A Study of the Dielectric Breakdown of SiO2 Films on Si by the Self- Quenching Technique

The authors have studied the dielectric breakdown of thermally grown SiO2 films on Si substrates by the technique in which a thin metallization is used to provide self-quenching of the breakdown. Each of the four possible combinations of p or n substrate and or - field-plate polarity shows its own distinctive properties and its own distinctive configuration of breakdown damage as viewed by optical microscope and scanning electron microscope. Some properties correlate with the nature of the substrate surface channel inversion versus accumulation other properties correlate with the field-plate polarity. The time evolution of the breakdown indicates that the current through the fault is limited by the spreading resistance of the substrate. A study of the currents and insulator charging at the onset of breakdown indicates that initiation of breakdown is by Fowler-Nordheim tunneling of electrons into the oxide. The occurrence of a current instability which can be enhanced by lowering the temperature indicates the possible importance of hole-electron pair production in the oxide with subsequent trapping of holes.