Band structure and valence-band offset of HfO2 thin film on Si substrate from photoemission spectroscopy

Synchrotron radiation photoemission spectroscopy and optical transmission spectrum measurements have been performed on an HfO2 thin film grown on a Si(100) substrate to determine the band structure of the HfO2/Si stack. The result shows a valence-band offset of 2.5 eV and a conduction-band offset of 2.2 eV for the HfO2/Si interface. The Schottky barrier height between Au and HfO2 is obtained from current density–voltage measurement. The characterization reveals that the dominant conduction mechanism in the region of low field under gate injection is Schottky emission. The energy-band diagram of an Au–HfO2–Si MOS stack was obtained from these results.