18.8% EWT-Cells with Screen-Printed Metallization and Single Step Side Selective Emitter Formation

In order to increase the conversion efficiencies of silicon solar cells, advanced cell structures with selectively doped areas receive an increasing interest. There is a strong need to separate the contacted diffusion profiles from the non-contacted. On the one hand, a high dopant concentration in the contact regime reduces the series resistance losses mainly due to lowered contact resistance. Additionally recombination is reduced by shielding the minority charge carriers from surface at the contact. On the other hand a low dopant concentration in the non-contact regime reduces the recombination losses and optimizes the spectral response of the cell.In this work phosphorus doped silicon oxide layers are used as a diffusion source for tube furnace diffusion processes. It is shown that the sheet resistance of the diffused area is controlled by the silane gas flow during the deposition of phosphorus doped silicon oxide. In order to analyze the influence of the diffused areas on the saturation current densities, symmetrical carrier lifetime samples are prepared. Therefore a stack system consisting of a thermally grown silicon dioxide and silicon nitride is used for passivation purposes on textured samples.

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Inkjet structured EWT silicon solar cells with evaporated aluminum metallization and laser-fired contacts

Fallisch

Stüwe

Neubauer

et al. 2010

2010 35th IEEE Photovoltaic Specialists Conference

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This work focuses on manufacturing inkjet structured Emitter Wrap-Through (EWT) silicon solar cells with a side selective emitter and an evaporated metallization. Inkjet structuring is a suitable technique for the formation of interdigitated structures used in back contacted silicon solar cells because it allows small feature sizes and has high alignment accuracy. Therefore all structuring steps in this EWT solar cell process are done with the help of inkjet masking. This includes the structuring of a silicon oxide passivation layer and the evaporated aluminum metallization. For all masking processes an acid-resistant inkjet hotmelt ink is used. An evaporated thick aluminum layer and laser-fired contacts (LFC) to contact the bulk region are introduced. Cell efficiencies above 15% prior to a forming gas anneal are reached. The best cell reaches an efficiency of 15.7% after a short annealing step on a hotplate

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18.8% EWT-Cells with Screen-Printed Metallization and Single Step Side Selective Emitter Formation

Cited by 3 publications

References 14 publications

Highly efficient industrially feasible metal wrap through (MWT) silicon solar cells

Highly efficient industrially feasible metal wrap through (MWT) silicon solar cells

Analysis of Phosphorus-Doped Silicon Oxide Layers Deposited by Means of PECVD as a Dopant Source in Diffusion Processes

Inkjet structured EWT silicon solar cells with evaporated aluminum metallization and laser-fired contacts

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