FBAR micro-pressure sensor based on thickness-excited shear mode

Abstract

The invention belongs to the field of microelectronic devices and provides a FBAR micro-pressure sensor based on a thickness-excited shear mode. The FBAR micro-pressure sensor comprises a silicon substrate, an insulating layer deposited on the upper surface of the silicon substrate, a Bragg reflective layer deposited on the upper surface of the insulating layer, a bottom electrode deposited on the upper surface of the Bragg reflective layer, an AlN piezoelectric film disposed above the bottom electrode and the Bragg reflective layer, a top electrode disposed on the upper surface of the AlN piezoelectric film and with a shape the same as that of the bottom electrode and a position corresponding to that of the bottom electrode, four micro-pressure sensitive layers deposited on the upper surface of the piezoelectric film, symmetrically arranged at the edge of the piezoelectric film and staggered with the top electrode, and a micro-pressure applying layer bonded to the micro-pressure sensitive layer. The FBAR micro-pressure sensor has a high Q value, high operating frequency, high resolution, high sensitivity, low energy consumption, good firmness and low cost, and can be widely applied to the field of the micro-pressure sensors.

Description

technical field [0001] The invention relates to an FBAR micro pressure sensor, in particular to an FBAR micro pressure sensor based on a thickness direction excitation shear wave mode, and belongs to the field of microelectronic devices. Background technique [0002] With the development of integrated circuit manufacturing technology, film bulk acoustic resonator (FBAR) develops rapidly. Because of its high quality factor, high resonance frequency, low insertion loss, high detection accuracy, compatibility with CMOS technology, and relatively small size. It satisfies the needs of handheld mobile and wearable devices very well, so it has obtained a wide range of commercial applications in the field of mobile communications. On this basis, its superiority in the field of sensors is arousing widespread research interest. [0003] Pressure is one of the most basic physical quantities, whether in daily life or in the industrial field, micro pressure sensors are widely used. Th...

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Problems solved by technology

The disadvantages of this solution are: 1. The micro pressure sensor adopts a back-etched structure, which will inevitably affect the mechanical firmness of the device due to the use of MEMS bulk silicon technology to etch and remove most of the silicon material from the back of the silicon wafer. , although a low-stress support layer is set, the yield rate is greatly reduced; Second, the micro pressure sensor adopts the longitudinal wave mode, and the longitudinal wave attenuates greatly in the liquid phase environment or viscous medium. The use of the longitudinal wave mode limits the FBAR micro Application fields and occasions of pressure sensors

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