TY - JOUR
T1 - Argon cluster ion beams for organic depth profiling
T2 - Results from a VAMAS interlaboratory study
AU - Shard, Alexander G.
AU - Havelund, Rasmus
AU - Seah, Martin P.
AU - Spencer, Steve J.
AU - Gilmore, Ian S.
AU - Winograd, Nicholas
AU - Mao, Dan
AU - Miyayama, Takuya
AU - Niehuis, Ewald
AU - Rading, Derk
AU - Moellers, Rudolf
PY - 2012/9/18
Y1 - 2012/9/18
N2 - The depth profiling of organic materials with argon cluster ion sputtering has recently become widely available with several manufacturers of surface analytical instrumentation producing sources suitable for surface analysis. In this work, we assess the performance of argon cluster sources in an interlaboratory study under the auspices of VAMAS (Versailles Project on Advanced Materials and Standards). The results are compared to a previous study that focused on C 60 q+ cluster sources using similar reference materials. Four laboratories participated using time-of-flight secondary-ion mass spectrometry for analysis, three of them using argon cluster sputtering sources and one using a C 60 + cluster source. The samples used for the study were organic multilayer reference materials consisting of a ∼400-nm-thick Irganox 1010 matrix with ∼1 nm marker layers of Irganox 3114 at depths of ∼50, 100, 200, and 300 nm. In accordance with a previous report, argon cluster sputtering is shown to provide effectively constant sputtering yields through these reference materials. The work additionally demonstrates that molecular secondary ions may be used to monitor the depth profile and depth resolutions approaching a full width at half maximum (fwhm) of 5 nm can be achieved. The participants employed energies of 2.5 and 5 keV for the argon clusters, and both the sputtering yields and depth resolutions are similar to those extrapolated from C 60 + cluster sputtering data. In contrast to C 60 + cluster sputtering, however, a negligible variation in sputtering yield with depth was observed and the repeatability of the sputtering yields obtained by two participants was better than 1%. We observe that, with argon cluster sputtering, the position of the marker layers may change by up to 3 nm, depending on which secondary ion is used to monitor the material in these layers, which is an effect not previously visible with C 60 + cluster sputtering. We also note that electron irradiation, used for charge compensation, can induce molecular damage to areas of the reference samples well beyond the analyzed region that significantly affects molecular secondary-ion intensities in the initial stages of a depth profile in these materials.
AB - The depth profiling of organic materials with argon cluster ion sputtering has recently become widely available with several manufacturers of surface analytical instrumentation producing sources suitable for surface analysis. In this work, we assess the performance of argon cluster sources in an interlaboratory study under the auspices of VAMAS (Versailles Project on Advanced Materials and Standards). The results are compared to a previous study that focused on C 60 q+ cluster sources using similar reference materials. Four laboratories participated using time-of-flight secondary-ion mass spectrometry for analysis, three of them using argon cluster sputtering sources and one using a C 60 + cluster source. The samples used for the study were organic multilayer reference materials consisting of a ∼400-nm-thick Irganox 1010 matrix with ∼1 nm marker layers of Irganox 3114 at depths of ∼50, 100, 200, and 300 nm. In accordance with a previous report, argon cluster sputtering is shown to provide effectively constant sputtering yields through these reference materials. The work additionally demonstrates that molecular secondary ions may be used to monitor the depth profile and depth resolutions approaching a full width at half maximum (fwhm) of 5 nm can be achieved. The participants employed energies of 2.5 and 5 keV for the argon clusters, and both the sputtering yields and depth resolutions are similar to those extrapolated from C 60 + cluster sputtering data. In contrast to C 60 + cluster sputtering, however, a negligible variation in sputtering yield with depth was observed and the repeatability of the sputtering yields obtained by two participants was better than 1%. We observe that, with argon cluster sputtering, the position of the marker layers may change by up to 3 nm, depending on which secondary ion is used to monitor the material in these layers, which is an effect not previously visible with C 60 + cluster sputtering. We also note that electron irradiation, used for charge compensation, can induce molecular damage to areas of the reference samples well beyond the analyzed region that significantly affects molecular secondary-ion intensities in the initial stages of a depth profile in these materials.
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U2 - 10.1021/ac301567t
DO - 10.1021/ac301567t
M3 - Article
C2 - 22897795
AN - SCOPUS:84866390166
SN - 0003-2700
VL - 84
SP - 7865
EP - 7873
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 18
ER -