Quantitative analysis with heavy ion E-TOF-ERD

Moderate-velocity heavy ion TOF-ERD combined with energy detection (E-TOF-E RD) is a powerful analytical technique, with large cross sections (similar to 10(-21) cm(2)/sr), high depth resolution (similar to 2 nm), and good mas s resolution (similar to 1 amu). Measurements on several oxides were perfor med with the E-TOF-ERD system at Sandia National Laboratories using 10-15 M eV Au and 6.5 MeV I incident beams. Commercially available multi-parameter acquisition software was used for data collection. Quantitative information about the composition of the oxide samples was obtained by converting the time domain spectra into the energy domain and analyzed with the computer s imulation code, SIMNRA. Use of these acquisition and simulation software co des will be discussed. Several problems associated with the use of moderate -velocity heavy ion E-TOF-ERD were identified during measurement and analys is of the oxide samples. These include (1) difficulty in accurately measuri ng the beam dose, (2) unreliable tabulated stopping powers for heavy ions, and (3) erosion of some thin oxides by Coulomb explosions caused by the bea m. These problems are also discussed. (C) 2000 Elsevier Science B.V. All ri ghts reserved.