Positive Bias Temperature Instability (PBTI) Characteristics of Contact-Etch-Stop-Layer-Induced Local-Tensile-Strained $\hbox{HfO}_{2}$ nMOSFET

Abstract

The positive bias temperature instability (PBTI) characteristics of contact-etch-stop-layer (CESL)-strained HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nMOSFET are thoroughly investigated. For the first time, the effects of CESL on an HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dielectric are investigated for PBTI characteristics. A roughly 50% reduction of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> shift can be achieved for the 300-nm CESL HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nMOSFET after 1000-s PBTI stressing without obvious HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si interface degradation, as demonstrated by the negligible charge pumping current increase (< 4%). In addition, the HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film of CESL devices has a deeper trapping level (0.83 eV), indicating that most of the shallow traps (0.75 eV) in as-deposited HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film can be eliminated for CESL devices.