Microscale Spatially Resolved Characterization of Highly Doped Regions in Laser-Fired Contacts for High-Efficiency Crystalline Si Solar Cells

A Roigé (1) , J Alvarez (2) , Jean-Paul Kleider (2) , I Martín (3) , R Alcubilla (3) , L.F. Vega

1 MATGAS Research Center
2 GeePs - Laboratoire Génie électrique et électronique de Paris
3 UPC - Universidad Polytecnica de Cataluña

—Laser-fired contact (LFC) processes have emerged as a promising approach to create rear local electric contacts in p-type crystalline silicon solar cells. Although this approach has been successfully applied in devices showing efficiencies above 20%, there is still a lack of knowledge about some specific features of LFCs at the submicron level. In this study, we used micro-Raman and microphotoluminescence (PL) spectroscopies to carry out a high-resolution spatially resolved characterization of LFCs processed in Al 2 O 3-passivated c-Si wafers. Relevant information concerning features such as local doping distribution and crystalline fraction of the laser-processed region has been obtained. In particular, interesting qualitative and quantitative variations concerning the doping profile have been observed between LFCs processed at different laser powers. Finally, conductive-atomic force microscopy measurements have allowed to identify the existence of highly conductive zones inside the LFCs greatly correlated with highly doped regions revealed by Raman and PL data. This study gives a detailed insight about the LFCs characteristics at the submicron level and their possible influence on the performance of final devices.

Keywords: micro-Raman spec-troscopy; laser-fired contacts (LFCs); microphotoluminescence spectroscopy; Index Terms—Crystalline silicon

Domains: Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]; Engineering Sciences [physics]; Micro and nanotechnologies/Microelectronics; Engineering Sciences [physics]; Electric power; Engineering Sciences [physics]; Optics / Photonic; Engineering Sciences [physics]; Materials

A Roigé, J Alvarez, Jean-Paul Kleider, I Martín, R Alcubilla, et al.. Microscale Spatially Resolved Characterization of Highly Doped Regions in Laser-Fired Contacts for High-Efficiency Crystalline Si Solar Cells. IEEE Journal of Photovoltaics, 2015, 5, pp.545. ⟨10.1109/JPHOTOV.2015.2392945⟩. ⟨hal-01231753⟩