Piezoresistivity-based devices are highly-acknowledged but not limited to the fields of automotive, roads, and infrastructures, ventilation, and air conditioning, and recently on wearable devices for health monitoring. Despite its brevity and precision of instrumentation, strain gauges are subjected to deviations due to adverse effects of temperature and oxidative environment. The selection of material that can withstand extreme environments is distinctively one of the most challenging tasks in the strain gauge process chain.

In this study, Taguchi design of experiment was utilized to optimize the SiOC film deposition on a large-area silicon substrate followed by lithographic deposition of structured Cr/Pt electrodes. Each element was assessed methodically to determine the piezoresistive behavior and shown to possess giant piezoresistivity with gauge factors in the range of 1–5 x 10³ at 25-700°C. A large charge carrier mobility in the SiOC thin films (i.e., 186 cm² V^-1 s^-1), as well as unique phase composition of C/SiC segregations dispersed on a C/SiOC matrix, were also seen. Carbon diffusion from the SiOC film to the substrate is identified to be responsible for this phenomenon as revealed by TEM and EELS analyses. The studied strain gauge elements were evaluated in both cyclic tensile and compression loads and showed excellent reversibility and short response times. The processing capability of the elements has been statistically assessed and revealed good robustness and replicability which may be further improved. The present work provides a robust and highly reproducible manufacturing process for an ultrasensitive strain gauge prototype and thus points towards a great potential concerning the use of silicon oxycarbides in MEMS-related applications.