Title :
Design of a high-Q CMOS-compatible MEMS tunable capacitor for RF applications
Author :
Nasirzadeh, N. ; Abbaspour, E. ; Dadashzadeh, G.
Author_Institution :
Urmia MEMS Lab., Iran Telecom Res. Center, Iran
Abstract :
A high-Q micromachined electro-mechanically tunable capacitor for RF application is presented. The proposed design is CMOS-compatible that can be integrated monolithically with CMOS circuit in a single die. In this structure there is no need for cantilever beams which introduce considerable series resistance to the capacitor and decrease the quality factor. So our varactor achieve better Q in a smaller area. The simulated 1 pF capacitor shows a Q of 40 at 1 GHz and a tuning range of 42%. Pull-in voltage is 3.6 V which is a reasonable value for submicron CMOS technologies. To improve the Q, the top plate is modified to a double layer structure. In this case the top plate consists of 1 μm thickness polysilicon and 0.5 μm aluminum deposited on top of it. This design shows a Q of 47 at 1 GHz.
Keywords :
CMOS integrated circuits; micromechanical devices; radiofrequency integrated circuits; varactors; 0.5 micron; 1 GHz; 1 micron; 3.6 V; CMOS circuit; CMOS-compatible tunable capacitor; RF application; aluminum deposition; capacitor design; double layer plate structure; high-Q MEMS tunable capacitor; monolithic integration; polysilicon; varactor; CMOS technology; Capacitors; Circuit simulation; Micromechanical devices; Q factor; Radio frequency; Structural beams; Tunable circuits and devices; Varactors; Voltage;
Conference_Titel :
Thermal, Mechanical and Multi-Physics Simulation and Experiments in Micro-Electronics and Micro-Systems, 2005. EuroSimE 2005. Proceedings of the 6th International Conference on
Print_ISBN :
0-7803-9062-8
DOI :
10.1109/ESIME.2005.1502824
