Combined stiffness-variable thin film pMUTs and preparation method thereof

Abstract

The invention provides combined stiffness-variable thin film pMUTs and a preparation method thereof. A combined stiffness-variable thin film structure is composed of circular thin film and annular thin film which surrounds the circular thin film in the circumferential direction and is concentric with the circular thin film; according to different working condition demands, the thickness of the circular thin film and the thickness of the annular thin film are adjusted separately to achieve combined stiffness-variable thin film; the overall structure of the combined stiffness-variable thin filmpMUTs sequentially comprises an upper electrode, a vibration thin film piezoelectric driving layer, a lower electrode, a vibration thin film structural layer, a thin film supporting structure and a base structure from top to bottom; when the combined stiffness-variable thin film pMUTs are used in a mode of emitting ultrasonic waves, the circular thin film and the annular thin film are excited according to a certain phase difference, the coupling effect among the circular thin film, a fluid medium and the annular thin film is achieved, and the unit ultrasonic wave emitting power is greatly increased; when the combined stiffness-variable thin film pMUTs are used for receiving the ultrasonic waves, the ultrasonic wide bandwidth receiving performance is achieved through the resonance frequencydeviation of the circular thin film and the annular thin film in the fluid medium. The combined stiffness-variable thin film pMUTs have the high emitting power and wide bandwidth receiving performance.

Description

technical field [0001] The invention relates to MEMS (Micro-electromechanical Systems) ultrasonic transducer technology, in particular to a variable stiffness film pMUTs (Piezoelectric Micromachined Ultrasonic Transducers) with high electromechanical coupling coefficient and a preparation method thereof. Background technique [0002] Ultrasound transducers have important application value for non-invasive in vivo medical diagnostic imaging. Traditional ultrasonic transducers are manufactured from piezoelectric ceramic materials such as lead zirconate titanate (PZT) or PZT polymer composites, which are sliced ​​or laser cut to form multiple individual components in one-dimensional or two-dimensional arrays. unit. Acoustic lenses, matching layers, backing layers, and electrical interconnects (e.g., flex cables, metal pins / wires), etc. are attached to each transducer unit to form a transducer assembly or probe, which is then A cable connects the probe to the control circuitry...

AI Technical Summary

Problems solved by technology

Traditional transducer arrays can generate sound pressures greater than 1 MPa, but require much larger element sizes and operate at lower frequencies

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