Multilayer structure for an elastic wave device

Abstract

The invention relates to a multilayer structure configured for an elastic wave device (11), particularly guided or quasi-guided with losses less than 5 mdB / λ, the elastic wave device comprising at least one transducer (19) and operating with an elastic wave having a shear wavelength λ and preferably with a frequency below 1 GHz, particularly with a frequency between 500 MHz and 1 GHz, more particularly between 600 MHz and 900 MHz, the multilayer structure comprising: a piezoelectric layer (3), a dielectric layer (5), and a base substrate (7), the piezoelectric layer (3) being lithium tantalate LiTaO3 (LTO), the dielectric layer (5) being silicon dioxide (SiO2), and the base substrate (7) being a silicon substrate, particularly silicon Si(100) or Si(111), characterized in that the piezoelectric layer (3) has a orientation (YXl) / θ with θ between 30° and 50°, in particular θ between 42° and 50°,even more preferably of θ = 30°, θ = 36°, θ = 42° or θ = 50° according to the standard definition IEEE 1949 std-176, and the product f×hLTO of the frequency f and the thickness hLTO of the dielectric layer (3) is less than 1 GHz.µm, preferably between 0.7 GHz.µm and 0.9 GHz.µm, ethSiO2 is greater than 500 nm, hSiO2 being the thickness of the dielectric layer. The invention also relates to a manufacturing method. Fig. 1,

Claims

transducers of at least two elastic wave devices are made on the same multilayer structure. [Fig. 1] 2 / 16 [Fig. 3] [Fig. 4] 50" FIG. 5a [Fig. 5b] 50" a / p [Fig. 5c] 36 11.5 - - 11 ---■ dk5d(a / p) 0.1 -0.05 -0.1 [Fig. 6a] [Fig. 6b] 50' a / p [Fig. 6c] 36 a / p RG. 6c FIG. 7a [Fig. 7b] 50 FIG. 7b [Fig. 7c] 36° Hb, / C [Fig. 8a] [Fig. 8b] 50' |R| fem~bim(%) 20- 10 c; [Fig. 8c] |Rj [Fig. 9b] FIG. 10 [Fig. 11] △f [MHz [Fig. 13] FIG. 14a [Fig. 14b] FIG. 14c [Fig. 14d] FIG. 14e [Fig. 14f]