Liquid silicate additive for alkaline texturing of mono-Si wafers to improve process bath lifetime and reduce IPA consumption

Basu, Prabir K.; Sarangi, D.; Shetty, Kishan Devappa; Boreland, M.

doi:10.1016/j.solmat.2013.01.037

Cited by 55 publications

(21 citation statements)

References 12 publications

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“…Brief details regarding the texturisation process recipes are given in Table 1. The role of the K 2 SiO 3 additive in KOH-IPA texturisation baths is discussed in reference [14]. With each of the three texture processes, forty five p-type Cz wafers (156 mm Â 156 mm, pseudosquare, 1-2 Ω cm resistivity) were textured and used for fabricating standard screen-printed solar cells with the following process sequence after texturisation: inline P emitter diffusion followed by inline chemical edge isolation and emitter etch back (final emitter sheet resistance 70 Ω/sq, surface dopant concentration $ 3 Â 10 20 cm À 3 ) [25], front PECVD amorphous silicon nitride (SiN x ) coating, screen printing (front Ag paste: DuPont PV 17F, rear Al paste: Monocrystal PASE 12D), co-firing.…”

Section: Methodsmentioning

confidence: 99%

“…Care should also be taken to achieve a narrow range of heights in the distribution (low standard deviation). Such a tailoring of pyramid height distributions may be achieved by using additives [14][15][16][17][18][19] to improve the control over alkaline texturisation processes in tandem with statistical characterisation of pyramid height distributions. These guidelines are developed for the case when current conduction through Ag crystallites is prevalent at the Ag/n þ Si interface.…”

Section: Guidelines To Tailor Pyramid Height Distributionsmentioning

confidence: 99%

“…As a result, there are no clear guidelines to tailor the anisotropic alkaline surface texturisation to improve Ag screen-printed contacts for mono-Si solar cells. Such guidelines would be especially useful since it has been shown in several previous studies that additives for alkaline texturisation baths enable improved control over the height and uniformity of pyramidal surface textures [14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of random pyramid surface texture on silver screen-printed contact formation for monocrystalline silicon wafer solar cells

Khanna

Basu

Filipovic

et al. 2015

Solar Energy Materials and Solar Cells

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Section: Methodsmentioning

confidence: 99%

Section: Guidelines To Tailor Pyramid Height Distributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of random pyramid surface texture on silver screen-printed contact formation for monocrystalline silicon wafer solar cells

Khanna

Basu

Filipovic

et al. 2015

Solar Energy Materials and Solar Cells

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“…The wafers were saw damage etched and textured in KOH/IPA/potassium silicate solution at 80 • C [13] to generate a random pyramid surface texture on both sides. The emitter diffusion was carried out using an industrial inline diffusion furnace (Despatch, DCF-3615), which has a doper section that feeds the wafers directly to a belt furnace for diffusion.…”

Section: A Sample Preparationmentioning

confidence: 99%

Electrical and Microstructural Analysis of Contact Formation on Lightly Doped Phosphorus Emitters Using Thick-Film Ag Screen Printing Pastes

Shanmugam¹,

Cunnusamy²,

Khanna³

et al. 2014

IEEE J. Photovoltaics

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Screen printing of the metallization of phosphorus diffused emitters is a well-established process for industrial silicon wafer-based solar cells. Previously, screen printed silver pastes typically required a very high phosphorus surface doping concentration to ensure a low-resistance ohmic contact. Recently, paste manufacturers have focused on the development of silver pastes capable of contacting phosphorus emitters with progressively lower surface concentrations, to minimize surface recombination losses and enable higher cell conversion efficiencies. In this paper, we report on the progress of contacting inline-diffused phosphorus emitters, of which the surface concentrations have been reduced by an etch-back process, using two different pastes. Solar cells with emitter surface concentrations ranging from 4.0 × 10 20 to 1.7 × 10 20 phosphorus atoms/cm 3 were made using two different silver pastes. We present a microstructural analysis of the contact formation, which indicates the possible dominant current transport mechanisms for the two pastes. A high density of silver crystallites formed with a very narrow interfacial glass layer makes the Sol 9600 paste suitable for contacting lowly doped phosphorus emitters. Efficiency gains of 0.2%-0.3% (absolute) were achieved, reaching a maximum efficiency of 18.6% on 156 mm × 156 mm p-type pseudo-square Cz mono-crystalline silicon solar cells.

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“…However, high concentration of KOH causes instability in the solution and etching rate. Therefore, uncontrolled nonuniformity in texturing occurs, and incomplete coverage of the pyramidal textured surface and wide variation in pyramid size can be seen . One of the solutions for the stability problem and thus lower the production cost is to apply an additional agitation that can help to lower the temperature of the solution for a stable IPA concentration.…”

Section: Introductionmentioning

confidence: 99%

Comparison of mechanical and ultrasonic agitation methods for mono c‐Si texturing

Bilgen

Turan

2016

Physica Status Solidi (a)

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Texturing of a mono crystalline Si wafer aims to create light trapping structures to reduce the reflection losses. Being a cheap and efficient process, alkaline texturing of Si wafers is commonly used in all industrial mono crystalline solar cell production lines. However, standard process with potassium hydroxide (KOH)-based solutions with isopropyl alcohol (IPA) addition suffers from instability, high material consumption, and nonuniformities in the shape and the distribution of the pyramid structures formed on the Si surface. In this work, we studied the effect of ultrasonic agitation (UA) during the etching process on the structural, optical, and electrical properties of mono crystalline Si solar cell as a function of process parameters. We have shown that UA improves optical and electrical performance of the cells by forming uniform pyramid structures. In addition, it also helps to lower the material consumption and Si removal from the surface by enabling less process time and temperature. Ultrasonic agitation of the etching solution proves to be a good modification of the wet process steps for the mono crystalline silicon solar cell technology.

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Liquid silicate additive for alkaline texturing of mono-Si wafers to improve process bath lifetime and reduce IPA consumption

Cited by 55 publications

References 12 publications

Influence of random pyramid surface texture on silver screen-printed contact formation for monocrystalline silicon wafer solar cells

Influence of random pyramid surface texture on silver screen-printed contact formation for monocrystalline silicon wafer solar cells

Electrical and Microstructural Analysis of Contact Formation on Lightly Doped Phosphorus Emitters Using Thick-Film Ag Screen Printing Pastes

Comparison of mechanical and ultrasonic agitation methods for mono c‐Si texturing

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