Surface microroughness observed during wet etching of silicon dioxide withhigh electric field stress

Surface microroughness during stepwise wet etching of silicon dioxide with high electric held stress was observed by atomic force microscopy (AFM). It was found that the rms (root mean square) value of the above oxide surface increased with increasing electric field stress. This indicates that the i nternal damage in silicon dioxide caused by the high electric field stress is distributed two-dimensionally and the degradation does not progress unif ormly. The depth profile of the rms value was also obtained during stepwise etching of the silicon dioxide, which may reflect the depth profile of the internal damage in the silicon dioxide caused by the high electric field s tress.