JPH048939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film forming apparatus used for laminating and forming a plurality of films having different materials or properties.

Conventionally, when a plurality of coatings having different materials and properties are laminated and formed, a common reaction furnace is used to form the plurality of coatings.

For example, when creating a non-single-crystal semiconductor device in which the first, second, and third non-single-crystal semiconductor films are stacked as a plurality of films, (1) placing the substrate in a reactor; The gas in the reactor is discharged, and a first gas containing a first semiconductor material gas and a first impurity gas is introduced into the reactor, and the first gas is converted into a first gas plasma. (2) depositing a first semiconductor material on the substrate to form a first non-single-crystalline semiconductor layer; evacuating the reactor, and introducing a second gas containing a second semiconductor material gas and a second impurity gas into the same reactor, and ionizing the second gas into a second gas plasma; Therefore, a second semiconductor material for forming a second non-single-crystalline semiconductor layer is deposited on the first non-single-crystalline semiconductor layer to form a second non-single-crystalline semiconductor layer, and (3) next, , the inside of the reactor is evacuated, and a third gas containing a third semiconductor material gas and a third impurity gas is introduced into the same reactor.
ionizing the gas into a third gas plasma, thereby depositing a third semiconductor material forming a third non-single crystal semiconductor layer on the second non-single crystal semiconductor layer to form a third non-single crystal semiconductor layer. A crystalline semiconductor layer was formed.

Therefore, the conventional non-single-crystal semiconductor layer forming apparatus can form the first, second, and third non-single-crystal semiconductor layers by
It was common for them to have a configuration in which they were formed using a common reactor.

For this reason, in the case of the conventional non-single crystal semiconductor layer forming apparatus, (1) when forming the second non-single crystal semiconductor layer, the first gas remains in the reactor even if it is evacuated; Therefore, the second non-single-crystal semiconductor layer cannot be formed to have the desired material or properties that are not affected by the first gas, and (2 ) When forming the third non-single crystal semiconductor layer, it is inevitable that the second gas will remain in the reactor even if it is evacuated. It has the disadvantage that it cannot be formed with a desired material or property that is unaffected by the second gas.

In this way, in the case of conventional film forming equipment, even when multiple films having different materials or characteristics are stacked and formed on the substrate to be processed, the reactor is not connected to the multiple films. , because they were commonly used, the film formed in the subsequent film formation process was influenced by the material used in the previous film formation process, and was formed to have the desired material or characteristics. I couldn't do it.

The present invention therefore seeks to propose a new coating-forming device that does not have the above-mentioned drawbacks.

According to the film forming apparatus according to the present invention, it is possible to easily form a plurality of films having different materials or properties, having desired materials or properties, and uniformly.

Hereinafter, embodiments of the film forming apparatus according to the present invention will be described in detail with reference to the drawings.

Example 1 In FIG. 1, the substrate 1 is a boat (for example, quartz).
I placed it next to 2.

In this example, a 10 cm square substrate with a thickness of 200 μm was used. This substrate was sealed in a reactor 3. This reaction vessel is capable of exciting, reacting or heating the reactive gas and substrate with high frequency energy from a high frequency heating furnace 4 of 1 to 100 MHz, for example 13.6 MHz. Furthermore, a heater 5 using resistance heating is installed outside of the heater 5. Exhaust is performed from 6 through valve 7 and through vacuum pump 8. The reactive gas reaches the inlet 9 and is chemically activated, decomposed or reacted at a position away from the substrate by high frequency induction energy 10, here microwave energy of 1 to 10 GHz, for example 2.46 GHz. In the container 7 of these 10 parts, reactive gases such as silicon compounds such as silane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), P- or N-type impurities mixed in as necessary, and further or germanium are added. , tin, lead, and even or thoroughly mixed with reactive gases containing nitrogen or oxygen. In addition, in the present invention, helium or neon is contained in a proportion of 5 to 99%, especially 40 to 99%.
90% mixed. Here, these reactive gases are chemically activated by high frequency energy 10, and some of them are caused to react with each other.

The reaction system 3 (including vessel 7) was set at 10 ⁻³ to 10 ² Torr, particularly 0.01 to 5 Torr. In order to carry out chemical activity away from the surface on which it is formed, there is a method using a catalyst proposed by the present inventor in a gas phase method.

For example, Special Publication No. 49-12033, Special Publication No. 53-14518
See No. 53-23667 and Special Publication No. 51-1389. The present invention actively utilizes high-frequency induction energy to activate the catalyst in the catalyst vapor phase method, thereby making the chemical activation or physical excitation more complete.

For the silicide gas 14, reactive gases include silane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), silicon tetrachloride (SiCl ₄ ), etc. Silane was used. Dichlorosilane is cheaper and may be used.

Boron as a P-type impurity from diborane 15
10 ¹⁷ cm ^-3 to a concentration of 10 mol%, and phosphine (PH ₃ ) was added as an N-type impurity.
The concentration was adjusted to 10 ¹⁷ cm ^-3 to 20 mol %. It may also be arsine (AsH ₃ ). During the reaction, carrier gas 12 was helium (He), neon (Ne), or an inert gas of these mixed with 5 to 30% hydrogen, but before and after the start of the reaction, inexpensive nitrogen (N) was used instead of liquid nitrogen. It was used by

Further, for additives such as tin (Sn), germanium (Ge), carbon (C), nitrogen (N), and lead (Pb), hydride or chloride gases thereof were introduced from 13. When these reactants were liquid at around room temperature, the liquid was bubbled and vaporized using helium, and then introduced into the reaction system 3 using helium.

The reaction system initially removes oxygen, etc. attached to the inner wall of the container.
After heating to 800-1200℃ in step 5 to remove the board, the boat 2 with the board 1 attached is placed in the container 3 from the exhaust port side.
I put it in. After this, this container 3 was evacuated by vacuum system 8 to a pressure of 10 ^-3 Torr. Furthermore, for a while, helium or neon was played from 12,
The reaction system was purged. Also, high frequency energy is applied to the container 7, and reactive gases 13, 14, 1
The required amount from Nos. 5 and 16 was introduced into container 7 and thoroughly mixed. Thereafter, it was introduced into a reactor 3. At this time 10～
Excitation or activation may be aided by 300W of radio frequency energy 4.

The growth rate of the coating is shown in FIG. As is clear from the drawing, the reactive gas is applied at a distance of 10° from the film forming surface.
cm to 3m Even if the distance is close to 1m, if the carrier gas is helium or neon, which accounts for 5 to 99% of the total introduced gas, for example, 70%, a film will be formed as shown by curve 22, and the uniformity of this film will vary depending on the formed film. Thickness
At 5000 Å, the difference was within ±2% both between lots and within a lot. For reference, when the same amount of nitrogen was used as the carrier gas, the result was 23, and almost no film was formed. Further, when 15 to 30% of hydrogen (H ₂ ) was added to helium, the uniformity of the film deteriorated to ±3 to 4%. When microwave energy was applied at a distance from the substrate, the growth rate was 22, but even when high frequency energy was applied by 4, the growth rate was 21, which did not increase the growth rate much.

The film formed using helium or neon as a carrier gas has a non-single crystal structure of polycrystalline or amorphous structure because the temperature is as low as room temperature to 400°C.

It is known that this non-single crystal structure generally has a large number of dangling bonds. For example, when nitrogen is used as the carrier gas in the device of the present invention, the density of the recombination centers is 10 ²⁰ to 10 ²² cm ^-3. many. However, if this carrier gas is helium or neon,
Since these gases, especially helium, can move freely in the film, the unpaired bonds are activated and have the effect of covalently bonding and neutralizing each other. Therefore, the density could be lowered to 10 ¹⁷ to 10 ¹⁹ cm ^-3 .

However, in this case, if the material is to be used as a semiconductor, it is necessary to lower this density to 10 ¹⁵ to ^{10 16} cm. For this reason, a method is generally known in which a film is formed by activating hydrogen using hydrogen as a carrier gas, and neutralizing the hydrogen by combining it with a dangling bond. However, when this hydrogen was used as a carrier gas instead of helium, the uniformity of the film became extremely poor, and under the same conditions as the apparatus shown in FIG. 1, it was ±8%.

Therefore, in the present invention, the carrier gas is helium or neon to create a uniform film,
Furthermore, after this film was produced, hydrogen or a gas containing helium in hydrogen was chemically activated by induction energy in the same reactor or in a different reactor. In the apparatus shown in FIG. 1, the high-frequency induction furnace 4 was used. At this time, it is preferable that the induced energy be directed perpendicularly to the substrate to facilitate injection and neutralization of hydrogen or helium into the substrate. Of course, this semiconductor layer is photo-annealed using a laser or similar strong light energy (for example, a xenon lamp) to make this non-single-crystal semiconductor into a single crystal, and either after this single-crystalization or at the same time as this photo-annealing. Neutralization using hydrogen or helium using this induction energy is extremely effective.

Especially, the carrier mobility is 10 by laser annealing.
It has increased by ~100 times and is almost close to the ideal state of a single crystal. However, this single crystallization alone cannot increase the density of recrystallization centers to 10 ¹⁴ to 10 ¹⁵ cm ^-3 .
It remained at 10 ¹⁸ to 10 ¹⁹ cm ^-3 . Therefore, induced energy annealing performed after or simultaneously with laser annealing has a great effect on producing ideal single crystal semiconductors.

As a result, it is possible to create a single layer film as a P-type or N-type semiconductor, and to create a PN junction, a PIN junction,
It was also possible to freely create multiple PNPN junctions, PNPN...PN junctions, etc. Therefore, the coating produced by the method of the present invention can be applied to semiconductor lasers, light emitting devices, and photoelectric conversion devices such as solar cells. Of course, it can also be applied to MIS field effect transistors or integrated circuits, and has great value.

When using the microwave shown in FIG. 1, a magnetron or the like is used for the microwave energy. However, since it is practically difficult to emit strong energy, in industrial production, activation at a position distant from the substrate may be performed using high frequency induction energy of 1 to 100 MHz.

Activation, excitation, or reaction of reactive gases by radiofrequency energy at a distance from the substrate is 0.5~
Even if the distance is close to 3m, especially 1 to 1.5m, the pressure of the system is
At 0.01 to 10 Torr, there was almost no decrease.

Example 2 FIG. 3 shows an example of an apparatus for forming a non-single crystal semiconductor layer according to the present invention, which has the configuration described below.

That is, the first, second, third and fourth systems,
, and has.

The first system is connected to the preliminary chamber 3 through the gate valve 44.
0 and a reaction chamber 45 including an excitation chamber 32 connected via a homogenizer 34.

In this reaction chamber 45, the substrates 31 and 31' are
The gate valve 44 is temporarily opened to allow air to be discharged from the preliminary chamber 30.

The coating forming apparatus according to the present invention shown in FIG.
On the board, PN junction, PIN junction, PNPN junction,
PNPN...It has a configuration that can automatically and continuously form multiple semiconductor layers of different conductivity types or the same conductivity type so that a PN junction or a shotgun junction with an MIS structure is formed.

That is, in order to uniformly form a plurality of films on a large number of objects to be formed, each of which has a pair of large substrates 31 and 31' stacked on each other with their back surfaces stacked on top of each other,
Reacting or activating the reactive gas at a position in the excitation chamber 32 remote from the substrate, which is the object to be formed;
The reaction or the reaction product or reactive gas in the active state is transported onto the surface of the substrate using a carrier gas with a high ionization voltage (24.19eV, 21.59eV) such as helium or neon while maintaining that state. I try to let them do it.

When forming a plurality of films on a substrate using the embodiment of the film forming apparatus according to the present invention, the substrate may be a conductive substrate (stainless steel, titanium, titanium nitride, or other metal), a semiconductor substrate (silicon, silicon carbide, etc.), or a semiconductor (silicon, silicon carbide). , germanium) substrate, insulator (alumina,
(organic substances such as glass, epoxy, polyimide resin, etc.)
Substrate or composite substrate (tin oxide, ITO on insulating substrate)
etc., conductive electrodes are selectively formed on an insulating substrate, and P or N type semiconductors are formed in a single layer or multiple layers on a substrate). . This substrate may be flexible or a rigid plate.

Furthermore, when forming a plurality of films on a substrate using the embodiment of the film forming apparatus according to the present invention, two
By stacking two substrates back to back and expanding the effective surface to be formed to twice that of a single substrate, the actual amount of reactive gas used can be reduced by half. can.

In an embodiment of the apparatus for forming coatings according to the invention, the reaction chambers 45, 45', 45'', 45'' are
100MHz, for example 13.6MHz high frequency heating source 35,
35', 35'', and 35'' are configured so that the reactive gas and the substrate can be excited, reacted, or heated. In this case, inside the reaction chamber,
The pressure is maintained at 10 ^-3 to 10 ² Torr, especially 0.01 to 5 Torr.

The present inventor proposed that the chemical activation of the reaction gas be performed away from the surface to be formed, as in the embodiment of the film forming apparatus according to the present invention. A gas phase method using a catalyst is disclosed. For example, Tokko Akira
No. 49-12033, Special Publication No. 14518, Special Publication No. 14518, Special Publication No. 53-
See No. 23667 and Special Publication No. 51-1389.

Further, an embodiment of the film forming apparatus according to the present invention is configured such that activation by the above-mentioned catalyst vapor phase method is performed by high frequency induction energy,
Therefore, according to the film forming apparatus according to the present invention,
Chemical activation or physical excitation can be more effectively applied to the reaction gas.

Furthermore, in an embodiment of the device for coating formation according to the invention, the excitation chamber 32 is provided with an energy source of 1-10 GHz from a high-frequency inductive energy source 33 arranged around the excitation chamber 32.
For example, the reactive gas introduced into the excitation chamber 32 is configured to be ionized into gas plasma using microwave energy of 2.46 GHz. In this case, if necessary, in the excitation chamber 32,
P or N type impurities, or germanium,
such as mixing tin, lead, or nitrogen or oxygen with reactive gases such as compounds of silicon such as silane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ),
It is configured to supply. Further, if necessary, helium or neon is supplied into the excitation chamber 32 so as to be mixed with the reaction gas at a ratio of 5 to 99%, particularly 40 to 90%.

Thus, embodiments of the coating forming apparatus according to the present invention supply a reactive gas to a high frequency induced energy source 3.
It is configured to chemically activate the gases by high frequency energy from 3 and cause some of the reactive gases to react with each other.

In this case, the reactive gases include silane (SiH ₄ ), dichlorosilane (SiH ₂ Cl ₂ ), trichlorosilane (SiHCl ₃ ), and silicon tetrachloride (SiCl ₄ ).
It is possible to use a silicide-reactive gas 14 such as, but it is preferable to use silane because it is easy to handle. Of course, inexpensive dichlorosilane may also be used.

An embodiment of the apparatus for forming a film according to the invention also provides diborane and boron as a P-type impurity in the excitation chamber 32 from one or more of the gas sources 40, 41, 42 at 10 ¹⁷ cm ^- Supply or phosphine (PH ₃ ), N-type impurity 10 ¹⁷ so that a film can be formed by introducing it at a concentration of ³ to 10 mol%.
Supply or arsine ((AsH ₃ )), as well as introducing N-type impurities, such that a film can be formed by introducing it at a concentration of cm ^-3 ~20 mol%. It is configured to supply and supply information such as:

In the embodiment of the film forming apparatus according to the present invention, helium (He) or neon (Ne) or hydrogen is added to these inert gases in the excitation chamber 32 during the reaction of the reaction gas as necessary. Gas sources 40, 41 are mixed with 5 to 30% of
and 42, as a carrier gas, or as an inexpensive nitrogen (N) before or after the start of the reaction.
is supplied as a carrier gas, tin (Sn),
It is configured to supply additives such as germanium (Ge), carbon (C), nitrogen (N), and lead (Pb) in the form of gaseous hydrides or chlorides thereof.

Further, in an embodiment of the film forming apparatus according to the present invention, the reaction chamber is heated to 800 to 1200°C,
Initially, oxygen and the like adhering to the inner wall of the container are removed, then the boat with the substrate 31 inserted therein is placed in the reaction chamber 45, and then the reaction chamber 45 is operated by the vacuum pump 36. A vacuum is drawn to a pressure of 10 ^-3 Torr, and then helium or neon is flowed into the reaction chamber 45 for a period of time to purge the reaction chamber.

Further, in the embodiment of the film forming apparatus according to the present invention, high frequency energy is applied to the reaction chamber 45, and a necessary amount of reactive gas is applied to the reaction chamber 45.
It is configured to be introduced within the In this case, the radio frequency energy is obtained from a radio frequency energy source 35 and has a power of 10-300W.

The embodiment of the coating forming apparatus according to the present invention also allows the reaction gas from one or more of the gas sources 40, 41 and 42 to be introduced into the excitation chamber 32 by opening and closing the valve 38, and the excitation thereof chemically exciting, activating or reacting the reactive gas and the carrier gas in chamber 32 with radio frequency induced energy from radio frequency induced energy source 33;
Next, the chemically excited, activated or reacted reaction gas and carrier gas are introduced into the reaction chamber 45 via the homogenizer 34. In this case, the reaction chamber 45 is configured such that the substrate 31 can be inserted therein, and the substrate 31 can be inserted at a rate of 3 to 30 minutes per minute as needed.
rotation in the directions indicated by 50 and 50' in the figure to effectively eliminate variations in the film growth rate on the substrate 31 between the excitation chamber 32 side and the exhaust section 36 side, thereby making the film uniform. It is configured to measure.

Further, in an embodiment of the coating forming apparatus according to the present invention, the substrate 31 and the reaction gas are reacted and excited in the reaction chamber 45 by high frequency induction energy from the high frequency induction energy source 35, while: The unnecessary reaction products and carrier gas are exhausted from the reaction chamber 45 through the exhaust pipe 37 by the vacuum pump 36, while the exhausted unnecessary reaction products and carrier gas are
It is configured to be purified by a purification device using a carrier gas such as helium, which has a filter, a trap, etc., and to be used again as a carrier gas. This kind of thing happens in other reaction chambers 4.
The same applies to 5', 45'', and 45.

As is clear from the above, by using the embodiment of the film forming apparatus according to the present invention, it is possible to form a film of a predetermined thickness in the system, for example, a film mainly composed of silicon and having a thickness of 10 Å to 10 μ. In this case, the film can be formed with impurities having I-type, P-type, or N-type conductivity introduced therein.

Further, in the embodiment of the film forming apparatus according to the present invention, after the treatment of the system is completed, reactive gases and flying reaction products from the system are evacuated and removed, and then, The boat is configured to move the boat on which the substrate is planted. Also,
During this movement, the system is configured so that the pressures in the system and the containers of the system are the same.

Furthermore, in the embodiment of the film forming apparatus according to the present invention, the system is configured to form a film containing silicon as a main component in accordance with the design, as in the system.

Further, in the embodiment of the film forming apparatus according to the present invention, when moving the substrate 31 from system to system,
It is configured to move the system substrates to the system, the system substrates to the system, and the system substrates to the preliminary chamber 59.

In Fig. 3, four systems, and, are used for forming a P-type film, for forming an I-type film (in a state where impurities are not artificially mixed), and for forming an N-type film in order to form a PIN junction. It is used for both general purpose and induction annealing purposes. However, if you want to form a PN, PI ₁ I ₂ N, PNPN, etc. junction instead of a PIN junction so that their planes are almost parallel to the substrate surface, you can use the corresponding number of systems. .

By using the embodiment of the film forming apparatus according to the present invention, a film having the same stoichiometry can be formed parallel to the surface of the substrate to be formed. In order to be uniform in the surface direction regardless of the type, Ge, Sn,
It can be formed so that the amount of additives such as Pb, N, O, and C is uniform in the surface direction. Furthermore, by changing the amounts and types of In, Ge, C, N, and O, the film can be formed so that Eg (energy band gap) changes continuously in the thickness direction. You can also do it. In this case, the amount of additive can be varied by means of valves 38, 38'.

As described above, since the film forming apparatus according to the present invention has a plurality of reaction chambers, a plurality of films having different materials or characteristics can be formed in separate reaction furnaces. Therefore, the material used in the previous film forming step does not affect the film formed in the next film forming step. In addition, in forming a film on the surface of the substrate, a reactive gas is chemically activated, excited, or reacted at a location away from the substrate, and the reactive gas is stoichiometrically adjusted at that location. are sufficiently mixed. As a result, it is possible to easily form a film in which a specific material is not unevenly distributed, that is, a film in which no large clusters are present.

In the above description, it has been described that a film mainly composed of silicon can be formed by the above-described embodiment of the film forming apparatus according to the present invention.

However, Si ₃ N _4-x to which nitrogen is added (0<x<4), Si _x Ge _1-x to which germanium is added (0<x<1), and tin to silicon are added. Si _x Sn _1-x (0<x<1), Si _x with lead added
Pb _1-x (0<x<1), SiO _2-x with oxygen added
(0<x<2), carbon-added Si _x C _1-x (0<
It goes without saying that it is also possible to form a film of a mixture represented by x<1).

Furthermore, by appropriately selecting the value of x in these mixtures, it is also possible to form a film made of not only Si but also Ge, Sn, etc.

Furthermore, it is also possible to form a film in which P- or N-type impurities are simultaneously mixed into the above-mentioned film.

In addition, transparent conductive coatings made of conductors, especially oxides or nitrides of tin, indium, or antimony, and transparent conductive coatings made of nitrides, such as titanium nitride, tantalum nitride, and tin nitride, are also available. , can also be formed.

Furthermore, when using the embodiment of the film forming apparatus according to the present invention, the energy band gap can be reduced in particular by W-N.
(WIDE TO NALLOW) configuration (W side 2~
3eV, N side 1~1.5eV), PIN,
To manufacture a photoelectric conversion element in which a transparent conductive electrode having the effect of an antireflection film is formed on a MINPN junction, PNPN junction, or MIPN junction type structure, and the photoelectric conversion efficiency is improved to 15 to 30%. It is industrially useful.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a manufacturing apparatus for forming a coating according to the present invention. FIG. 2 shows the characteristics of the coating obtained by the method of the present invention. FIG. 3 is a schematic diagram showing an embodiment of the film forming apparatus according to the present invention.

Claims (1)

[Claims] 1. After heating the reaction chamber in advance using a heating means,
Introducing a reaction gas into a reaction chamber and supplying microwave induction energy to the reaction gas to turn the reaction gas into plasma, and supplying high-frequency energy to the plasmatized reaction gas. A method for forming a film, characterized in that a film is formed on the substrate by excitation, reaction, and heating. 2. A means for introducing a reaction gas into the reaction chamber, a means for supplying microwave induction energy to the reaction gas, a heating means for heating the inside of the reaction chamber, and a means for exciting and reacting the reaction gas turned into plasma. and means for supplying high frequency energy for heating. 3. A plurality of reaction chambers arranged in sequence, a substrate moving means for sequentially moving the substrate to be processed into each of the plurality of reaction chambers without exposing the substrate to the atmosphere, and a reaction chamber. A reaction gas introducing means for introducing a gas, a plurality of exhaust means for respectively discharging the reaction gas to the outside, and a means for supplying microwave induction energy to the reaction gas introduced into the reaction chamber to turn it into plasma. A film forming apparatus comprising: a heating means for heating the inside of a reaction chamber; and a means for supplying high frequency energy for excitation, reaction and heating to a reaction gas turned into plasma.