Scanning probe microscopy characterisation of masked low energy implanted nanometer structures

Abstract

In order to fabricate and characterise nanometer structures, silicon wafers were implanted with masks ranging from several μm down to 200 nm in lateral dimensions. The masks were produced by an electron beam lithography, metal deposition and metal lift-off sequence. 10 keV 75 As + -ions were implanted to a fluence of 2.5×10 14 cm −2 to create nanometer-sized doped and undoped volumes. Characterisation of the ion-implanted patterns was carried out by etching away the metal masks and subsequently using atomic force microscopy (AFM) and scanning capacitance microscopy (SCM) images of the patterns. The simultaneous AFM and SCM measurements gave sharp contrasts between implanted and unimplanted regions, showing highly resistive swelled structures. The swelling also showed structure with a concave shape for implanted regions and a convex shape for unimplanted regions, which is most probably a result of damage evolution from the implantation.