Depth profiling of P shallow implants in silicon by electron-induced X-ray emission spectroscopy

Abstract

Electron-induced X-ray emission spectroscopy (EXES) combined with a semi-empirical electron scattering model, which describes the ionizations inside a material under electron irradiation, is used to determine the depth profile of shallow and ultra-shallow dopants in silicon. Two approaches are presented, depending on whether the shape of the profile is known or not. To test the method, X-ray intensities of implanted phosphorus atoms at various energies and doses in silicon are measured at a wide range of incident electron energies. From the experimental data combined with the model, the resulting profile parameters are determined. Comparison of secondary ion mass spectrometry and EXES associated with the electron scattering model shows that the proposed method is suitable for determining the shallow implant profiles with a depth resolution of one nanometer.