This article describes microprobes for noncontact scanning force microscopy that make use of a direct-oscillating thermally driven bimorph actuator with integrated piezoresistive readout sensor. The sensitivity has been increased using direct current for biasing and alternating current for exciting the thermally driven cantilever in a higher flexural mode. The cantilever operates in the phase-shift atomic force microscopy (AFM) detection technique. The main advantage of phase imaging is the higher z resolution at high scan rates and much lower forces than in height imaging with contact AFM. Critical dimensions measurements illustrating the imaging capability and resolution of our new scanning proximal probe are demonstrated.

We describe a microcantilever calorimeter consisting of an array of ten cantilevers. Each single cantilever is capable of detecting heat energy with the resolution of 50 nW Hz (Ϫ0.5) . The device is based on a Si microcantilever coated with a 1 m thick layer of SiO 2 deposited with a 700 nm thick layer of aluminum which forms a resistive microheater. Heat fluxes are monitored by detecting the cantilever deflection ͑bending͒ due to the bimaterial structure of the cantilever ͑dissimilar thermal expansion properties of SiO 2 and Al͒. The resistive microheater serves for calibration of the heat flux and for temperature sensing. In our design a piezoresistive Wheatstone bridge detector is applied for measurements of the cantilever beam deflection. The cantilever displacement detection system enables investigations in ultrahigh vacuum and low temperature conditions. The microcantilevers are manufactured in a one-dimensional array having ten individual microcantilevers which is the first step in the fabrication of an infrared detector array with spatial resolution. The displacement sensitivity versus temperature change of the described sensor array as a function of temperature change is of about 2 nm/K and an estimated resolution limit of temperature detection is Ϸ10 Ϫ3 K at 300 K. In order to demonstrate the cantilever bending sensitivity we employ the piezoresistive cantilever array as a picogram microbalance.

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Electronic noses based on polymer‐like carbon nitride (CNx) are investigated by these authors. The gas‐sensing properties of CNx are examined, focusing on the detection of humidity and ammonia. Two basic types of gas sensor—capacitance and microelectromechanical (see Figure)—are discussed. It is found that the sensors are highly sensitive, stable, and have short response and recovery times.

We report on the performance of a measurement system for the recognition of individual analytes and their binary mixtures which is based on a multiarray of four micromachined silicon cantivelers actuated at their resonance frequency. The cantilevers have been functionalized by organic polymers [polydimethylsiloxane (PDMS) and polyvinylpyridine (PVP)] and amorphous nitrogen-rich carbon nitride films. We found that the sensitivity and selectivity of the cantilevers coated with CNx films change according to the layer thickness. Our results show that the selected combination of sensitive layers ensures a wide range of specific, reversible and reproducible sensor responses upon exposure to methanol, 2-propanol, water and their binary mixtures. Further, it was found that the differences in recovery times of PDMS and CNx films after exposure to the two alcohols and their mixtures could be used especially for low analyte concentrations as a second characteristic in addition to the resonance frequency shift for the identification of individual components in the mixtures.

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