Macroscopic ion traps at the silicon-oxide interface

The drift kinetics of the mobile charge in SiO₂ films, its capture on ion traps localized at the Si-SiO₂ interface, and ion emission from these traps are investigated by measuring the capacitance-voltage characteristics, the dynamic current-voltage characteristics, and the thermally stimulated depolarization current of the insulator. The current components (peaks) associated with the emission of particles trapped on the interface during thermofield treatment are isolated in an explicit form. The charge of the surface ions is shown to be neutralized mainly by Si electrons, and the field dependence of the ion emission currents is characterized by an anomalous Schottky effect associated with opening of the ion-trap potential by the external field. The relationship between these traps and the potential inhomogeneities, i.e., potential wells for mobile particles, on the interface under consideration is discussed. It is noted that the mobile ions in the insulator can be used for interface potential inhomogeneity diagnostics. Fiz. Tekh. Poluprovodn. 32, 1439–1444 (December 1998)