Effects of Si-nanocrystal formation in dielectric layers on reliability of RF MEMS switches

In this paper, three different composite dielectric layers which consist of Si₃N₄ and SiO₂ layer have been fabricated by thermal oxidation and RF magnetron sputtering technique. They are, 1) single-dielectric-layer of silicon nitride (Si₃N₄), 2) single-dielectric-layer of silicon-oxide (SiO₂) with the embedment of Si-nanocrystals (Si-NC), 3) triple-dielectric-layer consisting of SiO₂/SiO₂+Si-NC/SiO₂ sandwich structure which have been fabricated by different process. Capacitances versus Voltage measurements have been preformed with a bias voltage and different time to observe the charge accumulation in those dielectric layers. The results show that the charge accumulation can be reduced by the formation of Si-nanocrystals in those different composite dielectric layers.