Regarding the gases for the manufacturing process of semiconductor devices, fast and sensitive sensors are needed to control trace moisture to less than 1 μmol/mol. A ball surface acoustic wave (SAW) sensor is promising technology for this purpose. In this study, we verify the response of a sol-gel SiOx film-coated ball SAW sensor to extremely low-concentration moisture using a cavity ring down spectroscopy (CRDS), the most sensitive commercially available moisture sensor, as a reference sensor. We clearly measured 17nmol/mol moisture by developing a sensor cell using metal O-rings reducing the leakage of moisture. The response time from 390 to 790 nmol/mol was one tenth of that for the CRDS, and the detection limit was estimated to be as low as 0.2 nmol/mol.
ASJC Scopus subject areas
- Physics and Astronomy(all)