Evaluation of diamond gauge factor up to 500 °C

Gauge factors of boron-doped polycrystalline diamond films were investigated in the ranges from room temperature to 500 °C and from 0 to 0.07 MPa of applied pressure. A VCR fitting was used as a package for a measurement at high temperature. Undoped and boron-doped polycrystalline diamond films were deposited on a Si substrate by hot filament chemical vapor deposition (CVD) method. A chip was fabricated with bulk micro machining technique. The gauge factors were evaluated in the ranges from room temperature to 500 °C in furnace. The calculated values of the gauge factors were found to vary in a range of 5–241. The gauge factors decreased with increased temperature from room temperature to around 100–300 °C. However, with higher temperature up to 500 °C, it increased.