Secondary electron microscopy dopant contrast image (SEMDCI) for laser doping

Lujia Xu*, Klaus Weber, Sieu Pheng Phang, Andreas Fell, Frank Brink, Di Yan, Xinbo Yang, Evan Franklin, Hua Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Laser doping has been the subject of intense research over the past decade, due to its potential to enable high-efficiency, low-cost silicon solar cell fabrication. Information about the doping profile that is created by the process is critical for process optimization but is generally difficult to obtain. We apply the technique of secondary electron image (SEI) contrast to the characterization of the cross sections of laser-doped lines. We demonstrate that this technique can be used for a large range of different dopant sources and different laser doping methods and that good dopant contrast can be obtained under a relatively wide range of microscope parameters. Comparison of dopant contrast and doping density profiles shows that the substrate doping is an important parameter that can significantly influence the dopant contrast, particularly at low (∼10 $18 cm$-3) and high (∼10 $20 cm$-3 ) dopant densities. When suitable calibration samples are used, the technique can be employed to obtain quantitative dopant density images for p-type laser-doped regions, albeit currently over a limited range of dopant densities and with relatively large error. Furthermore, the technique can be used to evaluate the risk of metallization shunts near the edges of dielectric film windows that are opened by the laser.

Original languageEnglish
Article number6451096
Pages (from-to)762-768
Number of pages7
JournalIEEE Journal of Photovoltaics
Issue number2
Publication statusPublished - 2013


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