Transient evolution of mechanical and electrical effects in microelectromechanical switches subjected to long-term stresses

Application of two different biasing waveforms in long-term stresses in RF MEMS switches is used to separate mechanical and electrical effects. Three different effects are shown: 1) permanent mechanical degradation (creep effect) after the first stress and relaxation period; 2) transient mechanical degradation (viscoelastic recoverable mechanism); and 3) transient electrical degradation (recoverable charge trapping). Such effects are extracted by monitoring the evolution of the actuation and release voltages in different RF MEMS switches subjected to dc biasing and recovery tests. This paper highlights the mechanical and the electrical degradation components in long-term stress tests with the aim of quantifying the weights of the different contributions.