Scanning Probe Microscopy using Higher-Mode Electrostatically-Actuated Microcantilevers

High-throughput scanning probe microscopy can be achieved by employing a large array of microcantilevers in parallel operation. Intermittent-contact operation of the microcantilevers is essential to reduce sample-damage and tip-wear. The first flexural bending mode of the microcantilevers is typically used in various intermittent-contact methods. The throughput of such methods is low due to the low resonant frequency and the high quality factor of the microcantilevers. The intermittent-contact methods often rely on demodulation electronics which renders them unsuitable for parallel scanning probe microscopy applications. In this paper, an intermittent-contact method is presented that uses the higher flexural bending modes of the microcantilevers for high-speed operation. The microcantilevers are electrostatically actuated at a higher normal flexural bending mode such that the tip comes out of contact from the sample-surface during each oscillation cycle. The scanning probe microscopy images are obtained by direct sampling of the micro cantilever deflection signal. This method is suitable for parallel scanning probe microscopy applications. Corroborating modeling and experimental results are presented.