Title :
Temperature dependence of vacuum encapsulated resonators for humidity measurement
Author :
Hennessy, R.G. ; Shulaker, Max M. ; Messana, Matthew W. ; Graham, Andrew B. ; Klejwa, N. ; Provine, J. ; Kenny, Thomas W. ; Howe, R.T.
Author_Institution :
Stanford Univ., Stanford, CA, USA
Abstract :
This paper demonstrates the effect of temperature on humidity measurements using a charge-biased microshell encapsulated single-anchored double-ended tuning fork resonator (DETF). The resonator is electrically connected to a metal bond pad on the external surface silicon dioxide. Changes in the ambient humidity alter the charge decay characteristics of the resonator by modifying the surface resistance of the oxide. This change is monitored by measuring the shift in resonant frequency due to electrostatic spring softening. Varying the temperature from 12°C to 32°C and the relative humidity (RH) from 0 to 60%, the temperature dependence of time decay ranged from -0.05/°C to -0.03/°C and the relative humidity dependence of time decay ranged from 0/RH to -15/RH.
Keywords :
encapsulation; humidity measurement; humidity sensors; micromechanical resonators; vibrations; DETF; ambient humidity; charge biased microshell encapsulated single anchored resonator; double ended tuning fork resonator; electrostatic spring softening; humidity measurement; metal bond pad; temperature 12 C to 32 C; temperature dependence; vacuum encapsulated resonator; Humidity; Humidity measurement; Resonant frequency; Surface resistance; Temperature measurement; Temperature sensors; Charge-biased; Double Ended Tuning Fork Sensor (DETF); Encapsulated; Humidity Sensor; Surface conduction;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS), 2011 16th International
Conference_Location :
Beijing
Print_ISBN :
978-1-4577-0157-3
DOI :
10.1109/TRANSDUCERS.2011.5969284
