Cesium profiles in silicon and in SiO2-Si double-layers as determined by SIMS measurements

Secondary ion mass spectrometry is used to determine

1. the range distributions of 10–100 keV cesium ions implanted into monocrystalline silicon and
2. the cesium profiles in SiO₂-Si double layers formed by implantation of cesium into silicon surfaces and subsequently converting the implanted layer into SiO₂ through thermal oxidation at 800°C and 1000°C.

In the first case (a) non-Gaussian distributions are observed for the implanted cesium atoms. Their projected ranges show a somewhat stronger energy dependence as predicted from LSS-theory. The values for standard deviations and third central moments are in good agreement with theory at low energies but are larger up to a factor of 1.5 at higher energies. In the second case (b) cesium ions present in the implanted silicon layer are introduced into the growing oxide layer during oxidation and pile up at both oxide interfaces.