PIEZORESISTIVE MICROSENSORS USING P-TYPE CVD DIAMOND FILMS

Chemical-vapor deposited semiconducting diamond is an excellent sensor material for harsh environments and high temperatures. The piezoresis tive gauge factors measured at 300 K are in the ranges 200-550 and 6-2 5 for homoepitaxial and polycrystalline p-type diamond films, respecti vely. The gauge factor for polycrystalline films decreases with decrea sing resistivity, but increases with increasing temperature. A multi-s ensor microchip, with a number of diamond test structures and a minimu m feature size of 5 mu m, has been fabricated using a six-mask process . The chip, employing diamond both as an electronic and a mechanical m aterial, is expected to help commercialize integrated diamond sensors in the near term.