Graphene-based piezoresistive pressure sensor and preparation method thereof

Abstract

The invention relates to a graphene-based piezoresistive pressure sensor and a preparation method thereof. The preparation method of the sensor comprises the following steps of preparing a graphene film on a metal substrate to form a metal / graphene film; coating PMMA on the surface of the graphene film to form a metal / graphene film / PMMA; carrying out bubbling and stripping on the graphene film coated with the PMMA on the metal substrate by an electrochemical method in order to obtain the graphene film / PMMA; transferring the graphene film / PMMA to an SiO2 / Si substrate and removing the PMMA to obtain the graphene film / SiO2 / Si; transferring the graphene film / SiO2 / Si to an SiC substrate; etching the SiO2 / Si substrate; patterning the graphene film; and evaporating a metal electrode on the graphene thin film to obtain the graphene-based piezoresistive pressure sensor. The graphene-based piezoresistive pressure sensor has the characteristics of good piezoresistive property, high sensitivity and fast response speed, and has wide market application value and prospect.

Description

technical field [0001] The invention relates to the technical field of pressure sensors, in particular to a graphene-based piezoresistive pressure sensor and a preparation method thereof. Background technique [0002] The piezoresistive pressure sensor is a sensor made of the piezoresistive effect of single crystal silicon material and integrated circuit technology. After the monocrystalline silicon material is subjected to force, the resistivity changes, and the electrical signal output proportional to the force change can be obtained through the measurement circuit. Silicon piezoresistive pressure sensors have been widely used in the measurement and control of pressure, tension, pressure difference, and other physical quantities that can be converted into changes in force (such as liquid level, acceleration, weight, strain, flow, vacuum). [0003] Resistance strain gauge is one of the main components of piezoresistive strain sensor. The working principle of the metal res...

AI Technical Summary

Problems solved by technology

[0004] At present, the processing methods of piezoresistive single crystal silicon piezoresistive films for piezoresistive pressure sensing mainly include: one method is to use an alkaline solution to perform anisotropic etching from the back of the silicon wafer, thereby forming a back cavity on the back of the silicon wafer. At the same time, a single crystal silicon pressure-sensitive film is formed on the front side; this method controls the thickness of the piezoresistive film by controlling the etching time, and cannot guarantee the uniformity and consistency of the thickness of the piezoresistive film within the chip and between the chips.

Another method is electrochemical corrosion. This method can obtain a lightly doped pressure-sensitive film on which piezoresistors can be made. However, this method needs to add a relatively expensive potentiostat and use a specially designed clamp to protect the front from being damaged. It is etched and applied voltage to the front side of the silicon wafer, which increases the equipment cost on the one hand, and increases the complexity of the process on the other hand, making the production efficiency very low

Another method is to bond glass on the back or front of the pressure sensor, but the high bonding temperature of silicon glass will affect the redistribution of carriers and affect the performance of the sensor; moreover, the reserved area for silicon glass bonding should be large enough to prevent The presence of particles affects the bonding quality and makes the chip size large

Images