Effects of microcontaminants in oxygen during gate oxide growth: interfacial effects and device reliability

The effects of different levels of water, nitrogen, and methane contamination in an oxidation ambient during the production of ultra-thin rapid thermal oxides have been investigated. Careful characterization of the oxidation and argon anneal steps have been performed. High levels of water and hydrogen in these ambients were shown to be generated during the process. Nuclear reaction analysis indicates that the final water level in the oxide depends on the water level in both the oxidation ambient and post-oxidation ambient. Increasing nitrogen concentrations in the oxidation ambient resulted in increased interface trap densities and the frequency of low field breakdown. Initial studies of methane in the oxidation ambient show that it also plays a similar role in oxide degradation.