Reconstruction of three-dimensional range distributions by a modified tomographic technique

Abstract

First, an overview of the present state of art of imaging of three-dimensional particle (or damage) distributions in the field of ion implantation is given. Usually, the direct measurement of three-dimensional distributions in the field of ion implantation is restricted to cases when the impinging ion beam diameter is small against the size of the corresponding distributions, i.e., to ion energies above typically 100 MeV and to microbeams of a few μm diameter. To gain information also for lower ion energies without the restriction in the beam diameter, a modified tomographic reconstruction technique has been developed recently by us and is described here in detail. Three-dimensional distributions are reconstructed from a number of one-dimensional depth profiles, implanted under various angles. Competing algorithms for the solution are discussed. For the mathematical technique chosen, some consistency tests are presented. Good accuracy of a sufficient number of input profiles is vital for the quality of the three-dimensional reconstruction