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

Negative bias-temperature instability (NBTI) in metal–oxide–semiconductor capacitors with SiO_xN_y/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 ∼0.3 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. © 2004 American Institute of Physics.