Reliability Improvement of 28-nm High-$k$ /Metal Gate-Last MOSFET Using Appropriate Oxygen Annealing

In this letter, performance and reliability of high-k/metal gate MOSFETs can be effectively improved using post metallization annealing. Both oxygen and nitrogen were shown to diffuse into a high-k/SiO
₂
interfacial layer to suppress the formation of oxygen vacancy, thus reducing the gate leakage current without increasing effective oxide thickness. In particular, with appropriate oxygen annealing, gate-induced drain leakage, drain-current degradation, and gate leakage current variation of high- k/metal gate-last MOSFETs can be efficiently suppressed.