Transient electronic conduction in thermally grown SiO2 has been shown to be limited by space-charge evolution. The space charge originates from trapping of the injected species. It induces a field which affects the emission of charges at the injecting electrode. The trapping of charge has been analyzed on the basis of three, essentially different, mechanisms: (1) first order trapping, (2) first order trapping which takes into account that trapped charges repel injected charges, and (3) trapping which increases during injection due to the generation of states. It is shown that implementation of the three trapping mechanisms yields a current versus injected charge plot which is given in the asymptotes by simple logarithmic functions. Intersection of the asymptotes directly yields the value of the capture cross section. From the slopes of the asymptotes the surface density(ies) of the trap(s) can be calculated. The method can be used without, a priori, assuming either the injection mechanism or the trapping mechanism. From the relative position of the intersection points the applicable mechanism can be derived, however. For thermal SiO2 on Si we determined, by this method, values of trap densities and capture cross sections which are typical for water-related traps. Furthermore, we derived that trapping mechanism (2) fits our data best.

Recent studies of the kinetics of dry oxidation of silicon have shown that the time dependence is more precisely described by a power-of-time law than by a linear-parabolic expression. This study shows the power law to be correct. This foHows from the interdependence of the experimental linear and parabolic rate constants. The linear-parabolic expression appears to be equivalent to the first terms of a series expansion of the power-of-time law. The omission of higher-order terms gives systematic deviations known as the "anomalous" initial regime. An ionic space-charge-limited growth model is introduced, based on the classical oxidation theory of Wagner and accounting for the effect of internal fields on conduction. First, it is shown that both the magnitude of ionic and electronic conduction are sufficiently high, which is illustrated for an oxide layer of 300 A growing at 870 ·C. It is made plausible that the oxide-fixed charge density, Qf, is sufficiently large at high temperatures to cause large internal fields. An expression is derived which accounts for the mutual Coulomb repulsion of charges in very dense space-charge layers. The excellent fit of the derived expression and its application will be discussed in part n.

In part I, the kinetics of dry oxidation of silicon has been investigated and a new model based on the classical oxidation theory including space-charge effects is proposed. In part II, the power-of-time law is shown to fit to the experimental results and the major conditions affecting the growth are investigated. The dependence on crystallographic orientation, the ‘‘crossover’’ effect, the nonlinear oxygen pressure dependence, the enhancing anneal effect, the peculiar growth on 2-D structures, and the silicon surface pretreatment effect are examined. As a practical application the model predicts the location of structural thin spots in the gate oxide of a metal-oxide-silicon capacitor.