A comparison of RTO and furnace SiO2 time-zero-breakdown characteristics

The breakdown features under ramp voltage stresses of rapid thermal oxidation (RTO) and conventional dry oxides were compared and the results analyzed according to a model that relates defect seriousness to an effective thinning of the nominal film thickness. A method is presented that allows the extraction of valid conclusions about film quality, even on the basis of data collected on samples of different area. From the obtained Weibull plots at least two modes of extrinsic breakdown are evident, each one related to a different type of defect. None of these two kinds of defects is found to be completely randomly distributed. The superior quality of RTO oxides is confirmed insofar as they exhibit lower densities of these defects