부산대학교 도서관

This paper reports implementation and wafer-level testing of a self-assembled tunable microelectromechanical systems (MEMS) inductor with electrostatic, electrothermal, and thermal tuning capability. The surface micromachined inductor was fabricated on a high-resistivity (HR) substrate ($\rho = 5$ ${\hbox{k}}\Omega\!\cdot \!{\hbox{cm}}$) using a doped polysilicon and Au–Cr metal combination as a bimorph structural layer for providing self-assembled elevation with an enhanced $Q$ factor. Extensive electro-thermo-mechanical and RF characterization was carried out for the inductor, the latter over a temperature range from ${-}{\hbox{30}}\ ^{\circ}{\hbox{C}}$ to 150 $^{\circ}{\hbox{C}}$ . Furthermore, the tunable inductor was integrated in the tank circuit of a CMOS oscillator and wafer-level MEMS-CMOS voltage-controlled oscillator testing revealed a best figure-of-merit of ${-}{\hbox{197.6}}$ dB with a frequency tuning range of 1.3–2.4 GHz with a power consumption of 3.07 mW.