A Highly Sensitive Piezoresistive Pressure Sensor Based on Oxygen-Doped Zirconium Nitride Thin Film

This paper reports the fabrication and characterization of a piezoresistive pressure sensor based on oxygen-doped zirconium nitride ($\mathrm{O}-\text{ZrN}$) thin film. The piezoresistive effect in O-ZrN thin film is experimentally demonstrated for the first time, enabling its implementation as a pressure sensor through stress-dependent resistivity near the metalinsulator transition. With transverse and longitudinal gauge factors of$\text{GF}_{\mathrm{t}}=-707$and$\text{GF}_{1}=-302, \mathrm{O}-\text{ZrN}$thin film exhibits approximately 6 to 7 times higher transverse piezoresistance and about 3 times higher longitudinal piezoresistance compared to doped silicon, as measured by four-point bending at room temperature. The$\mathrm{O}-\text{ZrN}$thin film piezoresistive pressure sensor achieved a sensitivity of$0.91 \text{mV} / \mathrm{V} / \text{kPa}$with a flat membrane and$0.61 \text{mV} / \mathrm{V} / \text{kPa}$with a cross-beam structure, demonstrating the feasibility of highly sensitive piezoresistive sensors based on phasetransition materials.