Solar cell

Abstract

In general, the present disclosure provides a solar cell including a hydrogen barrier layer and a hydrogen-containing dielectric layer. The invention also provides a method of manufacturing a solar cell, and a solar cell obtained or obtainable by such a method.

Description

Technical Field

[0001] Generally speaking, the present invention provides a solar cell, which includes a hydrogen barrier layer and a hydrogen-containing dielectric layer. The present invention also provides a method for manufacturing a solar cell, and a solar cell obtained or obtainable by such a method. Background Art

[0002] In recent years, space activities have grown exponentially, which means that the demand for space energy is very high. Solar cells provide a possible way to address this rapid growth in energy demand.

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

[0004] There is still a need for solar cells suitable for space applications, which are more resistant to degradation caused by space radiation and can be manufactured more cheaply and on a large scale. Summary of the Invention

[0005] A first aspect of the present invention is a solar cell, which includes a Si wafer and a dielectric layer deposited on the Si wafer, wherein the dielectric layer contains a hydrogen-containing dielectric material; and the solar cell further includes 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 including depositing a first hydrogen barrier layer on a dielectric layer, wherein the dielectric layer contains a hydrogen-containing dielectric material.

[0007] A third aspect of the present invention is a solar cell obtained or obtainable by the method as defined above. Brief Description of the Drawings

[0008] Figure 1 shows two exemplary process flows for manufacturing a self-healing solar cell according to the present invention using a hydrogen barrier layer.

[0009] Figure 2 Shows a schematic diagram of a solar cell according to the present invention produced by the second exemplary process flow of Figure 1.

[0010] Figure 3 Shows a schematic diagram of the hydrogen distribution in a solar cell according to the present invention before and after a high-temperature firing step.

[0011] Figure 4 Shows the minority charge carrier lifetime of a symmetric silicon test sample as a function of the dark annealing time of samples receiving different doses of 1 MeV electrons. After dark annealing, the lifetime of the irradiated samples increases, indicating that the solar cell can 'self-repair' radiation-induced defects.

[0012] Figure 5 Shows the simulated efficiency as a function of the bulk minority carrier lifetime. The simulation is performed using Quokka 3. Figure 4 The lifetime shown directly affects the efficiency of the solar cell. Detailed Description

[0013] 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.

[0014] Since 2000, hydrogen has been used in terrestrial solar cells for passivation purposes. It is typically provided to the cell by a hydrogen-containing dielectric layer (commonly used as an antireflection coating), which is activated by a rapid firing process. However, too much hydrogen can have a detrimental effect on solar cell performance (WO 2018094462A1). Applying an AlOx layer on top of the hydrogen-containing dielectric layer prevents hydrogen from escaping into the environment during the firing step and thus increases the hydrogen content in the Si bulk. This can lead to lower beginning-of-life (BoL) cell efficiency and significantly enhanced light-induced degradation due to light and elevated-temperature-induced degradation (LeTID) (Varshney, U. et al., Controlling Light-and Elevated-Temperature-Induced Degradation With Thin Film Barrier Layers. [Controlling Light-and Elevated-Temperature-Induced Degradation With Thin Film Barrier Layers] IEEE Journal of Photovoltaics, 2020.10(1): pp. 19-27). Therefore, this method is considered undesirable and not recommended for the manufacture of Si-based solar cells.

[0015] However, in the case of the space environment, an increase in the hydrogen concentration in the bulk means that radiation-induced damage can be repaired more effectively by hydrogen passivation. Although the initial BoL efficiency may be lower, this method enhances the cell's ability to self-repair from radiation and results in better end-of-life (EoL) efficiency, which is the most important metric for space solar cells.

[0016] Accordingly, the object of the present invention is to deliberately increase the bulk hydrogen content in silicon solar cells in order to improve their self-healing ability in response to space radiation, thereby increasing their lifetime and end-of-life (EoL) performance. This approach is counterintuitive in the art because, as discussed above, high hydrogen concentrations are generally regarded as detrimental to the performance of solar cells.

[0017] In the solar cell as described above, 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 results in increased radiation tolerance.

[0018] The solar cell preferably further includes at least one contact, and preferably includes contacts for electrons and holes. The at least one contact preferably includes polycrystalline Si / SiOx, aluminum alloy, phosphorus-diffused silicon, gallium-doped silicon, or boron-diffused silicon. For the avoidance of doubt, any other suitable contact material known to the person skilled in the art may be used.

[0019] 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.

[0020] A particularly preferred material for the first hydrogen barrier layer is AlOx. Accordingly, the first hydrogen barrier layer preferably contains AlOx. More preferably, the first hydrogen barrier layer consists essentially of AlOx. Even more preferably, the first hydrogen barrier layer consists of AlOx.

[0021] The first hydrogen barrier layer is used to prevent hydrogen from being released from the hydrogen-containing dielectric material during the manufacturing process of the solar cell. In doing so, the hydrogen released from the hydrogen-containing dielectric material during the manufacturing process is forced to migrate until it reaches the Si wafer. Accordingly, the bulk hydrogen content of the Si wafer increases, resulting in an improvement in the EoL characteristics of the above-described solar cell.

[0022] Accordingly, it is required that the first hydrogen barrier layer contains a material that is relatively impermeable to hydrogen (i.e., molecular hydrogen) under the conditions for manufacturing the solar cell.

[0023] Thus, in the solar cell of the present invention, preferably, the first hydrogen barrier layer has a first hydrogen permeation rate, and the hydrogen-containing dielectric layer has a second hydrogen permeation rate; wherein the first hydrogen permeation rate is at least one-tenth of the second hydrogen permeation rate. Preferably, the first hydrogen permeation rate is at least one-twentieth, at least one-fiftieth, or at least one-hundredth of the second hydrogen permeation rate.

[0024] The first hydrogen barrier layer preferably has 10 - 1000 / mm 2 、preferably 20 - 800 / mm 2, more preferably 50 - 500 / mm 2 and even more preferably 75 - 250 / mm 2 , such as about 25, about 50, about 75, about 100, about 125, about 150, about 175, about 200, about 225, or about 250 / mm 2 The pinhole density. A lower pinhole density is advantageous as it is associated with a reduced rate of permeation of hydrogen (e.g., molecular hydrogen) through the first hydrogen barrier layer.

[0025] The first hydrogen barrier layer preferably has a thickness between 0.1 and 200 nm, preferably between 1 and 50 nm. More preferably, the first hydrogen barrier layer has a thickness between 2 and 40 nm, still more preferably between 3 and 30 nm, even more preferably between 4 and 20 nm, and yet more preferably between 5 and 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.

[0026] The first hydrogen barrier layer must have a thickness large enough to exhibit the above-described hydrogen barrier properties (e.g., low permeability to hydrogen under solar cell manufacturing conditions). However, it should be understood that increasing the thickness of any layer in a solar cell will result in a corresponding increase in size, weight, cost, and manufacturing time (and thus yield), and thus any layer with a relatively high thickness may be undesirable. It has surprisingly been found that in the present invention, a hydrogen barrier layer as thin as about 10 nm is sufficient to produce the desired hydrogen barrier properties.

[0027] Thus, 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 consists essentially of AlOx, and still more preferably consists of AlOx.

[0028] The first hydrogen barrier layer can be deposited by any suitable method, such as any suitable method for depositing thin layers. Such methods are known to those skilled in the art and include, but are not limited to, vacuum thermal evaporation, electron beam evaporation, laser beam evaporation, arc evaporation, molecular beam epitaxy, ion plating evaporation, direct current 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 - enhanced chemical vapor deposition (PECVD), and atomic layer deposition (ALD)

[0029] The first hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD). The inventors of the present invention have surprisingly found that depositing the first hydrogen barrier layer by atomic layer deposition results in a hydrogen barrier layer that has low permeability to hydrogen (e.g., molecular hydrogen) during the manufacturing process of a solar cell (i.e., under typical solar cell manufacturing conditions). Without wishing to be bound by theory, it is believed that depositing the first hydrogen barrier layer using ALD results in a thin, uniform layer with a low pinhole density and low hydrogen (e.g., molecular hydrogen) permeability.

[0030] In a preferred solar cell as described herein, the first hydrogen barrier layer is deposited directly on the dielectric layer. "Deposited directly on" means that there is no intermediate layer between the first hydrogen barrier layer and the dielectric layer.

[0031] The solar cell of the present invention includes a dielectric layer, wherein the dielectric layer contains a hydrogen-containing dielectric material. The hydrogen-containing dielectric material preferably 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%. It has surprisingly been found that using a precursor of the hydrogen-containing dielectric material that contains hydrogen and, moreover, not taking steps to reduce, substantially remove, or completely remove the hydrogen derived from the precursor can advantageously result in hydrogen passivation of the Si wafer during subsequent manufacturing steps, as described above.

[0032] The dielectric layer can be a single layer or can include a stack of multiple dielectric thin films. Preferably, the dielectric layer is a single layer.

[0033] The hydrogen-containing dielectric material preferably contains TiO2, SiN, SiO x N y , SiOx, SiC, TiO x , ZrO x or SiC. In a particularly preferred embodiment, the hydrogen-containing dielectric material contains SiN. More preferably, the hydrogen-containing material consists essentially of SiN. Even more preferably, the hydrogen-containing material consists of SiN.

[0034] The solar cell can further include a second hydrogen barrier layer, wherein the second hydrogen barrier layer does not directly contact the first hydrogen barrier layer. "Does not directly contact" means that there is at least one intermediate layer, and preferably multiple intermediate layers, between the first hydrogen barrier layer and the second hydrogen barrier layer.

[0035] For example, the second hydrogen barrier layer can be deposited on the side of the Si wafer opposite to 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 arrangement, the second hydrogen barrier layer can advantageously prevent hydrogen from the hydrogen-containing dielectric material from migrating out of the Si wafer.

[0036] 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.

[0037] A particularly preferred material for the second hydrogen barrier layer is AlOx. Thus, the second hydrogen barrier layer preferably contains AlOx. More preferably, the second hydrogen barrier layer consists essentially of AlOx. Even more preferably, the second hydrogen barrier layer consists of AlOx.

[0038] The second hydrogen barrier layer has a third hydrogen permeation rate, wherein the third hydrogen permeation rate is as low as at least one tenth of the second hydrogen permeation rate. Preferably, the third hydrogen permeation rate is as low as at least one twentieth, at least one fiftieth, or at least one hundredth of the second hydrogen permeation rate.

[0039] The second hydrogen barrier layer preferably has a pinhole density of 10 - 1000 / mm 2 , preferably 20 - 800 / mm 2 , more preferably 50 - 500 / mm 2 and even more preferably 75 - 250 / mm 2 , such as about 25, about 50, about 75, about 100, about 125, about 150, about 175, about 200, about 225, or about 250 / mm 2 . A lower pinhole density is advantageous because it is associated with a reduced permeation rate of hydrogen (such as molecular hydrogen) through the second hydrogen barrier layer.

[0040] The second hydrogen barrier layer preferably has a thickness between 0.1 and 200 nm, preferably between 1 and 50 nm. More preferably, the second hydrogen barrier layer has a thickness between 2 and 40 nm, still more preferably between 3 and 30 nm, even more preferably between 4 and 20 nm, and even more preferably between 5 and 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.

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

[0042] The second hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD).

[0043] A second aspect of the present invention is a method of 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. Preferably, the method of manufacturing a solar cell is the method of manufacturing a solar cell as described above.

[0044] The method preferably includes the step of directly depositing the first hydrogen barrier layer on the dielectric layer. "Directly depositing on" means that there is no intermediate layer between the first hydrogen barrier layer and the dielectric layer.

[0045] The first hydrogen barrier layer can be deposited by any suitable method, such as any suitable method for depositing thin layers. Such methods are known to those skilled in the art and include, but are not limited to, vacuum thermal evaporation, electron beam evaporation, laser beam evaporation, arc evaporation, molecular beam epitaxy, ion plating evaporation, direct current sputtering (DC sputtering), radio frequency sputtering (RF sputtering), sol-gel technology, chemical bath deposition, spray pyrolysis technology, electroplating, electroless deposition, chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), and atomic layer deposition (ALD).

[0046] The first hydrogen barrier layer is preferably deposited by atomic layer deposition (ALD). The inventors of the present invention have unexpectedly found that depositing the first hydrogen barrier layer using atomic layer deposition produces a hydrogen barrier layer that has low permeability to hydrogen (such as molecular hydrogen) during the solar cell manufacturing process (i.e., under typical solar cell manufacturing conditions). Without wishing to be bound by theory, it is believed that using ALD to deposit the first hydrogen barrier layer results in a thin, uniform layer with a low pinhole density and a low hydrogen (such as molecular hydrogen) permeability.

[0047] A particularly preferred material for the first hydrogen barrier layer is AlOx. Thus, 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.

[0048] Thus, in a preferred method of the present invention, the method comprises depositing AlOx on a dielectric layer, preferably directly on the dielectric layer, by atomic layer deposition (ALD).

[0049] The method as described above preferably further comprises a bulk hydrogen implantation step after depositing the first hydrogen barrier layer, wherein the bulk hydrogen implantation step comprises heating the solar cell at a temperature between 400 °C and 900 °C, preferably between 500 °C and 800 °C. The selected temperature range is sufficient to cause hydrogen to migrate (e.g., diffuse) from the hydrogen-containing dielectric into the Si wafer, while not damaging any other materials or components of the solar cell.

[0050] Thus, in a 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%.

[0051] The hydrogen-containing dielectric material preferably comprises TiO2, SiN, SiO x N y , SiOx, SiC, TiO x , ZrO x or SiC. In a particularly preferred embodiment, the hydrogen-containing dielectric material comprises SiN. More preferably, the hydrogen-containing material consists essentially of SiN. Even more preferably, the hydrogen-containing material consists of SiN.

[0052] A third aspect of the present invention is a solar cell obtained or obtainable by the method as described above. Preferably, the solar cell obtained or obtainable by the method is the solar cell as described above.

[0053] Examples

[0054] Preparation Example

[0055] Full-sized cut commercial p-type silicon wafers with a resistivity of 0.5 - 3 ohm·cm and a thickness of 180 microns were used. First, contaminants on the wafer surface and saw marks generated during the wafer slicing process were removed. This was done using a wet chemical process called saw mark removal, where heated alkaline etching (potassium chloride, KOH) was used to remove a few microns of surface silicon.

[0056] After rinsing in deionized (DI) water and acid cleaning (a mixture of hydrofluoric acid and hydrochloric acid), the wafers were then subjected to another heated alkali bath (based on KOH), where random pyramid-shaped structures were formed on the surface. The size of these surface features was approximately 3 microns and produced a textured surface that reduced light reflection from the wafer surface.

[0057] Next, a few nanometers of surface silicon are removed using room-temperature mild alkaline etching and rinsed with DI water. Then comes a series of cleaning processes, such as RCA cleaning (RCA1 + RCA2 + HF soak) or a room-temperature acidic mixture of HF and HCl, to prepare the wafer for the next high-temperature step called emitter diffusion.

[0058] In this step, the phosphorus source POCl3 in gaseous form is deposited on the surface of the wafer inside a furnace heated to a temperature well above 750 °C. Then, the phosphorus contained in this source layer is driven into the surface and thus dopes the original p-type silicon, converting it to n-type silicon in the presence of oxygen and at a drive-in temperature of about 850 °C. This produces an emitter (phosphorus-doped silicon layer) approximately less than 500 nm thick. The phosphorus-containing source deposited on the wafer surface is called phosphosilicate glass, which is removed in an HF soak. This wet process is typically the start of another series of wet etchings, which include a mixture of concentrated acids (nitric acid (HNO3) + HF + acetic acid), dilute KOH etching, and the cleaning series as described before. DI water rinsing is always carried out between chemical etchings. The concentrated acid mixture is applied only to the back side of the wafer to remove the n-type silicon layer from the back side and the wafer edges, effectively flattening these surfaces. Typically, a few micrometers of silicon are etched from these areas. The front side is either kept intact throughout or slightly etched (less than a few nanometers) by the chemical vapors generated in the bath. This process - edge isolation - is very important for eliminating shunt paths and thus must be uniform and well-controlled.

[0059] After this final cleaning process, the wafer enters another furnace where a thin oxide layer is grown at about 700 °C and then through a plasma-enhanced chemical vapor deposition (PECVD) tool. Here, its front side (emitter or n-type side) is coated with an 80-nm layer of silicon nitride (SiNx), acting as a hydrogen-containing source and an antireflection coating (ARC) to further increase light absorption in the silicon bulk. A hydrogen-containing dielectric layer is also deposited on the back side, including aluminum oxide (AlOx) from a few nanometers to several tens of nanometers, and covered with an approximately 120-nm SiNx layer.

[0060] To form local contact points on the back side, a laser is used to locally remove the back-side dielectric layer in a pattern of dots or lines. Before screen-printing a silver contact grid pattern on the front side, silver paste is then screen-printed over the entire back side and dried. Then the wafer is placed in a belt furnace where it is further dried and the screen-printed contact metal is driven in to form an ohmic contact with the underlying silicon, forming a complete solar cell device.

[0061] Then, the solar cell device is placed into an atomic layer deposition (ALD) tool to deposit a hydrogen barrier layer on the surface of the cell. An AlOx layer with a thickness ranging from a few nanometers to one hundred nanometers is used. Due to the slow deposition rate, in order to achieve higher production yields, it is preferred to deposit a thinner layer. However, the actual required thickness depends on the final application of the device. For hydrogen barrier, a layer as thin as 10 nm is sufficient.

[0062] Then, the cell is passed through a belt furnace where the cell is subjected to a temperature in the range of 500 °C to 800 °C to activate the hydrogen from the hydrogen-containing dielectric layer and inject the mobile hydrogen atoms into the bulk in their appropriate form, thereby effectively passivating the bulk defects.

[0063] Alternative Preparation Method

[0064] In the second implementation method (process flow B), the hydrogen barrier layer is deposited after the backside dielectric deposition, as shown in Figure 1(B). Then follows the standard manufacturing sequence as described above. The advantage of this method is that the bulk hydrogen injection is combined with the co-firing step of forming the metal contacts, thus reducing the manufacturing cost.

[0065] Without being bound by theory, compared to the first method, this method is expected to result in a higher concentration of hydrogen injected into the bulk. This is because once the hydrogen atoms in the dielectric layer are activated during this firing step, due to the presence of the ALD AlOx layer, they are prevented from escaping into the environment, which forces them to penetrate more into the silicon bulk. In the first implementation method (process flow A), during the co-firing step, a certain amount of hydrogen will be lost to the environment, resulting in less hydrogen available in the final bulk hydrogen injection step (see Figure 3 ).

[0066] Experimental Results

[0067] In terms of device efficiency, the presence of more hydrogen in the bulk may lead to a lower beginning-of-life (BoL) efficiency. However, the resulting increased hydrogen concentration in the bulk improves the cell's ability to repair damage caused by space radiation, thereby enhancing its end-of-life (EoL) efficiency.

[0068] Experiments were conducted where passivated emitter and rear contact (PERC) lifetime test structure samples were fabricated as described above and irradiated with 1 MeV electrons at different energy densities from 1x10 12 to 1x10 15 electrons / cm 2 . Such test structures are necessary for determining the quality of the wafers and their lifetimes, which are directly related to their potential cell efficiency, as Figure 5 shown. Subsequently, the samples were dark annealed and their lifetimes were monitored regularly to study the repair effect. As Figure 4As shown, those samples exposed to 1x 10 12 electrons / cm 2 showed significant recovery.

[0069] We have demonstrated that even in the first method, the relatively small amount of hydrogen available in the silicon bulk is able to repair radiation-induced defects ( Figure 4 ), and thereby improve the performance of the solar cell ( Figure 5 ). Thus, including a hydrogen barrier layer deposited on a dielectric layer containing a hydrogen-containing dielectric, by self-healing defects caused by exposure to extraterrestrial radiation, results in an increase in the 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. The solar cell according to any one of the preceding claims, further comprising at least one contact, wherein the at least one contact comprises polycrystalline Si / SiOx, aluminum alloy, phosphorus-diffused silicon, gallium-diffused silicon or boron-diffused silicon.

5. The solar cell according to any one of the preceding claims, 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 contains AlOx.

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

8. The solar cell according to any one of the preceding claims, wherein, The first hydrogen barrier layer has a first hydrogen permeation rate, and the hydrogen-containing dielectric layer has a second hydrogen permeation rate; wherein the first hydrogen permeation rate is at least one-tenth as low as the second hydrogen permeation rate.

9. The solar cell according to any one of the preceding claims, wherein, The first hydrogen barrier layer has a pinhole density of 10 - 1000 / mm 2 , preferably 20 - 800 / mm 2 .

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

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

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

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

14. The solar cell according to any one of the preceding claims, wherein, The hydrogen-containing dielectric material includes TiO2, SiN, SiO x N y , SiOx, SiC, TiO x , ZrO x or SiC.

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

16. The solar cell according to any one of the preceding claims, 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, preferably wherein the second hydrogen barrier layer consists of AlOx.

18. The solar cell according to claim 16 or claim 17, wherein,The second hydrogen barrier layer has a third hydrogen permeation rate; wherein the third hydrogen permeation rate is at least one-tenth as low as the second hydrogen permeation rate.

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

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

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

25. The method according to any one of claims 22 to 24, wherein, The first hydrogen barrier layer contains AlOx, preferably wherein the first hydrogen barrier layer consists of AlOx.

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

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

28. The method according to any one of claims 22 to 27, wherein, The hydrogen-containing dielectric material includes TiO2, SiN, SiO x N y , 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 obtainable or obtained by the method according to any one of claims 22 to 29.

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