A Cone-Like TSV Structured ZnO NO₂ Gas Sensor that is Produced Using Room-Temperature Laser Drilling and Radio-Frequency Sputtering

A typical through-silicon via (TSV) has vertical and high aspect ratio holes, making special equipment required to deposit the film on the vertical hole walls. This study used room-temperature laser drilling to fabricate a cone-like TSV structure so that no special process equipment was required. Radio-frequency sputtering was used to deposit SiN x , ITO, and ZnO films on the cone-like TSV structure to form a ZnO NO 2 gas sensor. Scanning electron microscopy and focused ion beam results show that the ZnO film connects the front and back sides of the substrate, enabling sensing on both sides. If the concentration of NO 2 gas is increased, the sensor response increases and the average sensor response is 34,7%, with an inaccuracy of <± 1% for five 5 consecutive measurements using a NO 2 concentration of 3ppm. Reactions with NH 3 , CO, CO 2 , and SO 2 gases are almost insignificant, giving the cone-like TSV structure ZnO gas sensor good selectivity, stability, and reproducibility for NO 2 gas.