JPH10306372A - Ion beam sputtering device, production of semiconductor device and production of photoelectric converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent bad influence on semiconductor layer by ion beam sputtering and to produce an excellent semiconductor device. SOLUTION: This ion sputtering device has a primary means 11 of generating an ion beam and orientating the ion beam 121 toward a prescribed direction, a secondary means of holding a target 122 in a position to be irradiated with the ion beam so that the target 122 is sputtered by the irradiation of the ion beam orientated toward the prescribed direction, a third means of holding an electrically conductive substrate 124 provided with a semiconductor thin coating layer for depositing the sputtered target components and a fourth means of setting the electric potential of the electrically conductive substrate to non-earth one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic device such as a solar cell, a line light sensor or an area light sensor, or a thin film semiconductor layer constituting a thin film transistor, especially non-crystalline silicon, microcrystalline silicon or polycrystalline silicon. Pi formed of single crystal silicon
Ion beam sputtering apparatus for forming a conductive film on a thin film semiconductor layer having a semiconductor bonding layer such as an n-junction layer, a nip junction layer, and a pn junction layer, and a method for manufacturing a semiconductor device and a photoelectric conversion device It is about.

[0002]

2. Description of the Related Art A thin film semiconductor is formed into an element by forming a thin film semiconductor layer on a substrate on which a conductive film is provided, and then forming a conductive film on the thin film semiconductor layer. For example, in the above-described photoelectric conversion device such as a photovoltaic element, a thin film semiconductor layer as described above is provided on a substrate having a conductive surface, and a transparent conductive film is formed over the thin film semiconductor layer.

Conventionally, a conductive film such as a transparent conductive film has been formed on a thin film semiconductor layer by a vapor deposition method or a DC magnetron sputtering method.

[0004] For example, as a material of a transparent conductive film used in a photovoltaic element in which a semiconductor layer is formed on a conductive substrate via a reflective layer and a transparent conductive film is formed thereon, usually, In is used. ₂ O ₃ , SnO ₂ , ZnO, IT
O (indium tin oxide) and the like are known, and as a forming method thereof, a vacuum deposition method, a sputtering method, a CVD method,
Spray method and the like. Among these, ITO transparent conductive films are most often used because of their excellent transmittance, conductivity and etching characteristics. As a method for forming the ITO film, a DC magnetron sputtering method is widely used because of its superiority in characteristics of the formed film and its superiority in productivity.

In order for the photovoltaic element to generate electromotive force efficiently, a transparent conductive film having lower resistance and higher transmittance is required. However, for example, the substrate temperature at the time of film formation is relatively low, about 230 ° C. or less, and the deposition rate excellent in mass production is about 10 ° / sec. Suitable thickness is 50
When a transparent conductive film of about 0 ° to 1000 ° is formed, only a transparent conductive film having a sheet resistance of about 50Ω / □ is obtained.

A method for forming a transparent conductive film by ion beam sputtering described in Japanese Patent Application Laid-Open No. Hei 7-331413 has been proposed. According to the description in the above-mentioned published specification, a special compound semiconductor such as a homojunction CuInSe ₂ is used as a semiconductor layer. However, experiments by the present inventors have revealed that there are the following problems in applying the method to, for example, forming a conductive film on a thin film semiconductor layer having an amorphous nip junction.

That is, according to an experiment by the present inventors, when a conductive film such as a transparent conductive film is formed by ion beam sputtering on a thin film semiconductor layer on a conductive substrate on which a photovoltaic element is formed, A direct current flows from the conductive substrate toward the surface of the thin film semiconductor layer (this current is presumed to be caused by the flow of negative charges from the surface of the thin film semiconductor layer to the conductive substrate). Current flows intensively in an electrically weak portion of the thin-film semiconductor layer (a portion having a lower resistance compared to the surroundings), causing destruction (short) in that portion;
There was found. Therefore, the function as a photovoltaic element is:
Thus, the stability over time in long-term use has been worsened.

According to the inventor's findings based on the above-described experiment, it has been found that the cause of the above-mentioned short circuit is as follows. That is, in particular, a roll-shaped stainless steel is used as the conductive substrate, and after a thin-film semiconductor layer is provided on the roll-shaped stainless steel, a transparent conductive film is formed on the thin-film semiconductor layer by ion beam sputtering. Since the support part for supporting the roll-shaped stainless steel and the support roll for stabilizing the conveyance are made of a conductive material such as metal, the contact between these parts causes the rolled stainless steel As a result, the steel is grounded, and during ion beam sputtering, an electric field is generated between the potential on the surface side of the thin film semiconductor layer and the ground potential of the conductive substrate. Intensively flows from the conductive substrate toward the surface of the semiconductor layer through the low resistance portion existing in the thin film semiconductor layer.

In ion beam sputtering, the energy of plasma is higher than in DC magnetron sputtering or the like.
Therefore, the deterioration of the function of the photovoltaic element due to the current becomes a more serious problem. Further, plasma damage given to the semiconductor layer also becomes a problem.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved ion beam sputtering apparatus which suppresses the above-mentioned short circuit, and a method for manufacturing a semiconductor device and a photoelectric conversion device.

Further, another object of the present invention is to reduce plasma damage to a semiconductor layer due to ions during ion beam sputtering, and to continuously transport a roll-shaped conductive substrate suitable for mass production. It is an object of the present invention to provide an improved ion beam sputtering apparatus, and a method for manufacturing a semiconductor device and a photoelectric conversion device.

Another object of the present invention is to provide a powder having a uniform particle size, a dense distribution of particles, low resistance, high transmittance, excellent acid and alkali resistance, and heat resistance. It is an object of the present invention to provide an ion beam sputtering apparatus which is capable of forming a transparent conductive film which is excellent in durability and can be used for a long period of time, and a method for manufacturing a semiconductor device and a photoelectric conversion device provided with the transparent conductive film. .

[0013]

SUMMARY OF THE INVENTION The present invention comprises: a. First means for generating an ion beam and directing the ion beam in a predetermined direction; b. Holding the target at a position to be irradiated with the ion beam so that the target is sputtered by the irradiation of the ion beam in the predetermined direction.
Means, c. Third means for holding a conductive substrate provided with a semiconductor thin film layer for depositing the sputtered target component, d. A fourth means for setting the potential of the conductive substrate to a non-earth potential is provided.

The present invention also provides: a. Placing a target at a position in the ion beam sputtering apparatus where the ion beam is irradiated; b. Disposing a conductive substrate provided with a thin-film semiconductor layer at a position where a target component generated from the target in the ion beam sputtering apparatus is deposited; c. Generating an ion beam, directing the ion beam in a predetermined direction, irradiating the target with the ion beam, sputtering the target, and depositing the target component on the thin film semiconductor layer. A method of manufacturing a semiconductor device and a method of manufacturing a photoelectric conversion device, wherein the potential of the conductive substrate is set so that the conductive substrate has a non-earth potential at least during a period in which the target component is deposited. It provides the law.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Apparatus for Forming Transparent Conductive Conductive Film by Ion Beam Sputtering) FIG. 1 is a schematic configuration diagram showing an example of an ion beam sputtering apparatus for forming a transparent conductive film according to the present invention by ion beam sputter.

In FIG. 1, the apparatus of the present invention comprises an argon gas introducing pipe 111, an ionization heater 112 for exciting the introduced argon gas into ions, and an accelerator 113 for accelerating the generated ions into a beam and emitting the ions in a predetermined direction. An ion beam generator 11 provided in a vacuum chamber 114, a target 122 disposed at a position to receive the irradiation of the ion beam 121 in the predetermined direction, sputtered by the irradiation of the ion beam 121, and a sputtered target component 123. The conductive substrate 12 provided with the thin film semiconductor layer 41 described below and shown in FIG.
4. a substrate heating heater 1 for heating the conductive substrate 124
25 and a deposition chamber 12 having a thermocouple 127 for temperature control in a vacuum chamber 126, and open during the deposition of the target component 123 to electrically insulate the conductive substrate 124 from ground. This is an ion beam sputtering apparatus having a switch 13 set to. The opening of the switch 13 causes the conductive substrate 124
4 and the ground potential are insulated, and a transparent conductive film 42 shown in FIG. 4 described below is formed on the thin film semiconductor layer 41.

FIG. 2 illustrates another embodiment of the device of the present invention. The apparatus shown in FIG.
1. An ionization heater 112 for exciting the introduced argon gas into ions, and an accelerator 113 for accelerating the generated ions in a beam shape and emitting the ions in a predetermined direction are provided in a vacuum chamber 114.
An ion beam generator 11 provided therein, a target 122 disposed at a position to receive irradiation of the ion beam 121 in the predetermined direction, a target 122 sputtered by the irradiation of the ion beam 121, and a sputtered target component 123
Conductive layer 124 provided with the thin-film semiconductor layer 41 shown in FIG.
The deposition chamber 12 having a substrate heating heater 125 and a temperature control thermocouple 127 in a vacuum chamber 126, and the conductive substrate 124 with respect to the ground during the deposition of the target component 123. This is an ion beam sputtering apparatus having voltage applying means 21 set to a range of 100 volts or more and less than 0 volts.

In another embodiment of the present invention, the conductive substrate 124 is fixed to a substrate holder of an insulator (not shown) made of alumina, so that the conductive substrate 124 is grounded to a vacuum chamber 126 or the like. It can be electrically insulated from potential.

The voltage applying means 21 shown in FIG. 2 operates during the ion beam sputtering period.
Based on the fact that the potential state of the surface is a negative potential with respect to the ground, the conductive substrate 124 is in a range of −100 volts to less than 0 volts with respect to the ground, preferably,
A voltage in the range from −60 volts to less than 0 volt, particularly preferably in the range from −40 volts to less than 0 volt, can be applied. As a result, a transparent conductive film 42 shown in FIG. 4 described below is formed on the thin film semiconductor layer 41.

According to an experiment conducted by the present inventor, when the voltage applied to the conductive substrate 124 by the voltage applying means 21 exceeds −100 volts and increases to the negative side, plasma on the surface of the semiconductor layer 41 is reduced. Damage was found to occur.

FIG. 3 illustrates another embodiment of the present invention. In FIG. 3, a roll-shaped conductive substrate 31 formed by a roll made of metal such as a rolled stainless steel is conveyed continuously or stepwise in the direction of arrow 32. This roll-shaped conductive substrate 31
Is fixed by a bearing (not shown) in the substrate loading chamber 33 set in a vacuum state, and is wound around a take-up roll 331. On the other hand, the roll-shaped conductive substrate 31
The rear end portion is fixed by a bearing (not shown) of the substrate unloading chamber 34 set in a vacuum state, and is previously wound around a delivery roll 341. A drive source (not shown) for driving each bearing is provided in the substrate carrying-out chamber 34 and the substrate carrying-in chamber 33, and a feed roll for keeping the tension of the roll-shaped conductive substrate 31 moving in the horizontal direction constant. 332 and 342 are provided. Deposition chamber 35 and substrate loading chamber 33
, And between the deposition chamber 35 and the substrate unloading chamber 34 by a gas gate (not shown), so that the substrate 31 does not come into contact with the atmosphere.

The roll-shaped conductive substrate 31 used in the present invention is preferably formed on the roll-shaped conductive substrate 31 by, for example, JP-A-57-43413,
By using the roll-to-roll method and the apparatus described in Japanese Patent Application Laid-Open No. 299823 and the like, the below-described thin film semiconductor layer 41 shown in FIG. 4 is provided.

The roll-to-roll system and the apparatus used in the present invention are characterized in that a plurality of roll-shaped conductive substrates are separated by non-diffusion bonding means such as gas gate means during continuous conveyance of the roll-shaped conductive substrates. Thin film semiconductor having a semiconductor junction layer such as a pin junction layer, a nip junction layer, or a pn junction layer formed of non-single-crystal silicon such as amorphous silicon, microcrystalline silicon, or polycrystalline silicon by passing through a film formation chamber of A method and an apparatus for continuously forming a layer on a roll-shaped conductive substrate.

The rolled conductive substrate 31 on which the thin film semiconductor layer 41 is provided is placed in a deposition chamber 35 of an ion beam sputtering apparatus comprising an ion beam generator (not shown) and a deposition chamber 35. A transparent conductive film 42 is formed on 41. The ion beam generator and the deposition chamber 35 can be the same as those used in the embodiment shown in FIGS. 1 and 2 described above.

In the apparatus shown in FIG. 3, in order to electrically insulate the conductive substrate 31 from the ground during the deposition of the target component 352 generated by sputtering of the target 351, in the present embodiment, the conductive substrate 31 is electrically conductive. An insulating polyimide film (not shown) is previously adhered to the surface of each of the rolls 341, 342, 331, and 332 that comes into contact with the substrate 31 with a double-sided tape. Thereby, the conductive substrate 31
It was insulated from the potential of the ion beam sputtering device 35 connected to the ground. As the electrical insulating means, in addition to the above, an insulating material made of a resin such as Teflon, paper, or the like is applied to the surface of each of the rolls 341, 342, 331, and 332.
You may stick it. In addition, each roll 341, 342, 3
An insulating material such as paint may be applied to the surfaces of 31 and 332. The surface of each of the rolls 341, 342, 331, and 332 may be impregnated with a resin such as Teflon.
Further, as a bearing (not shown) of the rotating shaft of each of the rolls 341, 342, 331, and 332, a resin-made one such as Teflon or Delrin may be used. Also, some of these means may be combined.

Further, in the apparatus shown in FIG. 3, during the deposition of the target component 352, the conductive substrate 31
Can be connected to a non-earth potential. The voltage applied to the conductive substrate 31 by the voltage applying means 21 at this time is between −100 volts and less than 0 volt, which is the same potential as the self-bias potential between the conductive substrate and the ground potential generated during ion beam sputtering. It is good to set to the range. The voltage from the voltage applying means is not limited to a DC voltage, and an AC voltage, an RF voltage, or the like may be superimposed on the DC voltage.

An ion source of hot cathode electron bombardment can be used for generating an ion beam in the ion beam sputtering apparatus in the embodiment shown in FIGS.
The generated ion beam is incident into the deposition chamber 12 or 35 on a target arranged obliquely with respect to the ion beam, and sputters the target. As a target, for example, an ITO pellet (for example, 90 wt% of In ₂ O ₃ −
A mixed sintered body containing 10 wt% of SnO ₂ can be used. The relative density of the pellet may be 65% or more,
It is preferably at least 70%, more preferably at least 80%.

As the material of the above-mentioned target, IT
Other than O, SnO ₂ , In ₂ O ₃ , ZnO or the like may be used. Instead of a target using an oxide as described above, for example, a metal pellet of InSn or Zn is used, and oxygen is used as a reaction gas, whereby a transparent conductive oxide film can be formed.

During the period in which the transparent conductive film 42 is being deposited, the conductive substrate 124 or 31 and the deposition chamber 12 or 35 are deposited.
Is measured by a voltmeter as the self-bias Vself. The self-bias voltage (Vself) is set so as to satisfy −100 V ≦ Vself <0 V by sputtering conditions (ion beam current (preferably 1 A to 500 A), film forming pressure (preferably 3 × 10 ⁻⁵ to 1 × 10 ^{−). 2} Torr), oxygen partial pressure (preferably 0-5 × 10 ⁻⁴ Torr), distance between the conductive substrate and the target (preferably 50 mm-80
0 mm), ion extraction voltage (preferably 0.2 to 3)
0 kV)). Vself to further reduce plasma damage to semiconductor layers by ions
Is preferably -60 V <Vself <0 V, more preferably -4
Sputtering conditions (ion beam current, deposition pressure, distance between substrate and target, ion extraction voltage, etc.) may be selected so that 0 V <Vself <0 V.

In the apparatus of the present invention, the conductive substrate 12
As the heater 125 for heating the substrate 4 or 31 during the film formation period, a sheath heater, an infrared lamp, or the like can be used, and the indicated value of the thermocouple 127 installed immediately above the conductive substrate 124 or 31 can be used. Control to be constant.

As the conductive substrate 31 used in the present invention,
A 0.2 mm thick, 50 mm square stainless steel plate (sus430) that has been subjected to a BA (bright annealing) process in which the surface is annealed in an inert gas, a 0.2 mm thick, 3 mm wide
A stainless steel roll (sus430) having a length of 60 mm and a length of 300 m can be used with a surface treated with BA, but the present invention is not limited to these. The surface treatment is not limited to the above BA treatment. For example, after cold rolling, a roughened surface formed by forming uneven streaks on the surface by heat treatment and pickling treatment (for example, N
o. 2D steel sheet). In addition to the stainless steel plate (roll), the conductive substrate 31 may be a zinc steel plate, an aluminum plate (roll), a plated steel plate (roll), or a metal-plated plastic film (tape).
Etc. can also be used.

The conductive substrate 124 or 31 used in the present invention
May be provided with a reflective layer 43 formed of a metal film such as an aluminum film, a silver film, a nickel film, or a copper film. On the reflection layer 43, a transparent conductive film 44 such as a zinc oxide film or an ITO film may be deposited. The reflective layer 43 and the underlying transparent conductive film 44 are preferably formed by a DC magnetron sputtering method.

In the thin film semiconductor layer 41 on the conductive substrate 124 used in the present invention, a plurality of cells having a pin junction, for example, a tandem or triple element can be used. For example, a semiconductor layer for a photovoltaic element preferably used in the present invention is formed by a plasma CVD method. That is, power is supplied using SiH ₄ , PH ₃ , and H ₂ as material gases, an n-type a-Si layer is used as the n-type semiconductor layer 419, and an i-type semiconductor is used using SiH ₄ , GeH ₄ , and H _2. I-type a-SiGe layer as layer 418 followed by Si
Using H ₄ , BF ₃ , and H 2, p-type semiconductor layer 417
First n in which a type μc (microcrystal) -Si layer is sequentially formed
An ip cell is provided, and subsequently, an n-type semiconductor layer 416, an i-type semiconductor layer 415, and a p-type semiconductor layer 414 are provided as second-layer cells.
Are stacked, and the third n-type semiconductor layer 413 and the i-type a-SiGe layer are replaced with an i-type a-
A third cell having an i-type semiconductor layer 412 and a p-type semiconductor layer 411 which are semiconductor layers changed to a Si layer is stacked,
A semiconductor layer for a triple-type photovoltaic element in which the third cell is stacked as a top cell is exemplified. This thin film semiconductor layer 41 is not limited to amorphous, microcrystalline or polycrystalline. In addition, the number of times of nips is 1
All that is required is the above. Further, the thin film semiconductor layer 41 is not limited to the configuration of the nip junction, but may be a pin junction.
Various types of junctions such as junctions, pn junctions, and np junctions may be used.

(Method for Forming a Transparent Conductive Film by Ion Beam Sputtering) A method for forming a transparent conductive film using the apparatus shown in FIG. 1 will be described below according to the manufacturing procedure.

First, the substrate 124 is mounted on an insulator substrate holder (not shown), and the electrical resistance between the conductive substrate 124 and the deposition chamber 12 is measured with a tester. It was confirmed that it was insulated from the ground. The resistance value at this time is preferably as high as possible because the flowing current can be reduced, but it is preferable that the resistance value be 300 kΩ or more, preferably 600 kΩ or more, more preferably 800 kΩ or more.

Next, the chamber 114 is evacuated by a vacuum pump (not shown).
After reducing the pressure to an appropriate degree of vacuum to make a high vacuum chamber 114,
Argon gas was introduced into the high vacuum chamber 114. Also,
At this time, the conductive substrate 124 was heated to a predetermined temperature by the heater 14.

Thereafter, a power supply (not shown) controls the ion beam current of the ion gun and the ion extraction voltage, etc.
The transparent conductive film 42 is formed on the surface of the substrate 124, that is, on the thin film semiconductor layer 41 while controlling the argon flow rate and / or the opening degree of the exhaust valve, thereby controlling the film forming pressure and maintaining a desired self-bias voltage. Was formed to have a desired film thickness.

(Embodiment 1) In this embodiment, the apparatus shown in FIG. 2 was used. At this time, an n-type amorphous silicon layer (10 nm), an i-type amorphous silicon germanium layer (200 nm), a p-type microcrystalline silicon layer (5 nm) are formed on the conductive substrate 124 by a plasma CVD method in advance.
n-type amorphous silicon layer (10 nm), i-type amorphous silicon germanium layer (100 nm), p-type microcrystalline silicon layer (5 nm), n-type amorphous silicon layer (10 nm), i-type amorphous silicon layer (70 n
m), a triple cell was formed by sequentially depositing a p-type microcrystalline silicon layer (5 nm). The voltage V ₀ between the conductive substrate 124 and the ground is changed to a voltage of the following 11 points in a range of −120 volts ≦ V ₀ ≦ + 20 volts,
A transparent conductive film was formed, each transparent conductive film was provided, and 11 types of photovoltaic elements (elements functioning as solar cells) were manufactured according to the following procedures (1) to (5).

As voltage values at 11 points, +20 volts, +5 volts, 0 volts (earth), -5 volts,-
20 volts, -40 volts, -60 volts, -80 volts, -100 volts, -100 volts and -120 volts were selected.

(1) The conductive substrate 124 was fixed to a substrate holder (not shown) made of an insulator made of alumina. (2) When the electric resistance between the conductive substrate 124 and the deposition chamber 12 was measured with a tester, the resistance value showed a value on the order of MΩ, and it was confirmed that the substrate 124 was certainly electrically insulated from the ground. did. (3) The inside of the chamber 114 is evacuated by a vacuum pump (not shown) until the degree of vacuum reaches the order of 10 ⁻⁶ Torr, and the high vacuum chamber 114 is formed. Was introduced. (4) The output of the heater 125 was controlled so that the indicated value of the thermocouple 15 became 190 ° C. The film thickness is about 700 700
It was made to become. (5) The conductivity is adjusted by adjusting the ion beam current of the ion gun and the extraction voltage of ions by a power supply (not shown) and the film forming pressure by adjusting the argon flow rate and / or the opening of the exhaust valve as shown in Table 1 below. Substrate 124
Bias voltage Vself between the gate and the deposition chamber 12
Was set as described in Table 1 in the range of -120 volts ≦ Vself <0 volts. In addition, floating was short-circuited during film formation, and film formation was performed at Vself = 0 volt. Furthermore,
The voltage V ₀ applied to the conductive substrate 124 using a DC power supply
Was applied in the range of 0 volts <V ₀ ≦ + 20 volts.

[0041]

[Table 1]

200 lux of the photovoltaic device thus produced
(Looks) FIG. 5 shows the measurement results of the open-circuit voltage under a fluorescent lamp.

Further, a silver paste was screen-printed on the surface of the transparent conductive film 42 of the above-mentioned 11 types of solar cells to form a current collecting electrode, and irradiated with light of AM 1.5 (100 mW / cm ² ). FIG. 6 shows the obtained photoelectric conversion efficiency.

It can be seen from FIGS. 5 and 6 that when the voltage is between 0 (earth) volts and +10 volts, the function of the photovoltaic element is significantly reduced. This is because, when the negative charges generated on the surface of the semiconductor layer 41 flow from the semiconductor layer 41 toward the conductive substrate 124, the negative charges flow intensively in an electrically weak portion of the semiconductor layer 41 and are broken (short-circuited) in that portion. It seems to cause.

If the self-bias voltage becomes too large on the negative side (exceeds -100 volts and becomes more negative), the function of the photovoltaic element deteriorates. In particular, the open-circuit voltage significantly decreases at low illuminance. This is considered to be due to the fact that plasma damage to the semiconductor layer 41 by the flying ions has increased.

(Embodiment 2) In this embodiment, a roll-to-roll type ion beam sputtering apparatus shown in FIG. 3 capable of continuously transporting a long roll-shaped conductive substrate 31 is used. According to the following procedures (1) to (6), 11 types of photovoltaic elements (elements functioning as solar cells) were produced.

The transparent conductive film 42 was provided on the thin film semiconductor layer 41 according to the following manufacturing procedure. (1) A conductive substrate 31 provided with a triple cell and wound around a substrate delivery roll 341 is mounted in the substrate delivery chamber 34 in the same manner as in the first embodiment, and as shown in FIG.
It was wound around a substrate take-up roll 331 via a roll 332. (2) The conductive substrate 31 is provided with a double-sided tape on the surface of each of the rolls 341, 342, 331 and 332 in contact with the conductive substrate 31 in order to electrically insulate the ground from the deposition chamber 35 and the like. Then, an insulating polyimide film was stuck. (3) When the electric resistance between the conductive substrate 31 and the deposition chamber 35 was measured with a tester, the resistance value was on the order of MΩ,
Indeed, it was confirmed that the substrate 31 was electrically insulated from the ground. (4) After evacuating the ion beam generating chamber (not shown) using a vacuum pump (not shown) until the degree of vacuum reaches the order of 10 ⁻⁶ Torr, argon gas is introduced into the chamber, and 3 × 10 ^{− 4} Torr. Oxygen gas was introduced so that the oxygen (O ₂ ) partial pressure was 1 × 10 ⁻⁵ Torr. (5) The heater 14 has a thermocouple 15 indicated value of 200 ° C.
The output was controlled so that From the heat generated by the heater 14
One hour later, the transfer of the conductive substrate 31 was started. The substrate transfer speed at this time was 50 cm per minute. (6) The DC power source 36 provided as a voltage applying means between the conductive substrate 31 and the deposition chamber 35 causes the conductive substrate 3
With respect to 1 and the earth potential, the following 11 voltage values were selected within the range of -120 volts to +20 volts, and a film was formed for each voltage value.

The voltage value of the above 11 points is +20
Volt, +5 volt, 0 volt (ground), -5 volt, -20 volt, -40 volt, -60 volt, -8
0 volts, -100 volts, -110 volts and -12
0 volts was selected. The film formation pressure was the same as in Example 1.

The eleven types of photovoltaic elements thus produced were
FIG. 7 shows the measurement results of the open circuit voltage under a fluorescent lamp of 200 lux. Further, on the transparent conductive film 42, a silver paste was screen-printed to form a current collecting electrode, and a current collecting electrode of AM 1.5 (100 m
FIG. 8 shows the photoelectric conversion efficiency obtained under irradiation of light (W / cm ² ).

As can be seen from FIG. 7 and FIG.
In the case of (earth) volts to +10 volts, the function as a solar cell was significantly reduced. This is because when the electric charge generated on the surface of the thin film semiconductor layer 41 flows from the thin film semiconductor layer 41 toward the conductive substrate 31, the electric charge concentrates on the electrically weak portion of the thin film semiconductor layer 41, It is thought to cause destruction (short).

If the self-bias voltage becomes too large on the minus side (exceeds -100 volts and becomes more minus), the function of the photovoltaic element deteriorates. In particular, the open-circuit voltage significantly decreases at low illuminance. This is considered to be due to the fact that plasma damage to the semiconductor layer 41 by the flying ions has increased.

(Embodiment 3) This embodiment is carried out by using the apparatus shown in FIG.

The voltage applied to the conductive substrate 31 used in the second embodiment is omitted, and the conductive substrate 31 is set to high impedance. A transparent conductive film 42 was formed thereon.

The heater 14 is set so that the indicated value of the thermocouple 15 in the procedure (5) of the second embodiment is set to 180 ° C.
The procedure was the same as the procedures (1) to (5) of Example 2 except that the heating was controlled. In the ion beam generator used in this embodiment, the high vacuum chamber was evacuated to the order of 10 ^-6 Torr, and argon gas was introduced from the gas inlet tube so that the degree of vacuum was set at 0.2 mTorr. Was.

When the voltage between the conductive substrate 31 and the deposition chamber 35 was measured by a voltmeter during the deposition of the transparent conductive film, the self-bias value was changed to the indicated value Vself = -15.
It was confirmed that the value of -15 volt, which is the bolt, was almost maintained.

The photovoltaic element thus produced was cut out at intervals of 20 m with a width of 30 cm, and the open-circuit voltage was measured under a 200 lux fluorescent lamp. As a result, a good value of 0.46 volt ± 0.03 volt was obtained. Furthermore, a silver paste is screen-printed on the thin-film semiconductor layer 41 to form a collecting electrode, and the AM1.5 (10
When the characteristics were evaluated under light irradiation of 0 mW / cm ² ), an excellent conversion efficiency of 7.3 ± 0.2% was obtained in photoelectric conversion efficiency.

(Comparative Example 1) The same apparatus and film forming method as in Example 2 were used except that the conductive substrate 31 was connected to the ground in the apparatus used in Example 2 above.

When the photoelectric conversion efficiency of the photovoltaic device thus produced was measured by the same method as in Example 2, it was at most 2.0%. Observing the surface of the photovoltaic element with an IR camera when a DC current of 20 mA was applied between the two electrodes, the current collecting electrode of this comparative element was used as an anode and the conductive substrate 31 was used as a negative electrode. It was confirmed that a current path was established. This is because the conductive substrate 31 is electrically connected to the grounded deposition chamber 35 when the transparent conductive film 42 is formed on the thin film semiconductor layer 41.
The charge generated on the surface of the thin film semiconductor layer 41 is
It is considered that the current flows from No. 1 toward the conductive substrate 31 and, at this time, the current flows intensively in an electrically weak portion of the thin film semiconductor layer 41, which causes a destruction (short circuit) in that portion.

(Example 4) The procedure (4) of Example 3 was changed to the following procedure (4a), and the substrate transfer speed was changed from 50 cm / min to 70 cm / min in the procedure (5). The same apparatus and method as in Example 3 were used.

Procedure (4a) After evacuating the high vacuum chamber of the ion beam generator to a degree of vacuum of the order of 10 ^-6 Torr, argon gas was introduced to reduce the degree of vacuum to 1.5 × 10 ^-5 Torr. .

During the deposition of the transparent conductive film in this embodiment, the voltage between the conductive substrate 31 and the deposition chamber 35 was measured by a voltmeter.
f was -110 volts.

The photovoltaic element thus produced was used in Example 3.
The open-circuit voltage was as low as 0.05 volts or less for 80% of the samples as measured by the same method as in the above. Furthermore, a silver paste was screen-printed to form a collecting electrode, and the characteristics were evaluated under AM1.5 (100 mW / cm ² ) light irradiation. The photoelectric conversion efficiency of the 80% sample was as follows. , At most 3.5%.

When the current collecting electrode provided on the comparative device was used as an anode, the conductive substrate 31 was used as a negative electrode, and a DC current of 20 mA was applied between both electrodes, the device surface was observed with an IR camera. It was confirmed that a ball-shaped current path having a diameter of about 30 mm was formed at some points on the element surface. This is probably because some damage (short-circuit) was caused by plasma damage to the semiconductor layer 41 due to the ITO ions ionized by the ion beam when the transparent conductive film 42 was formed.

As the thin film semiconductor layer to which the present invention can be applied, in addition to the above-described semiconductor layer for a solar cell shown in FIG. 4, a thin film semiconductor layer for a thin film transistor used for a liquid crystal panel driven by active matrix driving, US Pat. No. 5,184,018, US Pat. No. 5,26
No. 2,649 or the like can be used.

[0065]

According to the present invention, the conductive substrate is electrically connected to the same potential as the high impedance or the self-bias by using the manufacturing method of the ion beam sputtering apparatus and the semiconductor device having the above characteristics. by doing,
By connecting to a non-earth and forming a transparent conductive film on the semiconductor layer formed on the conductive substrate, DC current hardly flows from the conductive substrate toward the semiconductor layer on the surface, and the semiconductor layer is destroyed ( Short) can be prevented. Further, the potential of the conductive substrate with respect to the ground is -100 volts or more and 0
By selecting sputtering conditions so as to be less than the volt, plasma damage to the semiconductor layer by ions can be reduced.

Further, according to the present invention, by controlling the potential of the conductive substrate to -100 volts or more and less than 0 volts with respect to the ground, it is possible to eliminate only the above-mentioned adverse effects on the semiconductor layer. , A dense film with a uniform particle size is obtained, low resistance, high transmittance, excellent acid and alkali resistance, and excellent heat resistance. A film can be formed.

Further, according to the present invention, the glow discharge
Since the sputtering chamber has a higher vacuum than the DC magnetron sputtering method, the occlusion of the discharge gas generated in the glow discharge device into the sputtered film is eliminated, and a high-purity thin film, that is,
A transparent conductive film with low resistance and high transmittance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ion beam sputtering apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of another ion beam sputtering apparatus of the present invention.

FIG. 3 is a schematic configuration diagram of another ion beam sputtering apparatus of the present invention.

FIG. 4 is a cross-sectional view of a semiconductor device used in the present invention.

FIG. 5 is a characteristic diagram measured according to the first embodiment.

FIG. 6 is a characteristic diagram measured according to the first embodiment.

FIG. 7 is a characteristic diagram measured by Example 2.

FIG. 8 is a characteristic diagram measured by Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ion beam generator 111 Gas introduction pipe 112 Ionization heater means 113 Beam acceleration means 114 High vacuum chamber 12, 35 Deposition chamber 121 Ion beam 122 Target 123 Target component 124 Conductive substrate 125 Heater for substrate 126 Vacuum chamber 127 Thermocouple 13 Switch 21 Means for applying voltage to conductive substrate 31 Rolled conductive substrate 32 Arrow mark indicating direction of movement of conductive substrate 33 Substrate carry-in chamber 331 Take-up roll 332, 342 Send roll 34 Substrate carry-out chamber 341 Send-out roll 352 Target component 41 thin film semiconductor layer 411, 414, 417 p-type semiconductor layer 412, 415, 418 i-type semiconductor layer 413, 416, 419 n-type semiconductor layer 42 transparent conductive film 43 reflective layer 44 underlying transparent conductive film

Claims (26)

[Claims] 1. A method comprising: a. First means for generating an ion beam and directing the ion beam in a predetermined direction; b. Holding the target at a position to be irradiated with the ion beam so that the target is sputtered by the irradiation of the ion beam in the predetermined direction.
Means, c. Third means for holding a conductive substrate provided with a semiconductor thin film layer for depositing the sputtered target component, d. An ion beam sputtering apparatus comprising: fourth means for setting the potential of the conductive substrate to a non-earth potential. 2. The ion beam sputtering apparatus according to claim 1, wherein the conductive substrate is a long conductive substrate. 3. The ion beam sputtering apparatus according to claim 1, wherein said fourth means includes means for insulating said conductive substrate from ground. 4. The means for applying a voltage to the conductive substrate so that the potential of the conductive substrate with respect to the ground is set to the same polarity as the potential of the surface of the thin film semiconductor layer with respect to the ground. The ion beam sputtering apparatus according to claim 1, further comprising: 5. The ion beam sputtering apparatus according to claim 4, wherein the voltage is set to -100 volts or more and less than 0 volt. 6. The ion beam sputtering apparatus according to claim 1, wherein said thin film semiconductor layer is a semiconductor layer having a semiconductor junction. 7. The ion beam sputtering apparatus according to claim 1, wherein the thin film semiconductor layer is a semiconductor layer having a semiconductor junction formed of non-single-crystal silicon. 8. The ion beam according to claim 1, wherein the thin film semiconductor layer is a semiconductor layer having a pin junction, a nip junction, a pn junction, or an np junction formed of amorphous silicon, microcrystalline silicon, or polycrystalline silicon. Sputtering equipment. 9. A. Placing a target at a position in the ion beam sputtering apparatus where the ion beam is irradiated; b. Disposing a conductive substrate provided with a thin-film semiconductor layer at a position where a target component generated from the target in the ion beam sputtering apparatus is deposited; c. Generating an ion beam, directing the ion beam in a predetermined direction, irradiating the target with the ion beam, sputtering the target, and depositing the target component on the thin film semiconductor layer. A method of manufacturing a device, comprising: setting a potential of the conductive substrate so that the conductive substrate has a non-earth potential at least during a period in which the target component is deposited. Law. 10. The method according to claim 9, wherein the conductive substrate is a long conductive substrate. 11. The potential of said conductive substrate is set by insulating said conductive substrate from ground.
3. The method for manufacturing a semiconductor device according to 1. 12. The semiconductor device according to claim 9, wherein a voltage is applied to the conductive substrate so that the potential of the conductive substrate with respect to the ground is set to the same polarity as the potential of the surface of the thin film semiconductor layer with respect to the ground. Manufacturing method. 13. The method of manufacturing a semiconductor device according to claim 12, wherein the voltage is set to be −100 volts or more and less than 0 volts. 14. The method according to claim 9, wherein the thin film semiconductor layer is a semiconductor layer having a semiconductor junction. 15. The method according to claim 9, wherein the thin film semiconductor layer is a semiconductor layer having a semiconductor junction formed of non-single-crystal silicon. 16. The semiconductor device according to claim 9, wherein the thin film semiconductor layer is a semiconductor layer having a pin junction, a nip junction, a pn junction, or an np junction formed of amorphous silicon, microcrystalline silicon, or polycrystalline silicon. Manufacturing method. 17. The method according to claim 9, wherein a transparent conductive film is formed by depositing the target component. 18. A. Placing a target at a position in the ion beam sputtering apparatus where the ion beam is irradiated; b. Arranging a conductive substrate provided with a thin-film semiconductor layer at a position in the ion beam sputtering apparatus where a target component generated from the target is deposited; c. Generating an ion beam, directing the ion beam in a predetermined direction, irradiating the target with the ion beam, sputtering the target, and depositing the target component on the thin film semiconductor layer. A method of manufacturing a device, wherein the potential of the conductive substrate is set so that the conductive substrate has a non-earth potential at least during a period in which the target component is deposited. Manufacturing method. 19. The method according to claim 18, wherein the conductive substrate is a long conductive substrate. 20. The potential of the conductive substrate is set by insulating the conductive substrate from ground.
9. The method for manufacturing a photoelectric conversion device according to item 8. 21. The photoelectric conversion according to claim 18, wherein a voltage is applied to the conductive substrate so that the potential of the conductive substrate with respect to the ground is set to the same polarity as the potential of the surface of the thin film semiconductor layer with respect to the ground. Equipment manufacturing method. 22. The method according to claim 21, wherein the voltage is set to -100 volts or more and less than 0 volts. 23. The method according to claim 18, wherein the thin film semiconductor layer is a semiconductor layer having a semiconductor junction. 24. The method according to claim 18, wherein the thin film semiconductor layer is a semiconductor layer having a semiconductor junction formed of non-single-crystal silicon. 25. The photoelectric conversion according to claim 18, wherein the thin film semiconductor layer is a semiconductor layer having a pin junction, a nip junction, a pn junction, or an np junction formed of amorphous silicon, microcrystalline silicon, or polycrystalline silicon. Equipment manufacturing method. 26. The method according to claim 18, wherein a transparent conductive film is formed by depositing the target component.