Micro machining process of high temperature pressure sensor gauge chip based on SIMOX SOI wafer

The successful batch fabrication of a piezoresistive pressure sensor chip is described based on separation by implantation of oxygen (SIMOX) SOI wafer. The micro machining process mainly includes SIMOX, homoepitaxy silicon, and heavy dose of boron ion implantation doping, thermal oxidation, passivation layer of silicon nitride and standard optical lithography, Inductively Coupled Plasma (ICP), multi-layer metallisation and Au sputtering and so on. The sensor packaged with this kind of sensing chip is presented with high accuracy and a good long-term stability in high temperature testing experiments up to 250?C.