Lateral implantation dose measurements of plasma immersion ion implanted non-planar samples

The homogeneity of plasma immersion ion implantation of non-planar samples was determined by Rutherford backscattering analysis. Half-cylinders made of carbon treated by argon ions served as a model system. The distribution of the implanted argon dose on the top plane and on the side plane of the samples was analysed. The results show a maximum dose at the centre of the top plane acid a decrease towards the edges. On the side plane the dose increases from top to bottom. These variations were up to fifty percent. Additionally, a variation in implantation depth depending on the energy of the implanted ions and on the angle of incidence was observed. These effects are due to the sample size and the process parameters determining the dimensions of the plasma sheath which wraps the sample. A possible explanation for these phenomena is based on the assumption that on their way from the plasma to the sample the ions do not follow bent electrical field lines which occur near the edges of a sample.