T. Ali

T. Ali
Fraunhofer Institute for Photonic Microsystems IPMS | IPMS · Center Nanoelectronic Technologies (IPMS-CNT)

M.Sc. in Nanoscience and Nanotechnology

About

69
Publications
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614
Citations

Publications

Publications (69)
Article
Full-text available
This paper reports 2bits/cell ferroelectric FET (FeFET) devices with 500 ns write pulse of maximum amplitude 4.5V for inference-engine applications. FeFET devices were fabricated using GlobalFoundries 28nm high-k-metal-gate (HKMG) process flow on a 300mm wafer. The devices were characterized, and statistical modeling of variations in the fabricated...
Article
Full-text available
Ferroelectric (FE) and antiferroelectric (AFE) materials are used for several memory-related and energy-related applications. Perovskite materials (e.g., bulk ceramics) remain the most common materials for many applications. However, due to large deposition thickness, these materials are not appropriate for future miniaturized devices. In 2011, FE...
Article
Full-text available
Ferroelectric hafnium oxide is of major interest for a multitude of applications in microelectronics, ranging from neuromorphic devices to actuators and sensors. While the electrical performance is commonly discussed in depth, the influence of the microstructure is often disregarded. However, in recent years more and more research groups shed light...
Conference Paper
In our work we describe and demonstrate an alternative approach of integrating 1T-1C FeFET having separated transistor (1T) without modifying frontend CMOS technology and an additional gate-coupled ferroelectric (FE) capacitor (1C) embedded in the interconnect layers. Starting from the results of FE capacitor integration and 1T-1C single cell chara...
Conference Paper
Study on the effect of nanosecond laser anneal (NLA) induced crystallization of ferroelectric (FE) Si-doped hafnium oxide (HSO) material is reported. The laser energy density (0.3 J/cm2 to 1.3 J/cm2) and pulse count (1.0 to 30) variations are explored as pathways for the HSO based metal-ferroelectric-metal (MFM) capacitors. The increase in energy d...
Conference Paper
Recently, hafnium oxide based ferroelectric memories gained great attention due to good scalability, high speed operation, and low power consumption. In contrast to the FRAM concept, the FeFET offers non-destructive read-out. However, the integration of the FeFET into an established CMOS technology entails several challenges. Herein, an 1T1C FeFET...
Conference Paper
HfO2-based ferroelectric FETs (FeFETs) offer excellent retention, scalability, and memory window. However, achieving high endurance is still challenging. Here, a fluorination treatment is presented that enables significant endurance and device stability improvement. Noise and charge pumping methods are applied to obtain deeper understanding of the...
Conference Paper
We report ferroelectric (FE) laminate HSO/HZO MFMIS FeFETs. An MFM/MIS area ratio control enables low voltage operation and 10 5 endurance. FE lamination (2 × 10 nm, 4 × 5 nm) and low FE anneal reduce the FeFET variability. Impact of the stack (MFMIS), material type/lamination, and FE anneal are studied for enhanced FeFET reliability and reduced va...
Preprint
div>This paper reports high precision, highly linear MAC operation conducted on 28nm ferroelectric (Fe) FET (FeFET) based 4Kb computing-in-memory (CIM) core with 1FeFET-1T structure. The CIM-macro consists of 4 Kbit ultra-high precision FeFET based synaptic core, ADCs, and peripheral components for data processing. The crossbar array in the synapti...
Conference Paper
Hafnium oxide-based ferroelectric tunnel junctions (FTJs) are novel nonvolatile memory devices with promising advantages such as non-destructive readout in comparison to conventional ferroelectric random access memories (FRAMs). Reliability aspects of FTJ devices need to be investigated, including their endurance, retention, ferroelectric switching...
Conference Paper
In recent years various emerging memory concepts are in discussion for versatile application as low power solution in edge devices or as high performance memory in novel computing architectures. Among others, ferroelectric memories based on CMOS compliant hafnium oxide are promising candidates for fulfilling the application requirements. In our pap...
Article
Full-text available
The properties of hybrid ferroelectric (FE) and antiFE (AFE) films integrated in a single capacitor stack is reported. The stack lamination (4 × 5 nm) or (2 × 10 nm) using an Alumina (Al2O3) interlayer, material type (Si-doped HfO2 (HSO) and Zr doped HfO2 (HZO)), precursor condition (TEMA-Hf and Hf/ZrCl4), or dopant concentration (Si and Zr) are in...
Article
Full-text available
This work presents 2 bits/cell operation in deeply scaled ferroelectric finFETs (Fe-finFET) with 1µs write pulse of maximum ±5V amplitude and WRITE endurance above 109 cycles. Fe-finFET devices with single and multiple fins have been fabricated on SOI wafer using a gate first process, with gate lengths down to 70 nm and fin width 20 nm. Extrapolate...
Article
Nonvolatile memories especially the ferroelectric (FE)-based ones such as ferroelectric tunnel junctions (FTJs) and ferroelectric field-effect transistors (FeFETs) have recently attracted a lot of attention. FTJs have been intensively researched for the last decade and found to be very promising memory devices due to their significant nondestructiv...
Article
Full-text available
A novel system-on-a-chip compatible one-transistor one-capacitor ferroelectric random-access memory array (1T1C FeRAM) based on ferroelectric Hf0.5Zr0.5O2 with a capacitor under bitline (CUB) structure was experimentally demonstrated. The CUB structure facilitates the application of post-metallization annealing on metal/ferroelectric/metal capacito...
Article
Full-text available
Non-volatile memories based on ferroelectric hafnium oxide, especially the ferroelectric field-effect transistor (FeFET), have outstanding properties, e.g. for the application in neuromorphic circuits. However, material development has focused so far mainly on metal–ferroelectric–metal (MFM) capacitors, while FeFETs are based on metal–ferroelectric...
Article
In this article, we present the capacitance-voltage (C-V) characteristics of HfₓZr₁₋ₓO₂metal-ferroelectric-metal (MFM) thin-film capacitors with various Zr doping, thicknesses, and annealing temperatures. The influence of doping, electric field cycling, and annealing temperature on tuning characteristics (tunability) was analyzed and an optimized b...
Conference Paper
Hafnium oxide based ferroelectric FETs (FeFETs) are highly suitable for in-memory computing applications like neuromorphic hardware due to their CMOS compatibility, high dynamic range, low power consumption and good linearity. Device-to-device and die-to-die variability play an important role, especially due to the polycrystalline nature of ferroel...
Article
Full-text available
Zirconium-doped hafnium oxide (HZO) crystallizes at low temperatures and is thus ideal to implement ferroelectric (FE) functionalities into the back end of line (BEoL). Therefore, metal-ferroelectric-metal (MFM) capacitors are of great interest. Placed in the BEoL, they can be connected either to the drain- or the gate-contact of a standard logic d...
Article
Full-text available
Reliability is a central aspect of hafnium oxide-based ferroelectric field effect transistors (FeFETs), which are promising candidates for embedded non-volatile memories. Besides the device performance, understanding the evolution of the ferroelectric behaviour of hafnium oxide over its lifetime in FeFETs is of major importance for further improvem...
Article
Full-text available
A multi-level cell (MLC) operation as a 1–3 bit/cell of the FeFET emerging memory is reported by utilizing optimized Si doped hafnium oxide (HSO) and hafnium zirconium oxide (HZO) based on ferroelectric laminates. An alumina interlayer was used to achieve the thickness independent of the HSO and HZO-based stack with optimal ferroelectric properties...
Article
Full-text available
In this article, we investigate the capacitance–voltage (C–V) characteristics of $$\text {Hf}_{x}\text {Zr}_{1-x}\text {O}_{2}$$ Hf x Zr 1 - x O 2 metal-ferroelectric-metal (MFM) thin-film capacitors with various Zr doping for varactor applications. The impact of field cycling during the wake-up process on the capacitance was analyzed. In addition,...
Article
Full-text available
The discovery of ferroelectricity in the fluorite structure based hafnium oxide (HfO2) material sparked major efforts for reviving the ferroelectric field effect transistor (FeFET) memory concept. A Novel metal-ferroelectric-metal-ferroelectric-insulator-semiconductor (MFMFIS) FeFET memory is reported based on dual ferroelectric integration as an M...
Conference Paper
Advanced non-volatile memory concepts such as the 1T1C ferroelectric (FE) random-access memory (FeRAM) and the 1T1C FE field-effect transistor (FeFET) can be realized by connecting a metal-ferroelectric-metal (MFM) capacitor placed in the back end of line (BEoL) of a microchip to the drain and gate contacts of a standard logic device, respectively....
Conference Paper
Recently, ferroelectric field-effect transistors (Fe-FETs) based on hafnium oxide (HfO 2 ) have been shown to be promising candidates for synaptic devices in neuromorphic applications. The polycrystalline structure of the ferroelectric layer strongly impacts the memory storage as well as the synaptic device performance, especially for highly scaled...
Conference Paper
In this work, the tuning properties of hafnium zirconium oxide (HZO) metal-ferroelectric-metal (MFM) thin film varactors are investigated. It is shown that varactors with 1:1 Hf:Zr stoichiometry and 10 nm thickness, crystallized with rapid thermal annealing (RTA) at 400°C for 60 s, show a maximum capacitance tunability of 32% at room temperature wi...
Article
Full-text available
Thin-film transistors (TFTs) based on amorphous indium-gallium-zinc-oxide (a-IGZO) have attracted vast attention for use in organic light-emitting diode (AMOLED) displays due to their high electron mobility and large current on–off ratio. Although amorphous oxide semiconductors show considerably less threshold voltage (Vth) variation than poly-sili...
Article
Full-text available
In spite of the increasing use of machine learning techniques, in-memory computing and hardware have increased the interest to accelerate neural network operation. Henceforth, novel embedded nonvolatile memories (eNVMs) for highly scaled technology nodes, like ferroelectric field effect transistors (FeFETs), are heavily studied and very promising....
Article
Full-text available
The hafnium oxide (HfO2) material system offers a unique combination of outstanding physical properties, that enable a manifold of novel integrated ferroelectric, piezoelectric, and pyroelectric applications. Long‐term stability is an essential concern for non‐volatile memory devices, sensors, and nano‐electromechanical systems (NEMS). Here, we rep...
Article
A novel hybrid antiferroelectric (AFE)-based charge trap (CT) memory is reported focusing on an amplified tunnel oxide field (ETO) via the dynamic of an AFE hysteresis dipole switching. The role of dynamic permittivity increase and the saturated polarization at the instant of the write operation are explored for enhanced ETO. The hybrid CT concept...
Conference Paper
Full-text available
Content addressable memory (CAM) is widely used for data-centric computing for its massive parallelism and pattern matching capability. Though the CAM density has been improved by replacing the area-consuming SRAM with compact emerging nonvolatile memories (NVMs), its implementation has been limited to single level cell. To further boost the CAM de...
Conference Paper
Full-text available
This paper presents an efficient crossbar design and implementation intended for analog compute-in-memory (ACiM) acceleration of artificial neural networks based on ferroelectric FET (FeFET) technology. The novel mixed signal blocks presented in this work reduce the device-to-device variation and are optimized for low area, low power and high throu...
Conference Paper
Full-text available
We report on antiferroelectric (AFE) hybrid charge trap (CT) memory with amplified tunnel oxide field via dynamic AFE hysteresis dipole switching. Memory window (4.5V), switching speed (<1μs), 10 years retention, and 10^5 endurance are reported. The HSO/HZO with tailored (FE,AFE) hysteresis are explored for low power and high-speed-boosted CT memor...
Conference Paper
A Novel MFMFIS FeFET based on dual MFM/MFIS integration in a single gate stack is reported. The external top and bottom contacts, dual ferroelectric (FE) layers, and tailored MFM/MFIS area ratio (AFI) shows flexible stack tuning for improved FeFET performance. A tradeoff between maximized MFM voltage and weaker FET channel inversion is notable in t...
Conference Paper
Full-text available
Hafnium based ferroelectric field effect transistors (FeFETs) are expected to be influenced by a high defect density of thick gate ferroelectric hafnium oxide. In order to quantify this noise source, we optimized noise and defect density investigation methods with respect to stable erase and program states of FeFETs. Understanding defect states and...
Conference Paper
Full-text available
The novel thin-film ferroelectric material hafnium oxide has revived the interest into ferroelectric memory concepts, which is due to the fact, that it facilitates CMOS and BEoL compatible integration. A major requirement hereby is the stability of the ferroelectric layer towards ionizing radiation, such as gamma and heavy ion exposure. In this stu...
Conference Paper
Full-text available
The discovery of ferroelectricity in thin films of doped hafnium oxide has led to a renaissance of ferroelectric (FE) memory concepts. Compared to all inspected dopants, zirconium doped hafnium oxide (HZO) crystallizes at the lowest temperatures. Thus, this material system is ideal for the implementation of FE functionalities into the back-end-of-l...
Article
Long data retention is a critical requirement for many of the potential applications of HfO₂-based ferroelectric field-effect transistors (FeFETs). However, methods for its rapid assessment are still missing. In this article, we report a detailed investigation of the retention and switching properties of FeFETs fabricated in the 28-nm high-k metal...
Article
We report on the temperature-dependent operation of fluorite-structure-based ferroelectric FET (FeFET) emerging memory. A temperature range (-40 °C to 40 °C) is used to explore the FeFET characteristic relation to operating temperature. The memory window (MW) shows a modulated response that features a reciprocal MW dependence on temperature, such t...
Article
We report on the high-temperature operation and reliability of the Si-doped hafnium oxide (HSO) ferroelectric FET (FeFET) emerging memory. In this study, we explore the role of high-temperature operation of the ferroelectric (FE) material on the FeFET in the temperature range of 40-120 °C. The inverse memory window (MW) dependence on temperature le...
Conference Paper
Improved characteristics of ferroelectric Si:HfO2 (HSO) MFIS FeFETs by tuning the substrate implant doping concentration is reported. Shallow implant doping gives the possibility to control the FeFET readout range, whereas the deep implant affects the Ioff current, resulting in a higher Ion -Ioff current ratio. Additionally, the implant tuning impr...
Cover Page
Full-text available
Hafnium Zirconium Oxide Films So far, the ferroelectric phase of prior amorphous hafnium zirconium oxide (HZO) films is achieved by using rapid thermal annealing. In article number 1900840 by David Lehninger and co‐workers, it is shown that a dedicated annealing step is not needed for the integration of ferroelectric HZO films into the back‐end‐of‐...
Conference Paper
The impact of the ferroelectric (FE) wakeup phenomenon on the reliability of fluorite structure-based laminated Si-doped hafnium oxide (HSO) FeFET memory cells is reported. The post wakeup cycling shows a strong change in the optimal program/erase (PG/ER) write conditions. A shift towards lower PG/ER switching conditions at a higher memory window (...
Article
Full-text available
The microstructure of ferroelectric hafnium oxide plays a vital role for its application, e.g., non-volatile memories. In this study, transmission Kikuchi diffraction and scanning transmission electron microscopy STEM techniques are used to compare the crystallographic phase and orientation of Si and Zr doped HfO2 thin films as well as integrated i...
Article
Full-text available
The discovery of ferroelectricity in thin doped hafnium oxide films revived the interest in ferroelectric memory concepts. Zirconium doped hafnium oxide (HZO) crystalizes at low rapid thermal annealing (RTA) temperatures (e.g. 400°C), which makes this material interesting for the implementation of ferroelectric functionalities into the back‐end‐of‐...
Conference Paper
Full-text available
We report 1-3 bit/cell FeFET operation through optimized HSO and HZO ferroelectric laminate layers using alumina interlayers. Memory window up to 3.5V, switching speed of 300ns, 10 years retention, and 10^4 endurance are reported. The gate stack lamination merits are discussed with insight potential of FeFET as an MLC memory.
Article
Full-text available
The local crystal phase and orientation of ferroelectric grains inside TiN/Hf0.5Zr0.5O2/TiN have been studied by the analysis of the local electron beam scattering Kikuchi patterns, recorded in transmission. Evidence was found that the ferroelectric phase of the layers is derived from an orthorhombic phase, most likely of space group Pca21. The ori...
Conference Paper
Full-text available
The utilization of FeFET technology in NAND based architectures is dependent on the role of pass voltage disturb of pass cells during the readout of selected cells. This disturb effect becomes dependent on the FeFET stack parameters and potential optimization for a disturb free operation. In this paper, the impact of pass voltage on the disturb pro...
Presentation
Full-text available
Hardware based neuromorphic computing, which requires a synaptic memory capable of retaining a multitude of addressable conductance states, opens a possibility to bypass the von-Neumann bottleneck [1]. Ferroelectric field effect transistors (FeFETs) based on doped hafnium oxide have been demonstrated as viable candidates for neuromorphic synapses [...
Poster
Full-text available
Since the discovery of ferroelectricity in HfO2 thin films [1], it obtained great research interest for the implementation into various integrated devices e.g. non-volatile memories or infrared sensors, due to its CMOS compatibility. As the ferroelectricity in HfO2 is assigned to the orthorhombic Pca21 phase [2], its phase fraction and orientation...
Presentation
Full-text available
Hafnium oxide based ferroelectric FETs (FeFETs) have been demonstrated as a viable memory implementation of synapses for neuromorphic computing and deep learning [1]. For a neuromorphic implementation the synaptic memory is mandatory to retain a multitude of addressable conductance states in order to resemble the weight function. In FeFETs this is...
Article
We report for the first time the integration of silicon-doped hafnium oxide (HSO) antiferroelectric (AFE) material for enhanced floating-gate Flash memory speed by means of field-enhanced AFE polarization switching. An analytical description of the metal-ferroelectric-metal-insulator-semiconductor (MFMIS) stack physics during a write operation is i...
Conference Paper
Full-text available
In this paper, we give a perspective and recent overview of the emerging memory FeFET by shading the light on different aspects of the memory operation. The key fundamental questions related to material development, device scalability effects, utilization as multi-bit storage, write conditions, and memory endurance capability are overviewed based o...
Conference Paper
Full-text available
We report insight on the performance of a gate first MFIS-HfO2 FeFET memory using a SiO2 interface layer. The FeFET devices show FE switching characterized by VT distribution for program/erase states. The endurance and memory window characteristic shows the effect of interface layer permittivity and charge trapping on FeFET performance. A small rea...
Conference Paper
Full-text available
Within the recent years, we have seen a strongly increasing need for optimized hardware solutions to improve artificial intelligence (AI) systems. Current deep neural network (DNN) accelerators are hereby still employing volatile memory solutions like DRAM and SRAM. Non-volatile memory solutions based on crossbar architectures, so-called resistive...
Article
Full-text available
We report the integration of a ferroelectric (FE) silicon-doped hafnium oxide material in ferroelectric field-effect transistor (FeFET) devices fabricated with an optimized interfacial layer in a gate-first scheme. The effect of increasing the permittivity (k) value of the interface layer on the performance of the metal-ferroelectric-insulator-semi...
Conference Paper
Full-text available
We report for the first time the effect of altering the interfacial buffer layer on the performance of a hafnium zirconium oxide (HfZrO2) based FeFET. The performance of 10 nm HfZrO2 MFIS based FeFET devices with gate first integration is studied for a high permittivity SiON buffer layer and contrasted to a standard SiO2 interface. The utilization...
Article
Full-text available
The recent discovery of ferroelectricity in thin film HfO2 materials renewed the interest in ferroelectric FET (FeFET) as an emerging nonvolatile memory providing a potential high speed and low power Flash alternative. Here, we report more insight into FeFET performance by integrating two types of ferroelectric (FE) materials and varying their prop...
Conference Paper
The 2011 discovery of a ferroelectric phase in doped hafnium oxide [1] and hafnium zirconium oxide solid solution [2] re-established the competitiveness of ferroelectric memory technologies. Mainly driven by the outstanding scalability and CMOS-compatibility of this new ferroelectric material, classical concepts such as FRAM, FeFET and FTJ are reen...