US Patent 10177735 Surface acoustic wave (SAW) resonator

An apparatus includes a silicon (Si) substrate having a first surface and a second surface, the silicon substrate having a resistivity at room temperature greater than approximately 1000 Ω-cm, and less than approximately 15000 Ω-cm; and a piezoelectric layer disposed over the substrate and having a first surface and a second surface. The piezoelectric layer may have a thickness in the range of approximately 0.5 μm to approximately 30.0 μm, and is substantially without iron (Fe).