Employing microsecond pulses to form laser-fired contacts in photovoltaic devices

Ashwin S. Raghavan, Todd Palmer, Katherine C. Kragh-Buetow, Anna C. Domask, Edward William Reutzel, Suzanne E. Mohney, Tarasankar Debroy

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Laser-fired contacts (LFCs) are typically fabricated with nanosecond pulse durations despite the fact that extremely precise and costly control of the process is necessary to prevent significant ablation of the aluminum metallization layer. Microsecond pulse durations offer the advantage of reduced metal expulsion and can be implemented with diffractive optics to process multiple contacts simultaneously and meet production demands. In this work, the influence of changes in laser processing parameters on contact morphology, resistance, and composition when using microsecond pulses has been fully evaluated. Simulated and experimental results indicate that contacts are hemispherical or half-ellipsoidal in shape. In addition, the resolidified contact region is composed of a two-phase aluminum-silicon microstructure that grows from the single-crystal silicon wafer during resolidification. As a result, the total contact resistance is governed by the interfacial contact area for a three-dimensional contact geometry rather than the planar contact area at the aluminum-silicon interface in the passivation layer opening. The results also suggest that for two LFCs with the same size top surface diameter, the contact produced with a smaller beam size will have a 25-37% lower contact resistance, depending on the LFC diameter, because of a larger contact area at the LFC/wafer interface.

Original languageEnglish (US)
Pages (from-to)1025-1036
Number of pages12
JournalProgress in Photovoltaics: Research and Applications
Volume23
Issue number8
DOIs
StatePublished - Aug 1 2015

Fingerprint

Laser pulses
Aluminum
Lasers
pulses
lasers
Silicon
Contact resistance
contact resistance
aluminum
pulse duration
silicon
Diffractive optics
wafers
diffractive optics
expulsion
Ablation
Metallizing
Silicon wafers
Passivation
passivity

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

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title = "Employing microsecond pulses to form laser-fired contacts in photovoltaic devices",
abstract = "Laser-fired contacts (LFCs) are typically fabricated with nanosecond pulse durations despite the fact that extremely precise and costly control of the process is necessary to prevent significant ablation of the aluminum metallization layer. Microsecond pulse durations offer the advantage of reduced metal expulsion and can be implemented with diffractive optics to process multiple contacts simultaneously and meet production demands. In this work, the influence of changes in laser processing parameters on contact morphology, resistance, and composition when using microsecond pulses has been fully evaluated. Simulated and experimental results indicate that contacts are hemispherical or half-ellipsoidal in shape. In addition, the resolidified contact region is composed of a two-phase aluminum-silicon microstructure that grows from the single-crystal silicon wafer during resolidification. As a result, the total contact resistance is governed by the interfacial contact area for a three-dimensional contact geometry rather than the planar contact area at the aluminum-silicon interface in the passivation layer opening. The results also suggest that for two LFCs with the same size top surface diameter, the contact produced with a smaller beam size will have a 25-37{\%} lower contact resistance, depending on the LFC diameter, because of a larger contact area at the LFC/wafer interface.",
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Employing microsecond pulses to form laser-fired contacts in photovoltaic devices. / Raghavan, Ashwin S.; Palmer, Todd; Kragh-Buetow, Katherine C.; Domask, Anna C.; Reutzel, Edward William; Mohney, Suzanne E.; Debroy, Tarasankar.

In: Progress in Photovoltaics: Research and Applications, Vol. 23, No. 8, 01.08.2015, p. 1025-1036.

Research output: Contribution to journalArticle

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AU - Mohney, Suzanne E.

AU - Debroy, Tarasankar

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