Hybrid-integrated RF MEMS-based reference oscillator using a silicon-ceramic composite substrate

In this paper, the design of a RF MEMS oscillator on a silicon-ceramic composite substrate using a high-Q Lamb-wave resonator as frequency-selective device is described. The MEMS resonator is designed on a 1.8 μm thick piezoelectric AlN layer, deposited on silicon using thin-film processes. The finite-element simulation results of the resonator structure are presented, and the derivation of the electrical equivalent-circuit is described. The active part of the MEMS oscillator, which was laid out in a Pierce topology, has been integrated in an application-specific integrated circuit fabricated in CMOS technology. Both, amplifying and frequency-selective parts are hybrid-integrated on a unique silicon-ceramic composite substrate, which enables a very compact high-quality module design with minimal parasitics. The MEMS oscillator serves as a technology demonstrator combining the advantages of microelectronic and microelectromechanical components towards a compact and power-efficient hybrid technology, e.g. for mobile communications or wireless sensors.