Sputtering of silicon surface during low-energy high-dose implantation with silver ions

We report on the results of first practical observations of sputtering of the Si surface during the implantation with Ag$^+$ ions with an energy of 30 keV depending on irradiation dose $D$ in the interval from 2.5 $\times$ 10$^{16}$ to 1.5 $\times$ 10$^{17}$ ion/cm$^2$ for a fixed value of ion beam current density $J$ = 8 $\mu$A/cm$^2$, as well as for variation of $J$ = 2, 5, 8, 15, and 20 $\mu$A/cm$^2$ at constant $D$ = 1.5 $\times$ 10$^{17}$ ion/cm$^2$. In the former case, the thickness of the porous Si (PSi) layer being sputtered increases monotonically to 50 nm at the maximum value of $D$; in this case, the effective sputtering ratio of the implanted Ag : PSi layer is 1.6. We have also established that the thickness of the sputtered layer increases with current density $J$.