A pressure micro sensor made of p-type diamond film was developed. A boron-doped diamond film of 2 #mu#m thick was grown on a nondoped polycrystalline diamond substrate by a conventional microwave plasma chemical vapor deposition system. A strain gauge pattern (path size: 500 #mu#m x 50 #mu#m) was produced by photolithography and reactive ion etching in oxygen plasma. A diaphragm structure was fabricated by mounting the diamond substrate on the base with a through hole. Relative change in the electrical resistance of the pressure sensor was proportional to the applied strain. Gauge factor of the sensor was about 20 at room temperature.
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