Fabrication of atmospheric pressure sensors using AU-AU bonding techniques for human activity monitoring

This paper reports a capacitive pressure sensor for human activity monitoring application, which is fabricated by Au-Au diffusion bonding in ambient pressure. The optimized condition for the Au-Au bonding was investigated. A maximum bonding strength of 26.7 MPa is achieved with a bonding temperature of 400^oC and bonding pressure of 5.5 MPa. By measuring the pressure-capacitance characteristics of the atmospheric pressure sensor, its sensitivity is found to be 7 fF/kPa with a good linearity in the ambient pressure range from 60 kPa to 100 kPa.