JP2014040635A - Sputter deposition method and method for manufacturing photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily clean a target.SOLUTION: A sputter deposition method includes: a deposition step of depositing a film on the predetermined number of substrates by applying a voltage to a target 140 while applying magnetic field onto a surface of the target 140 in a state in which argon gas is introduced in a chamber while reducing a pressure in the chamber, and thereby generating discharge in a discharge region on a surface side of the target 140; and a cleaning step of cleaning the surface of the target 140 by increasing a voltage to be applied while increasing amount of argon gas 152 to be introduced than those in the deposition, thereby expanding the discharge region 144 after the deposition step.

Description

  The present invention relates to a sputtering film forming method and a photoelectric conversion device manufacturing method, and more particularly to a sputtering film forming method using a magnetron sputtering device and a photoelectric conversion device manufacturing method.

  Japanese Patent Laid-Open No. 2002-38264 (Patent Document 1) is a prior art document that discloses a sputtering film forming method capable of cleaning a magnetron sputtering apparatus without exposing the target to a non-erosion region without opening to the atmosphere.

  In the sputter film forming method described in Patent Document 1, after forming a film on a predetermined number of objects to be processed, the target surface is cleaned by spreading a magnetic field along the direction of the target surface than during film formation. .

JP 2002-38264 A

  In the sputtering film forming method described in Patent Document 1, cleaning is performed by adding a magnetic material to a side portion along the target surface direction of a magnet body disposed at the time of film formation. In this case, it is necessary to attach the magnetic body to both sides of the magnet body during cleaning and to remove the magnetic body during film formation.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a sputtering film forming method and a photoelectric conversion device manufacturing method capable of easily cleaning a target.

  The sputter deposition method according to the present invention is a sputter deposition method in which a target component is deposited on a target object in a chamber by sputtering using a magnetic field. In the sputter deposition method, by applying a voltage to the target while applying a magnetic field to the surface of the target in a state where the gas is introduced while reducing the pressure in the chamber, a discharge is generated in the discharge region on the surface side of the target. A film forming step for forming a film on a predetermined number of objects to be processed, and after the film forming step, the discharge region is widened by increasing the voltage applied while increasing the amount of the gas introduced than during film formation. And a cleaning process for cleaning the surface of the target.

  In one form of this invention, the said gas is sprayed on the surface of a target in a cleaning process.

In one embodiment of the present invention, film formation is performed while the object to be processed is conveyed in the film formation step.
In an embodiment of the present invention, the predetermined number is decreased as the target life is late.

  The method for manufacturing a photoelectric conversion device according to the present invention is a method for manufacturing a photoelectric conversion device in which a photoelectric conversion device is manufactured by sequentially forming a film on each of a plurality of objects to be processed. A method for manufacturing a photoelectric conversion device includes a step of forming a photoelectric conversion layer on each of a plurality of objects to be processed, and sputtering using a magnetic field on each of the plurality of objects to be processed on which the photoelectric conversion layer is formed. A transparent conductive film forming step of forming a transparent conductive film by depositing a target component on a target object. In the transparent conductive film forming process, with the gas introduced while reducing the pressure in the chamber, a voltage is applied to the target while applying a magnetic field to the surface of the target to generate a discharge in a discharge region on the surface side of the target. Thus, a film is formed on a predetermined number of objects to be processed. In the middle of the transparent conductive film formation process, after forming a film on a predetermined number of objects to be processed, the discharge area is widened by increasing the voltage applied while increasing the amount of gas introduced compared to the time of film formation, and the surface of the target is formed. Clean it.

  In one embodiment of the present invention, in the transparent conductive film forming step, the discharge region is widened to clean the surface of the target, and then a film is formed on a predetermined number of objects to be processed.

  According to the present invention, the target can be easily cleaned.

It is a side view which shows the structure of the sputtering device which performs the sputtering film-forming method concerning one Embodiment of this invention. It is the top view which looked at the sputtering device of FIG. 1 from the arrow II direction. It is sectional drawing which shows typically the discharge area | region in the film-forming process. It is sectional drawing which shows typically the discharge area | region in a cleaning process. It is sectional drawing which shows the structure of the photoelectric conversion apparatus manufactured with the manufacturing method of the photoelectric conversion apparatus which concerns on one Embodiment of this invention. It is a systematic diagram which shows the structure of a vacuum film-forming apparatus.

  Hereinafter, a sputtering film forming method according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

  In the present embodiment, the case of forming a film to be the back electrode of the solar cell will be described as an example. However, the film formed by the sputtering apparatus is not limited to this, and films made of various materials can be formed. It is.

  FIG. 1 is a side view showing a configuration of a sputtering apparatus for performing a sputtering film forming method according to an embodiment of the present invention. FIG. 2 is a plan view of the sputtering apparatus of FIG. 1 as viewed from the direction of arrow II.

  As shown in FIGS. 1 and 2, the sputtering apparatus 100 according to this embodiment is an inline-type sputtering apparatus that forms a film while sequentially transporting a plurality of substrates 10 that are objects to be processed. As the substrate 10, for example, a substrate made of glass, quartz, plastic, or the like having insulating properties and translucency can be used.

  The sputtering apparatus 100 includes a chamber 110 that can be evacuated to a vacuum state. In addition, the sputtering apparatus 100 includes a substrate transfer mechanism, a target 140, and a gas supply unit 150 disposed in the chamber 110. Further, the sputtering apparatus 100 includes an exhaust pump 160 that is disposed on the side of the chamber 110 and depressurizes the inside of the chamber 110.

  In the present embodiment, the substrate transport mechanism is configured by a roller conveyor 130. However, the substrate transport mechanism is not limited to the roller conveyor, and may be, for example, a belt conveyor, an air floating substrate transport device, or a robot arm. The substrate 10 is conveyed by the roller conveyor 130 in the direction of the arrow in the figure.

  In the present embodiment, two targets 140 are arranged so as to be aligned in the transport direction of the substrate 10. Each of the two targets 140 has a flat outer shape and is disposed so as to face the main surface of the substrate 10 conveyed by the roller conveyor 130. Note that the number of targets 140 to be arranged is not limited to two and may be one or more.

  A space between the roller conveyor 130 and the target 140 becomes a discharge space. The target 140 is bonded and fixed to a backing plate (not shown) whose upper surface is fixed in the chamber 110 by a bonding material. A magnet (not shown) is disposed on the opposite side of the target 140 from the backing plate.

  The magnet forms a magnetic field in the discharge space and focuses the argon plasma that is glow-discharged in the discharge space. Specifically, the magnet is designed so that the magnetic field is closed between the outer magnetic pole and the inner magnetic pole, so that the generated plasma can exist only in the vicinity of the target 140.

The target 140 is made of tin oxide, zinc oxide, ITO (Indium Tin Oxide), or the like. Here, the tin oxide includes not only SnO ₂ but also tin oxide having various compositions represented by Sn _m O _n (m and n are natural numbers). Zinc oxide includes not only ZnO but also zinc oxide having various compositions represented by Zn _x O _y (x and y are natural numbers).

  Three gas supply units 150 are arranged in parallel at intervals in the transport direction of the substrate 10 so as to sandwich the target 140 therebetween. The gas supply unit 150 extends longer than the width of the substrate 10 in the width direction of the substrate 10 so that gas can be sprayed uniformly over the entire width direction of the substrate 10. The gas supply unit 150 has a jet port facing downward.

  The gas supply unit 150 ejects argon gas and oxygen gas as a process gas from the ejection port and introduces them into the chamber 110. The gas supply unit 150 is connected to a gas supply source via a mass flow controller that adjusts the flow rate of the introduced gas.

  Hereinafter, a sputtering film forming method according to an embodiment of the present invention will be described. The sputter film forming method according to the present embodiment is a sputter film forming method in which the components of the target 140 are formed on the substrate 10 as the object to be processed in the chamber 110 by sputtering using a magnetic field.

  FIG. 3 is a cross-sectional view schematically showing a discharge region in the film forming process. First, the argon gas 151 and oxygen gas are introduced from the gas supply unit 150 as shown in FIG. For example, argon gas 151 is introduced at a flow rate of 150 sccm and oxygen gas at a flow rate of 5 sccm. In this state, the substrate 10 is put on the roller conveyor 130 in the chamber 110 in the sputtering apparatus 100. The loaded substrate 10 is conveyed by the roller conveyor 130 in the direction indicated by the arrows in FIGS.

  While the substrate 10 passes through a position below the target 140, a voltage is applied to the target 140 to cause glow discharge in the discharge space. For example, a DC voltage of 13300 W is applied to the target 140. As shown in FIG. 3, in the film forming process, discharge occurs in the discharge region 143 on the surface side of the target 140. This glow discharge generates argon plasma. The argon plasma is focused by the magnetic field applied to the surface of the target 140 by the magnet and collides with the target 140.

  Thereby, atoms constituting the target 140 are blown off into the discharge space. By depositing the atoms on the main surface of the substrate 10 on which the atoms are transported, a film serving as a back electrode is formed on the main surface of the substrate 10. For example, a film made of ZnO to be a back transparent electrode is formed with a thickness of 50 nm by the target 140 on the upstream side, and a film made of Ag to be the back metal electrode is formed with a thickness of 200 nm by the target 140 on the downstream side.

  As shown in FIG. 3, an erosion region 141, which is a portion eroded by greatly contributing to sputtering, and a non-erosion region 142 other than that appear on the target 140. The size of the erosion region 141 is determined by the size of the discharge region 143.

  The atoms constituting the target 140 drifting in the discharge space are particularly concentrated and attached to the portion of the non-erosion region 142 that contacts the erosion region 141. In order to remove this deposit, a cleaning process is performed after the film formation process on the predetermined number of substrates 10 is completed.

  FIG. 4 is a cross-sectional view schematically showing a discharge region in the cleaning process. As shown in FIG. 4, in the cleaning process, the voltage applied to the target 140 is increased while increasing the amount of the argon gas 152 to be introduced compared to the time of film formation. For example, the flow rate of the argon gas 152 is set to 300 sccm. For example, the DC voltage applied to the target 140 is set to 15000 W.

  Then, the discharge region 144 on the surface side of the target 140 extends to a region including a portion in contact with the erosion region 141 in the non-erosion region 142. As a result, a discharge is generated even in a portion of the non-erosion region 142 where a large amount of deposits are attached, which is in contact with the erosion region 141, and the deposits can be removed from the target 140.

  As a result, the surface of the target 140 can be easily cleaned without opening the chamber 110 to the atmosphere.

  As shown in FIG. 4, by increasing the amount of argon gas 152 ejected from the ejection port of the gas supply unit 150, a part 153 of the ejected argon gas wraps around the surface of the target 140 and directly Be sprayed. The deposits can also be removed from the target 140 by a physical shock caused by the portion 153 of the argon gas.

  The amount of deposits on the target 140 tends to increase in the second half of the life of the target 140. For this reason, in the present embodiment, the predetermined number of films to be deposited on the substrate 10 before the cleaning process is performed is decreased as the target 140 reaches the end of its life.

  For example, when the 4000 substrates 10 that can be deposited in the first half of the life of the target 140 are not cleaned, the 4000 substrates 10 that can be deposited in the second half of the lifetime of the target 140 are deposited. The deposits can be effectively removed by gradually reducing the predetermined number of film formation between about 600 and 500 before cleaning.

  Note that the voltage applied to the target 140 in the cleaning process is preferably the maximum voltage within a range in which the components of the sputtering apparatus 100 are not affected by heat generated by the applied voltage and can be stably discharged.

  The flow rate of the argon gas 152 introduced in the cleaning step is preferably the maximum flow rate within the capacity limit of the mass flow controller and within a range where stable discharge is possible.

  By performing the cleaning process by the sputtering film forming method according to the present embodiment, it is possible to suppress the deterioration of the film forming quality due to the deposits on the target 140 during the lifetime of the target 140 and to perform cleaning without opening to the atmosphere. The sputter deposition apparatus can be operated at an operating rate.

  Hereinafter, a method for manufacturing a photoelectric conversion device according to an embodiment of the present invention that employs the above-described sputter deposition method will be described. First, the configuration of the photoelectric conversion device will be described.

  FIG. 5 is a cross-sectional view illustrating a configuration of a photoelectric conversion device manufactured by a method for manufacturing a photoelectric conversion device according to an embodiment of the present invention. As shown in FIG. 5, the photoelectric conversion device 200 manufactured by the method for manufacturing a photoelectric conversion device according to this embodiment includes a substrate 210 that is an object to be processed and a cell structure 220 provided on the substrate 210. doing.

  The cell structure 220 is formed on the transparent conductive film 230 provided on the substrate 210, the first pin type photoelectric conversion layer 240 provided on the transparent conductive film 230, and the first pin type photoelectric conversion layer 240. A second pin-type photoelectric conversion layer 250 provided; a transparent conductive film 260 provided on the second pin-type photoelectric conversion layer 250; and a reflective electrode 270 provided on the transparent conductive film 260. Yes.

  The first pin-type photoelectric conversion layer 240 is a photoelectric conversion layer made of amorphous silicon, and includes a first p-type semiconductor layer 241 provided on the transparent conductive film 230 and a first p-type semiconductor layer 241. A first i-type semiconductor layer 242 provided above and a first n-type semiconductor layer 243 provided on the first i-type semiconductor layer 242 are provided.

  The second pin-type photoelectric conversion layer 250 is a photoelectric conversion layer made of microcrystalline silicon, and includes a second p-type semiconductor layer 251 provided on the first n-type semiconductor layer 243, and a second p-type semiconductor layer. A second i-type semiconductor layer 252 provided on the semiconductor layer 251 and a second n-type semiconductor layer 253 provided on the second i-type semiconductor layer 252 are provided.

  Note that, in this embodiment, a super straight type photoelectric conversion device in which light is incident from the substrate 210 side will be described, but a substrate type photoelectric conversion device in which light is incident from the opposite side of the substrate 210 may be used. Good.

  As the substrate 210, for example, a light transmissive substrate such as a glass substrate, a resin substrate containing a transparent resin such as polyimide resin, or a substrate in which a plurality of these substrates are stacked can be used.

  Note that when the photoelectric conversion device is a substrate type photoelectric conversion device, the substrate 210 may be a non-transmissive substrate that does not transmit light, such as a stainless steel substrate.

  As the transparent conductive film 230, for example, a tin oxide film, an ITO film, a zinc oxide film, a single layer of a film obtained by adding a trace amount of impurities to these films, or a plurality of layers in which a plurality of these layers are stacked can be used. It is desirable that the transparent conductive film 230 can transmit a large amount of light and has good conductivity. When the transparent conductive film 230 is composed of a plurality of layers, all the layers may be formed from the same material, or at least one layer may be formed from a material different from the others.

  Moreover, it is preferable that the surface of the transparent conductive film 230 has irregularities as shown in FIG. Since the unevenness is formed on the surface of the transparent conductive film 230, the incident light incident from the substrate 210 side can be scattered or refracted to extend the optical path length. As a result, the light confinement effect in the first pin-type photoelectric conversion layer 240 can be increased, so that the short-circuit current density of the photoelectric conversion device 200 can be increased. As a method for forming irregularities on the surface of the transparent conductive film 230, for example, an etching method, a method by sandblasting, a method using crystal growth of the transparent conductive film 230, or the like can be used.

  The first pin-type photoelectric conversion layer 240 is an amorphous structure including a stacked body of a first p-type semiconductor layer 241, a first i-type semiconductor layer 242, and a first n-type semiconductor layer 243. It is a photoelectric conversion layer made of silicon.

  As the first p-type semiconductor layer 241, for example, a p-type such as a p-type amorphous silicon layer, a p-type microcrystalline silicon layer, a p-type amorphous silicon carbide layer, or a p-type amorphous silicon nitride layer. A single layer or a plurality of stacked layers of these layers can be used. When the first p-type semiconductor layer 241 includes a plurality of layers, all the layers may be formed of the same semiconductor material, or at least one layer may be formed of a different semiconductor material. Good. As the p-type impurity element doped into the first p-type semiconductor layer 241, for example, boron or the like can be used.

  As the first i-type semiconductor layer 242, for example, a single layer or a plurality of layers of an amorphous silicon layer can be used. The first i-type semiconductor layer 242 is an intrinsic semiconductor to which neither a p-type impurity element nor an n-type impurity element is doped. However, the first i-type semiconductor layer 242 is near the interface with the first p-type semiconductor layer 241 and the first n-type semiconductor layer. In the vicinity of the interface with H.243, the p-type impurity element and the n-type impurity element may be included in the first i-type semiconductor layer 242 in minute amounts. In order to control the band gap of the first i-type semiconductor layer 242, amorphous silicon carbide, amorphous silicon germanium, or the like to which elements such as carbon and germanium are positively added can be used.

  As the first n-type semiconductor layer 243, for example, an n-type amorphous silicon layer, a single n-type layer such as an n-type microcrystalline silicon layer, or a plurality of stacked layers of these layers can be used. it can. When the first n-type semiconductor layer 243 includes a plurality of layers, all the layers may be formed of the same semiconductor material, or at least one layer may be formed of a different semiconductor material. Good. As the n-type impurity element doped in the first n-type semiconductor layer 243, for example, phosphorus or the like can be used.

  As the first p-type semiconductor layer 241 and the first n-type semiconductor layer 243, the same semiconductor material as that of the first i-type semiconductor layer 242 may be used, or a different semiconductor material may be used. For example, a p-type amorphous silicon layer and an i-type amorphous silicon layer are used for the first p-type semiconductor layer 241 and the first i-type semiconductor layer 242, respectively, and n is used for the first n-type semiconductor layer 243. A type microcrystalline silicon layer may be used. Further, for example, a p-type amorphous silicon carbide layer is used as the first p-type semiconductor layer 241, an amorphous silicon layer is used as the first i-type semiconductor layer 242, and the first n-type semiconductor layer 243 is used as the first n-type semiconductor layer 243. An n-type microcrystalline silicon layer may be used.

  In this specification, “amorphous silicon” is a concept including “hydrogenated amorphous silicon”, and “microcrystalline silicon” is a concept including “hydrogenated microcrystalline silicon”.

  The second pin-type photoelectric conversion layer 250 is a microcrystalline silicon including a stacked body of the second p-type semiconductor layer 251, the second i-type semiconductor layer 252, and the second n-type semiconductor layer 253. It is a photoelectric converting layer which consists of.

  As the second p-type semiconductor layer 251, for example, a single layer of a p-type layer such as a p-type microcrystalline silicon layer, a p-type microcrystalline silicon carbide layer, or a p-type microcrystalline silicon nitride layer, or a stack of a plurality of these layers Multiple layers can be used. When the second p-type semiconductor layer 251 includes a plurality of layers, all the layers may be formed of the same semiconductor material, or at least one layer may be formed of a different semiconductor material. Good. As the p-type impurity element doped into the second p-type semiconductor layer 251, for example, boron or the like can be used.

  As the second i-type semiconductor layer 252, for example, a single layer or a plurality of microcrystalline silicon layers can be used. The second i-type semiconductor layer 252 is an intrinsic semiconductor layer to which neither a p-type impurity element nor an n-type impurity element is doped, but the vicinity of the interface with the second p-type semiconductor layer 251 and the second n-type semiconductor layer In the vicinity of the interface with the layer 253, a small amount of p-type impurity element and n-type impurity element may be contained in the second i-type semiconductor layer 252 in some cases.

  As the second n-type semiconductor layer 253, for example, an n-type amorphous silicon layer, a single n-type layer such as an n-type microcrystalline silicon layer, or a plurality of stacked layers of these layers can be used. it can. When the second n-type semiconductor layer 253 includes a plurality of layers, all the layers may be formed from the same semiconductor material, or at least one layer may be formed from a semiconductor material different from the other. Good. As the n-type impurity element doped into the second n-type semiconductor layer 253, for example, phosphorus or the like can be used.

  Note that as the second p-type semiconductor layer 251 and the second n-type semiconductor layer 253, the same semiconductor material as that of the second i-type semiconductor layer 252 may be used, or a different semiconductor material may be used. Also, the second p-type semiconductor layer 251 and the second n-type semiconductor layer 253 may be made of the same semiconductor material or different semiconductor materials.

  As the transparent conductive film 260, for example, a tin oxide film, an ITO film, a zinc oxide film, or a single layer of a film obtained by adding a trace amount of impurities to these films or a plurality of layers in which a plurality of these layers are stacked are allowed to transmit light. In addition, a conductive film can be used. When the transparent conductive film 260 includes a plurality of layers, all the layers may be formed from the same material, or at least one layer may be formed from a material different from the other.

  As the reflective electrode 270, a material having a high light reflectivity is often used. For example, a conductive layer such as an Ag (silver) layer, an Al (aluminum) layer, or a laminate of these layers is used. it can.

  The reflective electrode 270 reflects light that has not been absorbed by the first pin-type photoelectric conversion layer 240 and the second pin-type photoelectric conversion layer 250 to reflect the first pin-type photoelectric conversion layer 240 and the second pin. Since it can return to the type photoelectric conversion layer 250, it contributes to the improvement of photoelectric conversion efficiency.

  When the photoelectric conversion device is a substrate-type photoelectric conversion device, the reflective electrode 270 is shaped so as not to cover the entire surface of the photoelectric conversion device such as a comb shape from the viewpoint of entering light. It is preferable.

Hereinafter, a method for manufacturing the photoelectric conversion device according to the present embodiment will be described.
First, the transparent conductive film 230 is formed on the substrate 210. Here, the transparent conductive film 230 is formed by a method such as sputtering, CVD (Chemical Vapor Deposition), electron beam evaporation, sol-gel, spray, or electrodeposition.

  Next, for example, using a plasma CVD apparatus which is a large vacuum film forming apparatus having a large leak rate, the first pin type photoelectric conversion layer 240 is formed on the transparent conductive film 230 formed on the substrate 210 by plasma CVD. And the 2nd pin type photoelectric converting layer 250 is formed in this order.

  FIG. 6 is a system diagram showing the configuration of the vacuum film forming apparatus. As shown in FIG. 6, the vacuum film forming apparatus was installed so as to face the cathode 31 in the film forming chamber 41, the cathode 31 installed in the film forming chamber 41, and the film forming chamber 41. And an anode 32. The vacuum film forming apparatus also includes a gas introduction pipe 33 for introducing gas into the cathode 31, a gas discharge pipe 37 for discharging gas to the outside of the film forming chamber 41, and a gas discharge pipe 37. A gate valve 39 for adjusting the amount of gas to be generated and a pump 40 for sucking the gas discharged to the outside of the film forming chamber 41 are provided. The cathode 31 is connected to a high frequency power source 36 through an impedance matching circuit 35. The anode 32 is connected to ground.

In the vacuum film forming apparatus, after the gas inside the film forming chamber 41 is exhausted and the pressure inside the film forming chamber 41 is set to a pressure in the range of 10 ⁻⁴ Pa to 1 Pa, for example, the gate valve 39 is closed. When the film formation chamber 41 is sealed by, for example, a pressure increase when the gas enters the film formation chamber 41 from the outside of the film formation chamber 41 with time and the pressure inside the film formation chamber 41 increases. The rate (leak rate) is, for example, about 3 × 10 ⁻³ Pa · L / s.

  When the first pin type photoelectric conversion layer 240 and the second pin type photoelectric conversion layer 250 are formed, the substrate 210 provided with the transparent conductive film 230 is placed on the anode 32 of the vacuum film forming apparatus. The substrate 210 is placed on the anode 32 so that the transparent conductive film 230 faces the cathode 31.

Next, the gate valve 39 is opened and sucked by the pump 40, whereby the gas inside the film forming chamber 41 is discharged to the outside of the film forming chamber 41 through the gas discharge pipe 37 in the direction of the arrow 38. Is set to a pressure within a range of 10 ⁻⁴ Pa to 1 Pa, for example.

Thereafter, for example, at least one gas selected from the group consisting of SiH ₄ , H ₂ , B ₂ H ₆ , PH ₃ and CH ₄ is introduced into the cathode 31 from the gas introduction pipe 33 in the direction of the arrow 34. The gas is introduced between the cathode 31 and the anode 32 through a hole (not shown) provided on the anode 32 side of the cathode 31.

  Next, an AC voltage is applied between the cathode 31 and the anode 32 by the high frequency power source 36 to generate plasma of the gas introduced above, and the second plasma is formed on the transparent conductive film 230 installed on the substrate 210. 1 p-type semiconductor layer 241 is formed.

Thereafter, after the introduction of the gas into the film forming chamber 41 is stopped, the gas inside the film forming chamber 41 is discharged to the outside of the film forming chamber 41 through the gas discharge pipe 37 in the direction of the arrow 38, For example, the pressure inside 41 is set to a pressure within a range of 10 ⁻⁴ Pa to 1 Pa.

  By repeating the above steps, the first p-type semiconductor layer 241, the first i-type semiconductor layer 242, the first n-type semiconductor layer 243, the first n-type semiconductor layer 243 are formed on the transparent conductive film 230 provided on the substrate 210. Two p-type semiconductor layers 251, a second i-type semiconductor layer 252, and a second n-type semiconductor layer 253 are formed in this order. Thereby, the 1st pin type photoelectric converting layer 240 and the 2nd pin type photoelectric converting layer 250 are formed.

  Note that the first p-type semiconductor layer 241, the first i-type semiconductor layer 242, and the first n-type semiconductor layer 243 of the first pin-type photoelectric conversion layer 240 are formed in separate film formation chambers. However, from the viewpoint of cost reduction of the deposition apparatus, the first p-type semiconductor layer 241, the first i-type semiconductor layer 242, and the first n-type semiconductor layer 243 are formed in one deposition chamber. It is preferable to do.

  In addition, the second p-type semiconductor layer 251, the second i-type semiconductor layer 252, and the second n-type semiconductor layer 253 of the second pin-type photoelectric conversion layer 250 are formed in separate film formation chambers. However, from the viewpoint of cost reduction of the film formation apparatus, the second p-type semiconductor layer 251, the second i-type semiconductor layer 252, and the second n-type semiconductor layer 253 are combined in one film formation chamber. It is preferable to form.

  In addition, although the first pin type photoelectric conversion layer 240 and the second pin type photoelectric conversion layer 250 can be formed in one film formation chamber, in the present embodiment, the first pin type photoelectric conversion layer is formed. One film formation chamber is used for forming 240 and another film formation chamber is used for forming the second pin-type photoelectric conversion layer 250.

The first p-type semiconductor layer 241, the first i-type semiconductor layer 242, the first n-type semiconductor layer 243, the second p-type semiconductor layer 251, the second i-type semiconductor layer 252, and the first The pressure inside the film formation chamber 41 when the n-type semiconductor layer 253 is formed is, for example, in the range of 5 × 10 ² Pa or more and 1.7 × 10 ³ Pa or less.

  In the vacuum film forming apparatus, the high-frequency power source 36 may output either a continuous waveform (CW) AC output or a pulse-modulated (ON / OFF controlled) AC output. The frequency of the AC power output from the high-frequency power source 36 is generally 13.56 MHz, but is not limited thereto. For example, the frequency is several kHz to VHF band, several kHz to UHF band, and several kHz to microwave band. A frequency may be used.

  Next, a transparent conductive film 260 is formed on the second n-type semiconductor layer 253 of the second pin-type photoelectric conversion layer 250 formed as described above. Here, the transparent conductive film 260 is formed by the sputtering film forming method according to the embodiment.

  That is, the components of the target 140 are formed in the chamber 110 by sputtering using a magnetic field on each of the plurality of substrates 210 on which the first pin type photoelectric conversion layer 240 and the second pin type photoelectric conversion layer 250 are formed. A transparent conductive film 260 is formed by depositing on 210.

  In the transparent conductive film forming step, a voltage is applied to the target 140 while applying a magnetic field to the surface of the target 140 in a state where the argon gas 151 is introduced while decompressing the inside of the chamber 110, so that a discharge region on the surface side of the target 140. A film is formed on a predetermined number of substrates 210 by generating a discharge at 143.

  After forming a film on a predetermined number of substrates 210 during the process of forming the transparent conductive film, the discharge area 144 is widened by increasing the voltage applied while increasing the amount of the argon gas 152 introduced compared to the time of film formation. Clean the surface.

  In the transparent conductive film forming step, the discharge region 144 is expanded and the surface of the target 140 is cleaned, and then a transparent conductive film 260 is formed on a predetermined number of substrates 210. This film forming process and cleaning process are repeated during the lifetime of the target 140.

  A reflective electrode 270 is formed on the transparent conductive film 260 formed as described above. Here, the reflective electrode 270 can be formed by a method such as a CVD method, a sputtering method, a vacuum evaporation method, an electron beam evaporation method, a spray method, a screen printing method, or an electrodeposition method. As described above, the photoelectric conversion device of this embodiment can be manufactured.

  In addition, since the falling phenomenon of the deposit on the target 140 is likely to occur in a target made of a metal oxide and is difficult to occur in a target made of a metal, when the reflective electrode 270 is formed by a sputtering method, the above embodiment is used. It is not necessary to employ such a sputter deposition method.

  With the photoelectric conversion device manufacturing method according to the present embodiment, it is possible to suppress a decrease in film formation quality due to deposits on the target 140 during the lifetime of the target 140 and to clean the target 140 without opening it to the atmosphere. Since the sputter deposition apparatus can be operated at a high rate, a high-quality photoelectric conversion apparatus can be efficiently manufactured.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 210 Substrate, 31 Cathode, 32 Anode, 33 Gas introduction pipe, 35 Impedance matching circuit, 36 High frequency power supply, 37 Gas exhaust pipe, 39 Gate valve, 40 Pump, 41 Deposition chamber, 100 Sputter apparatus, 110 Chamber, 130 Roller conveyor, 140 target, 141 erosion region, 142 non-erosion region, 143, 144 discharge region, 150 gas supply unit, 151, 152 argon gas, 153 part of argon gas, 160 exhaust pump, 200 photoelectric conversion device, 220 cells Structure, 230, 260 transparent conductive film, 240, 250 n-type photoelectric conversion layer, 241 first p-type semiconductor layer, 242, 252 type semiconductor layer, 243 first n-type semiconductor layer, 251 second p-type Semiconductor layer, 253 Second n-type semiconductor layer 270 reflective electrode.

Claims (6)

A sputtering film forming method for forming a target component on a target object in a chamber by sputtering using a magnetic field,
By applying a voltage to the target while applying a magnetic field to the surface of the target in a state where gas is introduced while decompressing the inside of the chamber, and generating a discharge in a discharge region on the surface side of the target, A film forming step of forming a film on a predetermined number of the objects to be processed;
After the film forming step, a sputtering process comprising: a cleaning step for cleaning the surface of the target by expanding the discharge region by increasing the applied voltage while increasing the amount of the gas introduced compared to the film forming step. Membrane method.   The sputtering film forming method according to claim 1, wherein, in the cleaning step, the gas is sprayed onto the surface of the target.   The sputtering film forming method according to claim 1, wherein the film formation is performed while the object to be processed is conveyed.   The sputter deposition method according to any one of claims 1 to 3, wherein the predetermined number is decreased as the target becomes late in life. A method for manufacturing a photoelectric conversion device for manufacturing a photoelectric conversion device by sequentially forming a film on each of a plurality of objects to be processed,
Forming a photoelectric conversion layer on each of the plurality of objects to be processed;
Forming a transparent conductive film on each of the plurality of objects to be processed on which the photoelectric conversion layer has been formed by forming a target conductive film on the object to be processed in the chamber by sputtering using a magnetic field A process,
In the transparent conductive film forming step, a voltage is applied to the target while applying a magnetic field to the surface of the target in a state where a gas is introduced while decompressing the inside of the chamber, and a discharge region on the surface side of the target By forming a discharge at a predetermined number of the object to be processed,
After the film formation on the predetermined number of the objects to be processed in the course of the transparent conductive film formation step, the discharge region is widened by increasing the voltage applied while increasing the amount of the gas introduced than during film formation. A method for manufacturing a photoelectric conversion device, wherein the surface of the target is cleaned.   6. The method of manufacturing a photoelectric conversion device according to claim 5, wherein, in the transparent conductive film forming step, after the discharge region is widened and the surface of the target is cleaned, a film is further formed on a predetermined number of the objects to be processed.

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