PBTI improvement in gate last HfO2 gate dielectric nMOSFET due to Zr incorporation

PBTI in the Hf_xZr_yO gate dielectric low temperature full gate last process flow nMOSFETs was demonstrated to be reduced compared to the HfO₂ gate dielectric devices of a similar EOT. PBTI degradation in both stacks was successfully modeled within a common framework of fast and slow electron trapping components in the gate dielectrics. The fast component was assigned to the resonance electron trapping in the pre-existing high-κ dielectric defects while a slow, temperature dependent component could be attributed to the migration of the trapped electrons to unoccupied defect sites. Lower PBTI degradation in the Zr:HfO₂ stack was shown to be caused by a smaller fast electron trapping component.