A Comparative Study of Acoustic Loss in Piezoelectric on Insulator (POI) Substrates

This paper reports an experimental study of acoustic loss in multi-layer piezoelectric on insulator (POI) substrates. The propagation loss (PL) of shear-horizontal surface acoustic wave (SH-SAW) in LiTaO
3
/SiO
2
/poly-Si/high-resistance Si (LTOI) and LiTaO
3
/SiO
2
/Sapphire (LTOS) is studied and compared using unidirectional acoustic delay lines (ADLs). The SH-SAW in LTOS shows a significantly lower PL than that in LTOI when λ is small, indicating that insulating substrate can help further reduce dielectric loss. In addition, the electrical performance of ADLs in LTOS shows better temperature stability than that in LTOI. This work has shown the great potential of the LTOS substrate for high-performance filters and multiplexers applications.