A study to observe gaseous impurity ingress into an atmospheric pressure thermal oxidation furnace was carried out using an in-situ probe. Experimental measurements of trace moisture and oxygen deep within the furnace revealed that the level of infiltration into the furnace was critically dependent on the inert gas flow rate during loading. Different process recipes led to different impurity residence times within the furnace once the furnace door was sealed. The level of moisture ingress was directly correlated with the level of negative bias stress instability observed for metal gated MOS capacitors.
Nayar, V., Jackson, R., Filleul, M. L., Brunson, K., Uren, M. J., & Hodge, A. M. (1993). Optimisation of furnace oxidation of silicon with respect to negative bias stress instability. Microelectronic Engineering, 22(1-4), 47-50. https://doi.org/10.1016/0167-9317(93)90128-R