Evaluating the compressive stress generated during fabrication of Si doubly clamped nanobeams with AFM

Abstract

In this work, the authors employed Peak Force tapping and force spectroscopy to evaluate the stress generated during the fabrication of doubly clamped, suspended silicon nanobeams with rectangular section. The silicon beams, released at the last step of fabrication, present a curved shape that suggests a bistable buckling behavior, typical for structures that retain a residual compressive stress. Both residual stress and Young's modulus were extracted from experimental data using two different methodologies: analysis of beam deflection profiles and tip-induced mechanical bending. The results from the two methods are compared, providing an insight into the possible limitations of both methods.