Large area crystallization of amorphous Si with overlapping high repetition rate laser pulses

Abstract
This paper presents a pulsed laser crystallization technique, enabling large area crystallization of amorphous Si to produce grains having well-defined size and orientation. The method is developed by first determining the parameters influencing crystallization induced by single laser pulses of circular cross-sectional profile. In a second step, crystallization by overlapping round spots is examined. The experiments reveal three zones characterized by distinctly different crystallized morphologies following the laser irradiation. One of these zones corresponds to the regime of lateral crystal growth, wherein grains are driven towards the center of the spot by the radial temperature gradient. These findings are then applied to processing via line beam profiles that facilitate large area crystallization upon rapid translation of the specimen. Crystallization of extended areas hinges on the determination of the crystal growth length for a single spot. The pitch between successive pulses is then set on the basis of this information. It is shown that the pulse energy has only a weak effect on the crystal growth length. © 2012 Elsevier B.V.

Citation
Ryu S-G, Gruber I, Grigoropoulos CP, Poulikakos D, Moon S-J (2012) Large area crystallization of amorphous Si with overlapping high repetition rate laser pulses. Thin Solid Films 520: 6724–6729. Available: http://dx.doi.org/10.1016/j.tsf.2012.07.052.

Acknowledgements
This work was supported by a grant to CPG by the King Abdullah University of Science and Technology (KAUST).

Publisher
Elsevier BV

Journal
Thin Solid Films

DOI
10.1016/j.tsf.2012.07.052

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