Nanoscale structuration of semiconductor surface induced by cavitation impact

The results of studies of the complex structures formed on the semiconductor substrates exposed to the acoustic cavitation (AC) near the liquid-solid interface are reported. Gallium arsenide and silicon substrates were exposed to the cavitation impact initiated by the focusing a high-frequency (MHz) acoustic wave into the liquid nitrogen. Optical, atomic force and scanning electron microscopy methods as well as energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy were used for analysis of the surface morphology and chemical composition of semiconductor compounds. The formation of separated circular regions with the nanostructured surfaces inside was found. Electron micrograph images of the silicon surface show the creation of the dendritic objects inside of the ultrasonically structured region. The Raman spectroscopy and EDS data have confirmed the change of the chemical composition of the structured gallium arsenide surface and the Ga-N bond formation. The incorporation of nitrogen atoms into a silicon lattice has not been observed while XRD results have shown the formation of silicates of alkali metals on the silicon surface.