Irradiating nitrogen doped 6H-SiC(000l) crystals with a focused beam of an N2 pulse laser, we could form discrete
circularly placed nanohills on their surface. The necessary light intensities were close to the ablation threshold. The
evidence was obtained by atomic force microscopy and photoluminescence. The measurements demonstrated that in the
area acted upon, the surface morphology and the nitrogen concentration depended on the irradiation dose. Supplementary
data was obtained from the numerical modeling of the temporal depth dependence of the temperature in SiC in response
to an N2 laser pulse. The appearance of the nanohills is accounted for by a temperature-gradient gathering of nitrogen
into the subsurface focal area and by a rapid surface vaporization. The former process leads, via the melting point
decrease, to a local area melting, and the latter, via the surface temperature decrease, to the capping of the melt with a
thin solid lid. The interplay between the pressures exerted by the light and the liquid ends in a lid-peripheral extrusion of
a portion of the liquid and formation of the nanohills. The whole process proceeds in a clearly distinguishable and
repeatable two-stage mode.
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