阅读说明：本技术 薄膜蒸镀方法 (Film evaporation method ) 是由 刘宇 于 2018-07-04 设计创作，主要内容包括：本发明提供一种薄膜蒸镀方法,包括以下步骤：S1：在薄膜蒸镀装置中,将多个不同组分的靶材沿第一方向设置；S2：使衬底与所述靶材在所述第一方向上发生相对运动的同时使所述靶材蒸发,在所述衬底上沉积形成薄膜。(The invention provides a film evaporation method, which comprises the following steps: s1: in a film evaporation device, a plurality of targets with different components are arranged along a first direction; s2: and evaporating the target while the substrate and the target move relatively in the first direction, and depositing to form a film on the substrate.)

1. A film evaporation method is characterized by comprising the following steps:

s1: in a film evaporation device, a plurality of targets with different components are arranged along a first direction;

s2: and evaporating the target while the substrate and the target move relatively in the first direction, and depositing to form a film on the substrate.

2. A thin film evaporation method according to claim 1, wherein the plurality of targets of different compositions includes a first alloy target, a second alloy target, and a third alloy target arranged in this order along the first direction,

the composition of the first alloy target material comprises Cu_(0.01～1.0)In_(0.01～1.0)Ga_(0.01～1.0)Se_(0.01～3.0)；

The composition of the second alloy target material comprises Cu_(0.01～2.0)In_(0～1.0)Ga_(0～1.0)Se_(0.01～3.0)；

The composition of the third alloy target material comprises Cu_(0.01～2.0)In_(0.01～1.5)Ga_(0.01～1.0)Se_(0.01～3.0)。

3. The method of claim 2, wherein the first alloy target, the second alloy target and the third alloy target are sequentially and respectively made of Cu_0.1In_0.3Ga_1.0Se_0.5、Cu_2.0Se_0.5、Cu_0.1In_0.5Ga_1.0Se_0.5。

4. A method as recited in claim 1, wherein said plurality of different composition targets further comprises a buffer layer target disposed at a distal end of said plurality of different composition targets along said first direction.

5. The method of claim 4, wherein the buffer layer target is GdS target.

6. The method as claimed in claim 4, further comprising feeding H into said thin film deposition apparatus while performing said step S2₂And S, gas, wherein the buffer layer target is a Cd target.

7. The method of claim 1, wherein the evaporation temperature of the target is 500-1100 ℃.

8. The method according to claim 1, wherein step S2 comprises heating the plurality of compositionally different targets uniformly to a same temperature.

9. A method according to claim 1, wherein each target has a length in the first direction of 1m-5m, and the relative motion speed of the target and the substrate is less than or equal to 3 m/min.

10. The method of claim 9, wherein the target is spaced from the substrate by a distance of 5mm to 50 mm.

11. A method as claimed in claim 1, wherein step S2 comprises receiving the substrate by a substrate carrier and driving the substrate to move along a first direction.

12. The method according to claim 11, wherein the step S1 includes fixing the targets with different compositions on a same target fixing device along the first direction, the target fixing device having a cylindrical sidewall for fixing the targets, the first direction being a circumferential direction of the cylindrical sidewall, and the substrate supporting device being sleeved outside the target fixing device and having an arc-shaped supporting surface coaxially disposed with the cylindrical sidewall for supporting the substrate.

13. The method according to claim 11, wherein step S1 includes fixing the targets with different compositions along the first direction on a same target fixing device, wherein the target fixing device is flat, and the substrate holder has a flat carrying surface for carrying the substrate.

Technical Field

The invention relates to the field of film preparation, in particular to a film evaporation method.

Background

Copper indium selenide (CuInSe)₂CIS for short or CuInGaSe (CuIn)_xGa_1-xSe₂CIGS for short) thin-film solar cells are one of the research hotspots of solar cell materials in various countries because the thin-film solar cells have high photoelectric conversion efficiency, relatively low manufacturing cost, stable performance, no light-induced decay and lower price than the traditional crystalline silicon cells.

The CIGS thin-film solar cell mainly comprises a glass substrate, a molybdenum (Mo) back electrode, a CIGS absorption layer, a buffer layer, a window layer, an antireflection layer and an aluminum electrode, wherein the CIGS absorption layer is a core material in the solar cell, and one of key technologies for preparing the efficient CIGS thin-film solar cell is to obtain a high-quality absorption layer, namely a CIGS thin film. The preparation methods of the CIGS thin film are various, and the main preparation methods can be roughly classified into a vacuum preparation technology and a non-vacuum preparation technology. The vacuum preparation process mainly comprises a multi-source co-evaporation technology, a sputtering technology, a molecular beam epitaxy technology, a chemical vapor deposition technology and the like; and non-vacuum fabrication techniques include electrodeposition, spin coating, and screen printing. Although the preparation methods of the CIGS thin film are various, only the multisource co-evaporation technology and the selenization after sputtering are used for preparing the CIGS solar cell with high efficiency. Both evaporation and sputtering methods of preparation are used in japan, usa and germany, both in the laboratory and in the production line.

When a small-area CIGS thin film solar cell is prepared in a laboratory, the CIGS thin film deposited by the co-evaporation method has good quality and high cell efficiency, but the evaporation method cannot accurately control the element proportion, has poor repeatability and low material utilization rate, and is difficult to realize large-area uniform and stable film formation, so the application of the CIGS thin film solar cell in large-scale industrial production is limited.

Chinese patent application 200910089397.5 generated plasma around the selenium evaporation crucible in a direct current manner to ionize the selenium vapor, and the copper indium gallium was evaporated separately to deposit the CIGS film. The preparation method realizes the preparation of the CIGS thin film with large area by adopting a multi-element co-evaporation method. However, in this way, the copper indium gallium pre-fabricated layer is taken out of the vacuum chamber at risk of oxidation of the copper indium gallium, and in particular, the complete CIGS absorber layer deposited on the substrate must be taken out of the vacuum chamber several times at risk of oxidation of the respective evaporated layers. Moreover, this risk is not easily ruled out. Therefore, it is necessary to provide an evaporation method capable of effectively preventing the CIGS thin film from being oxidized during the evaporation process.

Disclosure of Invention

In view of the above, it is necessary to provide a thin film evaporation method for solving the problem that the CIGS thin film is easily oxidized during the evaporation process.

A film evaporation method comprises the following steps:

s1: in a film evaporation device, a plurality of targets with different components are arranged along a first direction;

s2: and evaporating the target while the substrate and the target move relatively in the first direction, and depositing to form a film on the substrate.

In one embodiment, the plurality of targets of different compositions includes a first alloy target, a second alloy target and a third alloy target arranged in sequence along the first direction,

the composition of the first alloy target material comprises Cu_(0.01～1.0)In_(0.01～1.0)Ga_(0.01～1.0)Se_(0.01～3.0)；

The composition of the second alloy target material comprises Cu_(0.01～2.0)In_(0～1.0)Ga_(0～1.0)Se_(0.01～3.0)；

The composition of the third alloy target material comprises Cu_(0.01～2.0)In_(0.01～1.5)Ga_(0.01～1.0)Se_(0.01～3.0)。

In one embodiment, the first alloy target, the second alloy target and the third alloy target respectively have the compositions of Cu in sequence_0.1In_0.3Ga_1.0Se_0.5、Cu_2.0Se_0.5、Cu_0.1In_0.5Ga_1.0Se_0.5。

In one embodiment, the plurality of different composition targets further includes a buffer layer target disposed at an end of the plurality of different composition targets along the first direction.

In one embodiment, the buffer layer target is an GdS target.

In one embodiment, the method further includes feeding H into the thin film evaporation apparatus while performing the step S2₂And S, gas, wherein the buffer layer target is a Cd target.

In one embodiment, the evaporation temperature of the target material is 500-1100 ℃.

In one embodiment, the step S2 includes heating the plurality of compositionally different targets to the same temperature.

In one embodiment, each target has a length in the first direction of 1m to 5m, and the relative motion of the target and the substrate has a velocity of less than or equal to 3 m/min.

In one embodiment, the target is spaced from the substrate by 5mm to 50 mm.

In one embodiment, the step S2 includes receiving the substrate by a substrate carrier and moving the substrate along a first direction.

In one embodiment, the step S1 includes fixing the targets with different compositions on the same target fixing device along the first direction, where the target fixing device has a cylindrical sidewall for fixing the targets, the first direction is a circumferential direction of the cylindrical sidewall, and the substrate supporting device is sleeved outside the target fixing device and has an arc-shaped supporting surface coaxially disposed with the cylindrical sidewall for supporting the substrate.

In one embodiment, the step S1 includes fixedly disposing the plurality of targets with different compositions on the same target fixing device along the first direction, where the target fixing device is a flat plate, and the substrate supporting device has a flat supporting surface for supporting the substrate.

According to the film evaporation method, the plurality of targets with different components are arranged along the first direction, and then the substrate and the targets are relatively displaced in the first direction, so that the materials of the plurality of targets are sequentially evaporated on the substrate to directly form the plurality of coating layers.

Drawings

FIG. 1 is a flow chart of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a thin film deposition apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic view of a heating device arrangement according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a thin film deposition apparatus according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of an annular thin film evaporation apparatus according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the thin film deposition apparatus and the thin film deposition method of the present invention will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only. The various objects of the drawings are drawn to scale for ease of illustration and not to scale for actual components.

Referring to fig. 1, an embodiment of the present invention further provides a thin film evaporation method, including the following steps:

s1: in a film evaporation device, a plurality of targets with different components are arranged along a first direction;

s2: and evaporating the target while the substrate and the target move relatively in the first direction, and depositing to form a film on the substrate.

According to the film evaporation method, the plurality of targets with different components are arranged along the first direction, and then the substrate and the targets are relatively displaced in the first direction, so that the materials of the plurality of targets are sequentially evaporated on the substrate to directly form the plurality of coating layers.

Referring to fig. 2, in a preferred embodiment, the target 300 comprises a CIGS target, preferably at least three alloy targets, corresponding to reference numerals 301, 302 and 303 in fig. 1 and 3, respectively, the composition of each of the three alloy targets preferably being: target material 301: cu_(0.01～1.0)In_(0.01～1.0)Ga_(0.01～1.0)Se_(0.01～3.0)；

Target 302: cu_(0.01～2.0)In_(0～1.0)Ga_(0～1.0)Se_(0.01～3.0)；

Target material 303: cu_(0.01～2.0)In_(0.01～1.5)Ga_(0.01～1.0)Se_(0.01～3.0)。

The CIGS target is used for preparing a CIGS thin film with a multilayer structure. Compared with the traditional solar cell with a single CIGS film layer, the solar cell with the CIGS film with the multilayer structure can have larger open-circuit voltage and short-circuit current, so that the photoelectric conversion efficiency of the CIGS film solar cell is improved to a great extent.

More preferably, the 3 targets 300 respectively have the following compositions:

target material 301: cu_(0.01～0.5)In_(0.01～0.5)Ga_(0.5～1.0)Se_(0.01～3.0)；

Target 302: cu_(1.0～2.0)In_(0～0.5)Ga_(0～0.5)Se_(0.01～3.0)；

Target material 303: cu_(0.01～0.5)In_(0.5～1.5)Ga_(0.5～1.0)Se_(0.01～3.0)。

The content and the distribution of Cu, Ga and In elements In the CIGS thin film are controlled by adjusting the content of Cu, Ga and In elements In each alloy target In the CIGS target, so that the energy band gap of a first thin film layer of the CIGS thin film evaporated by the CIGS target ranges from 1.3eV to 1.5eV, the energy band gap of a second thin film layer ranges from 0.9eV to 1.1eV, the energy band gap of a third thin film layer ranges from 1.1eV to 1.3eV, and the energy band gaps of three thin film layers stacked In the CIGS thin film prepared by the alloy material group are In double-band-gap gradient distribution In the thickness direction of the thin film. The open-circuit voltage and short-circuit current and conversion efficiency of a solar cell prepared by using the CIGS thin film are effectively improved.

In a preferred embodiment, the target 302 does not contain In element, and the In element In the second thin film layer of the CIGS thin film may be provided by diffusion of the In element evaporated from the target 301 and/or the target 303 In the thin film preparation apparatus, or by a separate In source material provided In the thin film evaporation apparatus (preferably, the amount of the separate In source is controlled so that the In content In the second thin film layer of the CIGS thin film is small). In another preferred embodiment, the target 302 does not contain Ga, the second thin film layer of the CIGS thin film does not contain Ga, or contains a small amount of Ga, and when the second thin film layer of the CIGS thin film contains Ga, the Ga may be provided by diffusion of Ga evaporated from the target 301 and/or the target 303 in the thin film evaporation apparatus, or by a separately-present Ga source material in the thin film preparation apparatus (preferably, the amount of the separately-present Ga source is controlled so that the Ga content in the second thin film layer of the CIGS thin film is small). By not including In and/or Ga elements In the target 302, more Cu and Se elements can be contained In the second thin film layer of the CIGS thin film, so that the surface of the second thin film layer of the CIGS thin film is In a copper-rich state.

In order to provide a CIGS thin film with a graded double band gap distribution, it is preferable that the target 301 provides a majority (e.g., 90% or more) of In and Ga elements (and may further provide a large amount of Se element), the target 302 provides a majority of Cu elements In the CIGS thin film, the target 303 provides the remaining Cu, In and Ga elements In the CIGS thin film (and may further provide the remaining Se element) and fine-tunes the element ratio on the surface of the CIGS thin film, and the third thin film layer of the CIGS thin film is slightly In-rich and the total amount of the elements In the CIGS thin film is In a preset ratio. Preferred CIGS thin film assemblies are CuIn_0.7Ga_0.3Se₂。

More preferably, the composition of the target 301 is Cu_0.1In_0.3Ga_1.0Se_0.5(ii) a The composition of the target 302 is Cu_2.0Se_0.5(ii) a The composition of the target material 303 is Cu_0.1In_0.5Ga_1.0Se_0.5. Accordingly, the target 301 is used for providing a thin film layer with an energy band gap of 1.4eV, the target 302 is used for providing a thin film layer with an energy band gap of 1.0eV, and the target 303 is used for providing a thin film layer with an energy band gap of 1.2 eV.

In one embodiment, the target 301 further includes an alkali metal element, and preferably, the alkali metal element included in the target 301 exists in the form of an alkali metal simple substance or an alkali metal compound, for example, may exist in the form of metal chloride such as NaF, KF, and the like. The alkali metal element is doped in the target material, so that the crystal structure in the CIGS thin film can be effectively optimized, and the thin film has a preferred orientation in a (112) direction. In addition, the cell prepared by using the CIGS thin film doped with the alkali metal element has higher open-circuit voltage and further has higher photoelectric conversion efficiency.

In another embodiment, the target material 303 further includes an alkali metal element, and preferably, the alkali metal element included in the target material 303 exists in the form of an alkali metal simple substance or an alkali metal compound, for example, it may exist in the form of NaF, KF, or the like, and the effect is substantially the same as the effect of the alkali metal element in the target material 301.

In one embodiment, the alkali metal doping may be performed only on the target 301 or the target 303, or both, and the content of the alkali metal element in the target 301 and/or the target 303 may be adjusted according to the actual performance requirements of CIGS. Preferably, the mass fraction of the alkali metal element in the target 301 or the target 303 is 0.01% to 0.1%, and the doping amount is such that the prepared CIGS thin film has a better open-circuit voltage.

In a preferred embodiment, the purity of the target 301, 302 and/or 303 is greater than or equal to 99.99% to ensure uniformity of the prepared CIGS thin film and uniformity of composition throughout the CIGS thin film. The purity refers to that the mass ratio of other components except the mentioned components in the target material is less than 0.01 percent. The high-purity CIGS target can ensure that the impurities in the prepared CIGS thin film are less, and the performance stability of the CIGS thin film is ensured, so that the photoelectric conversion efficiency of the thin-film solar cell prepared from the CIGS thin film is improved.

In order to vary the content of each element in the obtained CIGS thin film at different thickness positions of the CIGS thin film, and even separate at least three thin film layers with different components, the lengths of the target 301, the target 302, and the target 303 in the first direction may be in the order of meters, for example, each target has a length of 1 meter (m) to 5 m. The widths of the targets 301, 302, and 303 may be substantially the same.

Preferably, the length of the target 301 is greater than the length of the targets 302 and 303, respectively. The target 301 is used to provide most (e.g., 90% or more) of the In and Ga elements (and also provide most of the Se element) In the CIGS thin film, and by setting the length of the target 301 longer, the target 301 can be used to provide enough In, Ga, and Se elements without adjusting the movement rate of the substrate. Correspondingly, the thickness of the first thin film layer of the prepared CIGS thin film is larger than that of the second thin film layer and the third thin film layer.

At the same temperature, the evaporation rates of the elements Cu, In, Ga and Se are not consistent, so that the partial pressures of the vapor formed In the evaporation chamber by the elements Cu, In, Ga and Se are not consistent, and therefore, the compositions of the finally formed first thin film layer, second thin film layer and third thin film layer are not completely consistent with the compositions of the target 301, the target 302 and the target 303. In addition, since the target material is heated and evaporated, and then diffused in a certain range in the thin film evaporation device, the components of the first thin film layer, the second thin film layer, and the third thin film layer in the CIGS thin film do not completely correspond to the corresponding target materials 301, 302, and 303. In consideration of the characteristics which are not completely corresponding but are mutually related, the embodiment of the invention controls the content of elements in the three alloy targets in a proper range to enable the obtained three-layer film to have a perfect composition, and preferably realizes the gradient distribution of double band gaps.

Referring to fig. 4, the target 300 preferably further includes a buffer layer target 304 as a last target disposed at the end of the plurality of targets of different compositions along the first direction. After the evaporation of the CIGS thin film is finished on the substrate, the buffer layer can be continuously evaporated under the condition of not taking out a sample, and the oxidation of the CIGS thin film on the substrate is further prevented. Preferably, the composition of the buffer layer target 304 is solid sulfide, and specifically, the composition of the buffer layer target 304 is CdS. In another preferred embodiment, the thin film evaporation apparatus further comprises H₂S gasA feeding device, wherein the buffer layer target material can react with H₂S gas generates a metal target of a sulfide layer at high temperature, preferably a Cd target, and H gas generates a metal target of a sulfide layer at high temperature₂The S gas introducing device can introduce H into the film evaporation device in the evaporation process₂Cd steam and H formed by thermal evaporation of S gas₂And reacting the S gas to generate the CdS buffer layer. By forming the evaporation buffer layer, the vacuum degree in the cavity can be effectively reduced, and the gaseous substance in the cavity forms stable air pressure, so that the components and the thickness of the buffer layer deposited on the substrate are more uniform.

In one embodiment, in the thin film evaporation method, the length of each target is 1m-5m, and the relative movement speed of the target and a substrate to be evaporated is less than or equal to 3 m/min. More preferably, the relative motion between the target and the substrate is uniform, and of course, the relative motion may be non-uniform according to the consumption of the target or the actual demand of the substrate evaporation, and may be adjusted according to the actual process demand. The distance between the target and the substrate is 5mm-50mm, preferably 10mm-35 mm; more preferably, the distance is 15mm-25mm, and the arrangement of the distance ensures that components evaporated from the target material can be quickly deposited on the substrate, prevents the evaporation components of each target material from diffusing to other evaporation components of the target material and mixing, and ensures that the components of each coating layer are uniform and stable.

In one embodiment, step S2 includes receiving the substrate by a substrate carrier and moving the substrate in a first direction. Preferably, the substrate carrying device adsorbs the substrate by magnetic force or vacuum adsorption and drives the substrate to move along the first direction.

Preferably, the step S1 includes fixedly disposing the plurality of targets with different compositions on the same target fixing device along the first direction.

In a preferred embodiment, the target fixing device and the substrate carrying device are both flat, the substrate carrying device has a flat carrying surface for carrying the substrate, the target fixing device and the substrate carrying device are arranged in parallel, and the length directions of the target fixing device and the substrate carrying device are the same.

Preferably, the evaporation temperature of the target is 500 ℃ to 1100 ℃, more preferably 600 ℃ to 1000 ℃, and still more preferably 700 ℃ to 900 ℃, and in such a temperature range, the evaporation rate of the target is more stable, enabling the evaporation gas to be uniformly deposited on the substrate. In a preferred embodiment, the plurality of targets are heated to the same temperature, so that the evaporation rate of each target is uniform, which makes the deposition of the target composition on the substrate more uniform.

In another embodiment, the target fixing device has a cylindrical sidewall for fixing the target, the first direction is a circumferential direction of the cylindrical sidewall, the substrate bearing device is sleeved outside the target fixing device and has an arc-shaped bearing surface coaxially arranged with the cylindrical sidewall for bearing the substrate, and the target is fixed on a side of the target fixing device facing the substrate bearing device. The substrate moves from one end of the opening of the arc-shaped plate to the target direction, and moves out from the other end of the arc-shaped plate after circling for a circle. In this way, the technological process of film evaporation greatly reduces the floor area of the production equipment.

According to the film evaporation method, the plurality of targets with different components are arranged along the first direction, and then the substrate and the targets are relatively displaced in the first direction, so that the materials of the plurality of targets are sequentially evaporated on the substrate to directly form the plurality of coating layers.

In some preferred embodiments, the thin film evaporation method is implemented by using a thin film evaporation apparatus described below.

Referring to fig. 2 and fig. 3, an embodiment of the invention provides a thin film evaporation apparatus, including:

a target fixing device 100 for fixing a plurality of targets 300 having different compositions in a first direction;

the substrate bearing device 200 is used for bearing a substrate to be coated and enabling the substrate to be arranged opposite to the target 300; and

a heating device 400 for heating the target 300 to evaporate the material of the target 300 on the substrate to form a thin film;

the target fixing device 100 and the substrate carrying device 200 can make the target 300 and the substrate move relatively along the first direction.

According to the film evaporation device, the target material fixing device 100 is used for fixing the target materials 300 with different components, then the substrate and the target material 300 are relatively displaced, and the components of the target material 300 are sequentially evaporated on the substrate to directly form a plurality of laminated coating layers, so that the substrate does not need to be exposed in the air in the evaporation process of the plurality of coating layers, and the problem that the evaporation coating layer is easily oxidized is effectively avoided.

In one embodiment, the heating device 400 is disposed on the side of the target fixing device 100 in the length direction, and preferably, the heating device 400 is disposed on both sides. Preferably, the heating device 400 comprises a heating source 401, the heating source 401 is an optical radiation heat source, more preferably, the heating source 401 is a quartz lamp, and the shape of the quartz lamp is adapted to the shape of the target fixing device 100; the length direction of the quartz lamp is identical to the length direction of the target fixing device 100. In a preferred embodiment, the heating apparatus 400 further includes a light shielding plate 403, the light shielding plate 403 is disposed on a side of the light radiation heating source 401 away from the target fixing apparatus 100, and controls a heat radiation direction of the heating source 401 toward the target fixing apparatus 100, that is, a heat radiation direction toward the target 300. Alternatively, the heating device 400 provides heating in the range of 500 ℃ to 1100 ℃, preferably 600 ℃ to 1000 ℃, and more preferably 700 ℃ to 900 ℃, in which the evaporation rate of the target material is more stable, enabling the evaporation component to be deposited uniformly on the substrate.

Preferably, the heating device 400 is provided as one, and the heating source 401 of the heating device 400 can heat a plurality of targets 300 with different components at the same time, so as to heat the plurality of targets 300 to the same temperature, thereby generating steam for the targets 300, ensuring the consistent evaporation temperature of the plurality of targets 300, ensuring the uniformity of each coating of the coating, and greatly reducing the heating cost in the production process.

The target fixing device 100 and the substrate carrying device 200 can make the facing surfaces of the target 300 and the substrate parallel to each other.

In a preferred embodiment, the target fixing device 100 and the substrate supporting device 200 are both flat, the substrate supporting device 200 has a flat supporting surface for supporting the substrate, the target fixing device 100 is parallel to the substrate supporting device 200, and the length directions of the target fixing device 100 and the substrate supporting device 200 are the same. Accordingly, the quartz lamp is a straight quartz lamp, so that the heating temperature of each target 300 is uniform, and the substrate to be evaporated can be directionally moved by the power provided by the substrate carrying device 200, preferably, moved along a first direction, and sequentially passes through the targets 300 fixedly arranged on the target fixing device 100.

Preferably, the substrate is a stainless steel substrate, and correspondingly, the substrate carrying device 200 includes a conveyor belt, a magnetic block is disposed on the conveyor belt, the stainless steel substrate is attracted to and fixed on the conveyor belt by the magnetic block, and when the conveyor belt is in a moving state, the magnetic block moves along with the conveyor belt and drives the stainless steel substrate to move together with the stainless steel substrate, so as to generate a relative movement with the target 300, so that a plurality of stacked films with different compositions can be sequentially deposited on the stainless steel substrate. In another preferred embodiment, the conveyor belt itself is a magnetic chain or a magnetic belt, the stainless steel substrate is directly attracted and fixed to the conveyor belt and moves along with the conveyor belt, and when the conveyor belt is in a moving state, the magnetic block moves along with the conveyor belt and drives the stainless steel substrate to move together with the stainless steel substrate, so that the stainless steel substrate and the target 300 generate relative movement, and films with different compositions can be sequentially deposited on the stainless steel substrate.

In another preferred embodiment, the substrate is sucked and fixed on the conveyor belt by a vacuum device, so that the substrate moves directionally along with the conveyor belt. The substrate may be a glass, quartz or polymer substrate.

Preferably, the length of each target 300 is 1m-5m, and the speed of the relative movement of the target fixing device 100 and the substrate to be evaporated is less than or equal to 3 m/min. More preferably, the relative motion between the target fixing device 100 and the substrate is a uniform motion, and of course, the relative motion may also be non-uniform according to the consumption of the target 300 or the actual requirement of the substrate evaporation, and may be adjusted according to the actual process requirement.

Preferably, the distance between the substrate and the target 300 is 5mm-50 mm; preferably, from 10mm to 35 mm; more preferably, the distance is 15mm-25mm, and the arrangement of the distance ensures that components evaporated from the target material can be quickly deposited on the substrate, prevents the evaporation components of each target material from diffusing to other evaporation components of the target material and mixing, and ensures that the components of each coating layer are uniform and stable.

Preferably, the target fixing device 100 includes a fixing plate and a plurality of metal plates, the plurality of metal plates are fixedly disposed on the fixing plate, and the plurality of metal plates are used for fixing the plurality of targets 300 to the fixing plate. Preferably, the metal plate is a stainless steel plate and/or a copper plate, the target 300 is fixed on the target fixing device 100 through the stainless steel plate and/or the copper plate, and the target 300 is fixed on the stainless steel plate and/or the copper plate by at least one selected from welding, brass high-temperature fusion bonding, and/or high-temperature diffusion.

In a preferred embodiment, the target 300 comprises a CIGS target, preferably at least three alloy targets, corresponding to reference numerals 301, 302 and 303 in fig. 1 and 3, respectively, the composition of the three alloy targets preferably being: target material 301: cu_(0.01～1.0)In_(0.01～1.0)Ga_(0.01～1.0)Se_(0.01～3.0)；

Target 302: cu_(0.01～2.0)In_(0～1.0)Ga_(0～1.0)Se_(0.01～3.0)；

Target material 303: cu_(0.01～2.0)In_(0.01～1.5)Ga_(0.01～1.0)Se_(0.01～3.0)。

More preferably, the 3 targets 300 respectively have the following compositions:

target material 301: cu_(0.01～0.5)In_(0.01～0.5)Ga_(0.5～1.0)Se_(0.01～3.0)；

Target 302: cu_(1.0～2.0)In_(0～0.5)Ga_(0～0.5)Se_(0.01～3.0)；

Target material 303: cu_(0.01～0.5)In_(0.5～1.5)Ga_(0.5～1.0)Se_(0.01～3.0)。

Further preferably, the 3 targets 300 respectively have the following compositions:

target material 301: cu_0.1In_0.3Ga_1.0Se_0.5；

Target 302: cu_2.0Se_0.5；

Target material 303: cu_0.1In_0.5Ga_1.0Se_0.5。

In a preferred embodiment, the substrate to be evaporated sequentially passes through the 3 targets 300, i.e. sequentially passes through 301, 302 and 303, and 3 layers of films with different compositions are deposited on the surface of the substrate to be evaporated under the action of the heating device 400, so that the prepared CIGS film has a gradient band gap between the various film layers, and when the film is used in a cell, the conversion efficiency of the cell can be effectively improved.

Referring to fig. 4, preferably, the target 300 further includes a buffer layer target 304, the buffer layer target 304 is disposed on a side of the target 303 away from the target 302 along the first direction, and after the evaporation of the CIGS thin film on the substrate is completed, the buffer layer can be continuously evaporated without taking out a sample, thereby further preventing the oxidation of the CIGS thin film on the substrate. Preferably, the composition of the buffer layer target 304 is solid sulfide, and specifically, the composition of the buffer layer target 304 is CdS. In another preferred embodiment, the thin film evaporation apparatus further comprises H₂S gas inlet device, the buffer layer target material is capable of being connected with H₂S gas forming sulfide layer at high temperatureA metal target, preferably a Cd target, said H₂The S gas introducing device can introduce H into the film evaporation device in the evaporation process₂Cd steam and H formed by thermal evaporation of S gas₂And reacting the S gas to generate the CdS buffer layer. By forming the evaporation buffer layer, the vacuum degree in the cavity can be effectively reduced, and the gaseous substance in the cavity forms stable air pressure, so that the components and the thickness of the buffer layer deposited on the substrate are more uniform.

Preferably, the film evaporation device further includes a cooling device, the target fixing device 100 itself may be used as a cooling device, and the cooling device may also be fixedly disposed on a side of the target fixing device 100 away from the target, the cooling device is configured to control the temperature of the target 300, and the cooling device may, on one hand, cool the back of the target 300 and control the temperature of the target 300, so that the main body of the target 300 is in a solid state, and on the other hand, may also control the temperature of the surface of the target 300, so as to control the evaporation rate of the target 300 within a proper range.

Preferably, the film evaporation device further comprises a temperature adjusting device, preferably, the temperature adjusting device is arranged on one side of the substrate bearing device 200, which is away from the substrate, and is used for providing energy required by heating or cooling for the substrate, so that the vapor can be uniformly deposited on the substrate to form a stable film, only one temperature adjusting device is needed in the process of evaporating the substrate with a plurality of layers of films, and the temperature control cost in the production process is greatly reduced.

Optionally, since the Se element has high volatilization speed and is easy to be lost in the evaporation process, the thin film evaporation device also comprises a supply source of the Se element, so that the vapor pressure of Se vapor in the cavity is larger than 50kpa, and the Se element can be continuously and uniformly deposited on the substrate. Of course, the apparatus may be provided with a supply source of Cu, In, or Ga elements as appropriate.

Referring to fig. 5, in another embodiment, the target fixing device 100 has a cylindrical sidewall for fixing the target, the first direction is a circumferential direction of the cylindrical sidewall, the substrate supporting device 200 is sleeved outside the target fixing device and has an arc supporting surface for supporting the substrate, the arc supporting surface is coaxially disposed with the cylindrical sidewall, and the target 300 is fixed on a side of the target fixing device 100 facing the substrate supporting device 200. The substrate moves from one end of the opening of the arc-shaped plate to the direction of the target 300, and moves out from the other end of the arc-shaped plate after circling a circle. In this way, the film evaporation device greatly reduces the floor area of the production equipment.

Preferably, the heating device 400 may be disposed at an axial position of the target fixing device 100, or at least one of two radial sides of the target fixing device 100, and when the heating device 400 is disposed at the axial position of the target fixing device 100, the heating source 401 is preferably a straight quartz lamp, and a length direction of the straight quartz lamp is consistent with an axial direction of the target fixing device 100; when the heating device 400 is disposed on at least one side of the radial side surface of the target fixing device 100, the heating source 401 is preferably an annular quartz lamp, and the center of the annular quartz lamp coincides with the axis of the target fixing device 100. In summary, the heating source 401 is only required to be in a form that can ensure that each target 300 can be uniformly heated.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.