Effects of TiN Top Electrode Texturing on Ferroelectricity in Hf1-xZrxO2.

Robin Athle,Heera Menon,Anton E. O. Persson,Austin Irish,Mattias Borg,Rainer Timm

doi:10.1021/acsami.1c01734

Robin Athle, Heera Menon + Show 4 more

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https://doi.org/10.1021/acsami.1c01734

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Abstract

Ferroelectric memories based on hafnium oxide are an attractive alternative to conventional memory technologies due to their scalability and energy efficiency. However, there are still many open questions regarding the optimal material stack and processing conditions for reliable device performance. Here, we report on the impact of the sputtering process conditions of the commonly used TiN top electrode on the ferroelectric properties of Hf1–xZrxO2. By manipulating the deposition pressure and chemistry, we control the preferential orientation of the TiN grains between (111) and (002). We observe that (111) textured TiN is superior to (002) texturing for achieving high remanent polarization (Pr). Furthermore, we find that additional nitrogen supply during TiN deposition leads to >5× greater endurance, possibly by limiting the scavenging of oxygen from the Hf1–xZrxO2 film. These results help explain the large Pr variation reported in the literature for Hf1–xZrxO2/TiN and highlights the necessity of tuning the top electrode of the ferroelectric stack for successful device implementation.

Highlights

Ferroelectricity in HfO2 has since its discovery in 20111 been attracting strong interest for applications in nonvolatile memories and negative-capacitance transistors due to its strong remanent polarization (Pr ∼ 20−30 μC/cm2) and high coercive field (Ec ∼ 1−2 MV/cm2), as well as being compatible with and already used in complementary metaloxide semiconductor technology
Ferroelectric (FE) HfO2 can exhibit memristive behavior in ferroelectric tunnel junctions[2] (FTJs) and ferroelectric field effect transistors (FeFETs),[3] which indicates its potential for application in neuromorphic computation
By employing a combination of electrical characterization and grazing incidence X-ray diffraction (GIXRD), we reveal the importance of (111) textured TiN in achieving FE Hf1−xZrxO2

Summary

Introduction

Ferroelectricity in HfO2 has since its discovery in 20111 been attracting strong interest for applications in nonvolatile memories and negative-capacitance transistors due to its strong remanent polarization (Pr ∼ 20−30 μC/cm2) and high coercive field (Ec ∼ 1−2 MV/cm2), as well as being compatible with and already used in complementary metaloxide semiconductor technology.

Results

Conclusion