Browsing by Author "Bubb, IF"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Analysis of compound semiconductor materials using heavy ion recoil spectrometry
    (Australian and New Zealand Institutes of Physics, 1994-11-09) Walker, SR; Johnston, PN; Bubb, IF; Studd, W; Cohen, DD; Dytlewski, N; Hult, M; Whitlow, HJ; Zahring, C; Östling, M; Andersson, M; Martin, JW
    Heavy Ion Recoil Spectrometry has been used to examine various semiconductor material systems which cannot easily be studied using convensional ion beam techniques such as RBS. The technique enables the determination of seperate energy spectra for individual elements. This enables it to be used in many situations where RBS is inappropriate due to the superimposition of signals in the backscattering spectrum. We have employed Recoil Spectrometry to study; light element impurity concentrations, stoiciometry and metalisation contact systems for various compound semiconductor materials.- The experiments were performed at the ANTARES (TN Tandem) accelerator facillity at Lucas Heights using 61-91 MeV 12?I ions jn e incident " ' i ions cause nuclei of the sample to recoil following Rutherford scattering. The recoiling target nuclei are then analysed by a Time Of Flight and Energy (TOF-E) detector telescope composed of two timing pickoff detectors and a surface barrier (energy) detector. From the time of flight and energy, the ion mass can be determined and individual depth distributions for each element can be obtained.
  • No Thumbnail Available
    Item
    Efficiency enhancements to Monte Carlo simulation of heavy ion elastic recoil detection analysis spectra
    (Elsevier, 2002-05) Franich, RD; Johnston, PN; Bubb, IF; Dytlewski, N; Cohen, DD
    Monte Carlo (MC) simulation can be used to simulate heavy ion elastic recoil detection analysis spectra, including the broadening and tailing effects of multiple and plural scattering, although it is very costly in terms of computer time. In this work, kinematic relationships and experimental parameters are exploited to implement efficiency improvements in the MC modeling process. For thin films, incident ions that pass through the sample without undergoing a significant scattering event need not be tracked. Ions that might generate a detectable scattered or recoiled ion are predicted by generating, in advance, the impact parameters which will define its path. Light recoiled target atoms may be dealt with in the same way. For heavy atoms, however, the probability of large angle scattering events is so high that the paths of most recoil atoms are dominated by several scattering events with large angular deflections. © 2002 Published by Elsevier Science B.V.
  • No Thumbnail Available
    Item
    Scattering of ions beyond the single scattering critical angle in HIERDA
    (AIP Publishing, 2003-08-26) Johnston, PN; Bubb, IF; Franich, R; Cohen, DD; Dytlewski, N; Arstila, K; Sajavaara, T
    In Heavy Ion Elastic Recoil Detection Analysis (HIERDA), Rutherford scattering determines the number of scattered and recoiled ions that reach the detector. Because plural scattering is a major contributor to the spectrum and can mask important features and otherwise distort the spectrum it needs to be described correctly. Scattering more than once is a frequent occurrence so many ions scatter beyond the maximum scattering angle possible by a single scattering event. In this work we have chosen projectile/target combinations which enable the exploitation of the scattering critical angle to obtain spectra which are from ions which have all been scattered more than once. Monte Carlo simulation of the ion transport is used to study the plural scattering using a fast FORTRAN version of TRIM. The results of the simulations are compared with experimental measurements on samples of Si, V and Co performed with 20-100 MeV beams of Br, I and Au ions using ToF-E HIERDA facilities at Lucas Heights and Helsinki. © 2003 American Institute of Physics.