Quantitative measurements of the oxygen precipitate rate as a function of annealing were made in Czochralski-grown silicon wafers that contained different initial concentrations of oxygen. All wafers were annealed at 1000 °C for 15 min to ensure that the initial cluster-size distributions were identical in all samples of the same composition prior to the multi-step annealing treatments used for the precipitation studies. The experimental data are compared with numerical predictions for time-dependent nucleation within the classical theory of nucleation. Quantitative agreement is obtained between the measured and calculated densities of oxygen precipitates for nucleation temperatures greater than 600 °C, but only over a narrow range of oxygen composition. Below 600 °C, the measured density for all samples is orders of magnitude larger than is predicted from the model. Further, the measured data show an anomalously small temperature dependence for the induction time for nucleation that does not scale with the diffusion coefficient, as expected from the classical theory of nucleation. Fundamentally, the classical theory of nucleation cannot explain the time-dependent nucleation of oxygen precipitates for temperatures below 650 °C. A possible reason is given.

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A new kind of silicon wafer and a new class of materials engineering techniques for silicon wafers is described. This wafer, called the “Magic Denuded Zone” or MDZ wafer, is produced through the manipulation of the vacancy concentration and, in particular, vacancy concentration depth profiles in the wafer prior to the development of oxygen precipitates in subsequent heat treatments. The result is a wafer with ideal oxygen precipitation behavior for use in all types of integrated circuit applications. The methods used to prepare such wafers combine Frenkel pair generation with injection and the use of surface sinks. Simulations of the vacancy profiles produced by these techniques are presented and discussed. It is shown that within the range of vacancy concentration accessible by these techniques (up to ca. 1013 cm−3) the rate and oxygen concentration dependence of oxygen clustering can be substantially modified. Such techniques can be used to precisely engineer unique and desirable oxygen-related defect performance in silicon wafers both in terms of distribution and rate of defect formation. One result of the application of such techniques is an ideally precipitating silicon wafer in which the resulting oxygen precipitate profile (denuded zone depth and bulk density of precipitates) is independent of the concentration of oxygen of the wafer, the details of the crystal growth process used to prepare the wafer and, to a very large extent, the details of thermal cycles used to process the wafer into an electronic device. Optimal, generic and reliable internal gettering performance is achieved in such a wafer

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