Hot electron transport in Au-Hf O2 -Si O2 -Si structures studied by ballistic electron emission spectroscopy

Abstract

Hot electron transport in Au-Hf O2 -Si O2 -Si structures with 4 nm Hf O2 and 1.5 nm Si O2 interfacial layer have been investigated by ballistic electron emission spectroscopy (BEES). By controlling the hot electron kinetic energy and injection current, distinctly different barrier heights can be measured. BEES sweeping below -5 V with 1 nA injection current yields high barrier heights (∼3.8 eV), attributable to the interfacial Si O2 layer. BEES sweeping from -6 V with high injection current (5 nA and above) induced localized breakdown of the Si O2 interfacial layer, allowing the barrier height of the Hf O2 layer to be measured (∼1.9 eV). The energy-dependent effective mass of electrons in Hf O2 is also determined by fitting oscillations in the BEES current. © 2007 American Institute of Physics.