[en] Information about concentrations and profiles of impurities on or near surfaces is commonly obtained from secondary ion mass spectroscopy (SIMS) measurements. These may, however, yield misleading results when sharp profiles are measured. In this work, the results of computer simulations of SIMS measurements of light impurities (hydrogen, deuterium and lithium) on diamond are presented, using a modified version of the transport of ions in matter (TRIM) computer code which has been extended to include the continuously changing material during the SIMS profiling. The simulations show that elastic recoils, induced by the probing beam used in SIMS, can broaden an initially sharp profile and thus induce an apparent diffusion profile. The changes in matrix composition caused by the implantation of the probing beam can modify the depth scale. These are demonstrated by performing detailed computations for the technologically important cases of (i) a hydrogen-passivated diamond surface and (ii) a thin Li layer on top of a diamond surface. The results show that the exponential tail, experimentally measured by SIMS and interpreted as being due to diffusion of Li into diamond, can be fully explained by the art-effect of the SIMS measurement. Very good agreement between the simulated and measured SIMS profiles is obtained when it is assumed that Li is present only on the surface as a thin layer

[en] The structural and compositional changes which occur in InSb as a result of ion implantation have been studied. InSb samples were implanted with Cd (300 keV, 2 x 10¹⁴ cm^-2) and B (20 keV, 7.5 x 10¹⁵ cm^-2) ions at different temperatures (80-560 K). As a result of the implantation, swelling of the implanted layer was noticed. The step height due to this swelling was measured by interferometric methods, and the changes of composition by RBS, PIXE and Auger spectroscopy. The most severe swelling (up to 4200 A) is measured for 300 K Cd implantations. RBS shows a reduction in backscattering yield in the implanted region which is possibly caused by oxidation. PIXE and Auger measurements show that the implanted region is In-poor and O-rich. No swelling is detectable for B implantations. It is proposed that internal strain caused by agglomeration of defects is responsible for the oxidation and for the swelling. (orig.)

[en] The use of the ⁹Be(p,α)⁶Li(Esub(p)=330 keV) reaction as a tool for the profiling of implanted Be is described. Pile-up problems, caused by elastically scattered particles, requires a mylar foil to be introduced in front of the particle detector. This causes severe straggling and thus loss of depth resolution. A deconvolution technique, which is based on an iterative procedure, is described. With it, profiles are reconstructed with a depth resolution of 300 A. The present technique was used to assess the diffusion of Be implanted into InSb and GaAs during annealing. Pronounced diffusion accompanied by Be loss was found for GaAs (Tsub(ann)=1113 K, Tsub(melt)=1511 K), while hardly any changes in Be profiles for InSb (Tsub(ann)=670 K, Tsub(melt)=798 K) could be detected. (orig.)

[en] Short note

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[en] A windowless Si(Li) electron detector has been used in conjunction with the gas filled fission product separator JOSEF to study totally converted transitions in Zr and Mo isotopes. The existence of two β-decay modes in ⁹⁶Y, ⁹⁸Y and ¹⁰⁰Nb is confirmed. The half-lives of the β-decaying levels feeding O₂⁺ states in ⁹⁶Zr and ⁹⁸Zr are 6.0 +- 0.4 sec and 0.60 +- 0.05 sec, respectively. A search for other first excited O₂⁺ states shows that no such states are apparent in ¹⁰⁰Zr and ¹⁰⁴Mo. (orig.)

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[en] The β^-decay of ¹⁰²Y to levels in ¹⁰²Zr was investigated using the gas-filled recoil separator JOSEF. The singles γ spectrum, γ-γ and X-γ coincidences, and half-life were measured. Preliminary results from these measurements are reported. Only one isomer was observed with a Tsub(1/2) = 0.27 + 0.07 s. The β^-decay populated excited states in ¹⁰²Zr at 151.9(2⁺), 478.4(4sup(*)), 730.7 and 1242.1 keV. No evidence was found for the population of a low-lying 0⁺ state of the type seen in ¹⁰⁰Zr. The results are compared with earlier fission fragment studies, and implications for the systematics of even-even Zr nuclides are discussed. (orig.)