Large-area metallisation wrap through solar cells using electroless plating

Knauss, H.; Terheiden, Barbara; Fath, P.

doi:10.1016/j.solmat.2006.06.047

Cited by 13 publications

(6 citation statements)

References 3 publications

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“…Apart from LDSE and PERC type cells, Suntech Power has produced Pluto cells with stabilized efficiencies of 19% for Ni/Cu metallization [ 78 ]. Solar cell composed of Cu based metallization wrap through (MWT) cell structure was fabricated by Holger et al at the University of Konstanz, Germany [ 7 ]. Kaneka and Roth & Rao Research adopted the Cu contacts for Heterojunction type cells and presented higher efficiencies of 23.5% and 22.3% respectively [ 79 , 80 ].…”

Section: Cu Plating Contributionsmentioning

confidence: 99%

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

Rehman

Lee

2014

Materials

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Developing a better method for the metallization of silicon solar cells is integral part of realizing superior efficiency. Currently, contact realization using screen printing is the leading technology in the silicon based photovoltaic industry, as it is simple and fast. However, the problem with metallization of this kind is that it has a lower aspect ratio and higher contact resistance, which limits solar cell efficiency. The mounting cost of silver pastes and decreasing silicon wafer thicknesses encourages silicon solar cell manufacturers to develop fresh metallization techniques involving a lower quantity of silver usage and not relying pressing process of screen printing. In recent times nickel/copper (Ni/Cu) based metal plating has emerged as a metallization method that may solve these issues. This paper offers a detailed review and understanding of a Ni/Cu based plating technique for silicon solar cells. The formation of a Ni seed layer by adopting various deposition techniques and a Cu conducting layer using a light induced plating (LIP) process are appraised. Unlike screen-printed metallization, a step involving patterning is crucial for opening the masking layer. Consequently, experimental procedures involving patterning methods are also explicated. Lastly, the issues of adhesion, back ground plating, process complexity and reliability for industrial applications are also addressed.

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Section: Cu Plating Contributionsmentioning

confidence: 99%

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

Rehman

Lee

2014

Materials

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“…Ni deposition from alkaline bath maintained at 93 ∘ C without activation led to nonuniform silicide formation on p-type grooves which was attributed to nonuniform nucleation of Ni particles causing extreme migration at Ni/Si interface during silicidation [73]. Electroless Ni-Cu based metallization has been successfully demonstrated to contact n-and p-type regions for Emitter Wrap Through, Metal Wrap Through, and Metal Wrap Around solar cell structures [76][77][78]. of less than 3 mΩ-cm 2 has been reported on boron diffused emitter of 50-140 Ω/◻ with a two-step electroless Ni plating process [79].…”

Section: Contacting P-type Layer With Ni-cu Stackmentioning

confidence: 99%

Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

Raval

Solanki

2013

Journal of Solar Energy

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Given the high percentage of metal cost in cell processing and concerns due to increasing Ag prices, alternative metallization schemes are being considered. Ni-Cu based front side metallization offers potential advantages of finer grid lines, lower series resistance, and reduced costs. A brief overview of various front side patterning techniques is presented. Subsequently, working principle of various plating techniques is discussed. For electroless plated Ni seed layer, fill factor values nearing 80% and efficiencies close to 17.5% have been demonstrated, while for Light Induced Plating deposited layers, an efficiency of 19.2% has been reported. Various methods for qualifying adhesion and long term stability of metal stack are discussed. Adhesion strengths in the range of 1–2.7 N/mm have been obtained for Ni-Cu contacts tabbed with conventional soldering process. Given the significance of metallization properties, different methods for characterization are outlined. The problem of background plating for Ni-Cu based metallization along with the various methods for characterization is summarized. An economic evaluation of front side metallization indicates process cost saving of more than 50% with Ni-Cu-Sn based layers. Recent successful commercialization and demonstration of Ni-Cu based metallization on industrial scale indicate a potential major role of Ni-Cu based contacts in near future.

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“…More than 20% efficiencies have already been achieved at Fraunhofer ISE, Interuniversity Microelectronics Centre (IMEC), Kaneka, Roth & Rau Research and Schott Solar [78,[80][81][82][83]. Many research institutes have been involved in investigating metallization schemes composed of Ni/Cu metal stacks [8,10,13,42,[84][85][86][87][88][89][90].…”

Section: Current Industrial Trendsmentioning

confidence: 99%

Crystalline Silicon Solar Cells with Nickel/Copper Contacts

Rehman¹,

Lee²

2015

Solar Cells - New Approaches and Reviews

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In silicon solar cell technology, metallization plays an integral part in outlining the cost and efficiency of solar cells. Indeed, the development of better techniques for the metallization of silicon solar cells is vital for achieving higher efficiencies. Presently, screen-printed contacts are primarily employed in photovoltaic industry as they can be realized easily with high throughputs. However, screen-printing technology has the draw-backs of higher contact resistance and lower aspect ratios, degrading the solar cells performance. In recent years, an overall decrease in the photovoltaic module price index has occurred, while the higher cost of silver has disturbed this decrease adversely [ ]. The future of solar cell technology will involve decreasing the wafer s thickness as well as decreasing the use of silver according to the standards set out by the international technology roadmap for photovoltaics ITRPV [ ]. Metal contacts with superior electrical performance and lower production costs are vital for photovoltaic industrial production. In short, the pressing process of screen printing technology for thinner silicon wafers, along with expensive silver pastes, needs to be replaced by a fresh metallization technology. A series of workshops have been dedicated to the metallization of crystalline silicon solar cells, where various metallization techniques have already been inquired [ -]. All of these meetings have helped in understanding and reforming present-day advancements in solar cell metallization techniques.Among the capable metallization techniques, contacts composed of nickel/copper Ni/Cu metal stacks are considered to be one of the most feasible candidates for future metallization technologies. The use of such metal stacks offers precise and low contact resistance and also helps in improving solar cells efficiency [ ]. The most important feature is that the technique can be realized with lower material costs. Ni/Cu contact formations involve two major steps a Ni seed layer formation followed by a Cu metal deposition as a front electrode. The Cu metal stack over the Ni layer plays the role of the main contact to the front of the cell [ -]. The Cu © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. front metals stack is usually formed by an electro-plating process, which is a well-developed plating technique and can only be applied to conductors. Cu has also been deposited by an electroless plating process, but it also requires a seed layer at the silicon surface [ , ]. An auto-catalytic method of depositing Ni-phosphorus or Ni-boron by electroless plating bath compositions can be adopted to contact the semiconducting surface of silicon [ -]. The use of a seed layer i.e., Ni can help to plate metal stacks on semiconducting or even nonconducting materials. Ap...

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Large-area metallisation wrap through solar cells using electroless plating

Cited by 13 publications

References 3 publications

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

Review of the Potential of the Ni/Cu Plating Technique for Crystalline Silicon Solar Cells

Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

Crystalline Silicon Solar Cells with Nickel/Copper Contacts

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