Effects of SiOx barrier layer prepared by plasma-enhanced chemical vapor deposition on improvement of long-term reliability and production cost for Cu-plated amorphous Si/crystalline Si heterojunction solar cells

Adachi, Daisuke; Terashita, Toru; Uto, Toshihiko; Hernández, José Luis; Yamamoto, Kenji

doi:10.1016/j.solmat.2016.12.029

Cited by 53 publications

(41 citation statements)

References 11 publications

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“…However, little or none of this AR benefit will remain in an encapsulated module due to the refractive index of the polymer encapsulation foil having the same value of about 1.5 as the a-SiO2. Even more important for the ZnO:Al is the protective effect of the a-SiO2 capping for the module stability as shown previously [14] and which we demonstrate in this study. Fig.…”

Section: Introductionsupporting

confidence: 85%

“…Supported by optical simulations, we demonstrate an optical improvement of the SHJ finished cells when introducing an additional plasma-enhanced chemical vapor deposited (PECVD) silicon dioxide (a-SiO2) antireflection (AR) layer on top of the ZnO:Al. This double AR stack concept has been used in the past by other groups using different materials (ITO, IWO as TCO and MgF2 or SiO2 as AR coating) showing also a clear optical improvement due to the double layer [8][9][10][11][12][13][14][15]. However, little or none of this AR benefit will remain in an encapsulated module due to the refractive index of the polymer encapsulation foil having the same value of about 1.5 as the a-SiO2.…”

Section: Introductionmentioning

confidence: 99%

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ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%

Morales-Vilches

Cruz

Pingel

et al. 2019

IEEE J. Photovoltaics

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Silicon heterojunction solar cells (SHJ) have been increasingly attracting attention to the PV community in the last years due to their high efficiency potential and the lean production process. We report on the development of a stable baseline process for SHJ cells with a focus on the optical improvement of the solar cells' front side. An amorphous silicon oxide layer (a-SiO 2 ) was used as an anti-reflective coating (AR) on top of the finished SHJ devices. Both optical simulations and experimental results demonstrate a short circuit current density (J sc ) improvement of 0.4 mA/cm 2 when applying the a-SiO 2 AR, yielding maximum conversion efficiencies of 23.0 %. Full-size cells with 244-cm 2 total area have been produced using three front contact stacks: ITO as reference, ZnO:Al and ZnO:Al/SiO 2 showing the J sc improvement with the double AR configuration. Damp-heat tests on those samples are currently being carried out.

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Section: Introductionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%

Morales-Vilches

Cruz

Pingel

et al. 2019

IEEE J. Photovoltaics

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“…A different approach presented by Adachi et al and patented by Kaneka uses a SiO x ‐mask. The sequence consists of first screen printing a low temperature metal paste grid and then depositing the SiO x ‐mask.…”

Section: Parameters (Measured Under Stc) Of Two Identically Procesmentioning

confidence: 99%

Laser Transfer and Firing of NiV Seed Layer for the Metallization of Silicon Heterojunction Solar Cells by Cu-Plating

et al. 2017

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We present a laser-based method for the metallization of silicon heterojunction solar cells by Cu-plating. It consists of first applying a dielectric layer on the transparent conductive oxide (TCO) as a plating mask. Then, a NiV seed is transferred by laser induced forward transfer (LIFT) from a plastic carrier foil onto the wafer. In the second laser step, the NiV layer is fired through the dielectric layer to form a contact to the TCO. After the laser process, Cu-fingers are produced by plating. The dielectric plating mask remains on the cell. Parasitic plating is prevented by using an advanced reverse pulse plating process. With the first solar cells we reach a maximum efficiency of 22.2% and an efficiency gain of 0.5% abs compared to lowtemperature screen printing reference cells, due to a higher short circuit current and fill factor. The 30 mm wide fingers reach specific contact resistances down to 0.6 mV cm 2 and also, pass a tape adhesion test. We further demonstrate that the laser process does not cause any measurable open circuit voltage loss and that a precise alignment of the two laser steps is not necessary.Silicon heterojunction (SHJ) solar cells are believed to play a major role in the future PV market [1] . Compared to homojunction solar cells, they offer a superior module performance due to their higher open circuit voltage and their lower temperature coefficient. Moreover, the production is relatively simple and does not require high temperature steps. However, a drawback for this technology still is the metallization. Screen printed metallization can only be applied with special expensive low temperature silver pastes [2] , because the passivation by the amorphous silicon (a-Si) layers of SHJ cells cannot withstand temperatures above 200-250 C [3] . Lowtemperature silver pastes reach resistivities between 5 and 10 mVcm [4] , which is far higher than for standard silver pastes sintered at high temperature (>800 C). The typical width of industrially produced screen printed fingers on SHJ cells lies between 60 and 80 mm.Cu-plating as a low temperature metallization is a more suitable technology. Kaneka has recently presented a plated SHJ solar cell with 25.1% efficiency, which represents the world record for both-sidecontacted SHJ solar cells [5] . Depending on the masking approach, plated fingers can be much thinner than screen printed fingers and the resistivity of plated metal is very close to that of bulk Cu (1.7 mVcm). In fact, plating has shown to outperform low temperature screen printing due to a higher fill factor (FF) [6] and a higher short circuit current (J SC ) [7] . High peel forces (3-5 N/mm) for plated copper fingers on TCO have been measured with an intermediate seed layer [8,9] . In addition, plating imposes less mechanical stress onto the wafer than screen printing, which is an advantage in view of thinner wafers expected in the future [1] .In order to plate a grid structure on the TCO surface of SHJ cells, in most cases, a structured organic plating mask is applied, which covers...

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“…The SiO x on TCO acts as insulating mask to plate copper only onto the printed seed. Moreover it is an interesting approach for increased reliability of the solar cells …”

Section: Introductionmentioning

confidence: 99%

Native Oxide Barrier Layer for Selective Electroplated Metallization of Silicon Heterojunction Solar Cells

et al. 2019

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The metallization of silicon heterojunction (SHJ) solar cells by electroplating of highly conductive copper onto a multifunctional patterned metal layer stack is demonstrated. The approach features several advantages: low temperature processing, high metal conductivity of plated copper, no organic making, and low material costs (almost Ag‐free). A PVD layer stack of copper and aluminum is deposited onto the cell subsequently to TCO deposition. The aluminum layer is patterned with a printed etchant and its native oxide on the remaining areas inhibits plating. The full area aluminum layer while electroplating supports plating current distribution and allows homogeneous plating height distributions over the cell. The NOBLE (native oxide barrier layer for selective electroplating) approach allows reaching a first encouraging SHJ solar cell efficiency of 20.2% with low contact resistivity.

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Effects of SiOx barrier layer prepared by plasma-enhanced chemical vapor deposition on improvement of long-term reliability and production cost for Cu-plated amorphous Si/crystalline Si heterojunction solar cells

Cited by 53 publications

References 11 publications

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%

Laser Transfer and Firing of NiV Seed Layer for the Metallization of Silicon Heterojunction Solar Cells by Cu-Plating

Native Oxide Barrier Layer for Selective Electroplated Metallization of Silicon Heterojunction Solar Cells

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Effects of SiOx barrier layer prepared by plasma-enhanced chemical vapor deposition on improvement of long-term reliability and production cost for Cu-plated amorphous Si/crystalline Si heterojunction solar cells

Cited by 53 publications

References 11 publications

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO2 Front Electrodes Reaching a Conversion Efficiency of 23%

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO2 Front Electrodes Reaching a Conversion Efficiency of 23%

Laser Transfer and Firing of NiV Seed Layer for the Metallization of Silicon Heterojunction Solar Cells by Cu-Plating

Native Oxide Barrier Layer for Selective Electroplated Metallization of Silicon Heterojunction Solar Cells

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Product

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ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%

ITO-Free Silicon Heterojunction Solar Cells With ZnO:Al/SiO₂ Front Electrodes Reaching a Conversion Efficiency of 23%