Point contact conduction at the oxide breakdown of MOS devices

Experiment and simulation are combined to demonstrate that, provided that thermal effects are limited, the dielectric breakdown of SiO/sub 2/ films in MOS devices opens atomic-size conduction channels (with radius in the 1 to 10 nm range) which behave as point contacts. Depending on the size of the breakdown spot, the conduction properties are either those of a Sharvin point contact or those of a quantum point contact.