Wear-out and breakdown of ultra-thin gate oxides after irradiation

The enhancement of gate leakage current after exposure to ionising radiation is generally believed to be the major challenge for devices and circuits operating in harsh radiation environments. How ultra-thin gate oxides subjected to heavy ion irradiation react to a subsequent electrical stress performed at low voltages has been investigated. Even in devices exhibiting small (or even negligible) enhancement of the leakage current, the time-to-breakdown is substantially reduced in comparison with unirradiated samples due to the onset of a soft or hard breakdown, in contrast with previous results found on thicker oxides.