Nanoscale Structuration of Semiconductor Surface Induced by Cavitation Impact
- PDF / 323,669 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 12 Downloads / 176 Views
Nanoscale Structuration of Semiconductor Surface Induced by Cavitation Impact Tetyana G. Kryshtab1, Rada K. Savkina2, Alexey B. Smirnov2 1
Instituto Politécnico Nacional – ESFM, Department of Physics, Av. IPN, Ed. 9, U.P.A.L.M., 07738 Mexico D.F., Mexico 2 V. Lashkaryov Institute of Semiconductor Physics at NAS of Ukraine, pr. Nauki 41, 03028 Kiev, Ukraine
ABSTRACT 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. INTRODUCTION Interactions of the energetic flows beams with the solid surfaces demonstrate unique phenomena and promise new applications for surface modification technology. Solid surfaces can develop a wide range of useful topological features upon bombardment with ions, clusters of atoms and molecules, as well as on laser processing as a result of the deposition of large amounts of energy in the form of heat and pressure or as a result of the plasma effect. It is well known that ultrasonic cavitation also creates extreme energetic conditions with the local temperatures of about 5000K and the pressure of several hundred MPa [1]. It is necessary to notice also the possibility of the plasma generation in a cavitating liquid [2]. These extreme conditions are widely used in chemistry, as for example to synthesize nanoparticles [3], to enhance the electrochemical reactions and to modify the surface properties of electrodes [4], as well as to generate the novel materials in a liquid medium [5-7], etc. Cavitation near extended liquid-solid interfaces is very different from cavitation in pure liquids. The impingement of microjets and shockwaves on the surface creates the localized erosion, which can generate newly exposed, highly heated surface and even eject matter from the surface. This is a grave disadvantage in many industrial systems. Despite corrosion problem, the
A87
controlled cavitation near a solid surface proves a powerful tool for modern technologies like the salmonella destruction [8
Data Loading...
