High-Performance Operation and Solder Reflow Compatibility in BEOL-Integrated 16-kb HfO₂: Si-Based 1T-1C FeRAM Arrays

Abstract

16kbit 1T-1C FeRAM arrays are demonstrated at 130nm node with TiN/HfO2:Si/TiN ferroelectric capacitors integrated in the Back-End-of-Line (BEOL). 0 state and 1 state distributions measured on the arrays demonstrate perfect yield at 4.8V operation, with extrapolations suggesting memory window is still open at 6 sigma statistics. Programming speed down to 4ns at 4V is highlighted at the array level, together with endurance up to 10 7 cycles. Promising data retention up to 10 4 s at 125°C is measured on the arrays and, for the first time, solder reflow compatibility is demonstrated for HfO2-based FeRAM. Memory window on 16kbit arrays remains open down to 2.5V programming voltage and when capacitor area decreases from 0.36µm² down to 0.16µm², with calculated programming energy lower than 100fJ/bit. These results pave the way to competitive ultra-low power embedded non-volatile memories at more advanced nodes.

Neuromorphic devices based on fluorite‐structured ferroelectrics

“…Additionally, gate last FeFET with improved endurance and retention by reduced charge trapping were realized 27 . Furthermore, the first fully integrated functional capacitor‐based ferroelectric random‐access memory (FeRAM) devices were recently demonstrated 28,29 . Ferroelectric tunnel junctions (FTJs) having a tunneling electroresistance controlled by the spontaneous polarization of fluorite‐structured ferroelectrics were also demonstrated as a variant of memristive devices 30 .…”

“…27 Furthermore, the first fully integrated functional capacitor-based ferroelectric random-access memory (FeRAM) devices were recently demonstrated. 28,29 Ferroelectric tunnel junctions (FTJs) having a tunneling electroresistance controlled by the spontaneous polarization of fluorite-structured ferroelectrics were also demonstrated as a variant of memristive devices. 30 In 2020, it was suggested that the robust ferroelectricity of (Hf,Zr)O 2 can be retained even when the film thickness decreases to 1 or 1.5 nm, and it was further suggested that unit-cell-scale information storage would theoretically be possible because of the flat phonon band of ferroelectric HfO 2 .…”

Temperature‐Dependent Phase Transitions in HfxZr1‐xO2 Mixed Oxides: Indications of a Proper Ferroelectric Material

“…Uwe Schroeder,* Terence Mittmann,* Monica Materano, Patrick D. Lomenzo, Patrick Edgington, Young H. Lee, Meshari Alotaibi, Anthony R. West, Thomas Mikolajick, Alfred Kersch, and Jacob L. Jones DOI: 10.1002/aelm.202200265 ductor devices like ferroelectric capacitors, transistors, and tunnel junctions in recent years. Capacitor-based ferroelectric random access memory [2,3] and ferroelectric field effect transistors [4] using HfO 2based ferroelectrics have already been integrated into state of the art CMOS processes to prove the potential of this new ferroelectric material system. However, a detailed understanding of the ferroelectric phase formation process, including phase transitions, is necessary for continued development because such phase transitions determine ferroelectric device temperature stability.…”

“…However, a detailed understanding of the ferroelectric phase formation process, including phase transitions, is necessary for continued development because such phase transitions determine ferroelectric device temperature stability. Several phases were reported to be present or coexisting in doped HfO 2 or ZrO 2 films ranging from monoclinic (space group P2 1 /c), tetragonal (P4 2 /nmc), cubic ( 3 Fm m ), rhombohedral (R3m), and different orthorhombic phases that can be nonpolar (Pnma), antipolar (Pbca), nonpolar (Pbca), or polar (Pca2 1 ). [5,6] A remarkable property of the material is the phase coexistence between the nonpolar tetragonal and polar orthorhombic phase.…”

Ferroelectric Devices for Intelligent Computing

“…Doped-HfO 2 Ferroelectric Materials. Since the discovery of ferroelectricity in doped-HfO 2 films in 2011 [20], ferroelectric field-effect transistors (FeFETs) and ferroelectric random access memory (FeRAM) have received significant attention [21][22][23][24][25]. Polycrystalline doped-HfO 2 films are considered as promising gate-oxide materials owing to their excellent ferroelectric properties as well as high compatibility with the ultrascale CMOS process.…”