DEVELOPMENT OF A SCANNING ATOM-PROBE

In order to extend the applicability of the conventional atom probe (AP), a new AP named 'scanning atom probe (SAP)' is proposed. The SAP has a microextraction electrode which scans over a flat specimen surface with many microcusps. Then the electrode and a cusp forms a minute field ion microscope. Calculation of field distribution in the confined small space between the cusp apex and the electrode indicates that the field can be high enough to field evaporate the apex atoms and that the atom-by-atom mass analysis by the SAP is highly feasible. Accordingly, a trial SAP is under construction modifying a low-temperature UHV scanning tunneling microscope.