SOI (silicon on insulator) pressure sensor with self- temperature drift compensation

Abstract

The invention relates to an SOI (silicon on insulator) pressure sensor with self- temperature drift compensation, which comprises an SOI substrate, wherein the SOI substrate is provided with a bridge resistance configured into a wheatstone bridge; the surface of the bridge resistance, corresponding to the SOI substrate, is provided with a compensating resistance for carrying out temperature compensation on the wheatstone bridge; leads electrically connected mutually are arranged on the compensating resistance and the bridge resistance; the bridge resistance is separated from the compensating resistance through an isolation layer and a passivation layer; the isolation layer is covered on the SOI substrate; the passivation layer is covered on the isolation layer; the other side of the SOI substrate, corresponding to the side on which the bridge resistance is arranged, is etched to form a pressure cavity and a pressure sensitive film; and the pressure cavity and the pressure sensitive film are located right below the bridge resistance. The SOI pressure sensor with self- temperature drift compensation has a compact structure, realizes self- temperature drift compensation, has reduced cost, high stability, good consistency, wide application range, is suitable for batch production, and is safe and reliable.

Description

Technical field [0001] The invention relates to a pressure sensor, in particular to a temperature drift self-compensating SOI pressure sensor, which belongs to the technical field of MEMS sensors. Background technique [0002] The pressure sensor manufactured by using the piezoresistive effect of silicon uses ion implantation and diffusion in the integrated circuit process to form a set of diffusion resistors with almost equal resistance on the surface of the silicon chip. Metal interconnections are formed between the resistors and connected to form a Wheatstone. Power on the bridge. When the elastic sensitive diaphragm is deformed under the action of external pressure to generate stress, the bridge resistance on it changes accordingly, and the sensor outputs an electrical signal proportional to the external pressure, thereby realizing pressure measurement. [0003] Piezoresistive micro pressure sensor is the earliest researched and industrialized MEMS (Micro Electro Mechanical Sy...

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Problems solved by technology

[0004] In addition, since the resistor is a temperature-sensitive device, the zero point and sensitivity of the pressure sensor before compensation will change with the change of temperature, which greatly affects the accuracy of the sensor, and it is usually compensated for temperature drift

At present, pressure sensor compensation is divided into two types: hardware compensation and software compensation. The former requires a lot of manpower to test the temperature drift of each chip before compensation within the operating temperature range, and then select different devices, such as diodes and thermistors. The consistency is poor and the workload is heavy; and the software compensation cost is high. At present, most of the domestic compensation is for imported ASIC chips. The high price also limits the development of the domestic sensor industry.

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