Kelvin Probe Study of Dipole Formation and Annihilation at the HfO2/Si Interface

We used the Kelvin probe method to examine the dipole layers induced at the direct-contact HfO 2 /Si interfaces. Large negative voltage shifts of contact potential difference were observed for the HfO 2 /Si structures, indicating the existence of strong interface dipole layers (0.8–0.9 V). It was also found that the dipole strength decreased dramatically with ultrahigh vacuum annealing at about 600 °C, at which the interface Si–O bonds are likely to decompose.