Negatively charged deep level defects generated by Yttrium and Lanthanum incorporation into HfO2 for Vth adjustment, and the impact on TDDB, PBTI and 1/f noise

We studied the impact of Yttrium and Lanthanum incorporation into HfO
₂
on reliability (TDDB, PBTI and 1/f noise). They introduce smaller Weibull ß values and early failure in TDDB, with negative shift in PBTI. They are caused by the negatively charged interstitial oxygen defect generated by Yttrium and Lanthanum incorporation. The effect of Lanthanum is larger than that of Yttrium. It can be explained by the larger ion radius and molecular volume of La
₂
O
₃
than Y
₂
O
₃
. On the other hand, they are effective in noise reduction, as an effect of interface state density reduction. The key point in fabricating low V
_th
and highly reliable MOSFETs is the technology for suppression of this interstitial oxygen defect generation.