STOPPING POWER MEASUREMENTS OF H-1, HE-4 AND N-14 IN SI IN THE ENERGY-RANGE OF 0.02-1 MEV AMU/

In order to obtain precise stopping power data for ion beam analysis o f surface layers we have used high-quality target films produced by ad vanced molecular beam epitaxy. Thus, multi-delta-layers of Sb or Ge in an amorphous Si matrix have been tailored to define a set of targets for energy-loss measurements in backscattering geometry. The stopping powers of ions of H-1, He-4 and N-14 in the energy range of 0.02-1 MeV /amu have been obtained with a precision as high as about 1% with an a dditional systematic error of similar magnitude. Discrepancies of up t o 10% with recent experimental literature data will be discussed, Scal ing laws for electronic stopping have been checked by comparing theore tical predictions with our measurements. Very close agreement with the experimental data is obtained, if the projectile charge is described within the formalism given by Betz et al.