Ferroelectric Si-Doped HfO₂ Device Properties on Highly Doped Germanium

Abstract

Ferroelectric Si-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin films are integrated into three different device stacks with a p+ Ge substrate, a p+ Si substrate, and a TaN bottom metal gate. The ferroelectric behavior of the Si-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin films is strongly dependent on the bottom interfaces. The Si-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> thin films have favorably improved ferroelectric properties on the p+ Ge substrate due to the lack of a dielectric interfacial layer between HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and Ge. The low-voltage operation and cycling stability of Si-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ferroelectric thin films on Ge can lead to the realization of high performance, robust Ge ferroelectric field-effect transistors for nonvolatile memory applications.