Attonewton force detection using ultrathin silicon cantilevers

Abstract

A measured force resolution of ${\text{5.6×10}}^{\text{−18}}$ $\mathrm{N}/\sqrt{\mathrm{Hz}}$ at 4.8 K in vacuum using a single-crystal silicon cantilever only 600 Å thick is demonstrated. The spring constant of this cantilever was ${\text{6.5×10}}^{\text{−6}}\hspace{0.5em}\mathrm{N/m,}$ or more than 1000 times smaller than that of typical atomic force microscope cantilevers. The cantilever fabrication includes the integration of in-line tips so that the cantilever can be oriented perpendicular to a sample surface. This orientation helps suppress cantilever snap-in so that high force sensitivity can be realized for tip-sample distances less than 100 Å.