JPH05251356A - Formation method of film - Google Patents

Abstract

PURPOSE:To obtain the large growth speed of a film by a method wherein one out of an insulating layer and a semiconductor layer is formed on a substrate in a first reaction chamber by a CVD method and the other out of the insulating layer and the semiconductor layer is formed, by the CVD method, in a second reaction chamber which has been shut off from the first reaction chamber. CONSTITUTION:One out of an insulating layer and a semiconductor layer is formed, by a CVD method, on a substrate in a first reaction chamber; the substrate on which the insulating layer or the semiconductor layer has been formed in the first reaction chamber is moved to a second reaction chamber. The second reaction chamber is shut off from the first reaction chamber. The other out of the insulating layer and the semiconductor layer is formed in the second reaction chamber by the CVD method. A first film is formed by using, e.g. loading chambers (system I, system I'), a second film is formed by using, e.g. a reaction system (system II) for P-type semiconductor formation use, a third film is formed by using, e.g. a reaction system (system III) for I-type semiconductor formation use and a laminated structure by a plurality of film is formed by using, e.g. a reaction system (system IV) for N-type semiconductor formation use and unloading systems (system V, system V'). Thereby, the industrial throughput of the title formation method can be enhanced remarkably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an insulator layer and a semiconductor layer by utilizing electron cyclotron resonance of a multi-chamber system.

[0002]

2. Description of the Related Art A plasma CVD method utilizing only glow discharge in which a reactive gas is activated by a high frequency or DC electric field is known as a thin film forming technology by a gas phase reaction. This method is superior to the conventional thermal CVD method in that a film can be formed at a low temperature.

Furthermore, since the formed film can contain hydrogen or a halogen element for neutralizing recombination centers at the same time in an amorphous silicon semiconductor or the like,
Good PI, NI or PN junctions can be made.

However, in such a glow discharge CVD method, the film formation rate is extremely slow, and it has been practically required to increase the growth rate by 10 to 500 times.

On the other hand, there is known a CVD method using electron cyclotron resonance in which a film is formed under a pressure of 10 ⁻² to 10 ⁻⁵ torr, that is, a high vacuum of 1 × 10 ⁻² or less. This method is 5000A (Angstrom)
10 to 100 A for forming a thick film of 10 μm
(Ohm strong) / second and can be done at high speed. However, when forming multiple coatings in different reaction spaces,
After forming the first film in the first reaction space, the surface of the film is transferred to the second reaction space without exposing it to the atmosphere, and the second film is laminated on the first film. Is not known, and there is no attempt to carry out such a method during the formation of the film without completely closing the gate valve between the first reaction space and the second reaction space. Also,
In the film forming method using this electron cyclotron resonance, Si _x C to which hydrogen or a halogen element is added
Neither an example of forming _1-x (0 <x <1) nor an example of forming a P or N type silicon semiconductor having a microcrystalline or semiamorphous structure is known.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a film forming method for laminating an insulating layer and a semiconductor layer, wherein one of the insulating layer and the semiconductor layer is formed on the substrate by a CVD method in the first reaction chamber and the insulating layer is formed in the first reaction chamber. The substrate on which the layer or the semiconductor layer is formed is transferred to the second reaction chamber, the second reaction chamber is cut off from the first reaction chamber, and the other of the insulating layer and the semiconductor layer is formed by the CVD method in the second reaction chamber.

[0007]

The pressure of the reaction space formed by the ECR technique is 1 × 10 ^{-2 to} 5 × 10 ^-5 , particularly preferably 1 × 10 ^-3 to
Since the reaction is 1 × 10 ^-4 torr, which is lower than the pressure (0.1 to 0.5 torr) by the plasma glow discharge method that has been made so far, by one digit or more, the reaction step after one reaction step There is little residual impurity gas in the reaction space when transferring to. Therefore, the conventional glow discharge plasma CV
As is known in the D method, after forming a P or N type semiconductor layer, as a pre-step of forming the next semiconductor layer, in order to prevent the respective coatings from mixing with each other, each reaction after the coating formation is performed. It is not necessary to sufficiently vacuum the space and then open the gate valve partitioning each reaction space. Therefore, when the first coating is the P-type or N-type first non-single-crystal semiconductor coating, after the formation of this coating, the introduction of the reactive gas is simply stopped, and the second reaction located next to it is stopped. The substrate having the non-formed surface can be transferred to the space, and the industrial throughput can be significantly improved.

For example, when an amorphous silicon semiconductor is formed only by the direct excitation type glow discharge plasma CVD method, its growth rate is 1 A (ohm strong) / second, and one reaction chamber in the multi-chamber method is used. At the time of transferring to the next reaction chamber, each reaction space is evacuated to a high vacuum of 10 ⁻⁵ to 10 ⁻⁶ torr. However, in the multi-chamber method using the ECR of the present invention, it becomes possible to transfer the substrate from one reaction space to another reaction space continuously or substantially continuously.

Further, in the present invention, an I-type semiconductor layer (having a sufficient impurity concentration as compared with an intrinsic or substantially intrinsic or P or N-type semiconductor layer by the ECR method is formed on the surface on which the P or N-type semiconductor layer is formed. When the I-type semiconductor layer is formed, a very steep PI or NI junction interface can be formed. As a result, the PI produced by the method of the present invention
When a photoelectric conversion device is manufactured using an N-junction, extremely high conversion efficiency can be expected. Experimentally, it was possible to obtain a conversion efficiency of 12.9% at 1.05 cm ² .

Further, cyclotron resonance uses an inert gas or a non-product gas (a gas which itself produces only a gas when decomposed or reacted). Argon is a typical inert gas. But Helium,
Neon and krypton are used, and Si _x O _2-x (0≤x <2) and Si ₃ N _4-x (0 <x <are used as additives.
4) Inert gas is added to form a small amount of O, N
You may add and use it.

As the reactive gas, a product gas (a gas that decomposes or reacts to produce a solid) is used. As the product gas, a silicide gas is Si _n H _{2n + 2} (n
≧ 1), SiF _n (n ≧ 2), SiH _n F _4-n (1 <n
<4), germanium compound is GeH ₄ , GeF ₄ , G
eH _n F _4-n (n = 1, 2, 3), Si (CH ₃ ) _n H
_4-n (n = 1, 2, 3, 4), SnCl ₄ , SnF ₂ ,
SnF ₄ is a typical example. Further, as an additive, the product gas is added to other product gases such as B ₂ H ₆ and BF.
To form a P-type semiconductor and N-type semiconductor by adding ₃ or PH _3, AsH ₃ or the like doping gas.

These non-product gases are activated by cyclotron resonance and are mixed with the product gas in the reaction space outside this resonance region, and the excitation energy is transferred to the product gas. Then, the product gas receives extremely large electromagnetic energy, so that the product gas can be activated almost 100%, and the energy itself can be retained as the intrinsic activation energy instead of the kinetic energy. Further, by heating the substrate at a temperature of room temperature to 700 ° C., a coating can be formed on the surface on which the substrate is formed.

[0013]

The present invention will be described in detail below with reference to examples.

[Embodiment 1] FIG. 1 shows an outline of a cyclotron resonance type plasma CVD apparatus of the present invention.

In the drawing, the stainless steel reaction container (1 ') is provided with a load chamber and an unload chamber at the front or rear through a gate valve (not shown). A frame structure that forms a cylindrical space in the reaction container of Fig. 1 from this load chamber (the surrounding four sides are surrounded by stainless metal or an insulator, and the reactive gas in the active state spreads to the inner wall of the outer container to cause flakes. Structure to prevent it) (3
1) and (31 ′). Further, the substrate holders (10 ') arranged in this frame structure and the substrates (10) are provided as a pair so that the main surfaces are coated on both surfaces thereof. In the drawing, 10 substrates are divided into 5 holders (1
0 '). The cylindrical space of the container (1 ') is provided as the reaction space (1). This container (1 ')
A heating chamber (7 ') having a halogen lamp heater (7) is provided on the side of the. The frame structure and the substrate (10) are irradiated with infrared rays through the quartz window (19) and heated. Furthermore, since a glow discharge can be additionally provided as needed, a pair of mesh electrodes (2
3) and (23 ') are provided, and a 13.56 MHz or DC electric field is applied thereto from a high frequency or DC power supply (6).

Further, the non-product gas is supplied to the resonance space (2) from (18). This resonance space (2) is provided with air-core coils (used here as Helmholtz coils) (5) and (5 ') on the outside thereof and applies a magnetic field. A cooling pipe (12) is arranged inside this. At the same time, through the analyzer (4) by the microwave oscillator (3), for example, 2.4
A microwave of 5 GHz is supplied to the resonance space (2) through the quartz window (29). In this space, argon is added from (18) as a non-product gas to cause resonance. Then, a magnetic field (for example, 8
75 Gauss) is added by the air core coils (5), (5 ').

Therefore, the argon gas is excited and pinched by the magnetic field, and at the same time, resonates, and after being sufficiently excited, electrons (21) are released into the reaction space (1) as excited argon gas. At the outlet of the resonance space (2), the product gas is discharged (22) from the dobbing system (13) through the nozzle (17) into the reaction space through a plurality of nozzles (17). As a result, the product gas (22) is excited and activated by the electrons and the excited gas (21). And so that this activated gas does not flow back into the resonance space (2),
Care was taken with an insulator homogenizer (20).
In addition, the high frequency electric field generated by the pair of electrodes (23) and (23 ') is simultaneously added to these reactive gases.

As a result, there is substantially a buffer space (30) between the resonance space (2) and the reaction space, and electrons and excited gas (21) are emitted as they are poured into the entire reaction space. ing.

That is, an effort was made to maintain the excited state of the reactive gas even when the resonance space and the surface to be formed are sufficiently separated (generally 20 to 80 cm). (When only cyclotron resonance is used, the distance between the substrate and the end of the resonance space is as short as 5 to 15 cm, which induces non-uniformity of the thickness of the coating.) Moreover, the reactive gas is sufficiently supplied in the reaction space (1). In order to spread and make cyclotron resonance,
The pressure in the reaction space (1) and the resonance space (2) is set to 1 × 10 ^-3 ~
The pressure was set to 1 × 10 ⁻⁴ torr, for example, 3 × 10 ⁻⁴ torr. This pressure was adjusted by adjusting the exhaust amount of the vacuum pump (9) using the control valve (15) of the exhaust system (11) in combination with the turbo pump (14).

[Experimental Example 1] In Experimental Example 1, an amorphous silicon film is formed by using Example 1.

That is, the reaction space, height 30 cm, width
Each has a depth of 35 cm, and the internal dimensions of the reaction vessel are 40
cm, width and depth 50 cm, substrate (20 cm x 30 c
m, 10 sheets) as one batch. Further, the pressure of this reaction space was set to 3 × 10 ⁻⁴ torr, and argon was supplied as a non-product gas from (18) at 200 cc / min. In addition, H ₂ Si (CH ₃ ) ₂ / SiH ₄ = 1/7, and B
₂ H ₆ / SiH ₄ = 5/1000 was set, and it was supplied at 80 cc / min from (13-2). The initial high-frequency energy is 4
Supplied with 0 W output. Microwave is 2.45G
It had a frequency of Hz and was delivered at an output of 200-800 W, for example 300 W. The resonance intensities of the magnetic fields (5-2) and (5′-3) were adjusted so as to resonate in the range of 875 ± 100 gauss.

The substrate (10) used was a glass substrate or a substrate on which a transparent conductive film was formed. A non-single-crystal semiconductor, for example, an amorphous silicon semiconductor was formed on this formation surface, and unnecessary gas was discharged from the exhaust system (11). Then, when the substrate temperature is 250 ° C., the film formation rate is 4
It was possible to obtain 5 A (ohm strong) / second. This speed is 30 times faster than 1.5 A (ohm strong) / second obtained only by plasma CVD.

The dark conductivity of 4 is obtained as the electrical characteristics of the amorphous silicon film when no impurities are added.
× 10 ^-10 (Scm ^-1 ), photoconductivity (AM1 (100 m
It was possible to obtain 6 × 10 ⁻⁵ (Scm ⁻¹ ) under the condition of W / cm ² ). This value has the same characteristics as the amorphous silicon film in the plasma CVD method known so far, and can be used as an I-type semiconductor layer of a photoelectric conversion device having a PIN junction. High conversion efficiency can be expected.

[Experimental Example 2] In the ECR apparatus of FIG.
An attempt was made to form a non-single crystal semiconductor of P-type Si _x C _1-x (0 <x <1).

That is, H ₂ Si (CH ₃ ) ₂ is generated as a reactive gas which is the whole product by exciting argon into the resonance space.
/ SiH ₄ = 1/7, B ₂ H ₆ / SiH ₄ = 5/1
It was set to 000. Then the microwave output of ECR is 300
W, pressure 3 × 10 ⁻⁴ torr, substrate temperature 180 ° C.,
Optical Eg = 2.4 eV, electric conductivity 3 × 10 ⁻⁶ (Sc
m ⁻¹ ) could be obtained.

Others are the same as in Experimental Example 1.

[Experimental Example 3] Using the ECR apparatus of FIG.
i _x O _2-x (0 ≦ x <2) or Si ₃ N _4-x (0 ≦ x
<4) was formed. Oxygen or nitrogen was introduced into the resonance space together with argon gas. Furthermore, from (10), SiH
Introduced ₄ . Then, depending on the ratio of silane to oxygen or nitrogen, Si _x O _2-x (0 ≦ x <2) or Si ₃ N
The value of x of _4-x (0≤x <4) can be determined.
When x = 0 and SiO ₂ and Si ₃ N ₄ are formed,
It suffices to introduce oxygen or nitrogen in the same amount as argon.
Others are the same as those in Experimental Example 1.

[Experimental Example 4] Using the ECR apparatus of FIG.
An attempt was made to form a type microcrystallized non-single crystal semiconductor. _{That, SiH 4 / H 2 = 1} / 5~1 / 40, for example 1
/ 30, and a _{PH 3 / SiH 4 = 1/} 100. ECR
Output 400W, pressure 3 × 10 ^-4 torr, substrate temperature 25
It was set to 0 ° C. Then, an optical Eg of 1.65 eV and an electric conductivity of 50 (Scm ⁻¹ ) could be obtained. Especially EC
In the R method, even if the microwave output is increased, there is no sputtering effect on the substrate, so the average particle size is large.
It is more likely to be polycrystallized than having 0 to 300 A (ohm strong), and as a result, the crystallinity can be increased to 70% from about 50% in the glow discharge plasma CVD method. Further, comparing the amounts of hydrogen to be diluted, SiH ₄ / H ₂ = 1/80 to 1/300 was greatly diluted with hydrogen in the glow discharge method and the plasma CVD method, but in the ECR method, SiH ₄ / H was diluted. ₂
= 1/5 to 1/40, a semiconductor having a sufficient microcrystalline structure could be manufactured. Others are the same as in Experimental Example 1.

[Embodiment 2] This embodiment is a multi-chamber system in which Embodiment 1 (Experimental Examples 1 to 4) tried using FIG. 1 is integrated. Regarding this multi-chamber system, a patent (USP 4,
505,950 [1985.3.19], USP 4,4.
92,716 [1985.1.8]). However, in this embodiment, the multi-chamber system and the ECR method are integrated, and a multi-chamber system superior to the conventional one can be obtained. The present invention will be described with reference to FIG.

FIG. 2 shows the systems I, II, III, IV, V. Here, load chamber (system I, I '), first coating, eg P
Type semiconductor forming reaction system (system II), second coating such as I type semiconductor forming reaction chamber (system III), third coating such as N
Type semiconductor forming reaction system (system IV), unloading system (system V,
V ′), which is an example of producing a coating film having a laminated structure of a plurality of coating films. Then, for example, a PIN junction can be obtained as a laminated body.

The chambers of each system are (1'-1 '), (1'-
1), (1'-2), ... (1'-5) (1'-
5 '), respectively, especially (1-2), (1-
3) and (1-4) form a reaction space. In addition, (1-1 ') and (1-1) are provided as the load side space,
The space on the unload side has (1-5) and (1-5 ′). Furthermore, the doving system (13-2), (13-
3) and (13-4). Furthermore, the exhaust system (11)
Turbo molecular pumps (14-1), (14-2),
... (14-5), vacuum pumps (9-1), (9-
2), ... (9-5).

The systems (I ') and (V') are load and unload chambers, which are not shown.

The microwave for ECR is (8-2), (8) for at least one of the systems II, III and IV, here for all.
-3) and (8-4), and added as Helmholtz coils (5-2), (5'-2) ,. And the resonance space (2-2), (2-3), (2-
4), and the argon gas or a mixed gas of the argon gas and the non-product gas is (18-2), (18-3), (18-
4) has been added.

Respective chambers (1-1) and (1-
2), a buffer space (25-2) is provided, and a buffer space (2-2) is provided between (1-2) and (1-3).
5-3), a buffer space (25-4) between (1-3) and (1-4), and (1-4) and (1-
5) and buffer space (25-5). These buffer spaces facilitate the transfer of the substrate (10) and the substrate holder (frame structure forming a cylindrical space) (31) to a next chamber after forming a film in a predetermined chamber (reaction vessel). , The width of the gas is larger than the mean free path of the gas so that impurities and reaction products in one space are not mixed into the adjacent reaction space during the formation of the film, and the reaction spaces (1-1), ... -5) are separated from each other. Furthermore, a gate valve (25-1) between the load chamber (1-1 ′) and the load buffer chamber (1-1), and between the unload buffer chamber (1-5) and the unload chamber (1-5 ′). At the time of loading and unloading of the substrate and the substrate holder, the gate valve (25-6) changes the atmosphere into the reaction space (1-2) ... (1-4).
It was made not to mix in.

Further, the film formation of the systems II, III and IV corresponds to Experimental Example 2, Experimental Example 1 and Experimental Example 3, respectively, when a photoelectric conversion device having a PIN junction is to be produced.

Further, each of these coatings is provided in each chamber (1-
2), (1-3), (1-4) after forming,
In this ECR CVD method, the supply of product gas is stopped. Then, the supply of microwave energy is stopped. Further, the non-product gas argon is continuously supplied, or after the system is temporarily stopped, the system up to that point is continuously evacuated sufficiently similarly to the time of forming the film, and the substrate (10) and the substrate holder having the film structure are provided. (31) and (31) are moved to the adjacent reaction chamber by a moving mechanism (not shown in the drawing).

Even by such a step alone, it was found that the mixing of impurities at the PI bonding interface or the NI bonding interface was extremely small as compared with the conventional glow discharge plasma CVD method.

Therefore, the conversion efficiency of the photoelectric conversion device is 12.9% (1.05 cm ² ) (open voltage 0.92 V,
Short circuit current density 18.4 mA (ohm strong) / cm
^Two fill factors 0.76) could be obtained.

It is presumed that the reason why such high efficiency could be obtained is that in the ECR CVD method, the reactive gas does not sputter the surface to be formed with respect to the film formation. Further, the pressure at the time of film formation is 1/100 of 0.1 to 0.5 torr, as is known in glow discharge plasma.
Alternatively, it is 1 × 10 ⁻³ to 1 × 10 ⁻⁵ torr or less, for example, 3 × 10 ⁻⁴ torr. as a result,
When the introduction of the reactive gas is stopped, impurities in 1/100 or less time compared to the conventional glow discharge plasma CVD method,
It is possible to degas the active reactive gas from the chamber by a turbo pump.

[Embodiment 3] This embodiment is used for a method of manufacturing a thin film insulating gate type field effect semiconductor device. In Embodiment 2, a semiconductor film is formed in the reaction section of the system II and the system III is formed thereon. A silicon nitride film (Si ₃ N ₄ ) is formed by. Further, silicon oxide (SiO ₂ ) is formed by the system IV. The formation of each coating was in accordance with Experimental Examples 1, 2 and 3 in Example 1.

Thus, the semiconductor film is further provided on the substrate, and the two-layer gate insulating film is further laminated thereon.

Further, with such a structure, it is possible to omit two gate valves as compared with the multi-chamber system in which a vacuum gate valve is provided in each reaction section, so that the manufacturing apparatus can be expected to be inexpensive. Relocation from one chamber to the next can be done within 3 minutes,
It has a great feature that the throughput can be improved. As a modification of the above-described embodiment of the present invention, first, a P-type semiconductor is formed by the photo CVD method or the known glow discharge plasma CVD method. Furthermore, an I-type semiconductor film is formed to 0.7 μm by ECR CVD method.
m formed. Finally, ECR the N-type microcrystallized semiconductor
Forming by the CVD method is also effective.

[0043]

In general, the glow discharge method is 0.1 to 0.0.
Although pinholes with a size of 1 μm are easily observed in the film, the number of pinholes is reduced to about 1/10 in the cyclotron resonance type plasma CVD apparatus of the present invention (1 to 3 on average in a dark field of 100). / Field of view).

The present invention employs a multi-chamber system for ECR
The CVD method was performed in each chamber. Therefore, mass production is possible as compared with the conventionally known glow discharge method and the multi-chamber method using plasma, the PI or NI junction interface in the formed film becomes steep, and the film formation rate is high, so that the I layer is formed. It has become possible to reduce the amounts of oxygen and nitrogen that are undesirably mixed in to 5 × 10 ¹⁸ cm ⁻³ or less, respectively.

Since cyclotron resonance is used, a high film growth rate can be obtained.

As a semiconductor device, a photoelectric conversion device having a PIN or NIP junction, a light emitting element MIS. It may be an FET (field effect semiconductor device) or an SL light emitting element (super lattice element). Further, as its application, the present invention is effective for other semiconductor lasers or optical integrated circuits.

In addition to the plasma CVD method using the cyclotron resonance of the present invention, a light source such as a low pressure mercury lamp (having a wavelength of 185 nm), an excimer laser (wavelength 100 to 400 nm), an argon laser, a nitrogen laser, etc. is used. It is needless to say that the photo-assisted CVD function may be used together with.

If the product gas is not monosilane but disilane or a mixed gas of monosilane and fluorosilane (Si ₂ F ₆ ), further improvement in the film growth rate can be expected.

In the present invention, the substrate may be a silicon semiconductor, a glass substrate, a plastic substrate, a stainless steel substrate, or a structure in which an electrode is provided thereon.

The amorphous semiconductor formed is also S
Not only i, but also SiGe _1-x (0 <x <1), Si _x S
n _1-x (0 <x <1), C _x Ge _1-x (0 <x <1) having intrinsic or substantially intrinsic conductivity or P or N-type conductivity Good.

[Brief description of drawings]

FIG. 1 is a cyclotron resonance type plasma CVD according to the present invention.
It is an arrangement explanatory view showing an example of an apparatus.

FIG. 2 is a cyclotron resonance type plasma CVD of the present invention.
It is an arrangement | positioning explanatory drawing which shows the other Example of an apparatus. .

[Explanation of symbols]

 1 Reaction Space 1'Stainless Steel Reaction Container 2 Resonance Space 3 Microwave Oscillator 4 Analyzer 5, 5'Air Core Coil 6 High Frequency or DC Power Supply 7 Halogen Lamp Heater 7'Heating Chamber 9 Vacuum Pump 10 Substrate 10 'Substrate Holder 11 Exhaust System 12 Cooling Tube 13 Doping system 14 Turbo pump 15 Control valve 18 Non-product gas 19 Quartz window 20 Homogenizer 21 Excited gas 22 Product gas 23, 23 'Reticulated electrode 29 Quartz window 30 Buffer space 31, 31' Frame structure

Claims (1)

[Claims] 1. A CVD method is used to form one of an insulating layer and a semiconductor layer on a substrate in a first reaction chamber, and the substrate on which an insulating layer or a semiconductor layer is formed in the first reaction chamber is transferred to a second reaction chamber. A method for forming a film, in which the insulating layer and the semiconductor layer are laminated by cutting off the second reaction chamber from the first reaction chamber and forming the other of the insulating layer and the semiconductor layer by the CVD method in the second reaction chamber.