A Novel Topography and Elasticity Synchronous Measure Approach With an AFM

Atomic force microscopy (AFM) is a powerful tool to measure the topography or the mechanical properties of samples at the nanoscale. Currently, the method of force-distance curve analysis is usually adopted to obtain the mechanical properties by an AFM, which presents the drawbacks of long time consuming and impossibility to measure the topography and the mechanical properties simultaneously. To address these problems, this article proposes a novel topography/elasticity measurement approach, which efficiently obtains the topography and the mechanical properties of detected samples with a conventional AFM. To be specific, the set points for forward and backward scanning are carefully selected to be different, so as to yield different sample deformations and piezoactuator displacement, for the same point with forward and backward scanning. On this basis, a mathematical model is set up to simultaneously calculate the topography and Young's modulus of the sample surface by carefully analyzing the obtained data from the scanning processes. In addition, considering the effect of z-axis drift during the measurement process, an information fusion algorithm based on the least-squares method and the Kalman filter is proposed to successfully compensate for the drift and thus further improve the imaging quality. Experimental results are included to demonstrate the good performance of the proposed approach for topography and mechanical properties' measurement.