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Proceedings Paper

Role of processing parameters on morphology, resistance and composition of laser fired contacts
Author(s): A. Raghavan; T. A. Palmer; A. Domask; S. Mohney; E. W. Reutzel; T. DebRoy
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Paper Abstract

Laser processing is a single step, attractive alternative to current multi-step formation of ohmic contacts between an aluminum metallization layer and a silicon substrate in solar cell devices. However, small changes in laser parameters such as pulse duration, power density and laser wavelength can result in significant differences in the contact geometry and electrical properties. Here, the effects of power density and pulse duration on the morphology, resistance and surface concentration of laser fired contacts (LFCs) are examined experimentally. The minimum fluence threshold for forming a contact with measureable resistance through the 100nm SiO2 layer is determined to be 8 J/cm2. In addition, when forming the contact, an outer rim region accumulates on the surface that is comprised of aluminum and silicon. As a result, the entire contact is actually governed by the size of an inner crater region plus this outer rim material, which is in contrast to results reported in the literature for nanosecond pulse durations. These results are in good agreement with independent results reported in the literature for LFCs processed on wafers with substantially different base resistivity and using significantly different processing parameters.

Paper Details

Date Published: 16 September 2013
PDF: 8 pages
Proc. SPIE 8826, Laser Material Processing for Solar Energy Devices II, 882606 (16 September 2013); doi: 10.1117/12.2023978
Show Author Affiliations
A. Raghavan, The Pennsylvania State Univ. (United States)
T. A. Palmer, The Pennsylvania State Univ. (United States)
A. Domask, The Pennsylvania State Univ. (United States)
S. Mohney, The Pennsylvania State Univ. (United States)
E. W. Reutzel, The Pennsylvania State Univ. (United States)
T. DebRoy, The Pennsylvania State Univ. (United States)


Published in SPIE Proceedings Vol. 8826:
Laser Material Processing for Solar Energy Devices II
Edward W. Reutzel, Editor(s)

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