CN108624854B

CN108624854B - Novel device and method for preparing thin film

Info

Publication number: CN108624854B
Application number: CN201810696065.2A
Authority: CN
Inventors: 韩伟丹
Original assignee: Shanghai Zuqiang Energy Co ltd
Current assignee: Shanghai Zuqiang Energy Co ltd
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2022-07-05
Anticipated expiration: 2038-06-29
Also published as: CN108624854A

Abstract

The invention relates to a device and a method for preparing a film. The apparatus for preparing a thin film includes: a sputtering chamber for generating a metal precursor; the evaporation chamber is used for plating the evaporated metal precursor onto a substrate to form a thin film; the substrate bearing device is positioned in the evaporation chamber and used for bearing the substrate; the sputtering chamber is communicated with the evaporation chamber, and the substrate bearing device faces the sputtering chamber. The novel device and the method for preparing the film are simple, convenient to operate, and capable of realizing target source component proportion control by combining the advantages of various methods such as a magnetron sputtering method and a co-evaporation method, so that the CIGS film which is more uniform in distribution and has better Ga gradient is obtained, the conversion efficiency of a battery is improved, the evaporation energy consumption in a single co-evaporation method is reduced, the utilization rate of materials is improved, and meanwhile, high-speed deposition coating can be realized.

Description

Novel device and method for preparing thin film

Technical Field

The invention relates to a film coating technology, in particular to a novel device and a novel method for preparing a film.

Background

Solar cells have been gradually and widely used in various fields as green energy. The solar cell can directly convert sunlight into electric energy, and the key point for realizing the process is a chalcopyrite structure consisting of four elements of Cu (copper), In (indium), Ga (gallium) and Se (selenium). 4 elements are plated on the substrate by using the existing plating technology to form a P-type structure film in a P-N junction of the solar cell.

The existing coating technologies are various and can be divided into non-vacuum coating and vacuum coating. At present, the most widely studied and prepared battery with high efficiency is vacuum plating, which comprises: magnetron sputtering, co-evaporation, and the like. Although the magnetron sputtering method can prepare a solar cell with higher efficiency, the uniformity of the distribution of each element in the sputtering process is poorer, and an alloy phase and a single phase are easy to generate, for example, when a CIGS solar cell is manufactured, most of target materials applied in the prior art are mixed target materials, such as ternary target CuInGa, binary target CuGa, CuIn, GaSe, InSe and the like, so that an ideal Ga gradient is not easy to form, and the forbidden bandwidth is reduced. The conversion efficiency of the solar cell prepared by the co-evaporation method is higher than that of magnetron sputtering, the efficiency of the cell prepared by a laboratory through the three-step co-evaporation method can reach 22.6%, but the components of an evaporation source need to be accurately controlled during film forming, so that the requirements on equipment are extremely high, the energy consumption is high, the proportional components are not easy to control, and the industrialization is not easy.

Disclosure of Invention

Aiming at the problems that an alloy phase and a single phase are easy to generate during film coating by a magnetron sputtering method, the proportional components of each component are not easy to control during film coating by an evaporation method and the like in the prior art, the invention provides a device for preparing a film, which comprises the following components: a sputtering chamber for generating a metal precursor; the evaporation chamber is used for plating the evaporated metal precursor onto a substrate to form a thin film; the substrate bearing device is positioned in the evaporation chamber and used for bearing the substrate; the sputtering chamber and the evaporation chamber can be communicated, and the substrate bearing device faces to the sputtering chamber.

The apparatus for manufacturing a thin film as described above, wherein a shielding layer is further included between the sputtering chamber and the evaporation chamber.

The apparatus for manufacturing a thin film as described above, wherein the shielding layer includes an opening, the substrate support apparatus facing the opening.

The apparatus for manufacturing a thin film as described above, wherein the sputtering chamber further comprises a sputtering device and an emission source, wherein the sputtering device receives sputtering from the emission source.

The apparatus for manufacturing a thin film as described above, wherein the sputtering apparatus is a rotating apparatus.

The apparatus for manufacturing a thin film as described above, wherein the rotating means further comprises: a rotating bracket which rotates along a rotating shaft; a substrate positioned on the rotating support and rotating along the rotating axis; and a local heating device proximate to the substrate; wherein the localized heating device does not rotate along the axis of rotation.

The apparatus for manufacturing a thin film as described above, wherein the rotating frame comprises a fixed portion and a rotating portion, wherein the local heating means is installed at the fixed portion.

The apparatus for manufacturing a thin film as described above, wherein the evaporation chamber further comprises: a heating source configured to heat a substrate on the substrate carrier; and a thermocouple configured to monitor a temperature of the substrate.

The apparatus for preparing a thin film as described above, wherein the heating source is adjacent to the substrate holder and spaced apart from the substrate holder.

The apparatus for manufacturing a thin film as described above, wherein the thermocouple is located on the heating source or the substrate supporter.

A method of making a film comprising: plating a metal precursor on the substrate in a sputtering chamber; and within a vaporization chamber, the metal precursor plates to a substrate within the vaporization chamber. Wherein the sputtering chamber and the evaporation chamber are communicable.

The method as described above, further comprising: the sputtering chamber and the evaporation chamber are subjected to vacuum treatment.

The method as described above, further comprising: the evaporation chamber is filled with a metal atmosphere.

The method as described above, wherein the plating the metal precursor comprises sputtering multiple emitter source targets directly onto the substrate at the same time.

The method as described above, wherein the plating metal precursor comprises sputtering one or more emitter targets onto the substrate at different times to form different metal precursors.

The method as described above, further comprising rotating the substrate in front of the base plate.

The method as described above, wherein plating the metal precursor to the base plate within the evaporation chamber comprises evaporating the metal precursor from the heated substrate or a portion of the substrate.

The method as above, wherein the heating the substrate or a portion of the substrate to vaporize the metal precursor comprises: at a first temperature T₁Evaporating In and Ga; at a second temperature T₂Evaporating Cu to form a copper-rich phase; at a third temperature T₃The temperature evaporates In and Ga, forming a copper depleted phase.

The method as described above, wherein at the first temperature T₁A second temperature T₂And a third temperature T₃The evaporation step includes selenium plating.

The method for manufacturing a thin film in the apparatus for manufacturing a thin film as described in any one of the above, comprising: plating a metal precursor by a sputtering method; and plating the metal precursor onto a substrate using an evaporation method.

The novel device and the method for preparing the film are simple in device and convenient to operate, combine the advantages of various methods such as a magnetron sputtering method and a co-evaporation method, and the like, the target material required by the next step of evaporation can be separated by preparing the metal precursor through the sputtering method, so that the metal target material can be heated and evaporated independently, the control of the target source component proportion is realized, the CIGS film which is distributed more uniformly and has better Ga gradient is obtained, the conversion efficiency of a battery is improved, the evaporation energy consumption in the single co-evaporation method is reduced, the utilization rate of the material is improved, and meanwhile, the high-speed deposition film coating can be realized.

Drawings

Preferred embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of a hybrid sputter-evaporation apparatus according to one embodiment of the present invention; and

fig. 2 is a flow diagram of a hybrid sputter-evaporation method according to one embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof and in which is shown by way of illustration specific embodiments of the application. In the drawings, like numerals describe substantially similar components throughout the different views. Various specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to practice the teachings of the present application. It is to be understood that other embodiments may be utilized and structural, logical or electrical changes may be made to the embodiments of the present application.

The invention comprises a novel device for preparing the film, which combines the advantages of various coating methods, does not limit the form of the target material in pure metal, alloy or compound, and does not limit the phase state of the target material, namely solid state, liquid state and gaseous state. According to a preferred embodiment of the present invention, as shown in fig. 1, a magnetron sputtering device can be combined with a co-evaporation device, the magnetron sputtering device is modified, a vacuum evaporation device is introduced, and the two device coating methods are combined to complete coating.

Fig. 1 is a schematic view of a hybrid sputter-evaporation apparatus according to one embodiment of the present invention. As shown, the apparatus 100 includes two chambers, a sputtering chamber 110 and an evaporation chamber 120. The evaporation chamber 120 includes a substrate carrier (124). The substrate carrier 124 is used for carrying the substrate 121 and holding the substrate 121 at one side of the evaporation chamber 120. As shown, the evaporation chamber is in communication with the interior of the sputtering chamber. Thereby, the metal vapor in the sputtering chamber can move from the sputtering chamber 110 to the evaporation chamber 120 without hindrance, and is deposited on the substrate 121, completing the plating.

It should be noted that the evaporation chamber 120 and the sputtering chamber 110 are named herein only as a convenience to distinguish the features of the apparatus of the present invention in the schematic view, and the function of each part of the compartments is not strictly shown. For example, the sputtering chamber 110 is used to generate a metal precursor. In the sputtering chamber 110, a metal precursor may be produced by a sputtering method or a metal precursor may be formed by a co-evaporation method. Similarly, the evaporation chamber 120 may be coated by sputtering.

According to one embodiment of the present invention, an aperture structure may be provided on the wall 140 between the evaporation chamber 120 and the sputtering chamber 110 for drawing vacuum and filling gas. According to an embodiment of the present invention, only one hole may be provided to achieve the above-described functions, or a plurality of holes may be provided to achieve different functions, respectively. According to one embodiment of the present invention, the hole for filling gas is preferably provided at one side of the evaporation chamber 120.

According to one embodiment of the present invention, a shield layer 130 may be included between the sputtering chamber 110 and the evaporation chamber 120. The shielding layer 130 can block the free flow of gas in the chambers on both sides, thereby reducing cross contamination and improving the sputtering quality and efficiency. For example, the evaporation chamber 120 is filled with gaseous selenium, which may diffuse freely into the sputtering chamber 110. The shielding layer 130 may prevent the gaseous selenium from diffusing into the sputtering chamber 110 to interact with the metal emission source 112 therein, and prevent contamination of the metal emission source 112. According to an embodiment of the present invention, the shielding layer 130 includes a hole 1301 in the middle thereof, which can communicate the sputtering chamber 110 and the evaporation chamber 120, so that the metal emission source 112 in the sputtering chamber 120 can be sputtered onto the substrate 121 disposed in the evaporation chamber 120 through the hole 1301. Meanwhile, because the magnetron sputtering method and the co-evaporation method both need to complete coating in a vacuum environment, two chambers need to be vacuumized before coating. The holes 1301 are arranged to simultaneously evacuate both chambers.

According to an embodiment of the present invention, the shielding layer 130 can be an openable door structure, and the separation or communication between the two chambers can be adjusted according to the requirement of the coating process. According to an embodiment of the present invention, if the conditions such as the gas concentrations in the sputtering chamber 110 and the evaporation chamber 120 are controlled so that the flows of the vapor in the two chambers are reduced, the shielding layer 130 may not be provided.

According to one embodiment of the present invention, the sputtering chamber 110 includes a sputtering apparatus and an emission source. The sputtering device is used for receiving sputtering from an emission source. According to one embodiment of the present invention, the sputtering apparatus may be a rotating apparatus 111. It will be appreciated by those skilled in the art that a rotary apparatus is a preferred embodiment of the present invention since the efficiency of producing thin films can be improved. The solution according to the invention can also be implemented in the non-rotating case.

As shown, the rotating device 111 further comprises a rotating bracket (not shown) which can rotate along the rotation axis of the center line thereof, and the rotating direction can be counterclockwise or clockwise. For convenience of description, its operating state is described with its clockwise rotation. According to an embodiment of the present invention, a rotation shaft may be included at a center line position of the rotation bracket to rotate about the rotation shaft. According to another embodiment of the present invention, rails are provided at both ends of the rotating bracket, and the rotating means 111 is rotated in situ along the center line thereof on the rails. The above two rotating means rotating manners are only two embodiments of the present invention, and it should be understood by those skilled in the art that the rotating means rotating manners are not limited to the above two, and other similar manners that the rotating means can be fixed and rotated in place are within the scope of the present invention.

According to one embodiment of the present invention, the rotating support is coated with a substrate (shown as substrate 111 on the surface) that acts as a sputtering device that receives sputtering from a metal emitter 112. According to one embodiment of the invention, the substrate may be composed of graphite. According to one embodiment of the invention, the substrate may also be a smooth surfaced silicide or a mixture. The substrate can be a continuous cylindrical base or a rectangular graphite plate, and is assembled and spliced on the surface of the rotating bracket. According to one embodiment of the present invention, the substrate may also be a base that ultimately requires a coating.

As shown, the rotating device 111 includes a local heating device 1111 and a thermocouple (not shown) provided at a side close to the evaporation chamber 120. The thermocouple is configured to monitor the temperature of the heated portion of the substrate by the local heating device 1111. According to an embodiment of the invention, the local heating device 1111 may be a resistor with a suitable resistance. According to one embodiment of the present invention, one or more local heating units 1111 may be included to facilitate temperature control while allowing uniform heating of the substrate near one side of the evaporation chamber 120. One or more local heating units 1111 are disposed inside the rotating unit 111 at a side close to the substrate 121. According to one embodiment of the invention, the rotating means 111 comprises a stationary part and a rotating part. The local heating unit 1111 is fixed to the fixed portion of the rotating unit 111 and does not rotate with the rotating unit 111. When the rotating device 111 rotates to plate a metal target of a certain emission source in front of the local heating device 1111, the local heating device 1111 only heats the metal target in front of the local heating device 1111, so as to evaporate and plate the metal target to the substrate 121. When the rotating device 111 rotates to plate another metal target of the emission source in front of the local heating device 1111, the local heating device 1111 starts to heat the metal target again to evaporate the metal target. By adopting the design, different targets can be evaporated and plated on the substrate 121 respectively, and a film containing a proper amount of certain substances can be obtained by controlling the thickness of a film layer to be plated in combination with a thermocouple for monitoring the temperature of the substrate 121. For example, when a CIGS solar cell is manufactured, an ideal Ga gradient can be formed by controlling the evaporation amount of gallium, so that the forbidden bandwidth is increased, and the solar cell with higher efficiency is obtained.

According to an embodiment of the present invention, wherein the center line of the rotating means 111, the local heating means 1111, the hole 1301 and the center of the substrate 121 are positioned on the same horizontal plane.

According to one embodiment of the present invention, the sputtering chamber 110 includes an emission source 1121-1123 therein. According to one embodiment of the invention, different emission sources can be selected according to the film layer to be plated, and the emission sources can be metal simple substances, alloys, metal compounds and the like. According to one embodiment of the invention, all the emission sources can use pure metal target materials, so that the pollution to the sample is reduced, and the quality of finished products is improved. According to an embodiment of the present invention, a plurality of emission sources may be disposed at different positions relative to the rotating device 111, such as three

emission sources

1121 and 1123 disposed above, right and below the rotating device 111. It should be noted that the terms "up", "down", "left", "right", and the like are merely relative terms, and are not intended to limit the direction of the present invention and the direction when it is used. Each group of

emission sources

1121 and 1123 respectively faces the rotating device 111. According to one embodiment of the invention, the above is designed so as to sputter different emission sources onto the substrate at the same time.

According to an embodiment of the present invention, a plurality of sets of emission sources can be disposed at each of the emission source positions 1121-1123, and a sputtering film is simultaneously deposited on the substrate on the rotating device 111, so as to achieve a rapid film deposition. According to an embodiment of the present invention, a plurality of emission sources may be simultaneously disposed at the positions of the emission sources 1122 without disposing the rotating device 111, and the substrate may be directly coated with a film by a sputtering method.

A substrate carrier 124 is disposed in the evaporation chamber 120, and is fixed in the evaporation chamber 120 to carry and fix the substrate 121 toward the sputtering chamber 110. According to one embodiment of the present invention, the substrate carrier 124 may be a robot, a support structure, or the like. According to the embodiment of the present invention, any device capable of carrying and fixing the substrate 121 may be used as the substrate carrying device 124.

The evaporation chamber 120 is provided therein with a heating source 122 in addition to a substrate carrier 124. According to an embodiment of the present invention, the heating source 122 may be a resistor with a suitable resistance, and the temperature of the heating source 122 is further adjusted by changing the voltage and the current. The substrate 121 is disposed on the substrate carrier 124. The substrate 121 is formed into a final desired product, and a side thereof to be coated is faced to the hole rotating unit 111 and the local heating unit 1111, so that the metal precursor thereon is evaporated to the substrate 121 using the local heating unit. The heating source 122 is disposed on the other side of the substrate 121, and is used for heating the substrate 121 and controlling the temperature of the substrate 121. Between the heat source 122 and the substrate 121, there is a thermocouple 1221, which is present simultaneously with the heat source 122, for monitoring the temperature of the substrate 121, from which the amount of film plated thereon can be further estimated.

According to one embodiment of the present invention, the evaporation chamber 120 is filled with a gaseous element so that the co-evaporation coating is performed under an atmosphere. Different atmospheres are set according to different coating films. According to one embodiment of the present invention, the evaporation chamber is filled with gaseous Se (selenium) 123, and the co-evaporation coating is performed in a selenium atmosphere. According to an embodiment of the present invention, it is also possible to arrange the evaporation chamber to be gaseous Na (sodium), or a mixture of gaseous Se and gaseous Na. The above is only the case according to one embodiment of the present invention, and the evaporation chamber 120 may be any gaseous substance according to different coating requirements.

Fig. 2 is a flow diagram of a hybrid sputter-evaporation method according to one embodiment of the present invention. Taking the example of coating the absorption layer of a CIGS thin film solar cell, the substrate is already coated with a back electrode layer. As shown in the figure, in step 201, the substrate is mounted such that the back electrode layer faces the direction of the rotation device 111; and installing a transmitting source. According to one embodiment of the present invention, the emission source uses three pure metal targets, i.e., Cu, In, Ga with a purity of 99.999%, respectively placed on the top, right and bottom of the rotating device. Here, the use of the emission source in the present apparatus is not limited, and any target usable in the original apparatus may be used in the present apparatus. In addition, the positions of Cu, In and Ga are not limited to the positions set In the embodiment, and the positions and the sequence may be set arbitrarily, as long as the three emission sources are oriented In different directions of the rotating device. According to one embodiment of the present invention, multiple targets may be provided at each source position.

In step 202, a coating environment needs to be prepared. The thin film fabrication apparatus is evacuated and the evaporation chamber 120 is filled with gaseous selenium. According to one embodiment of the invention, the device is connected to a vacuum extraction device, which can be directly evacuated. The connection position is not shown in the figure, and may be any position that does not affect the occurrence of sputtering and evaporation. According to one embodiment of the invention, the location of the connection to the vacuum extractor may be to the left of the heating source 122.

In step 203, a metal precursor is prepared by magnetron sputtering. In the sputtering chamber, a metal emission source is sputtered onto the substrate by magnetron sputtering to form a metal precursor. According to one embodiment of the present invention, the plurality of sets of metal emission sources may be sputtered at the same time or may be sputtered one by one. The position of the metal emission source sputtering can be adjusted according to the requirement of the next preparation through a rotating device. The substrate may also serve as a base for the final coating. According to one embodiment of the invention, when the substrate is a base of the final coating, each group of emission sources can be provided with various metal targets, and the coating time is saved by sputtering coating at the same time.

In step 204, the metal precursor is plated onto the substrate by a co-evaporation method. The substrate here serves as the base for the final coating. By rotating the rotating device, the corresponding metal precursor is placed between the local heating device and the substrate. The local heating device is heated to a suitable temperature to respectively evaporate the different metal precursors sputtered on the substrate, so that the different metal precursors are plated on the surface of the substrate 121. According to one embodiment of the present invention, the evaporation coating is achieved by a three-step co-evaporation method. In the coating process, the heating source heats the base plate, and the temperature of the base plate is controlled to be lower than the temperature of the evaporated substrate, but the temperature difference is not large. In the first stepHeating one surface of the precursor with In and Ga to a temperature T before rotating the surface to a local heating device₁About 300 ℃ and 400 ℃ to evaporate In and Ga. Here, the order of evaporating In and Ga is not limited, and two precursors may be evaporated at the same time and plated on the substrate surface at the same time as Se In the evaporation chamber. Films containing various metal targets in different proportions can also be prepared by adjusting the evaporation temperature and time. In a second step, one side of the rotating device containing the precursor of Cu is rotated to a local heating device and is directed to the substrate to be heated to a temperature T₂About 450 ℃ and 600 ℃, and evaporating Cu vapor to plate Cu. According to an embodiment of the present invention, the temperature of the substrate 121 is detected by the thermocouple 1221, the amount of plated Cu is determined, and the film is controlled to be in a copper-rich state. In this step, Se is also plated on the substrate surface together with the gaseous Cu. In a third step, the first step is repeated, i.e. one side of the precursor with In and Ga is heated to the temperature T before the local heating device is rotated to one side of the precursor with In and Ga respectively₃About 400 ℃ and 600 ℃ to evaporate In and Ga. By monitoring the temperature of the substrate 121, the film was controlled to be in a copper depleted state. According to one embodiment of the invention, solar cells with copper-poor state CIGS films have higher conversion efficiencies. The copper-rich and copper-depleted states are referred to herein as the ratio of the Cu content of the film to the total amount of Ga and In. The copper-rich state is defined as the state with the ratio larger than 1, and the copper-poor state is defined as the state with the ratio smaller than 1.

Step 204 may be performed simultaneously with step 203, according to an embodiment of the present invention. Therefore, the coating time can be greatly saved, and the utilization rate of equipment is improved. Meanwhile, according to solar cells with different CIGS layers required by different regions, preset parameters can be adjusted to rapidly manufacture different CIGS layers.

The above is only one embodiment of the device of the present invention for plating the CIGS layer of a CIGS solar cell. According to one embodiment of the invention, the device and the method can also be applied to plating other film layers, such as other layers of solar cells. According to one embodiment of the present invention, the apparatus and method of the present invention is not limited to only plating CIGS thin film solar cells.

The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the scope of the present invention, and therefore, all equivalent technical solutions should fall within the scope of the present invention.

Claims

1. An apparatus for preparing a thin film, comprising:

a sputtering chamber for generating a metal precursor;

the evaporation chamber is used for plating the evaporated metal precursor onto a substrate to form a thin film;

the substrate bearing device is positioned in the evaporation chamber and used for bearing the substrate;

the sputtering chamber can be communicated with the evaporation chamber, and the substrate bearing device faces the sputtering chamber; a shielding layer is also arranged between the sputtering chamber and the evaporation chamber; the shielding layer comprises an opening, and the substrate bearing device faces the opening; the sputtering chamber further comprises a sputtering device and an emission source, wherein the sputtering device receives sputtering from the emission source, and the emission source comprises different emission sources located at different positions; the sputtering device is a rotating device; the rotating device further includes: a rotating bracket which rotates along a rotating shaft; a substrate positioned on the rotating support and rotating along the rotating axis; and a local heating device proximate to the substrate; the local heating device does not rotate along the rotating shaft; the rotating bracket comprises a fixed part and a rotating part, wherein the local heating device is arranged on the fixed part; the evaporation chamber further comprises: a heating source configured to heat a substrate on the substrate carrier; and a thermocouple configured to monitor a temperature of the substrate; wherein the heating source is close to the substrate bearing device and is spaced from the substrate bearing device; wherein the thermocouple is located on the heating source or on the substrate carrier.

2. A method of making a film comprising: plating a metal precursor on the substrate in a sputtering chamber; and within a vaporization chamber, the metal precursor plating to a substrate within the vaporization chamber; the sputtering chamber and the evaporation chamber are communicated; further comprising: carrying out vacuum treatment on the sputtering chamber and the evaporation chamber; wherein further comprising: filling a metal atmosphere in the evaporation chamber; the plating metal precursor comprises the step of directly sputtering a plurality of emission source targets onto the substrate at the same time; the plating metal precursor comprises sputtering one or more emission source targets on the substrate at different time to form different metal precursors; further comprising rotating the substrate in front of the base plate; plating the metal precursor to a substrate within the evaporation chamber comprises heating the substrate or a portion of the substrate to evaporate the metal precursor; the heating the substrate or a portion of the substrate to vaporize the metal precursor comprises: evaporating In and Ga at a first temperature T1; evaporating Cu at a second temperature T2 to form a copper rich phase; evaporating In and Ga at a third temperature T3 to form a copper depleted phase; the selenium plating step is included when the first temperature T1, the second temperature T2 and the third temperature T3 are evaporated; the method comprises the following steps: plating a metal precursor by a sputtering method; and plating the metal precursor onto a substrate using an evaporation method.