Surface acoustic wave microsensors using diffused substrates

Various Y-cut Z-propagating lithium niobate YZ-LiNbO₃ substrate configurations are investigated to develop efficient ways of confining the wave energy in surface acoustic-wave (SAW) microsensors based on waveguide structure. The core and cladding regions for the SAW waveguide sensors have been titanium in-diffused or out-diffused and in some cases metal overlays have been used. By varying the diffusion conditions, the SAW velocities in these regions can be controlled such that a channeled region with interface wave-reflection is produced while minimizing the wave-velocity-difference between the cladding and the core