Analysis of residual oxygen during a-IGZO thin film formation by plasma-assisted reactive sputtering using a stable isotope

This work assessed the effects of residual oxygen remaining on the surfaces of a plasma-assisted reactive sputtering chamber during the deposition of a-InGaZnOx (a-IGZO) thin films, based on employing a stable oxygen isotope together with thermal desorption spectroscopy. The absorption of oxygen by such films may affect the deposition process, especially in the case that residual oxygen is left on the chamber walls by a preceding deposition. Trials using 18O2 as a stable isotope of oxygen showed no evidence of the contamination of a-IGZO thin films by oxygen desorbed from the chamber walls. These results indicate that residual oxygen and other substances on the chamber walls can be expected to have little effect on the films when using this deposition technique.