Capacitive type ultrasonic sensor and manufacturing method thereof

Abstract

The invention discloses a capacitive type ultrasonic sensor. The capacitive type ultrasonic sensor comprises a silicon-doped substrate, a first electrode layer and a second electrode layer, wherein the first electrode layer is fixed on the silicon-doped substrate; the second electrode layer is arranged on the first electrode layer at intervals; the first electrode layer comprises an insulating layer, a side electrode and an intermediate electrode; the insulating layer is fixed on the silicon-doped substrate; the side electrode is fixed on the outer edge of the insulating layer; the intermediate electrode is fixed in the middle of the insulating layer; the side electrode is separated from the intermediate electrode through the insulating layer; the second electrode layer is separated from the side electrode and the intermediate layer through the insulating layer; and the insulating layer, the side electrode, the intermediate electrode and the second electrode layer form a cavity serving as a gap of a capacitance pole plate. The first electrode layer of the capacitive type microprocessing ultrasonic sensor adopts a double-layer electrode structure comprising the side electrode and the intermediate electrode. Compared with the traditional single-layer electrode structure, the double-layer electrode structure has the advantages of high sensitivity and high ultrasonic transmitting and receiving properties. The invention also provides a manufacturing method of the capacitive type ultrasonic sensor.

Description

【Technical field】 [0001] The invention relates to the field of sensors, in particular to a capacitive ultrasonic sensor and a preparation method thereof. 【Background technique】 [0002] Since the advent of medical ultrasound equipment in the early 1950s, ultrasound has occupied a large share of the medical imaging equipment market. Medical ultrasound can see through muscle and soft tissue, making this technology commonly used to scan many organs to assist in medical diagnosis and treatment. Obstetrical ultrasounds are also commonly used during pregnancy. With the continuous improvement of new technologies such as 3D and 4D, the quality of ultrasound images has been continuously improved, and thus the clinical effect has been improved. [0003] The core device in ultrasonic equipment is the ultrasonic sensor, which is the structure responsible for transmitting or receiving ultrasonic waves in the equipment. At present, the most mature sensor products in practical applicati...

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Problems solved by technology

[0007] 3. When the ambient temperature of traditional PZTs is higher than the Curie point (about 350°C), its piezoelectric properties will gradually disappear, resulting in sensor failure; while the operating temperature range of CMUTs is usually limited only by the metal layer on the surface of the film

[0010] However, traditional CMUTs have a single-layer upper and lower electrode structure, which has low sensitivity and low transmit and receive performance.

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