Synthesis of Porous Silicon with Silver Nanoparticles by Low–Energy Ion Implantation

Abstract

In this paper a new technique for synthesis of porous silicon layers with silver nanoparticles based on the method of low − energy and high − dose metal ion implantation into Si is proposed. For demonstration of this technique, room temperature Ag + ion implantation of polished Si wafer with ion energy of 30 keV, ion dose of 1.5 ⋅ 10 17 ion/cm 2 and ion current density of 8 μA/cm 2 was carried out. By high resolution scanning electron and atomic − force microscopy, electron probe microanalysis and Raman scattering we have shown that as a result of ion implantation a thin amorphous layer of porous Si is formed on the surface of irradiated Si with average pore sizes of 150—180 nm, pore depth of about 100 nm and wall thickness between pores of about 30—60 nm. Moreover, porous Si contains Ag nanoparticles with sizes of 5—15 nm. We established that during ion implantation the sputtering of Si surface by Ag + ions occurs which was not observed before. On the basis of these data we concluded that the proposed physical technique for porous Si formation compared to chemical techniques could be integrated into an advanced process of fabrication and improvement of electronic circuits based on industrial ion implantation.