Negative bias-temperature instabilities in metal-oxide-silicon devices with SiO2 and SiOxNy/HfO2 gate dielectrics

Negative bias-temperature instability (NBTI) in metal-oxide-semiconductor capacitors with SiOxNy/HfO2 gate dielectrics is compared to those with thermal SiO2 oxides. Activation energies for interface and oxide-trap charge densities for each device type, estimated from capacitance-voltage measurements versus temperature and electric field, lie in the range 0.2-0.4 eV. This suggests that the release of hydrogen from, e.g., oxide protrusions in Si, followed by the lateral motion of protons along the interface (activation energy similar to0.3 eV), may play a key role in NBTI. Passivation reactions between protons and Si-H can create interface traps, and proton capture by sub-oxide bonds (O vacancies) can lead to positive trapped-oxide charge. (C) 2004 American Institute of Physics.