Low Thermal Budget Fabrication and Performance Comparison of MFM Capacitors With Thermal and Plasma-Enhanced Atomic Layer Deposited Hf_0.45Zr_0.55O<i> _x </i> Ferroelectrics

Abstract

The ferroelectricity of Zr-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (HZO) thin films induced by low thermal budget annealing provides great potential to implement the ferroelectric functionalities into the back end of line (BEOL) process of the standard CMOS integrated circuits. However, most of previous works need high temperature annealing or long time annealing to acquire ferroelectricity. In this work, both annealing temperature and time are optimized to achieve optimal ferroelectricity of Hf <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.45</sub> Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.55</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> films produced by thermal atomic layer deposition (TALD) and plasma-enhanced atomic layer deposition (PEALD). The results indicate that the TALD and PEALD films exhibit maximum double remanent polarization ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2{P}_{r}$ </tex-math></inline-formula> ) of ~36.8 and ~ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$30.0 {{ \boldsymbol {\mu }}}\text{C}/$ </tex-math></inline-formula> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively, after annealing at 330 °C for 300 s. Furthermore, the characteristics of the above annealed films are comprehensively compared. It is found that the PEALD film exhibits a higher maximum-dielectric-constant, a higher breakdown electric field, and better endurance against switching cycles than the TALD one, but more severe wake-up effects. This is ascribed to the factor that the PEALD film contains more tetragonal phase and less defects than the TALD one. In this article, the PEALD film has moderate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P}_{r}$ </tex-math></inline-formula> and robust endurance, which is more promising for memory devices.