MATERIALS CHARACTERIZATION USING HEAVY-ION ELASTIC RECOIL TIME-OF-FLIGHT SPECTROMETRY

Materials characterisation by heavy ion elastic recoil time of night s pectrometry (HIERTOFS) at a forward recoil angle of 45 degrees has bee n investigated using 40-110 MeV chlorine and iodine ions. Measurements are compared with a computer simulation code that evaluates the resol ution components such as those due to straggling, multiple scattering, roughness and detector resolution both at the surface and at depth wi thin the sample. The code also simulates elastic recoil time of flight spectra, which compare favourably with RBS analysis techniques. The T oF detector has a timing resolution of the order 300 ps, a mass resolu tion, for 30 MeV gallium recoils, of 4-5 amu and a depth resolution of 150 Angstrom at the surface. The spectrometer to date has been used t o characterise such materials as YBCO thin films, GaAs structures and implanted silicon samples.