engleski

Laser-Induced Convection Nanostructures on SiON/Si Interface

The homogenized beam of an excimer KrF laser has been used to form rectangular millimeter-scale holes of vertical walls in the ~   m thick silicon-oxynitride (SiON) thin film deposited on Si <111> wafer. The regular rectangular craters in SiON layer have the flat bottom surface reaching the SiON/Si interface. At the same time horizontal thermal gradient causes the formation of the nanoscale Marangoni convection structures at the SiON/Si interface. The inhomogeneous pattern of the roll structures can be divided into domains of regular, irregular and chaotic organization. The roll diameter is about 200 nm while their average wavelength,    is, ~ 2  m, i.e. about 10 times larger than the laser wavelength, and decreases with increasing number of pulses. Numerical simulation of the Marangoni domain roll structures based on the simple Swift-Hohenberg equation has reproduced all observed types of the roll organization, including those which show the evolution of dislocations from the Eckhause instability.

Pattern formation ; Marangoni instability ; 47.20.Ky- Nonlinearity ; bifurcation and symmetry breaking ; 47.20.Lz - Secondary instabilities

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