Study of Cu-X alloy seed layer on ITO for copper-plated silicon heterojunction solar cells

Lee, Sangeun; Lee, Doo Won; Kim, Hanjun; Lee, Ah Reum; Lee, Soo Hong; Lim, Kyoung‐jin; Shin, Won-Suk

doi:10.1016/j.mssp.2018.07.002

Cited by 10 publications

(5 citation statements)

References 16 publications

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“…However, the connection with the Cu-Ni alloy seed layer exhibited stronger adhesion, as the connection remained intact after the tape test. Furthermore, tape tests conducted on SHJ solar cells with Cu-X/Cu/Ag busbars using different Cu-X seed layers confirmed that the Cu-Ni seed layer demonstrated better adhesion than Cu, Cu-Mn, and Cu-Al [19]. These studies emphasize the importance of improving the adhesion between copper and TCO layers to enhance the reliability and performance of copper metallization techniques for solar cell applications.…”

Section: Introductionmentioning

confidence: 77%

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Study of Microstructure and Mechanical Properties of Electrodeposited Cu on Silicon Heterojunction Solar Cells

Jing¹,

Shan²,

Huang³

et al. 2023

Metals

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This study investigated the use of a pure copper seed layer to improve the adhesion strength and reduce the residual stress of electroplated copper films for heterojunction technology in crystalline solar cells. The experiment involved depositing a copper seed layer and an indium tin oxide (ITO) layer on textured silicon using sputtering. This resulted in the formation of a Cu(s)/ITO/Si structure. Following this step, a 10 µm thick copper layer was electroplated onto the Cu(s)/ITO/Si structure. Various characterization techniques were employed to evaluate the electroplated copper films’ microstructures, residual stress, and adhesion strength. The microstructures of the films were examined using a scanning transmission electron microscope (STEM), revealing a twin structure with a grain size of approximately 1 µm. The residual stresses of the as-deposited and annealed samples were measured using an X-ray diffractometer (XRD), yielding values of 76.4 MPa and 49.1 MPa, respectively. The as-deposited sample exhibited higher tension compared to the annealed sample. To assess the adhesion strength of the electroplated copper films, peel-off tests were conducted at a 90° angle with a constant speed of 30 mm/min. The peel force, measured in units of N/mm, was similar for both the as-deposited and annealed samples. Specifically, the peel force for electroplating copper on the copper seed layer on the ITO was determined to be 2.6 N/mm for the maximum value and 2.25 N/mm for the average value. This study demonstrated that using a pure copper seed layer during electroplating can improve adhesion strength and reduce residual stress in copper films for heterojunction technology in crystalline solar cells. These findings contribute to the development of more reliable and efficient solar-cell-manufacturing processes.

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Section: Introductionmentioning

confidence: 77%

“…For instance, S.H. Lee researched copper-plated silicon heterojunction solar cells, focusing on using a Cu-X alloy seed layer on indium tin oxide [19]. They deposited 500 nm of Cu-X alloy seed layers by co-depositing copper with additives such as manganese (Mn), nickel (Ni), and aluminum (Al) using an evaporator.…”

Section: Introductionmentioning

confidence: 99%

Study of Microstructure and Mechanical Properties of Electrodeposited Cu on Silicon Heterojunction Solar Cells

Jing¹,

Shan²,

Huang³

et al. 2023

Metals

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“…After the copper seed layers were deposited, copper/silver (Cu/Ag) metal stacks were plated on the sample using the light-induced plating (LIP) technique. Additionally, adhesive contact between copper and ITO was evaluated by the tape test [14]. The results show that pure copper was mostly detached from the ITO surface after the tape test.…”

Section: Resultsmentioning

confidence: 99%

“…The results indicated that the adhesion between copper and AZO/Si is weak. It can imply that the adhesion strength will decrease as annealed temperature increases due to the voids emerging when the temperature is higher than 400 • C. Lee also reported a copper seed layer deposited on an indium tin oxide (ITO) by electron-beam evaporation [14]. After the copper seed layers were deposited, copper/silver (Cu/Ag) metal stacks were plated on the sample using the light-induced plating (LIP) technique.…”

Section: Resultsmentioning

confidence: 99%

Thermal Stability of the Copper and the AZO Layer on Textured Silicon

Chen

Tseng

2021

Coatings

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Transparent conductive oxide (TCO) film is the most widely used front electrode in silicon heterojunction (SHJ) solar cells. A copper metallization scheme can be applied to the SHJ process. The abundance of zinc in the earth’s crust makes aluminum-doped zinc oxide (AZO) an attractive low-cost substitute for indium-based TCOs. No work has focused on the properties of the copper and AZO layers on the textured silicon for solar cells. This work deposited an aluminum-doped zinc oxide layer and copper metal layer on textured (001) silicon by a sputtering to form Cu/AZO/Si stacks. The structures of Cu/AZO/Si are characterized by scanning electron microscope (SEM), scanning transmission electron microscope (STEM), and energy-dispersive X-ray spectrometer (EDS). The results show that the copper thin film detached from AZO in the valley of the textured silicon substrate at a temperature of 400 °C. Additionally, the gap between the copper and AZO layers increases as temperature increases, and the 65 nm thickness AZO layer was found to be preserved up to 800 °C.

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“…Initially evaporated Cu seed layers with subsequent electroplating were also shown to have good adhesion. [4][5][6] However, the metal evaporation technique needs a high vacuum chamber and does not provide high-throughput.…”

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confidence: 99%

Direct Electroplating on Indium-Tin-Oxide-Coated Textured and Polished Silicon Substrates via Transition Metal Alloyed Interlayers

Politze¹,

Scholz²,

Windgassen³

et al. 2022

J. Electrochem. Soc.

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Fe electroplating was used on polished or pyramidally textured indium-tin-oxide (ITO)-coated silicon substrates as an initial layer for subsequent Ni and Cu plating. Up to 15 μm thick Cu layers were deposited on the Ni/Fe intermediate layer. The adhesion strength of this metal layer stack was qualitatively shown using the scotch tape method and quantified by measuring the pull-off stress of the metal stack on ITO. 1.44 and 1.28 MPa was applied to pull off the metal stack from polished and pyramidally textured substrates, respectively. Electrical contact properties were measured by circular transmission line model structures. Very low contact resistivity for electroplated metal on ITO of 6.5E−7 and 9.0E−7 Ωcm2 with transfer lengths of 487 and 720nm are determined for polished and pyramidally textured substrates, respectively.

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Study of Cu-X alloy seed layer on ITO for copper-plated silicon heterojunction solar cells

Cited by 10 publications

References 16 publications

Study of Microstructure and Mechanical Properties of Electrodeposited Cu on Silicon Heterojunction Solar Cells

Study of Microstructure and Mechanical Properties of Electrodeposited Cu on Silicon Heterojunction Solar Cells

Thermal Stability of the Copper and the AZO Layer on Textured Silicon

Direct Electroplating on Indium-Tin-Oxide-Coated Textured and Polished Silicon Substrates via Transition Metal Alloyed Interlayers

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