Conducting-AFM spectroscopy on ultrathin SiO2 films

We study the dielectric degradation phenomena of ultrathin SiO₂ films using conducting-AFM spectroscopy in a vacuum (1᎒^-5 Pa). In successive current-voltage characteristics, a change of the carrier transport (from Fowler-Nordheim tunneling to direct tunneling) and current instability (which is due to a change in conductance of leakage path by isolated traps) are observed before 'breakdown'. As an example of a possible application of conducting-AFM spectroscopy, we investigate a change in conductivity at a 'breakdown' area.