Thermal Characterization of Dynamic Silicon Cantilever Array Sensors by Digital Holographic Microscopy

Abstract

In this paper, we apply a digital holographic microscope (DHM) in conjunction with stroboscopic acquisition synchronization. Here, the temperature-dependent decrease of the first resonance frequency (S1(T)) and Young’s elastic modulus (E1(T)) of silicon micromechanical cantilever sensors (MCSs) are measured. To perform these measurements, the MCSs are uniformly heated from T0 = 298 K to T = 450 K while being externally actuated with a piezo-actuator in a certain frequency range close to their first resonance frequencies. At each temperature, the DHM records the time-sequence of the 3D topographies for the given frequency range. Such holographic data allow for the extracting of the out-of-plane vibrations at any relevant area of the MCSs. Next, the Bode and Nyquist diagrams are used to determine the resonant frequencies with a precision of 0.1 Hz. Our results show that the decrease of resonance frequency is a direct consequence of the reduction of the silicon elastic modulus upon heating. The measured temperature dependence of the Young’s modulus is in very good accordance with the previously-reported values, validating the reliability and applicability of this method for micromechanical sensing applications.

A Surface Micromachining: HNA Etchant for Stiction-free Release of Micro/Nanomechanical Structures

“…Micro and nano electro mechanical systems (MEMS and NEMS) are of great interest due to their versatile application in atomic force microscopy [1], various sensors [2,3], actuators [4] and infrared detectors [5]. Especially the silicon nitride microcantilevers are extensively used as scanning probes in single-molecule force spectroscopy (SMFS) [6], mass sensors [7], and gas sensors [8,9].…”

Wavelet compression of off-axis digital holograms using real/imaginary and amplitude/phase parts

“…A 3D image of the object or 2D scenes of the registered environment can be reconstructed numerically (by model propagation of the wave using a computer) 4 or optically (by displaying this hologram on spatial light modulator and its illumination) 5,6 . Digital holography is widely used for microobjects and particle tracking 7 , detection of changes of refractive or reflective indices 8 , measuring temperature 9 , etc. The increase in the number of pixels in digital cameras has led to the growth of the file size of holograms.…”

Calibrated Phase-Shifting Digital Holographic Microscope Using a Sampling Moiré Technique

“…Although confocal laser scanning microscopy (CLSM), which can achieve high-precision 3-D measurement, has been developed, it cannot be used to measure a fast and dynamic object owing to its long scanning time. Digital holographic microscopes [1][2][3][4][5][6] can capture the 3-D information of an object without depth scanning and can focus at arbitrary depths. They can also obtain both intensity and phase information from holograms and thus can measure materials that are mostly transparent, such as biological cells and glass.…”