Articles you may be interested inTime-of-flight secondary ion mass spectrometry with transmission of energetic primary cluster ions through foil targets Rev. Sci. Instrum. 85, 033107 (2014); 10.1063/1.4869036Focused ion beam processing of organic crystal ( TMTSF ) 2 PF 6 . A combined conducting probe atomic force microscopy and secondary ion mass spectrometry study New Cs sputter ion source with polyatomic ion beams for secondary ion mass spectrometry applications Rev. Sci. Instrum. 78, 085101 (2007); 10.1063/1.2761021 Nanoscale elemental imaging of semiconductor materials using focused ion beam secondary ion mass spectrometry J.A cesium sputter ion source has been used to generate novel cluster and monoatomic primary ion beams for secondary ion mass spectrometry ͑SIMS͒. The source produces a variety of primary ion beam species with sufficient flux to be usable for both organic surface analysis and semiconductor depth profiling. The primary focus of this work is on the generation and use of carbon and carbon-containing cluster primary ion beams for SIMS. Stability of the sputter ion source is a few percent over 20 min, has useful lifetimes of weeks to months, and produces total primary ion beam currents for C 2 Ϫ ions, measured at the sample, of Ͼ1 A at an extraction voltage of 10 kV. Larger cluster ions (C x Ϫ xϭ4 -10 and CsC x Ϫ xϭ2 -8) are produced with tens of nA of beam current. Due to the divergence of the source, focused beam operation gives current densities under optimal conditions of 0.4-0.5 mA/cm 2 . Cluster bombardment studies of organic films using carbon clusters C x Ϫ xϭ1 -10 indicate that large enhancements ͑up to a factor of 800͒ in the secondary ion yield for characteristic molecular ions from organic samples can be obtained with the larger cluster ions. The signal enhancement can also be utilized in microfocus operation of the source for organic secondary ion imaging studies. For favorable organic samples, cluster bombardment with C x Ϫ , xϾ6 shows little evidence of degradation of the sample from the accumulation of primary beam-induced damage. This effect can be potentially utilized for depth profiling of organic thin films and for further enhancements in sensitivity for organic SIMS analysis. Depth profiling of low energy As implants in silicon with the CsC 6Ϫ primary ion demonstrates that as much as a factor of 6 improvement in apparent depth resolution can be obtained compared to profiles obtained under standard conditions using Cs ϩ bombardment. The flexibility of the source to produce monoatomic primary ion beams from virtually any target material is also being exploited to prepare low energy in situ ion implant standards for quantitative SIMS analysis.
A hot filament duoplasmatron ion source operating with argon has been modified by the addition of an enclosed expansion cup mounted to the extraction side of the duoplasmatron anode. Using sulfur hexafluoride (SF6) as a feed gas, this triplasmatron ion source has been used to generate SF5+ and F− primary ion beams for secondary ion mass spectrometry (SIMS). For positive primary ions, the current extracted from the source is composed of a series of SFx+ cluster ions (x=1–5) with the SF5+ ion being the most intense. SF5+ currents of ∼ 10–20 nA with a maximum of 40 nA are obtained at an extraction voltage of 10 kV. By applying a positive bias to the expansion cup, a localized secondary arc discharge is initiated giving 200 nA–300 nA of SF5+ with a current density of 0.5 mA/cm2. Depending on the operating parameters of the source, lifetimes of greater than 70 h have been achieved. For negative primary ions (with the cup removed), the current extracted from the source is primarily composed of F− ions with a maximum current of 3 μA. The source can be briefly dosed with SF6 and will generate F- beams for 1–2 days without any additional gas being added. Evaluation of the SF5+ and F− ion beams for common SIMS applications demonstrates that these novel primary beams offer significant advantages for depth profiling, organic surface characterization and imaging.
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