Removal of contamination and oxide layers from UHV-AFM tips

A tip made of Si on a piezoresistive AFM cantilever is evaluated by a scanning Auger electron microscope and a UHV-AFM. To remove contamination and oxide layers covering the tip surface, the AFM tip is ion-sputtered and oxidized to form a protective thin oxide layer that is easily desorbed by heating only. The tip can be easily heated by directly passing a small current into the cantilever. The quality of the AFM images improves with an AFM tip heated in the AFM chamber just before scanning. The possibility of evaluation of the AFM tip by a field emission microscope with a grid is also demonstrated.