solar cells

Abstract

Generally speaking, the present invention provides a solar cell comprising a hydrogen barrier layer and a hydrogen-containing dielectric layer. The present invention also provides a method for fabricating a solar cell, and a solar cell obtained or that can be obtained by such a method.

Description

[Technical Field]

[0001] Technical field Generally speaking, the present invention provides a solar cell comprising a hydrogen barrier layer and a hydrogen-containing dielectric layer. The present invention also provides a method for fabricating a solar cell, and a solar cell obtained or that can be obtained by such a method. [Background technology]

[0002] background In recent years, space activities have increased exponentially, which means that the energy demand in space is becoming extremely high. Solar cells offer one possible means of addressing this rapidly increasing energy demand.

[0003] Existing multi-junction (III-V) solar cells for space use are orders of magnitude more expensive than other types of current terrestrial solar cells and face challenges in large-scale production due to their highly complex manufacturing processes and expensive, scarce materials. Silicon-based solar cells, due to the use of abundant materials and simple manufacturing processes, are produced on a gigawatt scale for the terrestrial market. However, silicon-based solar cells have lower performance than III-V cells, degrade more severely from cosmic radiation, and have a very short lifespan when used in space activities.

[0004] There is still a need for solar cells suitable for space applications that are more resistant to degradation from cosmic radiation, and that can be manufactured more cheaply and on a larger scale. [Overview of the Initiative] [Means for solving the problem]

[0005] Summary of the Invention A first aspect of the present invention is a solar cell comprising a Si wafer and a dielectric layer deposited on the Si wafer, wherein the dielectric layer comprises a hydrogen-containing dielectric material, and the solar cell further comprises a first hydrogen barrier layer deposited on the dielectric layer.

[0006] A second aspect of the present invention is a method for manufacturing a solar cell, the method comprising depositing a first hydrogen barrier layer on a dielectric layer, the dielectric layer comprising a hydrogen-containing dielectric material.

[0007] A third aspect of the present invention is a solar cell obtained or obtainable by the method defined earlier herein. [Brief explanation of the drawing]

[0008] Brief explanation of the drawing [Figure 1A] This shows an exemplary process flow for manufacturing a self-healing solar cell according to the present invention, using a hydrogen barrier layer. [Figure 1B] This shows an exemplary process flow for manufacturing a self-healing solar cell according to the present invention, using a hydrogen barrier layer. [Figure 2] A schematic diagram of the solar cell according to the present invention, obtained from the second exemplary process flow in Figure 1, is shown. [Figure 3] A schematic diagram of the hydrogen distribution in the solar cell according to the present invention before and after the high-temperature firing step is shown. [Figure 4] The lifetime of minority charge carriers in a symmetric silicon test sample is shown as a function of the dark annealing time for samples exposed to various doses of 1 MeV electrons. The extended lifetime of the irradiated samples after dark annealing demonstrates that solar cells can "self-repair" radiation-induced defects. [Figure 5] The simulated efficiency is shown as a function of the bulk minority carrier lifetime. The simulation was performed using Quokka 3. The lifetime shown in Figure 4 directly affects the efficiency of the solar cell. [Modes for carrying out the invention]

[0009] Detailed description of the invention A first aspect of the present invention is a solar cell comprising a Si wafer and a dielectric layer deposited on the Si wafer, wherein the dielectric layer comprises a hydrogen-containing dielectric material, and the solar cell further comprises a first hydrogen barrier layer deposited on the dielectric layer.

[0010] Since the 2000s, hydrogen has been used in terrestrial solar cells for passivation purposes. Hydrogen is typically supplied to the cell by a hydrogen-containing dielectric layer (often used as an anti-reflective coating) and activated by a fast firing process. However, too much hydrogen can negatively affect the performance of the solar cell (International Publication No. 2018094462A1). By applying an AlOx layer on top of the hydrogen-containing dielectric layer, hydrogen escapes into the environment during the firing step, thus increasing the hydrogen content in the Si bulk. This can result in lower early-life (BoL) cell efficiency and a significant increase in photo-induced degradation due to high-temperature photo-induced degradation (LeTID) (Varshney, U., et al., Controlling Light- and Elevated-Temperature-Induced Degradation With Thin Film Barrier Layers. IEEE Journal of Photovoltaics, 2020. 10(1): p. 19-27). Therefore, this method is considered undesirable and is not recommended for the manufacture of Si-based solar cells.

[0011] However, in the context of the space environment, an increase in bulk hydrogen concentration means that radiation-induced damage can be repaired more effectively by hydrogen passivation. Despite the possibility of lower initial BoL efficiencies, this method enhances the self-healing ability of the battery from radiation, resulting in better EoL efficiencies, which are the most important metric for space solar cells.

[0012] Therefore, an object of the present invention is to intentionally increase the bulk hydrogen content in a silicon solar cell, enhance the self-repair ability to cosmic radiation, and thereby improve the lifetime and end-of-life (EoL) performance. This approach is counterintuitive in the technical field since a high hydrogen concentration is generally considered to have an adverse effect on the performance of solar cells as described above.

[0013] In the solar cell described above in this specification, the Si wafer is preferably a p-type Si wafer, an n-type Si wafer, or an intrinsic Si wafer. Particularly preferably, the Si wafer is a p-type Si wafer because this increases the radiation resistance.

[0014] The solar cell preferably further includes at least one contact, preferably including contacts for both electrons and holes. The at least one contact preferably includes poly-Si / SiOx, an aluminum alloy, phosphorus-diffused silicon, gallium-doped silicon, or boron-diffused silicon. To avoid misunderstanding, any other suitable contact material known to those skilled in the art may be used.

[0015] In the solar cell according to the present invention, the first hydrogen barrier layer preferably includes SiOx, SiNx, SiC, TiOx, MgFx, TaN, FeOx, ZrOx, or AlOx.

[0016] A particularly preferred material for the first hydrogen barrier layer is AlOx. Therefore, the first hydrogen barrier layer preferably includes AlOx. More preferably, the first hydrogen barrier layer consists essentially of AlOx. Even more preferably, the first hydrogen barrier layer consists of AlOx.

[0017] The first hydrogen barrier layer functions to prevent the release of hydrogen from the hydrogen-containing dielectric material during the manufacture of the solar cell. By doing so, the hydrogen released from the hydrogen-containing dielectric material during manufacture is forced to move to the Si wafer. As a result, the bulk hydrogen content of the Si wafer increases, leading to the improvement of the EoL characteristics of the solar cell described above.

[0018] Therefore, the requirement for the first hydrogen barrier layer is that it contains a material that is relatively impermeable to hydrogen (i.e., molecular hydrogen) under the conditions used to manufacture the solar cell.

[0019] In the solar cell of the present invention, preferably, the first hydrogen barrier layer has a first hydrogen permeability, and the hydrogen-containing dielectric layer has a second hydrogen permeability, wherein the first hydrogen permeability is at least 10 times lower than the second hydrogen permeability. Preferably, the first hydrogen permeability is at least 20 times, at least 50 times, or at least 100 times lower than the second hydrogen permeability.

[0020] The first hydrogen barrier layer preferably has a density of 10 to 1000 / mm 2 Preferably 20-800 / mm 2 , more comfortable 50~500 / mm 2 More preferably 75-250 / mm 2 For example, approximately 25, 50, 75, 100, 125, 150, 175, 200, 225, or 250 / mm 2 It has a pinhole density of . A lower pinhole density is advantageous because it correlates with a decrease in the permeability of hydrogen (e.g., molecular hydrogen) through the first hydrogen barrier layer.

[0021] The first hydrogen barrier layer preferably has a thickness of 0.1 to 200 nm, more preferably 1 to 50 nm. More preferably, the first hydrogen barrier layer has a thickness of 2 to 40 nm, even more preferably 3 to 30 nm, even more preferably 4 to 20 nm, and even more preferably 5 to 15 nm. The first hydrogen barrier layer preferably has a thickness of about 1 nm, about 2 nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8 nm, about 9 nm, about 10 nm, about 11 nm, about 12 nm, about 13 nm, about 14 nm, about 15 nm, about 20 nm, about 25 nm, about 30 nm, about 40 nm, or about 50 nm.

[0022] The first hydrogen barrier layer must have a sufficiently large thickness to exhibit the hydrogen barrier properties described above (e.g., low permeability to hydrogen under solar cell manufacturing conditions). However, it will be understood that any layer with a relatively large thickness may be undesirable, as increasing the thickness of any layer in a solar cell results in corresponding increases in size, weight, cost, and manufacturing time (and thus throughput). Surprisingly, in this invention, it has been found that a hydrogen barrier layer as thin as about 10 nm is sufficient to provide the desired hydrogen barrier properties.

[0023] Therefore, in one embodiment of the present invention, the first hydrogen barrier layer has a thickness of about 10 nm. Preferably, the first hydrogen barrier layer having a thickness of about 10 nm contains AlOx, more preferably is essentially AlOx, and even more preferably is AlOx.

[0024] The first hydrogen barrier layer can be deposited by any suitable method, for example, any suitable method for thin layer deposition. Such methods are known to those skilled in the art and include, but are not limited to, vacuum thermal deposition, electron beam deposition, laser beam deposition, arc deposition, molecular beam epitaxy, ion plating deposition, radio frequency sputtering (DC sputtering), radio frequency sputtering (RF sputtering), sol-gel techniques, chemical bath deposition, spray pyrolysis techniques, electroplating, electroless deposition, chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), plasma-excited chemical vapor deposition (PECVD), and atomic layer deposition (ALD).

[0025] The first hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD). Surprisingly, the inventors have found that by using atomic layer deposition for the deposition of the first hydrogen barrier layer, a hydrogen barrier layer having low permeability to hydrogen (e.g., molecular hydrogen) is produced during solar cell manufacturing (i.e., under typical solar cell manufacturing conditions). Without wishing to be bound by theory, it is believed that using ALD for the deposition of the first hydrogen barrier layer results in a thin, uniform layer with a low pinhole density, and as a result, the hydrogen (e.g., molecular hydrogen) permeability is reduced.

[0026] In the preferred solar cells described herein, the first hydrogen barrier layer is deposited directly on the dielectric layer. "Deposited directly on" means that there is no intervening layer between the first hydrogen barrier layer and the dielectric layer.

[0027] The solar cells of the present invention include a dielectric layer, and the dielectric layer includes a hydrogen-containing dielectric material. The hydrogen-containing dielectric material preferably contains hydrogen in the range of 5 to 40 atomic percent. In other words, the hydrogen-containing dielectric material preferably has a hydrogen concentration in the range of 5 to 40%. Surprisingly, by using a precursor of the hydrogen-containing dielectric material containing hydrogen and further not taking steps to reduce, substantially remove or completely remove the hydrogen derived from the precursor, as described above, it has been found that hydrogen passivation of the Si wafer can be advantageously achieved during subsequent manufacturing steps.

[0028] The dielectric layer can be a single layer or can include a stack of multilayer dielectric thin films. Preferably, the dielectric layer is a single layer.

[0029] The hydrogen-containing dielectric material is preferably TiO2, SiN, SiO x N y 、SiOx、SiC、TiO x 、ZrO xor includes SiC. In one particularly preferred embodiment, the hydrogen-containing dielectric material includes SiN. More preferably, the hydrogen-containing material consists of essentially SiN. Even more preferably, the hydrogen-containing material consists of essentially SiN.

[0030] The solar cell may further include a second hydrogen barrier layer, the second hydrogen barrier layer not in direct contact with the first hydrogen barrier layer. "Not in direct contact" means that at least one intervening layer, preferably more intervening layers, are present between the first hydrogen barrier layer and the second hydrogen barrier layer.

[0031] For example, the second hydrogen barrier layer may be deposited on the side of the Si wafer opposite the dielectric layer, such that the solar cell sequentially includes the first hydrogen barrier layer, the dielectric layer, the Si wafer, and the second hydrogen barrier layer. In this configuration, the second hydrogen barrier layer can advantageously prevent hydrogen from the hydrogen-containing dielectric material from moving out of the Si wafer.

[0032] In the solar cell according to the present invention, the second hydrogen barrier layer preferably comprises SiOx, SiNx, SiC, TiOx, MgFx, TaN, FeOx, ZrOx, or AlOx.

[0033] A particularly preferred material for the second hydrogen barrier layer is AlOx. Therefore, the second hydrogen barrier layer preferably comprises AlOx. More preferably, the second hydrogen barrier layer consists essentially of AlOx. Even more preferably, the second hydrogen barrier layer consists of AlOx.

[0034] The second hydrogen barrier layer has a third hydrogen permeability, which is at least 10 times lower than the second hydrogen permeability. Preferably, the third hydrogen permeability is at least 20 times, at least 50 times, or at least 100 times lower than the second hydrogen permeability.

[0035] The second hydrogen barrier layer preferably has a density of 10 to 1000 / mm 2 Preferably 20-800 / mm 2 , more comfortable 50~500 / mm2 More preferably 75-250 / mm 2 For example, approximately 25, 50, 75, 100, 125, 150, 175, 200, 225, or 250 / mm 2 It has a pinhole density of . A lower pinhole density is advantageous because it correlates with a decrease in the permeability of hydrogen (e.g., molecular hydrogen) through the second hydrogen barrier layer.

[0036] The second hydrogen barrier layer preferably has a thickness of 0.1 to 200 nm, more preferably 1 to 50 nm. More preferably, the second hydrogen barrier layer has a thickness of 2 to 40 nm, even more preferably 3 to 30 nm, even more preferably 4 to 20 nm, and even more preferably 5 to 15 nm. The second hydrogen barrier layer preferably has a thickness of about 1 nm, about 2 nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8 nm, about 9 nm, about 10 nm, about 11 nm, about 12 nm, about 13 nm, about 14 nm, about 15 nm, about 20 nm, about 25 nm, about 30 nm, about 40 nm, or about 50 nm.

[0037] The second hydrogen barrier layer can be deposited by any suitable method, for example, any suitable method for thin layer deposition. Such methods are known to those skilled in the art and include, but are not limited to, vacuum thermal deposition, electron beam deposition, laser beam deposition, arc deposition, molecular beam epitaxy, ion plating deposition, radio frequency sputtering (DC sputtering), radio frequency sputtering (RF sputtering), sol-gel techniques, chemical bath deposition, spray pyrolysis techniques, electroplating, electroless deposition, chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), plasma-excited chemical vapor deposition (PECVD), and atomic layer deposition (ALD).

[0038] The second hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD).

[0039] A second aspect of the present invention is a method for manufacturing a solar cell, the method comprising depositing a first hydrogen barrier layer on a dielectric layer, the dielectric layer comprising a hydrogen-containing dielectric material. Preferably, the method for manufacturing a solar cell is the method for manufacturing a solar cell described herein.

[0040] The method preferably includes the step of directly depositing a first hydrogen barrier layer onto a dielectric layer. "Directly deposited onto" means that there is no intervening layer between the first hydrogen barrier layer and the dielectric layer.

[0041] The first hydrogen barrier layer can be deposited by any suitable method, for example, any suitable method for thin layer deposition. Such methods are known to those skilled in the art and include, but are not limited to, vacuum thermal deposition, electron beam deposition, laser beam deposition, arc deposition, molecular beam epitaxy, ion plating deposition, radio frequency sputtering (DC sputtering), radio frequency sputtering (RF sputtering), sol-gel techniques, chemical bath deposition, spray pyrolysis techniques, electroplating, electroless deposition, chemical vapor deposition (CVD), low-pressure chemical vapor deposition (LPCVD), plasma-excited chemical vapor deposition (PECVD), and atomic layer deposition (ALD).

[0042] The first hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD). Surprisingly, the inventors have found that using atomic layer deposition for the deposition of the first hydrogen barrier layer results in a hydrogen barrier layer with low permeability to hydrogen (e.g., molecular hydrogen) during solar cell manufacturing (i.e., under typical solar cell manufacturing conditions). While we do not wish to be constrained by theory, it is thought that using ALD for the deposition of the first hydrogen barrier layer yields a thin, uniform layer with a low pinhole density, resulting in low hydrogen (e.g., molecular hydrogen) permeability.

[0043] A particularly preferred material for the first hydrogen barrier layer is AlOx. Therefore, the first hydrogen barrier layer preferably comprises AlOx. More preferably, the first hydrogen barrier layer consists essentially of AlOx. Even more preferably, the first hydrogen barrier layer consists of AlOx.

[0044] Therefore, a preferred method of the present invention includes the step of depositing AlOx onto a dielectric layer, preferably directly onto the dielectric layer, by atomic layer deposition (ALD).

[0045] The methods described herein preferably further include a bulk hydrogen injection step after the deposition of the first hydrogen barrier layer, the bulk hydrogen injection step including heating the solar cell to a temperature of 400 to 900°C, preferably 500 to 800°C. The temperature range is selected to be sufficient to cause the movement (e.g., diffusion) of hydrogen from the hydrogen-containing dielectric into the Si wafer without damaging any other materials and components of the solar cell.

[0046] Therefore, in the preferred method of the present invention, the hydrogen-containing dielectric material contains hydrogen in the range of 5 to 40% by atomic percentage. In other words, the hydrogen-containing dielectric material preferably has a hydrogen concentration in the range of 5 to 40%.

[0047] The hydrogen-containing dielectric material is preferably TiO2, SiN, or SiO2. x N y SiOx, SiC, TiO x ZrO x or includes SiC. In one particularly preferred embodiment, the hydrogen-containing dielectric material includes SiN. More preferably, the hydrogen-containing material consists of essentially SiN. Even more preferably, the hydrogen-containing material consists of essentially SiN.

[0048] A third aspect of the present invention is a solar cell obtained or obtainable by the method described herein. Preferably, the solar cell obtained or obtainable by this method is the solar cell described herein. [Examples]

[0049] Examples Preparation example A standard-sized, commercially available p-type silicon wafer with a resistivity of 0.5–3 Ω·cm and a thickness of 180 microns was used. First, contaminants and sawtooth damage resulting from the wafer slicing process were removed from the wafer surface. This was done using a wet chemical process called sawtooth damage removal, and several micrometers of surface silicon were removed using heated alkaline etching (potassium chloride, KOH).

[0050] After rinsing with deionized (DI) water and acid washing (a mixture of hydrofluoric acid and hydrochloric acid), the wafers were then subjected to another heated alkaline bath (KOH-based) in which a random pyramidal structure was formed on the surface. These surface features, approximately 3 microns in size, form an uneven surface that reduces the light reflectivity from the wafer surface.

[0051] Immediately afterward, surface silicon was removed by several nanometers using moderate alkaline etching at room temperature, and the wafer was rinsed with DI water. Subsequently, a series of cleaning steps, such as RCA cleaning (RCA1 + RCA2 + HF immersion) or a room temperature acid mixture of HF and HCl, were performed to prepare the wafer for the next high-temperature step called emitter diffusion.

[0052] In this step, a gaseous phosphorus source, POCl3, was deposited on the wafer surface in a furnace heated to a temperature well above 750°C. Next, the phosphorus contained in this phosphorus source layer was implanted onto the surface of the original p-type silicon, thereby doping the original p-type silicon with phosphorus and converting it from p-type to n-type at an implantation temperature of approximately 850°C in the presence of oxygen. This created an emitter (phosphorus-doped silicon layer) with a thickness of less than approximately 500 nm. The phosphorus-containing source deposited on the wafer surface is known as phosphate glass, which was removed by HF immersion. This wet process often involves a mixture of concentrated acid (nitric acid (HNO3) + HF + acetic acid), followed by another series of wet etchings including diluted KOH etching and the aforementioned washing. Rinsing with DI water was always incorporated between chemical etchings. The concentrated acid mixture was applied only to the back side of the wafer to remove the n-type silicon layer from the back side and wafer edges, substantially planarizing these surfaces. Typically, silicon was etched from these regions by several micrometers. The surface was either kept intact throughout or etched only slightly (less than several nanometers) by chemical vapors generated in the bath. This process, i.e., edge insulation, is crucial for eliminating short-circuit paths and therefore needs to be uniform and well-controlled.

[0053] After this final cleaning step, the wafer was placed in another furnace where a thin oxide layer was grown at approximately 700°C before passing through a plasma-excited chemical vapor deposition (PECVD) tool. Here, its surface (emitter or n-type side) was coated with an 80 nm silicon nitride (SiNx) layer acting as a hydrogen-containing source and anti-reflective coating (ARC) to further enhance light absorption in the silicon bulk. Additionally, a hydrogen-containing dielectric layer containing several nanometers to tens of nanometers of aluminum oxide (AlOx) was deposited on the back side, and the back side was capped with an approximately 120 nm SiNx layer.

[0054] To form localized contact points on the back surface, a laser was used to locally remove the dielectric layer on the back surface in either a dot pattern or a line pattern. Next, aluminum paste was screen printed across the entire back surface and dried, after which the front surface was screen printed with a silver contact grid pattern. Subsequently, the wafer was placed in a belt furnace, where the screen-printed contact metal was further dried and pressed to form resistive contacts with the underlying silicon, thereby forming the completed solar cell device.

[0055] Next, the solar cell device was placed in an atomic layer deposition (ALD) tool, and a hydrogen barrier layer was deposited on the surface of the cell. AlOx layers with thicknesses ranging from a few nanometers to 100 nanometers were used. Due to the slow deposition rate, thinner layers are preferable for higher throughput. However, the actual required thickness depends on the final application of the device. For a hydrogen barrier, a layer as thin as 10 nm is sufficient.

[0056] Next, the battery was passed through a belt furnace, where it was exposed to temperatures in the range of 500-800°C. This activated the hydrogen from the hydrogen-containing dielectric layer and injected readily mobile hydrogen atoms into the bulk in an appropriate manner, effectively passivating bulk defects.

[0057] Alternative preparation methods In the second implementation method (process flow B), as shown in Figure 1(B), a hydrogen barrier layer was deposited after dielectric deposition on the back surface. This was followed by the standard manufacturing procedure described above. The advantage of this method is that it combines a co-firing step that forms metal contacts with bulk hydrogen injection, thus reducing manufacturing costs.

[0058] While we do not wish to be constrained by theory, this method is expected to inject a higher concentration of hydrogen into the bulk compared to the first method. This is because activating the hydrogen atoms in the dielectric layer during this firing process prevents them from escaping into the environment due to the presence of the ALD AlOx layer, thereby forcing more hydrogen atoms to penetrate into the silicon bulk. In the first method (process flow A), a certain amount of hydrogen is lost into the environment during the co-firing step, leaving less hydrogen available for the final bulk hydrogen injection step (see Figure 3).

[0059] Experimental results Regarding device efficiency, the presence of more hydrogen in the bulk can result in lower early-life (BoL) efficiency. However, the resulting increase in bulk hydrogen concentration enhances the battery's ability to repair damage caused by cosmic radiation, thereby improving end-of-life (EoL) efficiency.

[0060] A passivation emitter and back-face contact (PERC) life test structure sample was prepared as described above, and a 1 × 10⁻⁶ sample was created. 12 ~1 × 10 15 electron / cm 2 Experiments were conducted irradiating the wafer with 1 MeV electrons of variable fluence. This test structure, as shown in Figure 5, is necessary to determine the wafer quality and lifespan, which are directly related to the potential battery efficiency. Subsequently, the samples were dark-annealed, and the restoration effect was investigated by periodically monitoring the sample lifespan. As seen in Figure 4, 1 × 10 12 electron / cm 2 Those samples exposed to it showed remarkable recovery.

[0061] The inventors have shown that in the first method, even relatively small amounts of hydrogen available in the silicon bulk can repair radiation-induced defects (Figure 4), thereby improving the performance of the solar cell (Figure 5). Therefore, by including a hydrogen barrier layer deposited on a dielectric layer containing a hydrogen-containing dielectric, defects caused by exposure to extraterrestrial radiation can be self-repaired, resulting in improved EoL efficiency of the solar cell.

Claims

1. A solar cell comprising a Si wafer and a dielectric layer deposited on the Si wafer, wherein the dielectric layer comprises a hydrogen-containing dielectric material, and the solar cell further comprises a first hydrogen barrier layer deposited on the dielectric layer.

2. The solar cell according to claim 1, wherein the Si wafer is a p-type Si wafer, an n-type Si wafer, or an intrinsic Si wafer.

3. The solar cell according to claim 2, wherein the Si wafer is a p-type Si wafer.

4. A solar cell according to any one of claims 1 to 3, further comprising at least one contact, wherein the at least one contact comprises polySi / SiOx, an aluminum alloy, phosphorus-diffused silicon, gallium-diffused silicon, or boron-diffused silicon.

5. The solar cell according to any one of claims 1 to 4, wherein the first hydrogen barrier layer comprises SiOx, SiNx, SiC, TiOx, MgFx, TaN, FeOx, ZrOx, or AlOx.

6. The solar cell according to claim 5, wherein the first hydrogen barrier layer comprises AlOx.

7. The solar cell according to claim 5 or 6, wherein the first hydrogen barrier layer is made of AlOx.

8. The solar cell according to any one of claims 1 to 7, wherein the first hydrogen barrier layer has a first hydrogen permeability, and the hydrogen-containing dielectric layer has a second hydrogen permeability, and the first hydrogen permeability is at least 10 times lower than the second hydrogen permeability.

9. The first hydrogen barrier layer has a density of 10 to 1000 / mm ２ Preferably 20 to 800 / mm ２ A solar cell according to any one of claims 1 to 8, having a pinhole density.

10. The solar cell according to any one of claims 1 to 9, wherein the first hydrogen barrier layer has a thickness of 0.1 to 200 nm, preferably 1 to 50 nm.

11. The solar cell according to any one of claims 1 to 10, wherein the first hydrogen barrier layer is deposited by atomic layer deposition (ALD).

12. The solar cell according to any one of claims 1 to 11, wherein the first hydrogen barrier layer is deposited directly on the dielectric layer.

13. The solar cell according to any one of claims 1 to 12, wherein the hydrogen-containing dielectric material contains hydrogen in the range of 5 to 40% by atomic percentage.

14. The hydrogen-containing dielectric material is TiO ２ SiN, SiO ｘ N ｙ , SiOx, SiC, TiO ｘ , ZrO ｘ A solar cell according to any one of claims 1 to 13, or comprising SiC.

15. The solar cell according to any one of claims 1 to 14, wherein the hydrogen-containing dielectric material includes SiN.

16. The solar cell according to any one of claims 1 to 15, further comprising a second hydrogen barrier layer, wherein the second hydrogen barrier layer is not in direct contact with the first hydrogen barrier layer.

17. The solar cell according to claim 16, wherein the second hydrogen barrier layer contains AlOx, and preferably the second hydrogen barrier layer is made of AlOx.

18. The solar cell according to claim 16 or 17, wherein the second hydrogen barrier layer has a third hydrogen permeability, the third hydrogen permeability being at least 10 times lower than the second hydrogen permeability.

19. The second hydrogen barrier layer has a pinhole density of 10 to 1000 / mm ２ , preferably 20 to 800 / mm ２ The solar cell according to any one of claims 16 to 18, having a pinhole density of

20. The solar cell according to any one of claims 16 to 19, wherein the second hydrogen barrier layer has a thickness of 0.1 to 200 nm, preferably 1 to 50 nm.

21. The solar cell according to any one of claims 16 to 20, wherein the second hydrogen barrier layer is deposited by atomic layer deposition (ALD).

22. A method for manufacturing a solar cell, the method comprising depositing a first hydrogen barrier layer on a dielectric layer, wherein the dielectric layer comprises a hydrogen-containing dielectric material.

23. The method according to claim 22, wherein the first hydrogen barrier layer is deposited directly on the dielectric layer.

24. The method according to claim 22 or 23, wherein the first hydrogen barrier layer is deposited by atomic layer deposition (ALD).

25. The solar cell according to any one of claims 22 to 24, wherein the first hydrogen barrier layer comprises AlOx, preferably the first hydrogen barrier layer is made of AlOx.

26. The method according to any one of claims 22 to 25, further comprising a bulk hydrogen injection step after the deposition of the first hydrogen barrier layer, wherein the bulk hydrogen injection step includes heating the solar cell to a temperature of 400 to 900°C, preferably 500 to 800°C.

27. The method according to any one of claims 22 to 26, wherein the hydrogen-containing dielectric material contains hydrogen in an atomic percentage range of 5 to 40%.

28. The hydrogen-containing dielectric material is TiO ２ SiN, SiO ｘ N ｙ The method according to any one of claims 22 to 27, comprising, or SiC.

29. The method according to any one of claims 22 to 28, wherein the hydrogen-containing dielectric material includes SiN.

30. A solar cell obtained or obtainable by the method described in any one of claims 22 to 29.

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