François Horréard oral presentation (PB3-Fri2-1-4)
Optimizing analytical conditions on the NanoSIMS 50L
1 CAMECA, 29 quai des Gresillons, 92622 Gennevilliers, France
2 Université de Pau et des Pays de l’Adour - CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux (IPREM) UMR 5254, 2 avenue du président Angot, 64053 Pau, France
The NanoSIMS is an original ion microprobe optimized for trace element and isotopic analysis and mapping. It incorporates a high mass resolution and high transmission magnetic sector mass analyzer with parallel detection of up to seven masses. Working in DC mode, it uses a primary beam of reactive species (Cs+ and O-) at normal incidence, down to 50nm lateral resolution, with a coaxial secondary ions extraction. 
Here we will show advances for different applications:
1) Small area depth profiling:
the NanoSIMS has been used up to now mostly for academic research [2, 3, 4]. But recent industrial applications have emerged from display industry and microelectronics for depth profiling from areas as small as a few µm2. We illustrate the pros and cons of direct versus reconstructed profiling, and discuss the challenges/solutions concerning sample topography and sample drift.
We also test the influence of primary species and their parameters on the depth resolution of small crater depth profiling in a standard semiconductor sample.
2) Optimization of sensitivity and lateral resolution:
A RF-plasma primary ion source is used on the NS 50L to generate O- primaries for detecting positive secondaries. O2 gas flooding that could further enhance positive ion yield is not available but O2+ primaries have rarely been used. Here we compare the sensitivity on a few selected elements, by varying the primary ions /secondary ions couples and conditions for the detection of Boron in Steel and Silicon (Cs+/ O-/ O2+), and for the detection of Copper, Zinc, Cadmium and Iron (M+/- / MxOy+/-,…) in typical resin-embedded standard samples representative for biology.
3) Increase of C and N sensitivity near the surface:
the automated, quick alternation of low energy/high current cesium deposition and high energy/small spot analysis is investigated in view to reduce the transient regime near the surface and optimize the yields of carbon and nitrogen when analyzing resin-embedded biological samples.