Employing Thermal Oxidation and Through-Silicon Via Technologies in CuO-Based Sensors for Room-Temperature NO2 Detection

Abstract

We present the development and characterization of room-temperature CuO gas sensor fabricated through a thermal oxidation process complemented by a through-silicon via (TSV) structure. The TSV structure is a tapered hole with the top width measuring approximately 190 um and narrowing to 103 um at the bottom. The CuO film serves as the sensing material, with its predominant (111) orientation confirmed through X-ray diffraction analysis. Transmission electron microscopy analysis indicated lattice spacing of 0.23 nm within the CuO samples, corresponding to the (111) plane. Sensor performance was evaluated at a room temperature of 25 °C, showing response rates of 19.3%, 34.6%, 39.3%, and 46.3% to NO2 concentrations of 0.5, 1, 2, and 5 ppm, respectively. Stability testing of the sensor at 1 ppm NO2 concentration across five cycles demonstrated a consistent response around 34.6% with a deviation of less than 2%. The CuO material exhibited enhanced selectivity for NO2 over other gases such as NH3, CO2, CO, H2, H2S, and SO2.