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Oscillators based on AlN thin-film bulk acoustic resonators are designed, fabricated and measured. The circuits are realised as silicon-on-silicon multichip modules where SiGe transistors are flip-chip mounted on a novel carrier substrate which includes monolithically integrated resonators and passive components. The paper describes the development and processing of the carrier substrate and resonators, as well as the development of the oscillator circuits.

Compositional analysis of aluminium oxy-nitride (AlON) films deposited by reactive magnetron sputtering was performed using time-of-flight elastic recoil detection analysis (ToF-ERDA) and X-ray photoelectron spectroscopy (XPS) with sputter profiling. The composition profiles of the films depend on deposition conditions. The benefits of the different analytical methods are discussed and comparison of the profiles is performed. Conversion of the depth scale from XPS sputter time to a nm scale is implemented and the ToF-ERDA profile fitted. Densities of the deposited AlON films are calculated indicating differing film quality in agreement with the composition profile extracted.

For use in thin film electroacoustic (TEA) technology a few hundred nanometre thick nickel silicide (NiSi) electrode would need to be fabricated. A complete fabrication process for the formation of over 200 nm thick silicide films has been optimised for use as an electroacoustic electrode. Optimisation of silicidation temperature and identification of the mono phase of silicide is demonstrated. Thick electrodes are formed by depositing multilayers of silicon and nickel pairs onto silicon (Si) substrates before rapid thermal annealing. The numbers of multilayers and relative material thicknesses are optimized for both surface roughness and electrical resistivity. The growth of textured aluminium nitride (AlN) has been investigated on the optimised surfaces.