Thin-Film Aluminum RF MEMS Switched Capacitors With Stress Tolerance and Temperature Stability

This paper presents an RF microelectromechanical system switched capacitor which is based on a thin-film alu minum circular beam geometry that exhibits reduced sensitivity to both initial residual stress and stress changes versus ambient temperature. This novel design results in a pull-in voltage slope of -55 mV/°C from -5°C to 125°C, a capacitance ratio of 20 (Cu=50 fF, Cd= 1 pF), a down-state quality factor of 85 at 3127 MHz (Zd= -j50 Ω), and a switching time ofd= -j50 Ω). The application areas are in high-linearity RF/microwave switches, phase shifters, and tunable matching networks and filters.