Characterization of local dielectric breakdown in ultrathin SiO2 films using scanning tunneling microscopy and spectroscopy

Research was conducted to examine the local dielectric breakdown of ultrathin SiO2 films grown on silicon substrates using scanning tunneling spectroscopy and scanning tunneling microscopy. A leakage current was observed at the quasibreakdown spots that passed through defect levels in the ultrathin oxide films. Several tunneling spectra derived from near leakage sites were also found to have clear negative differential resistance.