SH-Mode Spurious Suppression Over a Wide Frequency Range Technique for TC-SAW with Inserting Middle SiN Layer

This paper provides a feasibility study on suppressing a shear-horizontal (SH) type mode spurious over a wide frequency range. A proposed structure in this study inserts a material having a high acoustic velocity such as SiN between an SiO
2
layer and an interdigital transducers (IDTs) electrode layer. This proposed structure can control the SH-mode spurious while minimizing the effects of the Rayleigh-mode. This technology can be applied to improve the freedom of stack selection, such as creating a smaller die size by combining multiple bands on a single chip. This paper proposes the SH-mode spurious suppression over a wide frequency range by inserting the SiN layer between the SiO
2
layer and the electrode. Performance assessments and suppression mechanisms are shown by simulations. Actual SH mode suppression effects are then confirmed by fabricated resonators.