skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Longitudinal bulk acoustic mass sensor

Abstract

A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

Authors:
; ; ;  [1]
  1. Department of Micro and Nanotechnology-DTU Nanotech, Technical University of Denmark, DTU Bldg. 345 East, DK-2800 Kongens Lyngby (Denmark)
Publication Date:
OSTI Identifier:
21294201
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 95; Journal Issue: 3; Other Information: DOI: 10.1063/1.3168519; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AIR; ION BEAMS; NOISE; POLYCRYSTALS; SEMICONDUCTOR MATERIALS; SENSORS; SILICON; SOUND WAVES

Citation Formats

Hales, J. H., Teva, J., Boisen, A., and Davis, Z. J.. Longitudinal bulk acoustic mass sensor. United States: N. p., 2009. Web. doi:10.1063/1.3168519.
Hales, J. H., Teva, J., Boisen, A., & Davis, Z. J.. Longitudinal bulk acoustic mass sensor. United States. doi:10.1063/1.3168519.
Hales, J. H., Teva, J., Boisen, A., and Davis, Z. J.. 2009. "Longitudinal bulk acoustic mass sensor". United States. doi:10.1063/1.3168519.
@article{osti_21294201,
title = {Longitudinal bulk acoustic mass sensor},
author = {Hales, J. H. and Teva, J. and Boisen, A. and Davis, Z. J.},
abstractNote = {A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.},
doi = {10.1063/1.3168519},
journal = {Applied Physics Letters},
number = 3,
volume = 95,
place = {United States},
year = 2009,
month = 7
}
  • A new method of processing multivariate response data to extract chemical information has been developed. Sensor array response patterns are transformed into a vector containing values for descriptors of the detected vapor's properties. These results can be obtained by using a method similar to classical least squares, and equations have been derived for mass-transducing sensors or volume-transducing sensors. Polymer-coated acoustic wave devices are an example of mass-transducing sensors. However, some acoustic wave sensors, such as polymer-coated surface acoustic wave (SAW) devices give responses resulting from both mass-loading and decreases in modulus. The latter effect can be modeled as a volumemore » effect. In this paper, we derive solutions for obtaining descriptor values from arrays of mass-plus-volume-transducing sensors, and perform simulations to investigate the effectiveness of these solutions and the approximations used for cases having no closed form solutions. The results show that good estimations of vapor descriptors can be obtained by using a solution that is equivalent to the solution for mass-transducing sensor arrays, but with greater sensitivities due to the volume contribution. The most challenging case occurs when the volume sensitivities in the array vary widely and especially if polymers with similar interactive properties have very different volume sensitivities. Estimates from this most challenging case be improved using a nonlinear least squares optimization method. It is concluded that this new method of processing sensor array data can be applied to SAW sensor arrays even when the modulus changes contribute to the responses. The results also suggest ways to design SAW arrays to obtain the best results, either by minimizing the volume sensitivity or matching the volume sensitivities in the array.« less
  • The device described in this report derives its selectivity, reversibility, and durability from a simple, self-assembled monolayer and its sensitivity from a mass-sensitive surface acoustic wave (SAW) device. The coating design takes advantage of the interaction between organophosphonate nerve-agent simulants and a composite monolayer, consisting of Cu[sup 2+] tethered to the SAW device by an ordered, carboxylate-terminated n-alkanethiol monolayer. The rationale for this design is that Cu[sup 2+] and some of its chelates are hydrolysis catalysts for certain nerve agents. Thus, a surface layer of coordinatively unsaturated Cu[sup 2+] might be expected to provide selective and reversible binding sites formore » organophosphonates. The authors have demonstrated that this simple fabrication procedure incorporates all of the essential features of an ideal sensor: (1) it is selective for organophosphonates; (2) it is sensitive to 100 ppb of an important nerve-gas simulant; (3) it provides a reversible and proportional response to target analytes; (4) it is durable for periods of months. 19 refs., 3 figs.« less
  • A solidly mounted acoustic resonator was fabricated using a Ba{sub 0.60}Sr{sub 0.40}TiO{sub 3} (BST) film deposited by metal organic chemical vapor deposition. The device was acoustically isolated from the substrate using a Bragg reflector consisting of three pairs of Ta{sub 2}O{sub 5}/SiO{sub 2} layers deposited by chemical solution deposition. Transmission electron microscopy verified that the Bragg reflector was not affected by the high temperatures and oxidizing conditions necessary to process high quality BST films. Electrical characterization of the resonator demonstrated a quality factor (Q) of 320 and an electromechanical coupling coefficient (K{sub t}{sup 2}) of 7.0% at 11 V.
  • We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determinedmore » by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.« less
  • We report a simple and practical sensor for monitoring both the absolute position and advancing speed of liquid front in a microfluidic channel. The sensor consists of a longitudinal hot wire element - a two-terminal electrical device, with its length spanning the entire channel. The design, materials, fabrication method, and use of this sensor are extremely simple. Characterization results are presented.