The effect of a chemical downstream etching (CDE) environment on the oxide integrity and electrophysical properties of thin oxide metal-oxide-semiconductor capacitors was investigated with respect to the poly-buffered local oxidation process. CDE plasma-related effects were compared to that caused by exposure to high-density plasma. Two types of plasma-induced damage were isolated for both plasma exposures; one due to plasma charging manifests itself through antenna dependence of gate oxide integrity, while the other results in generation of defects (generation-recombination centers) in the silicon substrate. Experiments revealed that CDE is not a completely charging-free process; the charging effect was found to be lower than for the plasma-immersion system. Both types of plasma exposure may also cause defect generation in the silicon substrate. The level of damage, affecting oxide integrity, charge trapping, interface degradation, and defect density in the near-surface silicon region is significantly lower for CDE than for plasma-immersion systems.