Reliability Challenges for CMOS Technology Qualifications With Hafnium Oxide/Titanium Nitride Gate Stacks

It has been demonstrated that the introduction of HfO₂/ TiN gate stacks into CMOS technologies provides the means to continue with traditional device gate length scaling. However, the introduction of HfO₂ as a new gate dielectric and TiN as a metallic gate electrode into the gate stack of FETs brings about new challenges for understanding reliability physics and qualification. This contribution summarizes recent advances in the understanding of charge trapping and defect generation in HfO₂/ TiN gate stacks. This paper relates the electrical properties to the chemical/physical properties of the high-epsiv dielectric and discusses test procedures specifically tailored to quantify gate stack reliability of HfO₂/TiN gate stacks.