Self-Supporting Ultrathin DLC/Si3N4/SiO2 for Micro-Pressure Sensor

In this study, we firstly reported a micropressure sensor based on self-supporting diamond-like carbon (DLC)/Si3N4/SiO2 films with total thickness of 785 nm, where the DLC film was fabricated by a facile DC magnetron sputtering process. Particularly, the DLC film was selected as a hybrid sensitive and structural material due to its superior mechanical, piezoresistive properties and stability under harsh environment. Results showed that the sensitivity of the integrated sensor could reach 5.3 x 10(-5)/kPa within the pressure range of 0-60 kPa, together with the nonlinearity and the hysteresis was 5.7% FS (full scale) and 0.8% FS, respectively (at 20 degrees C). Most importantly, without any thermal insulation package, the sensitivity only changed slightly within +/- 7.0% even the temperature varied dramatically from -20 degrees C to 100 degrees C. Such excellent performance of the sensor was mainly originated from the good stability of atomic bond structure in DLC films, which was confirmed by the variable-temperature XPS test. In addition, the signal could be further compensated by the DLC thermal compensation resistor in which the temperature coefficient of resistance (TCR) was about -1247.3 ppm/degrees C. These results bring forward a promising strategy to fabricate themicro-pressure sensor with high structural sensitivity, stability as well as lightweight design for micro-electromechanical system (MEMS) used in harsh applications.

Automated summary

In this study, a micro-pressure sensor based on DLC/Si3N4/SiO2 films was reported, which demonstrated high sensitivity and stability. The sensor showed minimal sensitivity changes even with dramatic temperature variations. Additionally, the sensor could be compensated using the DLC thermal compensation resistor.