A highly CMOS compatible hafnia-based ferroelectric diode

Abstract

Memory devices with high speed and high density are highly desired to address the 'memory wall' issue. Here we demonstrated a highly scalable, three-dimensional stackable ferroelectric diode, with its rectifying polarity modulated by the polarization reversal of Hf 0.5 Zr 0.5 O 2 films. By visualizing the hafnium/zirconium lattice order and oxygen lattice order with atomicresolution spherical aberration-corrected STEM, we revealed the correlation between the spontaneous polarization of Hf 0.5 Zr 0.5 O 2 film and the displacement of oxygen atom, thus unambiguously identified the non-centrosymmetric Pca2 1 orthorhombic phase in Hf 0.5 Zr 0.5 O 2 film. We further implemented this ferroelectric diode in an 8 layers 3D array. Operation speed as high as 20 ns and robust endurance of more than 10 9 were demonstrated. The builtin nonlinearity of more than 100 guarantees its self-selective property that eliminates the need for external selectors to suppress the leakage current in large array. This work opens up new opportunities for future memory hierarchy evolution.

Emerging Opportunities for 2D Semiconductor/Ferroelectric Transistor‐Structure Devices

“…This offers a plausible solution to bridge the gap between thickness scaling ferroelectric oxides and CMOS technology. [79,130,131] The application of doped-HfO 2 thin films for NC-FET elements have attracted rapidly grown interests in the past few years. [109,132] Compared to P(VDF-TrFE), apart from the fact that doped-HfO 2 is a more silicon CMOS-technology compatible choice, precise thickness control of doped-HfO 2 film and subsequent in-situ buffer dielectric oxides growth could result in stronger dielectric properties, cleaner interface and thus better capacitance matching.…”

Ferroelectric Properties and Polarization Fatigue of La:HfO2 Thin‐Film Capacitors

“…[ 3 ] This discovery triggered great interest because it expands the application scope of HfO 2 from passive dielectric layers in FETs to active polar media in nonvolatile ferroelectric memories that have good compatibility with the current complementary metal–oxide–semiconductor (CMOS) integrated circuits. [ 4,5 ] In general, HfO 2 has three crystalline phases, that is, the room‐temperature monoclinic phase (m‐phase, space group: P 2 1 / c ) and the high‐temperature tetragonal (t‐phase, space group: P 4 2 / nmc ) and cubic (c‐phase, space group: Fm m ) phases. [ 6 ] But these phases are all centrosymmetric, forbidding ferroelectricity.…”

Recent Advances on Neuromorphic Devices Based on Chalcogenide Phase‐Change Materials

“…[25] In spite of such good performance, the filamentary RS devices suffer severely from large cycle-tocycle and cell-to-cell variability due to its defect-based mechanism, [26] and thus the mass industrial production is greatly hindered. Besides memristive oxides, other materials and devices such as Li-ion battery electrolytes, [27] 2D materials, [28][29][30][31] perovskites, [32] ionic liquid, [33] ferroelectric materials, [34,35] magnetic devices, [36,37] and even organic polymers [38,39] were reported to have the ability to carry out the neuromorphic computing tasks.…”