Description of the method:
The 3D-atomprobe is a technique to determine element distributions in solid samples on the atomic scale. Applying a pulsed high voltage (or LASER pulses) to a fine needle type sample, surface atoms get evaporated due to field emission processes and. The emitted ions are accelerated to a position sensitive detector. The flight-time between the pulse and detection is determined by the mass of the particle and the localization in x and y allows a reconstruction of the emitted position
Features of 3D-AP
The result of a measurement is a spacial distribution of elements. This distribution can also be used to generate a depth profile. The typical sample dimensions are 50nm*50nm*300nm and this is a volume containing about 45 billions of single atoms. Because of all particles leaving the sample are ionized they were detected and a quantification is inherent in the number of detected ions without any standard reference materials.
Sample preparation is in expense of time. Metallic conductive samples can be prepared by electropolishing but semiconducting or isolating samples require a preparation in a FIB (focused ion beam) analogue to the preparation of TEM lamella.
LEAP 4000X HR , CAMECA, Madison WI, USA/ Installation start december 2013.