High-isolation MEMS capacitive shunt switch

Many efforts have been made to find materials with high dielectric constant for the application of RF capacitive shunt switch in order to obtain large down-state capacitance and therefore high isolation. In this work, HfO2 dielectric was suggested for the application of RF shunt switch. The HfO2 dielectric prepared in this work had the break-down field higher than 20 MV/cm. The RF switch using 45-nm-thick HfO2 dielectric showed excellent performance. Its insertion loss is lower than 0.8 dB until 50 GHz at the up-state position. Its isolation is higher than 30 dB until 50 GHz at the down-state, particularly, higher than 50 dB in the range of 10 - 15 GHz.