Design of nano-gap piezoelectric resonators for mechanical RF magnetic field modulation

Novel piezoelectric MEMS resonators with magnetic shielding have been developed to mechanically generate RF magnetic fields in the megahertz frequency range from static magnetic fields. Thermally evaporated thin film nickel iron (NiFe) (10–20 nm) was deposited with a saturation flux density of 0.5 T, coercivity of 500 A/m and a high relative permeability of 3.7 × 103. Aluminum nitride (AlN) resonators developed for high frequency operation, resonate in a contour mode to increase and decrease a gap surrounding the resonator. This gap, 200–350 nm, is formed using an amorphous silicon sidewall deposition as a sacrificial spacer. Resonators with frequencies up to 60 MHz have been fabricated and tested with design improvements to increase planarity.