Multilayer structure for an elastic wave device

Abstract

The invention relates to a multilayer structure 1 configured for an elastic wave device 11. The elastic wave device comprises at least one transducer 19 and operates with an elastic wave having a shear wavelength λ and a frequency between 100 MHz and 50 GHz. The multilayer structure comprises a piezoelectric layer 3, a dielectric layer 5, and a base substrate 7, the piezoelectric layer 3 being made of Lithium Niobate (LiNbO3), the dielectric layer 5 being made of Silicon Oxide (SiO2), and the base substrate 7 being a silicon substrate, in particular Silicon (100) or (111).According to one aspect, the piezoelectric layer 3 has, according to the standard definition IEEE 1949 std-176, an orientation (YXl) / θ with θ between 26° and 64°, in particular, between 26° and 41°, and more particularly between 36° and 41°, hLNO / λ is between 0.16 and 0.21, in particular 0.17 and 0.20, hLNO being the thickness of the piezoelectric layer (3) and λ the shear wavelength of the elastic wave device 11 and, hSiO2 / λ is between 0.19 and 0.23, hSiO2 being the thickness of the dielectric layer 5. According to a second aspect, hLNO / λ is greater than 0.30, hLNO and hSiO2 / λ is greater than 0.25, hSiO2. According to a third aspect hLNO / hSiO2 = between 0.75 and 0.85 preferably between 0.79 and 0.81. Fig. 1.