Diamond-like carbon based micro-pressure sensor with ultra-thin sensitive membrane

in this study, diamond-like carbon (DLC) piezoresistive film and ultra-thin sensitive membrane structure (580 nm thick Si3N4/SiO2) were used for the micro-pressure sensors to improve the sensitivity. High power impulse magnetron sputtering (HiPIMS) process was used to deposit DLC film with high gauge factor (GF), and the wet-etching process was used to fabricate the ultra-thin sensitive structure. Based on Raman spectra, the size of sp2 clusters slightly increased after the release of the internal stress, which might reduce the GF of the DLC film. However, the DLC based sensor still showed high sensitivity of 3.2×10-4/kPa, good non-linearity of 2.4% FS and satisfied repeatability. This work showed an efficient and economical method to improve the performance of the micro-pressure sensors.