Electronic properties of ultrathin high-κ dielectrics studied by ballistic electron emission microscopy

Abstract

Ballistic electron emission microscopy was employed in order to investigate the electronic properties of sub-nanometer high-κ dielectrics (CeO2 and La2O3). The authors found that such a thin dielectric sandwiched between Au and n-Si fails to exhibit the same electronic barrier as its bulk counterpart, but it can still significantly attenuate the ballistic electron transport. The authors attribute the observed smaller barrier height to quantum tunneling and/or induced gap states. The results suggest that such ultrathin high-κ dielectrics in a metal-dielectric-semiconductor structure do not show a fully formed electronic barrier.