### Abstract

The effects of multilayer contamination of mean resonant frequency and frequency fluctuations in thickness-shear resonators are studied. A model based on mass-loading of contaminant molecules with adsorption and desorption rates is developed. Equations relating the change in mean frequency and frequency fluctuations to adsorption and desorption rates are derived. Since the adsorption and desorption rates are functions of pressure and temperature, the change in mean frequency and spectral density of frequency fluctuations is studied with respect to pressure and temperature. Calculations are performed for a 10 MHz thickness-shear resonator. Frequency-temperature and frequency-pressure curves are plotted for the 10 MHz resonator. The curves do not follow a cubic polynomial function and have a magnitude in the range of 10 ppm. The mean square of frequency fluctuations under multilayer contamination is significantly greater than that under monolayer contamination. The spectral density of frequency fluctuations at 1 Hz is quite constant in a wide range of temperatures (-50 to 100°C) when the values of heat of absorption for the second and subsequent layers are close to that of the first layer. The magnitude of spectral density of frequency fluctuations is about -120 dBc (Hz^{2}/Hz).

Original language | English (US) |
---|---|

Pages (from-to) | 387-393 |

Number of pages | 7 |

Journal | Proceedings of the Annual IEEE International Frequency Control Symposium |

State | Published - May 1 1990 |

Event | Proceedings of the 44th Annual Symposium on Frequency Control 1990 - Baltimore, MD, USA Duration: May 23 1990 → May 25 1990 |

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### All Science Journal Classification (ASJC) codes

- Electrical and Electronic Engineering
- Control and Systems Engineering

### Cite this

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**Simulation of noise processes in thickness-shear resonators caused by multilayer adsorption and desorption of surface molecules.** / Yong, Yook-Kong.

Research output: Contribution to journal › Conference article

TY - JOUR

T1 - Simulation of noise processes in thickness-shear resonators caused by multilayer adsorption and desorption of surface molecules

AU - Yong, Yook-Kong

PY - 1990/5/1

Y1 - 1990/5/1

N2 - The effects of multilayer contamination of mean resonant frequency and frequency fluctuations in thickness-shear resonators are studied. A model based on mass-loading of contaminant molecules with adsorption and desorption rates is developed. Equations relating the change in mean frequency and frequency fluctuations to adsorption and desorption rates are derived. Since the adsorption and desorption rates are functions of pressure and temperature, the change in mean frequency and spectral density of frequency fluctuations is studied with respect to pressure and temperature. Calculations are performed for a 10 MHz thickness-shear resonator. Frequency-temperature and frequency-pressure curves are plotted for the 10 MHz resonator. The curves do not follow a cubic polynomial function and have a magnitude in the range of 10 ppm. The mean square of frequency fluctuations under multilayer contamination is significantly greater than that under monolayer contamination. The spectral density of frequency fluctuations at 1 Hz is quite constant in a wide range of temperatures (-50 to 100°C) when the values of heat of absorption for the second and subsequent layers are close to that of the first layer. The magnitude of spectral density of frequency fluctuations is about -120 dBc (Hz2/Hz).

AB - The effects of multilayer contamination of mean resonant frequency and frequency fluctuations in thickness-shear resonators are studied. A model based on mass-loading of contaminant molecules with adsorption and desorption rates is developed. Equations relating the change in mean frequency and frequency fluctuations to adsorption and desorption rates are derived. Since the adsorption and desorption rates are functions of pressure and temperature, the change in mean frequency and spectral density of frequency fluctuations is studied with respect to pressure and temperature. Calculations are performed for a 10 MHz thickness-shear resonator. Frequency-temperature and frequency-pressure curves are plotted for the 10 MHz resonator. The curves do not follow a cubic polynomial function and have a magnitude in the range of 10 ppm. The mean square of frequency fluctuations under multilayer contamination is significantly greater than that under monolayer contamination. The spectral density of frequency fluctuations at 1 Hz is quite constant in a wide range of temperatures (-50 to 100°C) when the values of heat of absorption for the second and subsequent layers are close to that of the first layer. The magnitude of spectral density of frequency fluctuations is about -120 dBc (Hz2/Hz).

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M3 - Conference article

SP - 387

EP - 393

JO - Proceedings of the Annual IEEE International Frequency Control Symposium

JF - Proceedings of the Annual IEEE International Frequency Control Symposium

SN - 0161-6404

ER -