CHARADES

Radio-frequency (RF) signal processing is largely based on various components built on single crystal materials generally patterned and structured using planar technologies on wafers for the manufacturing of acousto-electrical devices (surface or bulk acoustic wave devices), optical wave-guides or electro-optical components (modulators, interferometers). One can therefore achieve a large number of functions but some of the corresponding devices are submitted to functionnal flaws independant of the material properties and characteristics (these materials - quartz, lithium niobate or tantalate - exhibit a high level of maturity from an industrial point of view) but related to the usual machining or patterning limits for manufacturing guiding or excitation/detection structures, which prevents to overcome the corresponding functionnal limitations. The CHARADES project then is devoted to the development of technologies capable to upset the corresponding scientific domains and to allow for major evolutions of the manufacturing of new components exploiting the most advantages of single crystal materials required for achieving the targetted functions. Particularly, a new method based on simultaneous sawing/polishing techniques is implemented for the fabrication of high aspect ratio structures (ridges, aspect ratio in excess of 100) providing devices exhibiting unique guiding and trapping capabilites. New functionnalities hence are accessible and the demonstration of the corresponding innovative potential is achieved for acousto-electrical resonators used as sources, filters and sensors and in optics for waveguides, sensors and electro-optical modulators for telecommunication purposes. In parallel, technologies based on deep reactive ion etching are implemented to allow first for batch fabrication of devices on large diameter wafers and second to push ahead the operation limits of the considered devices (frequencies, compactness). Finally, a significant part of the project is dedicated to the theoretical analysis and the experimental investigation of cross-coupled physical phenomena, favored by the ultimate machining capabilities and the specific configuration of the structures developped in the CHARADES project.