Impact of CF4/O2 Plasma Passivation on Endurance Performance of Zr-Doped HfO2 Ferroelectric Film

Abstract

The impact of fluorine (CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> ) and oxygen (O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) plasma passivation on HfZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> (HZO)-based ferroelectric capacitor was investigated. When fabricating the capacitor, the order of passivation treatment was varied to improve the endurance characteristic. In detail, the CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment was applied to one of the three different layers (i.e., (i) Si substrate, (ii) dielectric, and (iii) HZO layer in the capacitor). Those capacitors were annealed at three different temperatures, i.e., 400 °C, 500 °C and 600 °C. The pristine remnant polarization (2P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> ) of capacitors was improved with CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> passivation. However, the endurance performance was varied depending on various fabrication conditions. The capacitor with the CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> plasma treatment on Si substrate showed two orders of magnitude improvement in its endurance performance. The order of passivation significantly affected the ferroelectric properties. This is due mainly to the variation of atomic bonding of Hf/Zr and O atoms in HZO layer. The variation of atomic bonding was quantitatively confirmed by XPS analysis.