Optimization of post-deposition annealing temperature for improved signal-to-noise ratio in In <sub>2</sub> O <sub>3</sub> gas sensor
Wonjun Shin, Seongbin Hong, Yujeong Jeong, Gyuweon Jung, Jinwoo Park, Donghee Kim, Byung-Gook Park, Jong‐Ho Lee
Abstract
Abstract This paper investigates the effects of post-deposition annealing (PDA) temperature on H 2 S gas sensing and low-frequency noise characteristics of In 2 O 3 gas sensors. In 2 O 3 thin-films are deposited using the radio frequency (RF) sputtering method at an RF power of 150 W and post-annealed at various temperatures (200, 300, and 400 °C). The response of the In 2 O 3 gas sensor to H 2 S decreases with increasing PDA temperature due to the increase of grain size. However, the In 2 O 3 post-annealed at 200 °C shows the largest 1/ f noise since the damaged sensing material-substrate interface is not fully recovered by the PDA. The sensors post-annealed at a higher temperature (300 °C and 400 °C) recover the damaged interface. Thanks to its moderate response and noise level, the sensor post-annealed at 300 °C shows the largest signal-to-noise ratio.