"The objective of the project is to develop and manufacture µSJA based on silicon technologies. To reach the required output velocities of the µSJA, the chamber and the exit channel or nozzle will be optimized using different analytic and numeric methods. Based on the results of the optimization, a design will be investigated and transferred to silicon based structures. The production of the µSJA will be performed in the clean rooms of the ZfM and will be realized on wafer-level. The two different parts of the µSJA, the cavity and the diaphragm are micro-machined and wafer bonded in order to form the actuator. The diaphragm-wafer’s backside is wet etched in order to produce a membrane in two different thicknesses, 40 µm and 70 µm. The cavity-wafer in contrast, is prepared by a sequential etching process with the same etchant. In the first step the orifice will be preliminary etched with a depth of 400 µm. The second step equates the continuing etching of the orifice and the production of the cavity geometry. The achievements of these two processes are 3D nozzle structures of the orifice in a required aspect ratio and a very small cavity, resulting in a higher pressure gradient which leads to a much higher jet velocity compared to a dry anisotropic etched orifice combined with a huge cavity. This creates the main advantage compared to known layouts. Then, the two parts are bonded to form a small cavity with an orifice on the one side and a diaphragm on the opposite side. Finally, the piezo disc will be mounted on the back side of the diaphragm into the wet etched cavity. To integrate the electro mechanical transducer, in this case the PZT element, into the system, investigations of reactive bonding technologies for the use of PZT silicon bonding will be done. Thus, the strength of the low temperature bond of the ceramics, concerning low inducted mechanical stress, can be optimized."
Fields of science
Call for proposal
See other projects for this call