Soft support bridge type silicon micro-piezoelectric ultrasonic transducer chip and prepration method thereof

Abstract

The invention relates to a soft support bridge type silicon micro-piezoelectric ultrasonic transducer chip which comprises a silicon substrate with a square conical hole which is small at the top and big at the bottom in the center; a silicon layer and a first oxidation layer are sequentially covered on the front surface of the silicon substrate, and a second oxidation layer is covered on the back surface; the corresponding silicon layer and the first oxidation layer above the square hole of the front surface of the silicon substrate constitute a square vibration membrane, one pair of opposite sides of the square vibration membrane respectively etch a vertical narrow slot, and the vertical projection of each narrow slot is positioned on the inner side of the hole edge above the front surface of the silicon substrate; a lower electrode, a piezoelectric membrane and an upper electrode are sequentially deposited on the square vibration membrane; a polyimide membrane is deposited on various parts on the front surface of the silicon substrate; and the square vibration membrane which is etched with the vertical narrow slots and the polyimide membrane commonly constitute a soft support anti-sound leakage bridge type vibration membrane. The anti-sound leakage bridge type structure is used on the vibration membrane of the transducer; in order to avoid sound leakage through the narrow slots, the soft polyimide membrane is deposited on the narrow slots, which has little effect on vibration of the vibration membrane and can still keep high sensitivity.

Description

Soft support bridge silicon micro piezoelectric ultrasonic transducer chip and preparation method thereof technical field The invention relates to the field of silicon micro-piezoelectric ultrasonic transducers, in particular to a soft-support bridge-type silicon micro-piezoelectric ultrasonic transducer chip and a preparation method thereof. Background technique Silicon micro-ultrasonic transducers are mainly composed of piezoelectric and capacitive types. Silicon micro-piezoelectric ultrasonic transducers are composed of piezoelectric layers, vibrating membranes, and metal electrodes. Compared with silicon microcapacitor ultrasonic transducers, piezoelectric ultrasonic transducers have a simple structure and simple manufacturing process; and low impedance, they are suitable as transmitting transducers. At present, the vibrating membrane of the silicon micro piezoelectric ultrasonic transducer is fixed on four sides, so when the ultrasonic transducer vibrates, the sensiti...

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Problems solved by technology

At present, the vibrating membrane of the silicon micro piezoelectric ultrasonic transducer is fixed on four sides, so when the ultrasonic transducer vibrates, the sensitivity of the ultrasonic transducer is relatively low due to the small strain of the piezoelectric layer.

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