On determining the spot size for laser fluence measurements

B. Farkas, Z. Geretovszky

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Energy fluence, defined as pulse energy over irradiated area, is a key parameter of pulsed laser processing. Nevertheless, most of the authors using this term routinely do not realize the problems related to the accurate measurement of the spot size. In the present paper we are aiming to approach this problem by ablating crystalline Si wafers with pulses of a commercial KrF excimer laser (λ = 248 nm, τ = 15 ns) both in vacuum and at ambient atmosphere. For any pulse energy, the size of the ablated area monotonously increases with increasing number of pulses. The difference in the ablated area could be as high as a factor of three when 2000 consecutive pulses impinge on the surface. The existence and extent of the gradual lowering of multi-pulse ablation threshold queries the applicability of routinely used procedure of dividing the pulse energy with the size of the ablated area exposed into either carbon-paper or a piece of Si with one or a few pulses when determining the fluence. A more quantitative way is proposed allowing comparison of results originating from different laboratories.

Original languageEnglish
Pages (from-to)4728-4732
Number of pages5
JournalApplied Surface Science
Volume252
Issue number13 SPEC. ISS.
DOIs
Publication statusPublished - Apr 30 2006

Fingerprint

Laser pulses
fluence
Lasers
Excimer lasers
Ablation
pulses
Pulsed lasers
lasers
Carbon
Vacuum
Crystalline materials
Processing
energy
excimer lasers
ablation
pulsed lasers
wafers
atmospheres
vacuum
thresholds

Keywords

  • PLA
  • PLD

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Condensed Matter Physics

Cite this

On determining the spot size for laser fluence measurements. / Farkas, B.; Geretovszky, Z.

In: Applied Surface Science, Vol. 252, No. 13 SPEC. ISS., 30.04.2006, p. 4728-4732.

Research output: Contribution to journalArticle

Farkas, B. ; Geretovszky, Z. / On determining the spot size for laser fluence measurements. In: Applied Surface Science. 2006 ; Vol. 252, No. 13 SPEC. ISS. pp. 4728-4732.
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