Microstructure modified HfO/sub 2/ using Zr addition with Ta/sub x/ C/sub y/ gate for improved device performance and reliability

Abstract

For the first time we report on the development of a novel hafnium zirconate (HfZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) gate dielectric with a Ta <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> metal gate. Compared to HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , the new HfZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> gate dielectric showed: (1) higher transconductance, (2) less charge trapping, (3) higher drive current, (4) lower NMOS V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> , (5) reduced C-V hysteresis, (6) lower interface state density, (7) superior wafer-level thickness uniformity, and (8) longer PBTI lifetime. We attribute these improvements to a microstructure that is modified by addition of Zr to HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>