SENSITIVE ELEMENT FOR ACOUSTIC LIQUID SENSOR Russian patent published in 2017 - IPC G01N29/02 H01L41/09 

FIELD: physics.

SUBSTANCE: sensitive element contains a flat plate of monocrystalline silicon, a piezoelectric material deposited on the plate surface and associated with a system of interdigital converters for exciting and receiving acoustic plate oscillation modes, a local bath for liquid analyte. The piezoelectric material is applied to both plate surfaces, is made in the form of zinc oxide films having different thicknesses, the film of greater thickness of h₁ is communicated with a system of interdigital converters, and the film of a smaller thickness of h₂ forms the local bath bottom. The plate thickness H is much greater than the thickness h₁, h₂. The plate plane coincides with the crystallographic plane (001), and the propagation direction of the acoustic plate modes - with the direction of <100> monocrystalline silicon. The acoustic plate oscillation modes are weakly dispersive quasi-longitudinal modes with a phase velocity close to the phase velocity of the bulk longitudinal wave in the crystallographic direction of <100> monocrystalline silicon, and satisfy the given conditions.

EFFECT: increasing the efficiency of electromechanical conversion, reducing the vertical component of the elastic displacement in the local bath.

3 cl, 7 dwg