Loud Noise Level Piezoresistive Sensors

Sensor is one of the rapid developing high technoledgies that draw the world's attention today. As the environment of measurement becomes worse, sensor level of the defense and the civilian area is constantly improving, especially in military, higher requirements on measurement components are in need. They are requried to be of high precision, high reliablity, low power, small volume, resistance impact, good consistency and so on. Among them, the ability of measurement and control system of noise and the precision of improvement are particularly urgent needed. Therefore, trying to use silicon pressure resistance effect and electronic line in the signal regulation technology of loud level pressure resistance type noise sensor is of significant importance.In this thesis, the operating principle, the design process, the production process and the test results will be described in detail. In the process of designing a sensor, principle detect loud noise level index of Piezoresistive sensor is used in this thesis. The probe of the sensor is made of single-crystal silicon Piezoresistive effect principle. After exposured to sound pressure, single crystal silicon in its resistance will change, and different resistivities of the Crystal up have different changes. Four silicon chip resistors are produced in different directions using semiconductor Planar process, and connected into a Wheatstone e-bridge. Through reasonable design, when single crystal silicon is affected by the sound pressure, on the e-bridge, two of an arm's resistance increases, while two of another arm's resistance is reduced, so that under a certain power excitation, e-bridge will output a signal which has a proportional relationship with the measured sound pressure. Then, the purpose of measuring noise signal is achieved.