The main objective of this proposal is the development of new fabrication technologies for the next generations of microwave electro-acoustic devices used in mobile and land based communications. These new technologies are to be based on the use of thin piezoelectric films grown on various bulk substrates such as Si, glass, polydiamond, etc. Suggested materials are AlN and PZT on high velocity substrates such as polycrystalline diamond, as well as Si, glass and others. Large area fabrication technologies are also to be developed to demonstrate the industrial viability of the new technologies. Further, prototype filters operating between 2 and 7 GHz will be designed, fabricated and tested. Finally, a test subsystem representing a block in a real communication system will be constructed using the fabricated devices to test the latter in real systems.
The broad objective of this proposal is to develop and test new technologies based on new thin piezoelectric films for the fabrication of the next generations of microwave electro-acoustic devices used in mobile and land based communications. Specific objectives include the synthesis of the piezoelectric films with high Q- factor, high coupling coefficient, low propagation losses and low TCF. The latter are also dependent on the substrate, so a number of substrate materials will be explored to achieve the above objectives. Another objective is to demonstrate the industrial viability of the new fabrication processes for which purpose the latter will be further developed for large area substrates. Further, prototype bandpass filters will be designed and manufactured. Finally, a communications subsystem will be constructed using the prototype filters to test the latter in real systems as well as to demonstrate the viability of the new technologies.
The work in the proposed project can be roughly divided into four main phases - materials development work, fabrication technology, prototype design and fabrication, and demonstrator construction respectively. In the materials development phase a range of piezoelectric materials in combination with a number of substrate materials will be explored. This includes the synthesis of thin piezoelectric films of AlN, PZT and related materials on Si, glass, polycrystalline diamond, etc. The growth processes will be optimised in view of obtaining layered structures with desired electro-acoustic properties, i.e. high coupling coefficient, high Q-factor, low propagation losses and low TCF. To this end a number of PVD deposition processes will be explored namely DC, pulsed DC and RF reactive sputter deposition. The compositional and structural properties of the films will be studied with ESCA, RBS, SIMS, XRD, hires XTEM, AFM, SEM, etc, and will be related to the above electro-acoustic properties. The second phase includes the development of all fabrication processes on large area substrates - deposition, lithography, etching, metallisation and micromachining. Scaling up the deposition processes requires the development a new PVD reactor in view of growing films on large area wafers with uniformity better than 1%. The third phase includes the design and fabrication of prototype SAW and BAW filters according to given specifications. The fabricated devices will be rigorously characterized and tested. In the fourth phase a communications subsystem will be designed and constructed using the filters fabricated in phase 3 to demonstrate and test the new devices in real systems. It represents a frequency up-converter consisting of a voltage-controlled oscillator, a mixer, a lw-RF (2-3 GHz) and a high-RF (7-10 GHz) bandpass filters. RF measurements and characterization as well as testing of the subsystem will be carried out.
Funding SchemeCSC - Cost-sharing contracts
164 80 Stockholm
06560 Sophia Antipolis, Valbonne