Phase Separation and Sodium Passivation in Silicon Oxides Grown in HCl / O 2 Ambients

Abstract

The interrelationship which exists between sodium passivation and phase separation in silicon oxides thermally grown in ambients was investigated using the capacitance‐voltage bias temperature stress technique in conjunction with transmission electron microscopy. Oxides were grown in 0, 3, 6, and 10 volume percent (v/o) for various times at 1100°, 1150°, and 1200°C. The threshold in passivation characteristic of these oxides was shown to be a steep portion of a continuous, smooth curve, rather than a sharp discontinuity. The microstructural investigation showed that the development of the additional, chlorine‐rich phase correlates well with passivation. The development of this phase, characterized by growth and coalescence, is modeled in terms of phase transformation kinetics.