Alloying and doping of CdSeTe

Abstract

The invention relates to an evaporation arrangement for an evaporation system designed for evaporating a mixture consisting of at least two different evaporation source materials. The evaporation arrangement comprises at least one crucible with an evaporation material storage volume that can be filled with at least two different evaporation source materials, and at least one partition wall arranged within the crucible such that the evaporation material storage volume is divided into at least two evaporation material storage subvolumes within the crucible. Each evaporation material storage subvolume is designed to hold one of the at least two different evaporation source materials.An evaporation opening area of ​​each evaporation material storage volume corresponds to a desired ratio of the respective evaporation source material within the evaporated mixture, the evaporation properties of the respective evaporation source material, and the evaporation parameters.

Description

[0001] The invention relates to an evaporation arrangement for depositing alloyed and / or doped layers with an adjustable ratio of the alloy and / or doping components, taking into account specific evaporation parameters of the alloy and / or doping materials used.

[0002] Alloying and / or doping in layer deposition processes is a key issue, especially when alloying and / or doping profiles along the layer thickness are desired. Particularly in the fabrication of thin-film photovoltaic devices, specific bandgap values, even bandgap gradient profiles, along the thickness of the photovoltaically active layers are desirable to achieve optimized efficiencies. For example, in CdTe-based thin-film photovoltaic devices, alloying and / or doping profiles within the CdTe-based absorber layer are desirable to optimize efficiency. Several approaches are known from the prior art, mainly involving complex methods for the deposition of alloyed and / or doped layers.One approach uses pre-mixed evaporation materials, but the composition of such pre-mixed materials is not stable over the deposition time and temperature due to the different evaporation properties of the pre-mixed materials. Another approach involves depositing pure materials alternately or sequentially and achieving alloying and / or doping through subsequent heat treatments. The disadvantage here is that subsequent heat treatments, possibly using chemical agents, are not easily controlled to achieve specific bandgap values, and such methods become increasingly complex with respect to the deposition sequences of the layers.

[0003] The object of the invention is therefore to provide an evaporation arrangement suitable for evaporation processes of alloyed and / or doped layers with an adjustable ratio of the alloying and / or doping materials.

[0004] The problem is solved by an evaporation arrangement according to the independent claim. Specific embodiments are the subject of the dependent claims.

[0005] According to the invention, an evaporation arrangement for an evaporation system configured for the evaporation of a mixture consisting of at least two different evaporation source materials comprises at least - a crucible with an evaporation material storage volume that can be filled with at least two different evaporation source materials, - at least one partition wall arranged within the crucible such that the evaporation material storage volume is divided into at least two evaporation material storage subvolumes within the crucible, each evaporation material storage subvolume being designed to accommodate one of the at least two different evaporation source materials, with an evaporation opening area of ​​each evaporation material storage subvolume corresponding to the desired ratio of the respective evaporation source material in the evaporated mixture, the evaporation properties of the respective evaporation source material and the evaporation parameters.

[0006] Advantageously, such an evaporation arrangement allows the size of the partial volumes within the crucible to be designed depending on the deposition rates of the at least two different evaporation source materials under specific deposition parameters such as crucible and substrate temperature as well as pressure, in order to achieve the desired mixing ratio of the at least two different evaporation source materials. Furthermore, such an evaporation arrangement is advantageously modular and scalable, so that it can be adapted for different deposition processes, sizes, and layer thicknesses simply by multiplying components of the evaporation arrangement. The evaporation arrangement according to the invention can also be combined with known evaporation arrangements or evaporation sources from the prior art.Furthermore, based on data from specific evaporation source materials under specific evaporation conditions, such as pressure, time, and temperature, the desired alloy and / or doping composition can be estimated and applied to specific designs of the evaporation arrangement. This allows for the adjustment of the alloy and / or doping ratio and results in specific dimensions for the at least two partial volumes. Moreover, this evaporation arrangement enables the production of alloyed and / or doped layers with an alloy and / or doping gradient by arranging several evaporation arrangements sequentially, for example, in a continuous or so-called inline evaporation system and / or process.

[0007] An evaporation arrangement according to the invention is an arrangement suitable for converting at least two solid evaporation source materials into the vapor phase in order to coat a substrate, and suitable for arrangement within a sublimation chamber of an evaporation system. In embodiments, the evaporation arrangement denotes a vacuum evaporation arrangement. "Vacuum" means any pressure within a sublimation chamber that is lower than normal pressure, wherein in embodiments the pressure is in the range of 1 mbar to 10 -6 mbar (100 Pa to 10 -4 Pa), preferably 10 -1 mbar up to 10 -3 mbar (10 Pa to 0.1 Pa).

[0008] An evaporation source material according to the invention is any material that is suitable for coating a substrate and sublimates under certain conditions, such as pressure and temperature.

[0009] The evaporation arrangement according to the invention is suitable for stationary or continuous evaporation systems and / or processes, comprising bottom-up and / or top-down evaporation systems and / or processes. The evaporation arrangement according to the invention is suitable for arrangement within a sublimation chamber of a bottom-up evaporation system, wherein the bottom-up evaporation system comprises at least one sublimation chamber, means for evacuating and / or venting the at least one sublimation chamber, means for holding and / or transporting a substrate to be coated, means for heating and / or cooling the sublimation chamber and / or the substrate, at least one evaporation source for evaporating or sublimating a contained evaporation source material, and means for heating the at least one evaporation source.The evaporation arrangement according to the invention is further suitable for arrangement within a sublimation chamber of a top-down evaporation system, wherein the top-down evaporation system comprises at least one sublimation chamber, means for evacuating and / or ventilating the at least one sublimation chamber, means for holding and / or transporting a substrate to be coated, means for heating and / or cooling the sublimation chamber and / or the substrate, at least one evaporation source for evaporating or sublimating a contained evaporation source material, means for heating the at least one evaporation source, and means for guiding the evaporated source material.In top-down evaporation systems, the evaporation arrangement according to the invention can be used above the substrate to be coated, wherein the evaporated source material is transported to the substrate to be coated by means of means known from the prior art for guiding the evaporated source material.

[0010] In embodiments, the evaporation arrangement according to the invention forms the at least one evaporation source.

[0011] Furthermore, such an evaporation system can be used as a batch system in stationary coating processes, i.e. by providing at least one evaporation arrangement with the crucible, filled with at least two evaporation source materials, evaporating the materials and exchanging or refilling the crucible when a defined quantity of material has evaporated and the coating process is interrupted.

[0012] A crucible according to the invention comprises an evaporation source that includes an evaporation material storage volume. This volume can be filled with at least two different evaporation source materials and is suitable for heating the contained evaporation source materials above their sublimation or evaporation temperatures to enable the sublimation or evaporation of the at least two evaporation source materials upwards towards the top of the crucible. The crucible comprises a bottom and at least one side wall of a height that limits the evaporation material storage volume and defines a surface area of ​​the crucible, and thus an external shape of the crucible. The external shape of the crucible is not limited as long as the crucible has an open top end, a bottom end, and at least one side wall.This means that the outer shape of the crucible can be, for example, a right or oblique cylinder with a circular or oval face at the top and / or bottom, or any type of right or oblique prism, such as a cuboid, or any other solid shape. The crucible has a cross-section, for example, a cross-section with a circular, oval, or square face in a plane perpendicular to the height of the crucible or to its side wall. The cross-section has a first and a second lateral dimension that are perpendicular to each other and oriented within the plane of the crucible, where the first lateral dimension can be the width of the crucible and the second lateral dimension the length of the crucible.The first lateral dimension or width of the crucible is oriented along the substrate transport direction when the evaporation arrangement according to the invention is used in a continuous evaporation system and / or process. Preferably, the crucible is a prism with a four-sided, preferably rectangular, surface at the top and bottom of the crucible. In further embodiments, the crucible comprises four side walls, each of which is connected to a surface of the four-sided, preferably rectangular, surface at the lower end or bottom of the crucible. The upper side of the crucible is open so that evaporated or sublimated material can rise towards the substrate to be coated.

[0013] The crucible can be heated by known heating elements, such as a heating lamp, an RF coil, or a resistance heater. These heating elements can be located on the outside of the crucible, at a distance from the crucible, or even inside the crucible, for example, within at least one side wall and / or the bottom of the crucible. Such heating elements can be physically separate from the crucible and transfer heat energy over a greater distance by radiation or convection. Advantageously, the crucible can be heated in such a way that a temperature gradient develops along the height of the crucible, with the highest temperature at the top.

[0014] In embodiments, the crucible can be heated such that the at least two storage volumes for the evaporating material within the crucible are each heated differently in order to achieve different temperatures and thus specific evaporation rates of the at least two evaporation source materials located in the at least two storage volumes for the evaporating material. This can be achieved, for example, by heating each of the at least one side wall associated with one of the at least two storage volumes for the evaporating material differently, perhaps by means of control devices, in order to achieve different temperatures within the at least two volumes.

[0015] At least one partition according to the invention is a wall arranged within the crucible that divides the evaporation material storage volume into at least two evaporation material storage subvolumes within the crucible, wherein the evaporation source materials contained in each of the formed subvolumes are not in contact with each other. In embodiments, the at least one partition is heatable. This is particularly advantageous for evaporation materials with low thermal conductivity, such as CdTe powder. In further embodiments, the at least one partition is in contact with the bottom and the side wall of the crucible. In further embodiments, the at least one partition is arranged parallel to at least one side wall of the crucible and perpendicular to the bottom of the crucible.In a rectangular crucible, the at least one partition can be arranged parallel to a longitudinal or a short side of the crucible, preferably parallel to a longitudinal side. In further embodiments, the at least one partition arranged in the crucible is attached to at least one side wall of the crucible by means of any known fastening means, preferably by means of releasable fastening means. Advantageously, this allows the at least one partition to be redesigned depending on the evaporation source materials located in the evaporation material storage volumes and their specific evaporation properties at certain parameters, as well as the desired alloy and / or doping ratio.In some embodiments, the at least one partition within the crucible is arranged such that at least two evaporation material storage volumes of the same size are formed; in other words, the at least one partition is arranged centrally in the at least one crucible and divides the evaporation material storage volume into two identical volumes. In further embodiments, the at least one partition within the crucible is arranged such that at least two volumes of different sizes are formed, the sizes of which correspond to the specific evaporation properties and a desired ratio of the at least two different evaporation source materials in the volumes.

[0016] In further embodiments, the at least one partition can be arranged at an angle at the bottom of the crucible, forming at least two evaporation material storage subvolumes, each with a changing cross-section along a direction from the bottom or lower end to the upper end of the crucible. A changing cross-section means a cross-section that increases or decreases along this direction. Advantageously, this allows for large subvolumes with a reduced evaporation surface area for rapidly evaporating evaporation source materials and smaller subvolumes with an increased evaporation surface area for slowly evaporating evaporation source materials.Furthermore, the vapor ratio between the at least two evaporation material storage volumes, each filled with evaporation source material, can be advantageously adjusted by adjusting the angle at which the at least one partition wall is arranged at the bottom of the crucible.

[0017] In further embodiments, a plurality of partitions are arranged within the crucible, such that several partitions form a plurality of evaporation material storage volumes. The plurality of partitions can be arranged at equal or different distances from one another, depending on the vapor pressure of the evaporation source materials located in each of the formed evaporation material storage volumes and the specific desired alloy and / or doping ratio.

[0018] An evaporation opening area of ​​an evaporation material storage volume is defined as an area suitable for directing evaporated or sublimed material from the storage volume to the top of the crucible. This evaporation opening area can be defined solely by a cross-section of the respective volume at the level up to which the volume is filled with evaporation source material, i.e., by the area of ​​the evaporation source material at its evaporation surface. In other embodiments described later, the evaporation opening area can be defined by additional devices that limit the amount of material evaporating from the storage volume to the top of the crucible.In each case, the evaporation opening area of ​​each evaporation material storage volume corresponds to a desired ratio of the respective evaporation source material within the evaporated mixture, the evaporation properties of the respective evaporation source material, and the evaporation parameters. Advantageously, this allows the evaporation opening area of ​​different partial volumes to be adjusted to a desired ratio of different evaporation source materials within the evaporated mixture.

[0019] In preferred embodiments, the evaporation arrangement further comprises at least one intermediate cover with a plurality of openings, which is arranged on or within at least one of the evaporation material storage volumes. In this case, the combined opening area of ​​all openings in the intermediate cover associated with an evaporation material storage volume defines the evaporation opening area of ​​the respective evaporation material storage volume.

[0020] In some embodiments, such an intermediate cover covers only one of the at least two evaporation material storage volumes and corresponds to one evaporation material storage volume. In this case, the evaporation arrangement can include one intermediate cover for each of the at least two evaporation material storage volumes. For example, if there are two evaporation material storage volumes formed within the crucible, the evaporation arrangement can include two intermediate covers. If there are multiple evaporation material storage volumes formed by arranging multiple partitions within the crucible, the evaporation arrangement can include multiple intermediate covers, where the respective number of evaporation material storage volumes and intermediate covers can be the same.

[0021] At least one intermediate lid according to the invention is a plate-shaped element of any form that corresponds to at least one outer shape of at least one of the evaporation material storage volumes and limits at least one of the evaporation material storage volumes in a vertical direction from the bottom to the top of the crucible. The at least one intermediate lid is suitable for allowing sublimated evaporation source materials to pass upwards to the top of the crucible, i.e., in the direction of a substrate to be coated. The outer shape of an evaporation material storage volume is limited by the side walls of the crucible and the at least one partition wall that forms the at least two volumes, and comprises any cross-section depending on the arrangement of the at least one partition wall within the crucible and the outer shape of the crucible.

[0022] In further embodiments, the at least one intermediate lid is attached to or above the at least one partition and / or to a side wall of the crucible by means of any known fastening means, preferably releasable fastening means. In embodiments, the at least one intermediate lid is arranged perpendicular to a side wall of the crucible and parallel to the bottom of the crucible.

[0023] In some embodiments, the intermediate lid covers at least more than one of the evaporation material storage volumes and comprises a plurality of openings, wherein the plurality of openings includes at least two subsets of openings corresponding to the at least two evaporation material storage volumes within the crucible. That is, each subset of openings corresponds to a single evaporation material storage volume. In some embodiments, the intermediate lid covers all evaporation material storage volumes.

[0024] This advantageously reduces the number of components within the evaporation arrangement. Such an intermediate lid can completely cover the crucible's storage volume for the evaporating material, conforms to the crucible's outer shape, and can limit the storage volume vertically from the bottom to the top of the crucible. Furthermore, the at least two sets of openings allow for the adjustment of the alloy and / or doping ratio of the at least two different evaporated source materials.

[0025] In further embodiments, each of the plurality of openings can have any cross-sectional shape, for example a round or square shape, whereby the cross-sectional shape of some or all of the openings can be the same or different.

[0026] Each subset of openings defines the opening area of ​​the respective evaporation material storage volume via an opening area of ​​the corresponding subset of openings. By varying the ratio of the opening areas of different subsets of openings, the alloy and / or doping ratio can be adjusted, depending, for example, on deposition parameters such as the pressure and temperature of the substrate to be coated and the crucible.

[0027] In embodiments, the opening area of ​​a respective evaporation material storage subvolume is defined by an opening area of ​​the corresponding subset of openings, wherein the ratio of the opening area of ​​a first subset of openings to the opening area of ​​a second subset of openings is in the range of 1:1 to 1:1000.

[0028] In embodiments, the ratio of the opening area of ​​a first subset of openings to the opening area of ​​a second subset of openings is in the range of 1:10 to 1:1000. This is advantageous when a doped layer is to be deposited onto the substrate to be coated. It can be advantageous if the evaporation source material, which forms a dopant material, is housed in the evaporation material storage volume corresponding to the subset of openings with the smaller opening area, while the evaporation source material to be doped is housed in the evaporation material storage volume corresponding to the subset of openings with the larger opening area.

[0029] In further embodiments, the ratio of the opening area of ​​a first subset of openings to the opening area of ​​a second subset of openings is in the range of 1:1 to 1:20. This is advantageous when an alloyed layer is to be deposited onto the substrate to be coated.

[0030] Larger ratios, e.g. 1:10 to 1:1000, are preferred when using doping materials, while for alloy applications more uniform ratios in the range of 1:1 to 1:20 are preferred.

[0031] In alloys, the allocation of the evaporation source materials to the subsets of openings and thus to the evaporation material storage subvolumes depends on the desired proportion within the layer to be deposited on the substrate and the evaporation parameters, such as the growth rate of the evaporation source materials used.

[0032] In some embodiments, the evaporation arrangement further comprises a heated lid. Such a heated lid is known from the prior art in evaporation systems and directs sublimated evaporation source materials upwards to a substrate to be coated. In some embodiments, the heated lid is arranged near the upper end of the at least one crucible. In other embodiments, the heated lid is arranged near the upper end of the at least one crucible without any physical contact between the heated lid and the crucible. Advantageously, this allows the heated lid to be heated independently of the crucible. This can be achieved by arranging at least one spacer between the heated lid and the upper end of the crucible. Such a spacer can, for example, be a quartz plate or a ceramic plate that insulates the heated lid and the crucible from each other.

[0033] A heated lid according to the invention is a plate-shaped element of any form, for example, polygonal, that limits the storage volume of the evaporating material in the vertical direction at the upper end of the crucible. In embodiments, the heated lid has the same shape and dimensions as the surface formed at the upper end of the crucible by at least one side wall of the crucible. Such a heated lid is in direct physical contact with the evaporating material and, in embodiments, is heated in such a way as to prevent resublimation, i.e., deposition of the evaporated material on the heated lid. In embodiments, the heated lid is a four-sided, preferably rectangular, element with a thickness in the range of 3 mm to 20 mm.The heated lid can be heated by known heating elements, such as a heating lamp, an RF coil, or a resistance heater. These heating elements can be located on the outside of the heated lid, at a distance from it, or even integrated within the heated lid. Alternatively, the heated lid itself can be a heating element, meaning it is made of a material that heats up when an electric current passes through it. To transfer the sublimated material onto a substrate to be coated, the heated lid includes a multitude of openings that allow the passage of the sublimated vaporization material. This multitude of openings forms the surface area of ​​the heated lid, which, among other things, determines the deposition rate onto the substrate.The cross-sectional area and shape of a single opening, as well as the distribution of the plurality of openings within the heated lid, are based on prior art lids commonly used in bottom-up sublimation setups, such as close-spaced sublimation setups. In embodiments, the plurality of openings within the heated lid is distributed such that more openings with a larger combined cross-sectional area are arranged at the periphery of the heated lid to compensate for reduced sublimation rates at the side walls of the pot compared to the center. The cross-section of each of the plurality of openings can have any desired shape, for example, a round or rectangular shape.

[0034] In embodiments, the crucible, the at least one partition, the at least one intermediate lid and / or the heatable lid are made of graphite, ceramic or polycrystalline materials such as silicon carbide, preferably graphite.

[0035] In embodiments, the evaporation arrangement comprises at least one intermediate lid, wherein the heated lid is arranged above the at least one intermediate lid along the vertical direction from the bottom to the top of the crucible. Advantageously, this allows the sublimated evaporation source materials contained in the at least two evaporation material storage volumes to mix in the space between the at least one intermediate lid and the heated lid, so that the heated lid conveys an already mixed volume of evaporated material to the substrate, thereby forming a homogeneously alloyed and / or doped layer on the substrate to be coated.

[0036] In further embodiments, the heated lid is positioned above the at least one intermediate lid at a distance ranging from 5 mm to three times the lateral dimensions of the crucible. The distance between the two lids determines the degree of mixing of the generated vapors, depending on the size and shape of the openings within the at least one intermediate lid and the heated lid. For example, with a crucible having a first lateral dimension or width of 10 cm, a distance of up to 30 cm between the at least one intermediate lid and the heated lid may be advantageous to ensure thorough mixing. The distance can be considerably smaller; for instance, a distance equal to the width of the crucible is preferred if mixing with a given material combination can be achieved with less effort or by an advantageous arrangement of lid openings.

[0037] In embodiments, the at least one partition wall has a height of 20% to 80% of the height of the crucible. Advantageously, this allows the at least one intermediate lid to be arranged within the heated volume of the crucible, so that no additional heating of the at least one intermediate lid is required.

[0038] In preferred embodiments, the at least one partition wall has a thickness in the range of 1 mm to 10 mm, preferably in the range of 2 mm to 3 mm.

[0039] In preferred embodiments, the at least one intermediate cover has a thickness in the range of 1 mm to 10 mm, preferably in the range of 2 mm to 3 mm.

[0040] Another aspect of the invention is the use of an evaporation arrangement according to the invention in an evaporation system and / or in an evaporation process for the production of alloyed and / or doped layers.

[0041] Advantageously, this enables the production of alloyed and / or doped layers in a simpler and more efficient manner than is known from the prior art, without having to use complex layer sequences and temperature treatments.

[0042] In embodiments, an evaporation arrangement according to the invention is used in a bottom-up evaporation system, for example in a known close-spaced sublimation (CSS) system, for the production of CdTe-based solar cell devices with alloyed and / or doped CdTe-based absorber layers, for example CdTe alloyed with CdSe or CdTe doped with a known dopant material. Such CdTe-based absorber layers can be formed by a plurality of CdTe-based absorber layers, wherein a layer stack forms a CdTe-based absorber layer.

[0043] In further embodiments, an evaporation arrangement according to the invention is used in a bottom-up evaporation process, for example in a CSS process for the production of CdTe-based solar cell devices with alloyed and / or doped CdTe-based absorber layers.

[0044] In further embodiments, an evaporation arrangement according to the invention is used in a top-down evaporation system and / or process, such as those known from the production of CdTe-based solar cell devices with alloyed and / or doped CdTe-based absorber layers.

[0045] In embodiments, a plurality of evaporation arrangements according to the invention can be used in succession, wherein the individual evaporation arrangements of the plurality of evaporation arrangements differ with respect to the evaporation source materials or with respect to the ratios of the opening areas of the evaporation material storage partial volumes in the respective evaporation arrangements. This means that the size and ratio of the evaporation material storage partial volumes formed in each individual evaporation arrangement vary and / or specific designs of the at least one intermediate cover with different ratios of the opening areas of the partial sets of openings in each evaporation arrangement can be provided. These embodiments enable the generation of gradients of the alloy and / or doping within the layers deposited on the substrate.

[0046] To realize the invention, it is advantageous to combine the described embodiments and features of the claims as described above. The embodiments of the invention presented in the preceding description are examples for illustrative purposes, and the invention is not limited thereto. Any modification, variation, and equivalent arrangement as well as combination of embodiments is to be considered as falling within the scope of protection of the invention. Exemplary embodiments

[0047] The accompanying drawings serve to further illustrate embodiments of the invention and form part of this description. The drawings depict embodiments of the present invention and, together with the description, explain the principles. Further embodiments of the invention and many of the intended advantages will become more readily apparent upon studying the following detailed description. The elements of the drawings are not necessarily shown to scale. Identical reference numerals denote corresponding similar parts. Fig. Figure 1 shows an embodiment of an evaporation arrangement in a side view, Fig. Figure 2a shows an embodiment of an evaporation arrangement in a top view. Fig. Figure 2b shows another embodiment of an evaporation arrangement in a top view. Fig. Figure 3 shows another embodiment of an evaporation arrangement in a side view, Fig. Figure 4 shows an embodiment of the use of an evaporation arrangement in a process for producing an alloyed layer, Fig. Figure 5 shows an embodiment of the use of an evaporation arrangement in a method for producing a doped layer.

[0048] Fig. Figure 1 shows a side view of an embodiment of an evaporation arrangement (1) according to the invention. The evaporation arrangement (1) comprises a crucible (10) with an evaporation material storage volume (100) that can be filled with at least two evaporation source materials, and at least one partition (11) arranged within the crucible (10) such that the evaporation material storage volume (100) is divided into at least two evaporation material storage subvolumes (101, 102) within the crucible (10). The crucible (10) has a bottom (104) and at least one side wall (103) of a height that limits the evaporation material storage volume (100) and defines a lateral surface of the crucible (10) and thus an external shape of the crucible (10). The at least one partition wall (11) is located against the side wall (103) and the bottom (104) of the crucible (10).The crucible (10) has a rectangular cross-section with a width of 17 cm as the first lateral dimension (105) and a length of 150 cm as the second lateral dimension (106). The arrangement (1) also includes at least one intermediate lid (12) arranged inside the crucible (10) above the at least one partition (11). In this embodiment, the evaporation arrangement (1) further includes at least one heatable lid (13) arranged near an upper end of the crucible (10) above the at least one intermediate lid (12) at a distance of 5 mm to 500 mm in the vertical direction from the bottom to the upper end of the crucible (10). The at least one heatable lid (13) does not have direct contact with the crucible (10) because at least one spacer (14) is arranged between the at least one heatable lid (13) and the upper end of the crucible (10). Such a spacer can, for example, be a ceramic plate.

[0049] Fig. 2a and Fig. Figure 2b shows top views of different embodiments of an evaporation arrangement (1), each without the at least one heated lid (13) in order to show details of the at least one intermediate lid (12) more clearly. Fig. 2a shows round-shaped openings (120) and Fig. 2b rectangular, slit-like openings (120). Visible are the side walls of the crucible (10), which define an outer shape of the crucible (10), here a rectangular shape with rounded corners. The intermediate lid (12) is arranged inside the crucible (10) and has a plurality of openings (120). The at least one partition (11) on which the intermediate lid (12) rests is shown by dashed lines and abuts the side wall of the crucible (10). The plurality of openings (120) comprises at least two subsets of openings (121, 122) corresponding to the at least two evaporation material storage subvolumes (101, 102) as described in Fig. 1 is shown and formed by the arrangement of the at least one partition (11) in the crucible (10). Each subset of openings (121, 122) defines an opening area of ​​the subset. By varying the ratio of the opening areas of different subsets of openings (121, 122), the ratio of the alloy and / or doping can be adjusted. In one embodiment, the evaporation arrangement can be used to deposit an alloyed layer, for example, a CdTe layer alloyed with CdSe. In this case, CdSe is filled into one of the at least two evaporation material storage subvolumes and CdTe into the other.Furthermore, due to the different evaporation properties of CdSe and CdTe at a given crucible temperature and pressure, the opening area of ​​the subset of openings corresponding to the partial volume filled with CdSe must be approximately 20 times larger than the opening area of ​​the subset of openings corresponding to the partial volume filled with CdTe in order to achieve a 1:1 ratio of CdSe:CdTe on the substrate to be coated.

[0050] Fig. Figure 3 shows a further embodiment of an evaporation arrangement (1) according to the invention in a side view similar to that shown in Fig. Figure 1. The at least one partition (11) is arranged at an angle on the bottom of the at least one crucible (10), such that at least two evaporation material storage volumes (101, 102) are formed, each having a varying cross-section along a direction from the bottom or lower end to the upper end of the at least one crucible (10). In this embodiment, the storage volume (101) has a decreasing cross-section and the storage volume (102) has an increasing cross-section, each along a direction from the bottom or lower end to the upper end of the at least one crucible (10).

[0051] Fig. Figure 4 shows an embodiment for the use of an evaporation arrangement according to the invention in a bottom-up evaporation process for depositing, for example, a CdTe-based absorber layer with an alloy gradient of CdSe along the layer thickness of the CdTe-based absorber layer. Fig. Figure 4 shows evaporation arrangements (A) to (D) for a CSS process for depositing CdTe-based absorber layers. Evaporation arrangements (A) and (D) are known from the prior art and comprise a heatable crucible (10) and a heatable lid (13) which is arranged at the upper end of the crucible (10) with spacers (14). In this embodiment, evaporation arrangements (A) and (D) are filled with CdSe and CdTe, respectively. Evaporation arrangements (B) and (C) are evaporation arrangements according to the invention, as shown in Figure 4. Fig. 1 described. The evaporation arrangements (B) and (C) each comprise a partition (11) arranged within the respective crucible (10) such that two evaporation material storage volumes (101, 102) are formed. In each of the evaporation arrangements (B) and (C), the volume (101) is filled with CdSe and the volume (102) with CdTe. Furthermore, both arrangements (B) and (C) comprise an intermediate lid (12) with a plurality of openings, which have two sets of openings corresponding to the volumes (101, 102). Fig. Figure 4 schematically illustrates a difference in the subset of openings in the intermediate cover (12) for the evaporation arrangements (B) and (C). Such a combination of known and inventive evaporation arrangements (A) to (D) is suitable for the bottom-up deposition of a CdTe-based absorber layer alloyed with CdSe. The substrate transport direction in this exemplary inline bottom-up evaporation process is indicated by an arrow. This combination makes it possible to deposit a CdTe-based absorber layer with a CdSe gradient. The evaporation arrangement (A) enables the deposition of a pure CdSe layer of a specific thickness, followed by a CdSe-alloyed CdTe layer of a specific thickness and with a CdSe:CdTe ratio of 1:1, defined by the ratio of the opening areas of the two subsets of openings in the intermediate cover (12) in the evaporation arrangement (B).The following evaporation arrangement (C) enables the deposition of a further CdSe-alloyed CdTe layer of a specific thickness and with a different CdSe:CdTe ratio of 1:2, defined by a different ratio of the opening areas of the two subsets of openings in the intermediate cover (12) in the evaporation arrangement (C). The CdTe-based absorber layer is completed by the deposition of a pure CdTe layer, made possible by the known evaporation arrangement (D) in . Fig. 4. In this embodiment, the CdSe:CdTe ratio of 1:1 is achieved by a ratio of 20:1 between the opening area of ​​the first subset of openings in the intermediate cover (12), corresponding to the partial volume (101) filled with CdSe, and the opening area of ​​the second subset of openings in the intermediate cover (12), corresponding to the partial volume (102) filled with CdTe. The CdSe:CdTe ratio of 1:2 is achieved by a ratio of 10:1 between the opening area of ​​the first subset of openings in the intermediate cover (12), corresponding to the partial volume (101) filled with CdSe, and the opening area of ​​the second subset of openings in the intermediate cover (12), corresponding to the partial volume (102) filled with CdTe. It should be noted again that a specific ratio of the opening areas of the subsets of openings is only valid for a specific set of deposition parameters such as pressure, temperature of the substrate to be coated and of the crucible.

[0052] Fig. Figure 5 shows an embodiment for the use of an evaporation arrangement according to the invention in a bottom-up evaporation process for the deposition of, for example, a doped CdTe-based absorber layer similar to Fig.4. In this embodiment, the evaporation arrangement (A) enables the deposition of a pure CdSe layer by filling the crucible (10) with CdSe. Subsequently, a CdSe-alloyed CdTe layer can be deposited using the evaporation arrangement (B), wherein the partial volume (101) is filled with CdSe and the partial volume (102) with CdTe. The evaporation arrangement (C) enables the deposition of a doped CdTe layer, wherein the partial volume (101) is filled with CdTe and the partial volume (102) with a dopant material, such as Cu or a material containing an element of group 15 (according to the current IUPAC classification), such as As2Te3, Cd2As3, As2Se3, SbCl3, Cd3Sb2, As2Se3, Sb2Te3, PCl3, AsCl3, VF5, VCl4, VCl3, PH3, AsH3, SbH3, BiH3, VH5, BiF3, AsBr3, AsI3, SbF3, SbBr3, Sbl3, BiCl3, BiBr3, BiI3.Naturally, the subset of openings within the intermediate lids (12) in the evaporation arrangements (B) and (C) can be adjusted according to the desired alloy and / or doping levels, depending on the deposition parameters. The evaporation arrangement (D) enables the deposition of a pure CdTe layer by filling the crucible (10) with CdTe evaporation material. Reference sign 1, B, C Evaporation arrangement according to the invention 10 crucibles 100 evaporation material storage volume 101, 102 Evaporation material storage partial volume 103 Side wall of the crucible 104 Bottom of the crucible 105 first lateral dimension of the crucible 106 second lateral dimension of the crucible 11 Partition wall 12 intermediate covers 120 opening 121, 122 Subset of openings 13 heated lids 14 spacers A, D Evaporation arrangements according to the state of the art

Claims

[1] Evaporation arrangement (1) for an evaporation system designed for the evaporation of a mixture consisting of at least two different evaporation source materials, comprising at least - a crucible (10) with an evaporation material storage volume (100), fillable with at least two different evaporation source materials, - at least one partition (11) arranged within the crucible (10) such that the evaporation material storage volume (100) is divided into at least two evaporation material storage subvolumes (101, 102) within the crucible (10), wherein each evaporation material storage subvolume (101, 102) is designed to accommodate one of the at least two different evaporation source materials, wherein an evaporation opening area of ​​each evaporation material storage subvolume (101, 102) corresponds to a desired ratio of the respective evaporation source material within the evaporated mixture, the evaporation properties of the respective evaporation source material and the evaporation parameters. [2] Evaporation arrangement (1) according to claim 1, characterized by, that the evaporation arrangement (1) further comprises at least one intermediate cover (12) having a plurality of openings (120) and arranged on or within at least one of the evaporation material storage partial volumes (101, 102). [3] Evaporation arrangement (1) according to claim 2, characterized by , that the at least one intermediate lid (12) covers at least more than one of the evaporation material storage subvolumes and comprises a plurality of openings, wherein the plurality of openings (120) comprises at least two subsets of openings (121, 122) corresponding to the at least two evaporation material storage subvolumes (101, 102) within the crucible (10). [4] Evaporation arrangement (1) according to claim 3, characterized by, that the opening area of ​​a respective evaporation material storage subvolume (101, 102) is defined by an opening area of ​​the corresponding subset of openings (121, 122), wherein the ratio of the opening area of ​​a first subset of openings (121) to the opening area of ​​a second subset of openings (122) is in the range of 1:1 to 1:1000. [5] An evaporation arrangement (1) according to any one of claims 1 to 4, characterized by , that the evaporation arrangement (1) further comprises a heatable lid (13). [6] Evaporation arrangement (1) according to any one of claims 1 to 5, characterized by , that the at least one partition (11) has a height of 20% to 80% of the height of the crucible (10). [7] Evaporation arrangement (1) according to any one of claims 1 to 6, characterized by , that the at least one partition wall (11) has a thickness in the range of 1 mm to 10 mm. [8] Evaporation arrangement (1) according to any one of claims 1 to 7, characterized by , that the at least one intermediate cover (12) has a thickness in the range of 1 mm to 10 mm. [9] Use of an evaporation arrangement (1) according to any one of claims 1 to 8 in an evaporation system and / or in an evaporation process for the production of alloyed and / or doped layers.

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