A novel Dual Gap MEMS varactor manufactured in a fully integrated BiCMOS-MEMS process

This paper presents the design and manufacturing of a novel Dual Gap MEMS varactor which operates before the pull-in ensuring continuous tuning range. The device is based on interdigitated DC and RF electrodes, allowing uniform distribution of the electrostatic force. The tunable capacitor has been embedded in the BEOL (Back End Of Line) metallization stack of a state of the art Si/SiGe BiCMOS semiconductor process allowing for easy integration with MMIC. Two different variants have been manufactured showing a maximum capacitive ratio of 2.12 and 4.46 respectively. By using mechanical stoppers, very stable down state capacitance values have been measured.