Yigezu Birhane - Academia.edu (original) (raw)
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Papers by Yigezu Birhane
Microelectronic Engineering, 2014
We report a novel fabrication process for the batch fabrication of insulated conductive scanning ... more We report a novel fabrication process for the batch fabrication of insulated conductive scanning probe microscopy (SPM) probes for electrical and topographic characterization of soft samples in liquid media at the nanoscale. The whole SPM probe structure is insulated with a dielectric material except at the very tip end and at the contact pad area to minimize the leakage current in liquid. Additionally, the geometry of the conducting layer in the probe cantilever and substrate is engineered to reduce the parasitic capacitance coupling with the sample. The electrical characterization of the probes has shown that parasitic capacitances are significantly reduced as compared to fully metallized cantilevers.
ABSTRACT We have developed self-sensing piezoresistive microcantilevers optimized for the measure... more ABSTRACT We have developed self-sensing piezoresistive microcantilevers optimized for the measurement of (biomolecular) forces. Typical dimensions are 250 µm in length, 8-20 µm in width and 450 nm in thickness, with spring constants of about 1 mN/m. The devices have been electromechanically tested on wafer and show good force resolutions in air between 35 and 130 pN depending on the cantilever dimensions. We have also tested the electromechanical behavior of the cantilevers in liquid environment and we show that both the force sensitivity and the noise characteristics of the devices are not noticeably degraded as compared with their response in air. This opens the way to the use of the cantilevers in single molecule force spectroscopy of biomolecules.
Microelectronic Engineering, 2014
We report a novel fabrication process for the batch fabrication of insulated conductive scanning ... more We report a novel fabrication process for the batch fabrication of insulated conductive scanning probe microscopy (SPM) probes for electrical and topographic characterization of soft samples in liquid media at the nanoscale. The whole SPM probe structure is insulated with a dielectric material except at the very tip end and at the contact pad area to minimize the leakage current in liquid. Additionally, the geometry of the conducting layer in the probe cantilever and substrate is engineered to reduce the parasitic capacitance coupling with the sample. The electrical characterization of the probes has shown that parasitic capacitances are significantly reduced as compared to fully metallized cantilevers.
ABSTRACT We have developed self-sensing piezoresistive microcantilevers optimized for the measure... more ABSTRACT We have developed self-sensing piezoresistive microcantilevers optimized for the measurement of (biomolecular) forces. Typical dimensions are 250 µm in length, 8-20 µm in width and 450 nm in thickness, with spring constants of about 1 mN/m. The devices have been electromechanically tested on wafer and show good force resolutions in air between 35 and 130 pN depending on the cantilever dimensions. We have also tested the electromechanical behavior of the cantilevers in liquid environment and we show that both the force sensitivity and the noise characteristics of the devices are not noticeably degraded as compared with their response in air. This opens the way to the use of the cantilevers in single molecule force spectroscopy of biomolecules.