Title :
Tunable piezoelectric MEMS resonators for real-time clock
Author :
Serrano, Diego Emilio ; Tabrizian, Roozbeh ; Ayazi, Farrokh
Author_Institution :
Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
Abstract :
This paper reports on the design, simulation and characterization of small form factor, tunable piezoelectric MEMS resonators for real time clock applications (32.768 kHz). The structures were fabricated on a thin-film AlN-on-SOI substrate to enable piezoelectric actuation of an out-of-plane flexural mode, as well as electrostatic frequency tuning by utilizing the handle layer as a DC voltage electrode. Resonators of only a few hundred of μm in size exhibit greater than 3100 ppm of tuning using voltages no larger than 4 V; this tuning sufficiently compensates for frequency variations across temperature from -25 to 100°C. The devices exhibit low motional impedance that is completely independent of the tuning potential.
Keywords :
atomic clocks; circuit tuning; crystal resonators; micromechanical resonators; piezoelectric actuators; silicon-on-insulator; thin film devices; AlN on SOI; MEMS resonators; electrostatic frequency tuning; out-of-plane flexural mode; piezoelectric actuation; real-time clock; thin-film substrate; tunable piezoelectric resonators; Acoustic beams; Electrodes; Micromechanical devices; Oscillators; Resonant frequency; Silicon; Tuning;
Conference_Titel :
Frequency Control and the European Frequency and Time Forum (FCS), 2011 Joint Conference of the IEEE International
Conference_Location :
San Fransisco, CA
Print_ISBN :
978-1-61284-111-3
DOI :
10.1109/FCS.2011.5977885
