Proton-exchanged wet etching of recessed-structure SAW filter

An improved method for fabricating recessed-structure surface acoustic wave (SAW) filters is reported. The relation between proton-exchanged duration and etched depth are studied, as well as the relation between internal reflection, etched depth, and thickness of the aluminum electrode. Experimental results show that the devices have superior performance, and ideas for further improvement of the fabricated SAW device are discussed.