Influence of the first thermal cycles of an IC process on oxygen precipitation in CZ silicon wafers: a detailed analysis

Abstract

The oxygen precipitation kinetics, the oxide precipitate density (N_p) and the denuded zone width (DZ) in standard CZ silicon wafers coming from the supplier and randomly sampled were determined after annealing at temperatures from 950 to 1100 degrees C. Correlations between the precipitation kinetics factors and the precipitate densities were clearly established and interpreted using the usual precipitation models. A clear relationship between the DZ values and the precipitate densities was obtained. How a further high-temperature anneal such as a CMOS well drive-in at 1160 degrees C affects these parameters was experimentally determined. All these results can be well interpreted in terms of selective precipitate growth from a population of microprecipitates. Practical recommendations for improved internal gettering are deduced from this work.