ALUMINUM NITRIDE ON SAPPHIRE FILMS FOR SURFACE-ACOUSTIC-WAVE CHEMICALSENSORS

The development of a small surface acoustic wave (SAW) device on a pie zoelectric aluminum nitride/sapphire substrate for possible use as a c hemical vapor sensor is discussed. Aluminum nitride films on sapphire substrates were prepared, and prototype SAW devices with a resonant fr equency of 267 MHz were designed and fabricated. Experimental results showed that the substrates support SAWs at the fundamental as well as the second and third overt-one frequencies. This article presents the early results in the development of the piezoelectric aluminum nitride SAW chemical sensor. The design of the SAW device is described in det ail, and initial results of its temperature and impedance characterist ics are given.