Role of heat accumulation in the multi-shot damage of silicon irradiated with femtosecond XUV pulses at a 1 MHz repetition rate

0466618 - FZÚ 2017 RIV US eng J - Journal Article
Sobierajski, R. - Jacyna, I. - Dlužewski, P. - Klepka, M.T. - Klinger, D. - Pelka, J. B. - Burian, Tomáš - Hájková, Věra - Juha, Libor - Saksl, K. - Vozda, Vojtěch - Makhotkin, I. - Louis, E. - Faatz, B. - Tiedtke, K. - Toleikis, S. - Enkisch, H. - Hermann, M. - Strobel, S. - Loch, R.A. - Chalupský, Jaromír
Role of heat accumulation in the multi-shot damage of silicon irradiated with femtosecond XUV pulses at a 1 MHz repetition rate.
Optics Express. Roč. 24, č. 14 (2016), s. 15468-15477. ISSN 1094-4087
R&D Projects: GA MŠMT(CZ) LH14072; GA ČR(CZ) GA14-29772S
Institutional support: RVO:68378271
Keywords : free-electron lasers * damage * x-rays * soft x-rays * extreme ultraviolet (EUV) * semiconductor materials * materials processing
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 3.307, year: 2016

The role played by heat accumulation in multi-shot damage of silicon was studied. Bulk silicon samples were exposed to intense XUV monochromatic radiation of a 13.5 nm wavelength in a series of 400 femtosecond pulses, repeated with a 1 MHz rate (pulse trains) at the FLASH facility in Hamburg. The observed surface morphological and structural modifications are formed as a result of sample surface melting. Modifications are threshold dependent on the mean fluence of the incident pulse train, with all threshold values in the range of approximately 36-40 mJ/cm(2). Experimental data is supported by a theoretical model described by the heat diffusion equation. The threshold for reaching the melting temperature (45 mJ/cm(2)) and liquid state (54 mJ/cm(2)), estimated from this model, is in accordance with experimental values within measurement error. The model indicates a significant role of heat accumulation in surface modification processes.
Permanent Link: http://hdl.handle.net/11104/0264888