Design and simulation of atomic force profiling of high aspect ratio samples using 2D subresonant force spectroscopy

A 3D Atomic Force Microscopy (AFM) approach is designed that targets high-aspect ratio profile measurements with minimal tip-sample forces and simulations have been performed to assess the performance. This approach aims at alleviating the challenges of a) lateral sideways tip motion, b) accessibility of small trenches and c) excessive tip-sample forces leading to tip sample damage and elastic deformations. In this approach, two-dimensional force measurements are generated using a cantilever that is compliant in both torsional and bending direction. A new high-speed scan head has been designed that enables a new subresonant scanning mode that detects, measures and responds in the attractive force regime. In this manner, smaller distances between the cantilever tip and the sample, with potentially damaging repulsive forces, are avoided. Completion of the designed demonstrator is expected to yield sub-nanometer accurate measurements of sample profiles including trenches that can be 30nm wide and depths of 90 nm and more.