Characterization of ion-implanted silicon-insulator interfaces by reflected optical second harmonic generation

Optical second harmonic generation has been applied for the study of the ion-implanted SiO2Sib(1 1 1) interface and Si(1 1 1) surfaces. Experimental results of real-time measurements of the second harmonic generation signal during thermal oxide etching are presented and analyzed taking into consideration various contributions to the non-linear-optical response from oxide/silicon interface such as the silicon substrate, the static electric field, the inhomogeneous deformation and the crystalline oxide interlayer. The symmetry properties of the thermal oxide/Si(1 1 1) interface have also been studied by measuring the rotational dependences of the second harmonic generation signal before and after oxide etching. It is shown that second harmonic rotational anisotropy and intensity strongly depend on the disordering of the interface and surface induced by ion implantation.