High-isolation lateral RF MEMS capacitive switch based on HfO2 dielectric for high frequency applications

In this paper, we have developed an electrothermally driven RF MEMS capacitive switch, where the HfO2 film, deposited by atomic layer deposition (ALD) process, was used as insulation dielectric between signal line and ground line. Thanks to high permittivity and excellent electrical and thermal isolation properties of the HfO2 film, as well as high driving force of the electrothermal actuator, the isolation of the proposed switch coated with the HfO2 film was up to 60 dB at 35 GHz and the bandwidth of isolation better than 25 dB was 10.5 GHz. The results demonstrate that the HfO2 film is a good candidate material serving as sidewall dielectric to realize the lateral capacitive switch with high RF performances.