High‐Temperature Contact Formation on n‐Type Silicon: Basic Reactions and Contact Model for Seed‐Layer Contacts

Hörteis, M.; Gutberlet, T.; Reller, Armin; Glunz, Stefan W.

doi:10.1002/adfm.200901305

Cited by 94 publications

(44 citation statements)

References 23 publications

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“…21 In addition, Ag particles show minor corrosion characteristics. 16,22 In our study, after we removed metal residues and the glass layer with an alkaline solution, we observed craters of different sizes on the Si substrate surface. The surface profiles of both sides were measured using α-step profilometry (Figure 6a).…”

Section: Resultsmentioning

confidence: 90%

Fabricating 43-μm-Thick and 12% Efficient Heterojunction Silicon Solar Cells by Using Kerfless Si(111) Substrates

Chen

Wang

et al. 2015

ECS J. Solid State Sci. Technol.

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A 43-μm-thick Si(111) substrate was obtained using the stress-induced lift-off method with a screen-printed metal paste layer as the stress-generation layer. The reflection of the metal-removed side of the Si(111) substrate was lower than that of the exfoliated side because of high surface roughness resulting from the reaction between the metal paste and the silicon substrate at 700 • C. After aggressive etching with an alkaline solution for the peeled silicon substrate, the efficiency of the heterojunction silicon solar cell was improved from 0.87% to 12%. For decades, silicon (Si)-based solar cells have been the conventionally used products in the photovoltaic (PV) industry. The Si solar cell module price is lower than 0.75 USD/W, which could be mainly attributed to the extensive research on and development of these cells and support from local governments.1 Although the price of poly-Si decreased markedly from 450 USD/kg in 2008 to 20 USD/kg in 2015, the price of poly-Si accounts for more than 50% of the cost of a Si solar cell.2 Thus, reducing the use of Si is the most effective method for reducing the cost of a Si solar cell. Therefore, the thickness of a Si substrate will be reduced from 200 μm in 2010 to 120 μm in 2020.2 In addition, reducing the thickness can further increase the cell efficiency, which is generally achieved by enhancing the open circuit voltage (Voc).3,4 Recently, a 98-μm-thick and 24.7% efficient heterojunction Si (HJS) solar cell, with a Voc of 750 mV, was developed by Panasonic. 5Using a thin Si substrate obtained by applying a kerfless process, which can potentially reduce the cost of solar cells, has become a major topic recently.6-11 Kuzma-Filipek et al. used a 30-μm-thick epitaxial Si film grown on a highly doped P + -Si substrate with a porous multilayer structure to obtain a 16.2% efficient Si solar cell. 6 Petermann et al. used a 43-μm-thick and freestanding epitaxial Si film by using the layer transfer technique to obtain a 19% efficient Si solar cell.7 High-efficiency solar cells can be fabricated using these thin epitaxial Si substrates; however, the high-temperature fabrication process (>1000• C) and expensive epitaxy system increase the cost. The stress-induced lift-off method, which is based on the thermal expansion difference between a deposited metal film and a Si substrate, could be an alternative because it entails a simple, low-temperature (<900• C) process for obtaining a thin Si substrate. 8,12,13 Dross et al. compared the differences between Si(111) and Si(100) substrates after exfoliation and obtained a 50-μm-thick and 10% efficient Si solar cell.9 Saha et al. further alleviated the difficulty of handling thin Si substrates and obtained a 25-μm-thick and 14.9% efficient Si solar cell. 10 We recently reported the thermal stress-induced pattern transfer technique, which is a combination of the thin-film deposition process and the layer transfer technique, and obtained a 3-μm-thick Si film with a textured surface. The short-circuit current of the HJS solar cell fabr...

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Section: Resultsmentioning

confidence: 90%

Fabricating 43-μm-Thick and 12% Efficient Heterojunction Silicon Solar Cells by Using Kerfless Si(111) Substrates

Chen

Wang

et al. 2015

ECS J. Solid State Sci. Technol.

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“…22,23) A very thin glass contact layer of about 10 to 100 nm is formed between the Ag front electrode and the semiconductor silicon by a firing process and an ohmic contact is realized. 24,25) For PV modules using EVA as an encapsulant, moisture (H 2 O molecules) diffuses into 26) and reacts with EVA by a hydrolytic reaction, and acetic acid is produced. [27][28][29][30] The acetic acid produced corrodes the glass contact layer, and the ohmic contact property rapidly degrades when the corrosion proceeds to some extent.…”

Section: Lidmentioning

confidence: 99%

Development of highly efficient, long-term reliable crystalline silicon solar cells and modules by low-cost mass production

Irie¹,

Tanabe²,

Atobe³

et al. 2018

Jpn. J. Appl. Phys.

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To reduce photovoltaic (PV) power generation costs, the reduction of PV module manufacturing costs, the improvement of cell and module efficiencies, and the long-term output power warranty of PV modules are necessary. Using the high-quality, low-cost crystal growth technology, we developed a high-quality casting process by the seed-cast method. Using a seed-cast wafer, an efficiency of 20.54% has been obtained with passivated emitter and rear cells (PERCs). The ohmic contact degradation of front electrodes and potential-induced degradation are the typical modes that significantly affect the module lifetime. Considering the field stresses induced by ultraviolet light, heat and humidity (H&H), and the electrical potential difference, sequentially combined stress tests of small modules and additional stress tests of field-aged modules are performed. The test results for the modules fabricated using our technology indicated that the modules have a sufficiently long lifetime of more than 30 years and are potential-induced degradation (PID)-free under these stresses in Japanese domestic environments.

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“…It is still not clear how does glassy-phase, which is a molten phase of the glass frit, etch or interact with the SiN x ARC? It was reported that the SiN x ARC can be opened during the firing step by a reaction between the PbO (glass) and SiN x (Horteis et al, 2010). In the reaction, lead oxide (PbO) was reduced to lead.…”

Section: Interface Microstructurementioning

confidence: 99%

Silicon Solar Cells: Structural Properties of Ag-Contacts/Si-Substrate

Lin¹,

Hsu²,

Hsu³

2011

Solar Cells - Silicon Wafer-Based Technologies

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High‐Temperature Contact Formation on n‐Type Silicon: Basic Reactions and Contact Model for Seed‐Layer Contacts

Cited by 94 publications

References 23 publications

Fabricating 43-μm-Thick and 12% Efficient Heterojunction Silicon Solar Cells by Using Kerfless Si(111) Substrates

Fabricating 43-μm-Thick and 12% Efficient Heterojunction Silicon Solar Cells by Using Kerfless Si(111) Substrates

Development of highly efficient, long-term reliable crystalline silicon solar cells and modules by low-cost mass production

Silicon Solar Cells: Structural Properties of Ag-Contacts/Si-Substrate

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