Effect of La and Al addition used for threshold voltage shift on the BTI reliability of HfON-based FDSOI MOSFETs

In this paper, the Bias Temperature Instability effects of Lanthanum (La) and Aluminum (Al) incorporation, used for threshold voltage adjustment by dipole formation at the SiO ₂ /HfON interface into the FDSOI gate dielectrics has been studied. When compared at the same oxide electric field (Eox), incorporation of La causes significant enhancement of intrinsic NBTI (Negative Bias Temperature Instability) effect and it reduces the already low PBTI (Positive Bias Temperature Instability) effect. On the other hand, comparison at the same Gate voltage (Vg) does not show the same behavior possibly due to the reduction of oxide field (Eox) by La dipole effect. Incorporation of Al does not have a significant impact on NBTI but it causes significant enhancement of PBTI, when compared both at the same Eox or same Vg. NBTI/PBTI degradations well correlate to the La and Al effective doses in the gate dielectrics.