Characterization of microtips for scanning tunneling microscopy

Abstract Progress in STM, in particular for the interpretation of the tunnel signals, is related to the possibility to sharpen and to regenerate in situ the tip which is used as the probe. Three techniques are now available to produce tips with controlled geometry at the atomic level. By the use of FIM to characterize the geometry, and FEM and FEM-FES to study the tunneling properties and electronic structure, we show that microtips produced by a technique based on the pseudo-stationary profile principle suited the best.