Fabrication of Electroacoustic Devices for Integrated Applications

Sammanfattning: Electroacoustic technology has in many ways revolutionised the wireless telecommunication industry. The IC compatible fabrication technique of thin film electroacoustic devices has so far provided a considerable increase in device performance and reduction in size. At the moment, new areas where this technology can be of use is under investigation. In particular, thin film bulk acoustic wave resonators are promising candidates for biochemical and gravimetric sensor applications.For bulk acoustic waves, the thesis addresses a number of aspects in the design, fabrication, characterisation, and integration of thin film electroacoustic devices. The object of the studies conducted in the thesis has been to improve on design and thereby optimise the performance of the device to fit a particular application of interest. For high frequency and high power applications, a conceptually new design of the solidly mounted resonator has been investigated. A 1 GHz plate wave resonator with a much higher Q factor than its surface acoustic counterpart have also been fabricated. A multi-chip-module 2 GHz microwave oscillator featuring a monolithically integrated solidly mounted resonator and a flip chip transistor have been fabricated and characterised with a phase noise of -125 dBc/Hz at 100 kHz. For sensor applications, the fabrication of shear mode solidly mounted resonators featuring c-axis inclined AlN films has been studied. A process for the bonding of a microfluidic system on top of the resonator has been realised. Further, the effect of conductive liquids on the resonator performance has been investigated.For surface acoustic wave devices, acoustic manipulation of particles in microfluidic channels has been studied. Two functional devices have been fabricated by bonding piezoelectric substrates to glass or fused silica superstrates. By generating an interface acoustic wave, that propagates along the bonded interface, manipulation of sub-micrometer particles was realised.