Piezoelectric acoustic wave devices based on heterogeneous integration technology

Piezoelectric acoustic wave devices are essential for most of electronics, and thus there should be merits of their integration with other components on chip scale. For this kind of integration, however, there are technical problems in terms of process temperature limit, thermal expansion mismatch, process incompatibility, die size mismatch etc. To overcome such problems, the wafer-to-wafer transfer of films and devices was adopted. The applications of hetero-geneously-integrated acoustic devices described here are mainly related to frequency selection and control for future wireless communication, network sensors etc.