Study of mechanical strains in implanted silicon slices

Abstract

In this paper the influence of Ar + and He + ion bombardment on mechanical stress formation in silicon and SiSiO 2 structures is studied. Ion bombardment was carried out at energies of 50–175 keV, ion flux densities of 0.1–10 μA cm −2 and fluences up to 10 17 cm −2. Double-beam laser interferometry was used for contactless registration with high accuracy of deformation of the samples during the process of ion implantation. We obtained that the stresses induced by ion implantation in silicon are a complex function of ion kind, fluence and flux density. The sign of strains for the oxidized slices is opposite to that for the unoxidized ones. Large deformations are obtained during He + implantation in the oxidized samples. The experimental results are directly dependent on ion damage level. The formation of mechanical stresses in SiO 2 is related to the amount of SiO and SiSi bonds which changes under ion bombardment.