-amorphous, hereinafter referred to as SAS) or 5
Instead of a non-single crystal such as a micro polycrystal (hereinafter referred to as PC) with a size of ~20 OA, the result is an amorphous structure full of sputtered electrical defects. In order to eliminate this structure, the substrates are
Even if the plasma reaction requires a high energy of 200 to 500 W with a separation distance of 0 to 40 mm, typically 20 to 25 mm, the distance between the substrates to obtain the substantial plasma energy of this spacing must be set on the surface to be formed. It is characterized in that it has the same characteristics when controlled at a distance of 100 W and is formed into a film with a substantially weak power of 20 to 50 W.

Therefore, in the present invention, when silicon carbide (SixOl-KO<x<1) is to be produced as a reactive gas as a starting material, a material having a carbon-silicon bond is used. That is, hydrides or halides having a carbon-silicon bond, such as tetramethylsilane (si (+4) (simply referred to as TMS), tetraethylsilane (E!i (0
, sound), S Lx (C!)C1pXC'1m (14
X4 criminal Si, (b)lF9. , xH, (1=x≦3) and other reactive gases are used to make it easier to obtain 5i-C bonds in the reaction product.0Also, when trying to obtain a film containing silicon as the main component, 5inHzsc (n21) silane, S
When trying to obtain 0 carbon using i F or a mixture of these gases, acetin, mt and ethylene (O) were mainly used.
i), silicon carbide (SiXOugly0<X(1)) or carbon (
C) (If you put these together, 5iKO+<(04xko1)
Therefore, when referring to silicon carbide below, 5i
x (supposed to mean 3z-4 (0<xko1)) is produced.

Furthermore, a monovalent or V-valent impurity is added to the formation surface to form P type, 1 type (intrinsic or substantially intrinsic without artificially adding impurities including autodoping, etc.), and N
A type of semiconductor or semi-insulator was fabricated. - Furthermore, when such a reactive gas is used, the reaction tube is heated to a pressure of 1 atm or less, particularly 0.01 to 10 tOrr, typically 0,
Even at an electromagnetic energy of 50 W or less under a pressure of 3 to (L 6i; orr), for example, 0.1 to loOMHz %
13.56MHz, or 1-4GH2 special K 2.
It is possible to form a film at 45 GHz.
In other words, a low energy plasma OVD device could be achieved.

Further, when a high energy plasma atmosphere of 50 to 500 W is applied, the formed silicon carbide becomes microcrystalline, and as a result, in P type or N type, boron or phosphorus is added to 0.1 to
When adding 5 CH (here, the ratio of (&H1 or PH,)/(carbide gas or carbide silicide gas to decsilide gas) is added, the electrical conductivity is 10 to 10 (U) at low energy. cm) I is 9-things are 10-10 (
2 am) and was able to increase it approximately 1,000 times.

Furthermore, silicon carbide obtained using this high energy method has 5
The so-called SA with a microcrystalline structure with a size of ~20OA
In such a SAS that was able to have an S structure, the ionization rate of the P or N type impurity (9), which becomes an acceptor or donor, is set to 97 to 97.
100%, and all of the added impurities could be activated.

The plasma vapor phase method of the present invention will be explained below with reference to the drawings. Figure 1 shows the plasma using the present invention (held in a British jig of a 3VD device, and shown in the drawing as having a configuration of 7 stages and 2 rows, 1 in total). The substrate and the jig are placed in advance in a separate room in front of the reaction tube through the inlet CO), and a vacuum is created by the pulp (32) rotary pump (3). , is introduced into the reaction tube by a self-merging device, and a mixer mixing plate (35) is also placed at the same time.Both the reaction tube and a separate chamber are placed in a vacuum state, so that even the slightest amount of oxygen (air) is allowed to enter the reaction tube. Efforts were made to prevent contamination.Furthermore, by closing the opening/closing doors (3), the substrate was placed between the electrodes (9 (10) and (10)) as shown in the drawing.

The substrates are arranged at intervals of 10 to 40 mm, typically 20 to 25 mm, and the reactive gas produced by this jig is sent to the mixer (8) in front of the reaction tube (c) so that the formation surface is the substrate. The underside or the vertically arranged sides with their backsides superimposed on each other. In the drawings, when the upper side is upward, the upper surface of the substrate is covered to prevent the formation surface from becoming sharp. This is due to the decomposition and reaction of reactive gases, which cause the reaction products to adhere uniformly and form a film, and when this film is formed, flakes, etc., which are released from the reaction tube wall, are forced to the top surface due to gravity. This is because a large number of them fall, which induces the generation of pinholes. Further, if the drawing shows the reaction system from above, the substrates (1) are arranged vertically with their back surfaces facing each other. Using gravity to remove flakes to the bottom in this way is extremely important when considering mass production yield. Furthermore, this board (1)
A pair of electrodes (c) are inserted into the reaction tube (c) into which an electric field of electromagnetic energy is applied perpendicularly or parallel to the substrate.
? ), (10) were arranged vertically or horizontally. An electric furnace (5) is provided outside the electrode, and the substrate (1) is heated to 100-500°C, typically 300C.

The reactive gas is a carrier gas such as helium.
, diborane, an impurity with a value of 1, was introduced from 04, phoshine, an impurity with a value of 1, was introduced from 0Q, and silane, a silicide gas, an additive with a value of 1, was introduced from 0Q.

In addition, when using reactive gas TMS (e) having carbon-silicon bonds, it is liquid in the initial state, so it cannot be used in a stainless steel container.
C). This container is controlled at a predetermined temperature by an electronic constant temperature layer (c).

This TMS has a boiling point of 25°C, and the rotary pump 0■ is evacuated through the pulp α force, and the inside of the reaction column is 0.01
~1qtOrr especially 0. o2~Q, was maintained at '4tOrr. By doing this, TMS can be vaporized at a pressure lower than 1 atmosphere, and as a result, without special heating. Introducing this vaporized TMS at a concentration of 100 cm into the reaction tube via a flow meter makes it easier to control the flow rate than the conventional method of bubbling the container Q1) to release reactive gas. is possible with high precision and is technically important.

In practice, when a flowmeter becomes clogged, helium is introduced from αη in the drawing.

These reactive gases were mixed with helium, which is a carrier gas, at a predetermined ratio and introduced into the reaction column (c). Electromagnetic energy is applied between the electrodes (9) and (-10), for example, by applying high frequency (13,56 MH2), thereby applying an electric field in a direction that solidifies the film accumulated on the surface to be formed. . By doing this, the presence of voids etc. in the formed silicon carbide or silicon was reduced by utilizing the flight of the reactive gas moved by the electric field. Furthermore, in this plasma discharge, after the reactive gas passes through the mixing chamber (8) and is mixed, it is decomposed or reacted in the excitation chamber (c), and a reaction product is formed on the substrate. Using. Electromagnetic energy is a power source (
4) DC high frequency was mainly used. Of course, microwaves (1 to 4 GHz) may also be used, particularly by supplying them to the excitation chamber (c). In this way, a silicon carbide film was formed on the surface to be formed. For example, the substrate temperature was 300'O, the high frequency energy output was 25w1 silane or TMS 5occ/min, and the carrier gas was He 250'Dcc/min. (A film growth rate of 160 A/min could be obtained in the reactive gas/He door 5.

Furthermore, in order to form this film, a P/N junction, a PN junction, a P/IFIN junction, etc. were formed by laminating the necessary reaction products to the required thickness.

After a film has been formed on the surface to be formed in this way, the reactive gas is sufficiently purged from the inside of the reaction cylinder, the opening/closing door (34) is opened, and the mixing plate for the mixer (3 minutes, jig (
3) The above substrate was moved to a separate room using an automatic extraction tube, with both the reaction tube and the separate room being vacuumed (below 0.01'torr). Furthermore, after closing the opening/closing door (3), the pulp was opened in a separate room (31) and air was filled into the first part, and the board on which the film and film had been formed was taken out. As is clear from the embodiment of the present invention, the reactive gas is mixed in the mixer (8), and then the reactive gas is mixed in the exhaust port (6) in a layered manner (microscopically, it was in random motion when it was turned into plasma). The substrate is placed parallel to this flow, and the film thickness on the surface to be formed is 0.1 to 3μ with a variation within +5%.
It is characterized by having a coating formed to a thickness of .

Further, at this time, plasma is generated using a glow discharge method, and a feature is that the electrode is placed outside the reaction tube so that plasma can be generated uniformly over a large number of substrates.

Also, when forming the coating, instead of 7 stages and 2 rows as shown in the drawing,
When making the reaction tube long such as 20 stages and 20 rows, 0.4 to
0.2.0.1.0, 05torr instead of rr
It is important to maintain a low pressure in order to obtain uniformity of the film quality, especially between the front row and the rear row.

In addition, in order to prevent uncontrollable oxide gases such as oxygen from entering the reaction column, a separate chamber was provided, and the process was combined with the atmosphere through this separate chamber to reproduce the properties of the obtained film. It was extremely important for gaining sex.

In FIG. 2, the substrates are arranged horizontally in the direction of the exhaust port (6) in FIG. Figure 2 (0) and Figure 2 (B
) as well as (A), but in (B) and (0) there is a possibility that flakes may be mixed into the formed film (A)
, compared to (D), it was possible to make a higher quality film with a smaller amount.

Figure 2 (D) is a terrorist attack in which both the electrode and substrate are vertical.
LeQ Jl(t Qaq t(JIAJlttAeLi
t&ll.

A photoelectric conversion device having a P-N junction was provided on a substrate using the device and Wago of the present invention.

That is, as shown in FIG. 2(A), a vertical cross-sectional view is shown in which P-type silicon carbide (C) (S i XC1-
A O('
The semiconductor (31) having an N structure is formed by combining TMS and Diporan with BLH/TMs -0,3~ in Figure 1 from the surface on which it is formed.
It was added as 2 pieces. Then, the energy band width was 2.0-2.5 eV, and the band width did not become smaller like when diborane was added to silane by 1% or more. In this way, the P-type layer (38) was After forming to a thickness of ~800 A, TMS was added to the intrinsic or substantially intrinsic silicon or into the silicon in the thickness direction to gradually increase the energy range upward from the substrate side. Silicon carbide as an intrinsic semiconductor was made to a thickness of 0.3 to 1 μm.As shown in Fig. 1, TMS was introduced and silane was introduced from O to 0.5 μm.
By changing ``g to L 6eV to 1.9
It can be changed up to θVK.

For example, in a photoelectric conversion device such as a solar cell, this intrinsic semiconductor 09) is formed to a thickness of 0.4 to 1μ, and the Eg is formed as a P layer (
2, OeV or more, especially 2.1-2.5eV) (3B)
-1 layer (1.5~2.08V) (39) -N layer (
Add 0.5 to 5 molt of 'PH, with TMS as the main component again to the top surface of K (C) so that αO) is 2, OeV or more (especially 2.3 to 3.3 eV), and N-type S i
X O,, (30) was formed to a thickness of 50-20 OA.

Further, FIG. 2(B) shows a structure in which a transparent conductive film α2) for light incidence is formed on a glass substrate (4'7).

This can be done by forming a multilayer film of 1.000 to 200 OA thick on glass and a 200 to 500 Å thick NESA layer (SnO) on the glass.
Therefore, since they are not absorbed by impurities, all of them can be introduced into one layer, and furthermore, this (39) narrow kg
In particular, the P layer (3B) on the incident light side is wide 1! Xg, and during this period,
The counter electrode (42) α3 of the electron fist hole is created by the depletion layer
) direction. As a result, A M'l (-100mw/c
In J, a conversion efficiency of 10-12q6 could be obtained in a 1 cm'' cell.

Of course, when manufacturing this photoelectric conversion device, the device shown in Fig. 1 was fabricated by integrating the separate rooms into a 3-stage KN stack, moving the 2 layers in the first stage to another room, and then transferring them to the second stage (middle stage). Alternatively, a horizontal reaction system in which one layer is formed in a reaction tube and the upper layer is transferred through a separate chamber to produce an N layer may be stacked in three stages.

Alternatively, a two-tiered device may be used in which the P layer and the first layer are formed in the same reaction tube, and the N layer is formed in another reaction tube.
(To) This is how it is! In addition, we were able to independently and precisely improve impurity control for the P layer and N.

As is clear from the above description, the present invention is extremely useful for manufacturing not only photoelectric conversion devices or light emitting devices, but also various semiconductor devices such as field effect semiconductor devices and photosensor arrays using the same reaction tube. The company provided important manufacturing equipment and a manufacturing method, which allows for the production of non-uniform substrates on 100 to 500 substrates in the same amount of time as it would take to make 4 strips of 10 cm with a conventional vertical plasma 0VD device. It can produce crystalline semiconductor films and is suitable for extremely high-volume production. Furthermore, by arranging the electrode structure or substrate as in the present invention, a conversion efficiency of 10% could be obtained in a photoelectric conversion device having a PIN structure, and the film quality was also extremely excellent.

In the present invention, silicon carbide (SixOHO≦1)
It was mainly written down. However, if gel(ho)man is used as the reactive gas, 5ixGe+=□(0≦xri1) can be obtained, and the first P-N structure is replaced with silicon and silicon carbide, and then the second P-Ge+ is formed with silicon and silicon carbide. N structure made of silicon and germanium silicide! It is also possible to obtain a so-called tandem structure.

[Brief explanation of drawings]

FIG. 1 shows the plasma vapor phase deposition of the present invention. FIG. 2 shows a part of FIG. 10 FIG. 3 shows a vertical cross-sectional view of a photoelectric conversion device obtained by the plasma vapor phase method of the present invention using the apparatus shown in FIG. ；Out(1 personmine 2yo 43 漉3eup

Claims (1)

[Scope of Claims] 1. A pair of electromagnetic energy supplying electrodes for turning a reactive gas into plasma are provided on the outside of the reaction tube, and a heating device is provided outside of the electrodes to surround the reaction tube.1. The plasma vapor phase apparatus 02 is characterized in that a reactive gas flows forward in the reaction cylinder and a substrate having a surface to be formed can be arranged along the flow of the reactive gas. A plasma vapor phase apparatus according to the first aspect of the present invention, characterized in that a plurality of stages or rows are arranged in parallel at a distance of 1 to 4 cm from each other on the formation surface of the substrate. 3. A plasma vapor phase apparatus according to claim 1, characterized in that a forward force of the reaction tube and a mixer are provided to suppress the plasma.