Ellipsometric analysis of silicon surfaces textured by ns and sub-ps KrF laser pulses

Z. Tóth, I. Hanyecz, A. Gárdián, J. Budai, J. Csontos, Z. Pápa, M. Füle

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Efficiency of solar cells can be enhanced by lowering their surface reflectance. A possible method to produce textured surfaces with low reflectance is by irradiating them with multiple low intensity nano-, pico- or femtosecond length laser pulses. In this study, the treatment of single crystal silicon surface by series of sub-ps and ns pulses from KrF excimer lasers was investigated. The change in surface properties was observed by spectroscopic ellipsometry, scanning electron microscopy and Raman spectroscopy. Spatial and temporal temperature distributions due to single laser pulse irradiations were numerically calculated and used for interpretation of experimental results. Ellipsometry and Raman spectroscopy clearly indicated that in the case of the sub-ps laser irradiation the first laser pulse caused the formation of a ∼ 15 nm thick amorphous silicon layer. In the case of the irradiation by ns laser pulses, the thickening of the top oxide layer and the appearance of a modified, less crystalline silicon layer, up to ∼ 200 nm thickness was observed. A series of ns laser pulses resulted in cycles of surface melting followed by recrystallization, which introduced partial degradation of crystalline structure. As indicated by scanning electron microscopy images and decreasing fitting quality of the ellipsometric spectra, the surface became structured after 5 and 100 laser shots in the case of sub-ps and ns length laser pulses, respectively.

Original languageEnglish
Pages (from-to)631-636
Number of pages6
JournalThin Solid Films
Volume571
Issue numberP3
DOIs
Publication statusPublished - Nov 28 2014

Fingerprint

Silicon
Laser pulses
silicon
pulses
lasers
Raman spectroscopy
ellipsometry
irradiation
Irradiation
Crystalline materials
Scanning electron microscopy
Spectroscopic ellipsometry
reflectance
Ellipsometry
Excimer lasers
scanning electron microscopy
Laser beam effects
Amorphous silicon
Oxides
Surface properties

Keywords

  • Amorphization
  • Black silicon
  • Ellipsometry
  • Laser texturing
  • Recrystallization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

Cite this

Ellipsometric analysis of silicon surfaces textured by ns and sub-ps KrF laser pulses. / Tóth, Z.; Hanyecz, I.; Gárdián, A.; Budai, J.; Csontos, J.; Pápa, Z.; Füle, M.

In: Thin Solid Films, Vol. 571, No. P3, 28.11.2014, p. 631-636.

Research output: Contribution to journalArticle

Tóth, Z. ; Hanyecz, I. ; Gárdián, A. ; Budai, J. ; Csontos, J. ; Pápa, Z. ; Füle, M. / Ellipsometric analysis of silicon surfaces textured by ns and sub-ps KrF laser pulses. In: Thin Solid Films. 2014 ; Vol. 571, No. P3. pp. 631-636.
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