A DLC/W-DLC multilayered structure for strain sensing applications

The strain dependence in tungsten-containing diamond-like carbon (W-DLC) film was investigated. The W-DLC film was deposited onto Si substrate by plasma enhanced chemical vapor deposition and DC magnetron co-sputtering of tungsten metal target. The strain dependence of resistance was measured by four-point bending test under well controlled temperature condition. The observed dependence was linear one and calculated gauge factor is 6.1. The high value of the gauge factor is originated from the piezoresistive effect. In addition, double layered structure of DLC/W-DLC film was fabricated. The double layerness and interface structure were investigated by transmission electron microscope. No clear boundary between DLC and W-DLC was observed. This was because of the continuous carbon matrix from the bottom layer of W-DLC to top DLC layer.