The moisture resistance of plasma enhanced chemical vapor deposited (PECVD) oxide films used in ultralarge scale integrated (ULSI) device applications has been characterized using infrared (IR) spectroscopy. The differences in the moisture absorption characteristics between tetraethylorthosilicate (TEOS) and silane-based PECVD oxides are presented. Our results indicate that the film thickness and the as-deposited film stress are important factors in controlling the moisture resistance of these PECVD oxides; the deposition of these PECVD oxides using higher O-2:TEOS ratios enhances moisture resistance; the use of N2O instead of O-2 as the oxidizing agent incorporates nitrogen as well as Si-H bonds in the film which enhance moisture resistance, and that an in situ N-2 plasma post-treatment of PECVD TEOS-O-2 films improves the moisture barrier characteristics of the these oxide films.