A Si-Glass based pressure sensor with a single piezoresistive element for harsh environment applications

A Si-Glass based MEMS piezoresistive pressure sensor is designed for harsh environment applications, such as vibration, shock and environment conditions with humidity, alkalescence or acidity, electrostatic particles and so on. The sensor chips were fabricated using SOI wafer-glass anodic bonding technology, which enables a single boron-implanted piezoresistor to be on lower surface of silicon diaphragm and be vacuum-sealed in glass cavity. The sensing signals were led out by using the embedded Al electrode structure at the bonding interface of Si-glass to connect single piezoresistor, and two large-area Ni-Au pads are used to electrically connect to the print circuit board (PCB) by using the drag soldering technology instead of gold wire bonding. The characteristics of voltage-pressure were measured with constant current under different temperature conditions. A temperature compensation technology is used to calibrate the measured results, by which the sensitivity of 116 mV/ (mA·MPa) and accuracy of 5.8% F.S. are obtained.