
Saturday, April 12, 2025
Neumonda and Ferroelectric Memory Company Collaborate in the Commercialization of Non-Volatile DRAM

Friday, January 17, 2025
3D Vertical Ferroelectric Capacitors for Memory Scaling
3D vertical ferroelectric capacitors are revolutionizing memory technology, offering higher density and performance by leveraging vertical structures to overcome planar scaling limits. Using aluminum-doped hafnium oxide (Al:HfO₂), these capacitors achieve stable remnant charge, low voltage operation, and enhanced scalability, addressing advanced applications in AI and edge computing. Recent innovations, such as the TiN/Al:HfO₂/TiN configuration introduced by Dongguk University, South Korea, demonstrate improvements in endurance and integration. This progress builds on foundational work by Qimonda and Fraunhofer IPMS-CNT in Dresden Germany, including Tim Böscke's pioneering discovery of ferroelectricity in hafnium oxide and Johannes Müller's ALD advancements using ALD process developments FHR and ASM tools. These developments cement Al:HfO₂ as a DRAM and CMOS-compatible solution for next-generation non-volatile memory technologies.
A recent study, 3D Vertical Ferroelectric Capacitors with Excellent Scalability (by Eunjin Lim et al Dongguk University, South Korea)), introduces a 3D vertical ferroelectric capacitor with a TiN/Al:HfO₂/TiN configuration. It employs a unique architecture with multiple small holes sharing a common pillar electrode, enhancing ferroelectric properties and scalability. Analyses using advanced microscopy confirm its structural integrity, while the device demonstrates high endurance, minimal variability, and excellent retention. This architecture also supports integration into one-transistor n-capacitor ferroelectric memory with vertical transistors.
Importantly, Earlier work by Fraunhofer IPMS-CNT, including the 2012 study Incipient Ferroelectricity in Al-Doped HfO₂ Thin Films, first demonstrated ferroelectric properties in HfO₂ thin films doped with aluminum. This research identified an antiferroelectric-to-ferroelectric phase transition, influenced by Al concentration and annealing conditions, and attributed ferroelectricity to a non-centrosymmetric orthorhombic phase (Pbc2₁). This foundational work highlighted the potential of Al:HfO₂ for applications in memory and sensing technologies.
The later paper High Endurance Strategies for Hafnium Oxide-Based Ferroelectric Field Effect Transistors further emphasized Al:HfO₂’s scalability and compatibility with CMOS technology. It explored strategies to improve endurance and reduce interfacial stress, including modifying interfacial materials and exploring MFS structures. These strategies balance performance, reliability, and scalability, supporting the broader adoption of ferroelectric memory.
In Johannes Müller's PhD thesis (2014, Fraunhofer IPMS-CNT), the Atomic Layer Deposition (ALD) processes for hafnium oxide (HfO₂) and aluminum-doped hafnium oxide (Al:HfO₂) utilized advanced deposition equipment to achieve precise doping and phase control. The processes were performed using a 300 mm FHR ALD 300 and an ASM PULSAR 3000®, both of which are designed for high-uniformity deposition on large substrates, such as 300 mm wafers. These tools facilitated the use of tetrakis(ethylmethylamino)hafnium (TEMAHf) and trimethylaluminum (TMA) as precursors for hafnium and aluminum, respectively, along with oxidants like water or ozone. By tailoring precursor ratios, deposition temperatures, and annealing conditions, the processes ensured the stabilization of the orthorhombic Pbc2₁ phase, critical for the ferroelectric properties of Al:HfO₂ films. These advancements highlight the scalability and compatibility of ALD-fabricated Al:HfO₂ films with CMOS technology.
The patent US 2009/0057737 A1, authored by Tim Böscke et al., describes a method for fabricating integrated circuits with a dielectric layer that exhibits enhanced properties, such as high dielectric constants and ferroelectricity. The process involves forming a preliminary dielectric layer, such as hafnium oxide or doped hafnium oxide (e.g., aluminum- or silicon-doped), using techniques like Atomic Layer Deposition (ALD). The dielectric layer is initially amorphous and undergoes a phase transition to a crystalline state upon heating above its crystallization temperature. The method includes precise doping of the dielectric layer to stabilize desirable phases, such as orthorhombic or tetragonal, which are essential for achieving ferroelectricity. A covering layer, often a conductive electrode material, is deposited before annealing to assist in crystallization and enhance material properties. The innovations outlined aim to improve memory applications, such as capacitors and transistors, by offering higher storage densities, lower leakage currents, and compatibility with advanced CMOS processes. This patent is foundational in the development of ferroelectric hafnium oxide-based technologies.
Sources:
- 3D Vertical Ferroelectric Capacitors with Excellent Scalability: 3D Vertical Ferroelectric Capacitors with Excellent Scalability | Nano Letters
- Mueller, S., et al., Incipient Ferroelectricity in Al‐Doped HfO₂ Thin Films, Advanced Functional Materials, 2012. Wiley Online Library
- High Endurance Strategies for Hafnium Oxide-Based Ferroelectric Field Effect Transistor, Fraunhofer IPMS, 2016. (N-432037.pdf): N-432037.pdf
Ferroelektrizität in Hafniumdioxid und deren Anwendung in nicht-flüchtigen Halbleiterspeichern Ferroelektrizität in Hafniumdioxid und deren Anwendung in nicht-flüchtigen Halbleiterspeichern - US 2009/0057737A1 (prev. QIMONDA AG, now NAMLAB GGMBH) https://patentimages.storage.googleapis.com/56/02/b2/d476f4848ffe82/US20090057737A1.pdf
Sunday, October 27, 2024
3D Ferroelectric NAND for Ultra-High Efficiency Analog Computing-in-Memory by SK hynix
3D FeNAND with Ultra-High Computing-in-Memory Efficiency: AI models containing up to trillions of parameters require substantial memory resources to handle the vast amounts of data. Energy-efficient analog computing-in-memory (CIM) devices such as 3D vertical NAND architectures are emerging as potential solutions because they offer high areal density and are non-volatile. SK hynix researchers will detail how they achieved analog computation in ultra-high-density 3D vertical ferroelectric NAND (FeNAND) devices for the first time. They used gate stack engineering techniques to improve the analog switching properties of 3D FeNAND cells, and achieved an unprecedented ≥256-conductance-weight levels/cell. The 3D FeNAND arrays improved analog CIM density by 4,000x versus 2D arrays, and demonstrated stable multiply-accumulate (MAC) operations with high accuracy (87.8%) and 1,000x higher computing efficiency (TOPS/mm2) versus 2D arrays. This work provides an efficient method to implement the processing of hyperscale AI models in analog CIM chips for edge computing applications, where speed and low power operation are the critical requirements, not extreme accuracy.
Above:
(1) is a comparison of 2D and 3D
arrays for analog-CIM applications.
(2) is a TEM analysis of the 3D FeNAND, showing (a) a top-down view
of the device; (b) a cross-sectional view at low magnification; (c) a cross-sectional
view at high magnification; and (d) a schematic illustration of the FeFET cells
in the 3D FeNAND array.
IEDM 2024 Paper #38.1, “Analog Computation in Ultra-High Density 3D FeNAND for TB-Level Hyperscale AI Models,” J.-G. Lee and W.-T. Koo et all, SK hynix https://www.ieee-iedm.org/press-kit
Thursday, November 25, 2021
Watch again - Material development for MRAM and FRAM stacks at Fraunhofer IPMS-CNT
Material development for MRAM and FRAM stacks
Saturday, April 17, 2021
Unraveling the different causes behind ferroelectricity in HfO2
Interplay between oxygen defects and dopants: effect on structure and performance of HfO2-based ferroelectrics
Monica Materano et alInorg. Chem. Front., 2021, Advance Article https://doi.org/10.1039/D1QI00167A
Tuesday, February 23, 2021
Progress and future prospects of negative capacitance electronics: A materials perspective
1. Robust ferroelectricity at 5 nm thickness and below
2. Compatibility with CMOS technology
3. Thermal stability on silicon
4. Conformal deposition on 3D substrates
5. Large electronic bandgap and conduction band offset to Si
Progress and future prospects of negative capacitance electronics: A materials perspective
Thursday, February 18, 2021
Ferroelectric Field Effect Transistors (FeFETs) Bring Promise And Challenges
CEO interview: FMC’s Pourkeramati on roadmaps, turning away investors
https://www.eenewsanalog.com/news/ceo-interview-fmcs-pourkeramati-roadmaps-turning-away-investors
Saturday, January 11, 2020
A comparasion of Hafnium and Zirconium ALD precursor comparison
HfxZr1 − xO2 thin films for semiconductor applications: An Hf- and Zr-ALD precursor comparison editors-pick
Journal of Vacuum Science & Technology A 38, 022402 (2020); https://doi.org/10.1116/1.5134135Monica Materano, Claudia Richter, Thomas Mikolajick, and Uwe Schroeder
Sunday, November 3, 2019
An ultrathin integrated nanoelectromechanical transducer based on ALD ferroelectric hafnium zirconium oxide
- stable frequency references
- wideband spectral processors
- high-resolution resonant sensors.
Saturday, November 17, 2018
Researchers from University of Groningen, the Netherlands confirm ferroelectricity in nanosized HfO2 crystals
Figure shows inside view of vacuum chamber in which the process of 'pulsed laser deposition' takes place, used to create the hafnium oxide crystals in this study. On the left the glowing substrate on which the film is growing with atomic control; in the center the blue plasma of ions that is created by shooting a laser on a target with the right chemical composition (target visible on the right side of the figure). | Photo Henk Bonder, University of Groningen
Ferroelectric materials have a spontaneous dipole moment which can point up or down. This means that they can be used to store information, just like magnetic bits on a hard disk. The advantage of ferroelectric bits is that they can be written at a low voltage and power. Magnetic bits require large currents to create a magnetic field for switching, and thus more power. However, according to the scientific community, the aligned dipoles in ferroelectric materials are only stable in fairly large groups; thus, shrinking the crystals results into the loss of dipole moment obstructing ferroelectricity based storage devices.
Nevertheless, eight years ago, the first publication by ex-Qimonda experts and researchers from Fraunhofer and RWTH Aachen (Appl. Phys. Lett. 99, 102903 (2011); https://doi.org/10.1063/1.3634052) announced that hafnium oxide thin films were ferroelectric when thinner than ten nanometres and that thicker films actually lost their ferroelectric properties. This triggered many groups across the globe to dig deeper and confirm the claim of researchers from NamLab. Noheda and her group at University of Groningen was also one of them. Since the ferroelectric hafnium oxide samples used in the study carried out at NaMLab were polycrystalline and showed multiple phases, obscuring any clear fundamental understanding of such an unconventional phenomenon, Noheda and her group decided to study these crystals by growing clean (single-phase) films on a substrate.
Using X-ray scattering and high-resolution electron microscopy techniques, the group observed that very thin films (under ten nanometres) grow in an entirely unexpected and previously unknown polar structure, which is necessary for ferroelectricity. Combining these observations with meticulous transport measurements, they confirmed that the material was indeed ferroelectric. Surprisingly, they noticed that the crystal structure changed when the layers exceeded 10 nm, thus reaching the same conclusion as of the Namlab.
In the substrate that UG researchers used, the atoms were a little bit closer than those in hafnium oxide which strained hafnium oxide crystals a little. Moreover, at a very small size, particles have a very large surface energy, creating pressures of up to 5 GPa in the crystal. This altogether forces a different crystal arrangement and in turn polar phase in the HfO2 film.
One contradicting finding of the UG researchers is that the HfO2 crystals do not need a ‘wake-up’ cycle to become ferroelectric. The thin films investigated at NamLab turned ferroelectric only after going through a number of switching cycles (wake-up cycles) needed to align the dipoles in “uncleaned” samples grown via other techniques. In case of the pulsed laser deposition setup and the substrate used at UG, the alignment is already present in the crystals.
Meanwhile, NaMLab has explored ferroelectric properties in atomic layer deposition (ALD) based thin-films of doped HfO2, and has achieved revolutionary results (LINK). A variety of dopant materials (Si, Al, Ge, Y, Gd, La and Sr) with a crystal radius ranging from 50 to 130 pm has been studied in addition to a mixed Hf1-xZrxO2. The aim is to develop a memory concept with the HfO2 based ferroelectric transistors (FeFET) as building blocks. The FeFET is a long-term contender for an ultra-fast, low-power and non-volatile memory technology. In these devices the information is stored as a polarization state of the gate dielectric and can be read non-destructively as a shift of the threshold voltage. The advantage of a FeFET memory compared to the Flash memory is its faster access times and much lower power consumption at high data rates. In the framework of a project together with GLOBALFOUNDRIES and Fraunhofer IPMS, which was funded by the Free State of Saxony, a one-transistor (1T) FeFET eNVM was successfully implemented at NaMLab in a 28 nm gate-first super low power (28SLP) CMOS technology platform using only two additional structural masks (LINK). The electrical baseline properties remain the same for the FeFET integration, demonstrating the feasibility of FeFET as low-cost eNVM.
Guest Blog by: Abhishekkumar Thakur, Fraunhofer IKTS / TU Dresden
Location: Dresden, Germany
LinkedIn: www.linkedin.com/in/abhishekkumar-thakur-16081991
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