A Thousand State Superlattice(SL) FEFET Analog Weight Cell

Aabrar, Khandker Akif; Kirtania, Sharadindu Gopal; Lu, Anni; Khanna, Abhishek; Chakraborty, Wriddhi; Jose, Matthew San; Yu, Shimeng; Datta, Suman

doi:10.1109/vlsitechnologyandcir46769.2022.9830333

Cited by 8 publications

(4 citation statements)

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“…The accumulation of charged defects and charge trapping/detrapping processes at the interface between the electrode and HZO are the primary root causes of polarization fatigue and Pr variation after field cycling [50]. Reducing the overlap between each intermediate polarization state is crucial for multi-level cell (MLC) operation [51][52][53]. Figure 6(a) illustrates the endurance data of process A and process B3 under eight different write biases (from −0.5 to −2 V).…”

Section: Reliable Triple-level Cell Operationmentioning

confidence: 99%

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Wang,

Liu,

Chen

et al. 2024

Nanotechnology

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A novel defect control approach based on laminated HfO2/ZrO2 with multifunctional TiN/Mo/TiOxNy electrode is proposed to significantly improve the endurance and data retention in HZO-based ferroelectric capacitor. The O-rich interface reduces leakage current and prolong the endurance up to 1E11 cycles while retaining a 2Pr value of 34 (μC/cm^2) at 3.4MV/cm. Using first-principles calculations and experiments, we demonstrate that the enhancement of endurance is ascribed to the higher migration barrier of oxygen vacancies within the laminated HZO film and higher work function of MoOx/TiOxNy between top electrode and the insulating oxide. This 2.5-nm-thick TiOxNy barrier further increase the grain size of HZO, lowering the activation field and thus improving polarization reversal speed. This interfacial layer further decreases the overall capacitance, increases the depolarization field, thereby enhancing the data retention. By fitting the data using the Arrhenius equation, we demonstrate a 10-year data retention is achieved at 109.6 °C, surpassing traditional SS-HZO of 78.2 °C with a 450°C RTA (required by backend-of-the-line). This work elucidates that interfacial engineering serves as a crucial technology capable of resolving the endurance, storage capability, and high-temperature data retention issues for ferroelectric memory.

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Section: Reliable Triple-level Cell Operationmentioning

confidence: 99%

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Wang,

Liu,

Chen

et al. 2024

Nanotechnology

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“…Hafniabased superlattices were investigated to tailor the distribution of coercive fields for non-volatile memory applications, [40] and to increase the domain density. [41] In general, ferroelectric oxide superlattices are still relatively unexplored but are an exciting playground for the investigation of exotic phenomena [42] such as topological effects. [43] The manuscript is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

“…[ 38 ] Epitaxial relationship between Hf‐rich and Zr‐rich nanolayers was observed in ALD‐deposited nanolaminates, [ 39 ] also referred to as “superlattices.” Hafnia‐based superlattices were investigated to tailor the distribution of coercive fields for non‐volatile memory applications, [ 40 ] and to increase the domain density. [ 41 ] In general, ferroelectric oxide superlattices are still relatively unexplored but are an exciting playground for the investigation of exotic phenomena [ 42 ] such as topological effects. [ 43 ]…”

Section: Introductionmentioning

confidence: 99%

Back‐End‐of‐Line Integration of Synaptic Weights using HfO₂/ZrO₂ Nanolaminates

Bégon‐Lours,

Slesazeck,

Falcone

et al. 2024

Adv Elect Materials

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In artificial neural networks, the “synaptic weights” connecting the neurons are adjusted during the training. Beyond silicon, functionalizing the back‐end‐of‐line (BEOL) of CMOS circuits with novel materials is a key enabler for deploying neural network accelerators. The hardware implementation of the synaptic weights requires linear and reprogrammable resistive elements. In ferroelectric tunnel junctions, the resistance is programmed by controlling the configuration of the ferroelectric domains with electrical pulses. From ferroelectric HfZrO4 to HfO2–ZrO2 nanolaminates (NL), the crystallization temperature lowers below the upper limit of 400 °C required for CMOS BEOL. The device footprint is reduced, and the maximum‐to‐minimum conductance ratio increases from 7 to 32. Operated with pulses in the ultra‐fast (20 ns) and biological (500 µs) timescales, the synaptic plasticity exhibits several regimes. Dynamic hysteresis mode characterization after up to 1011 switching cycles indicates the coexistence of ferroelectric and non‐ferroelectric effects such as defect rearrangement. Temperature‐dependent transport measurements in the Ohmic (linear) regime support these conclusions. Multi‐level resistive switching is achieved in HfO2–ZrO2 NL co‐integrated to CMOS in the BEOL. 1T‐1R operation is demonstrated, paving the way for hardware implementation of synaptic weights for in‐memory neuromorphic computing.

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“…The impact of ∆Id D2D increases with scaling and the memory array size [3,16]. Although multi-level FeFETs have been demonstrated recently [15,17,18], they were limited to a standalone device, and in some cases, the reported channel current necessitates very complex and expensive read circuits. Previously, an effective reduction of ∆Id D2D on a 300mm wafer was reported by shunting an external resistor at the drain terminal of the FeFETs [16].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of Multiply-Accumulate Operation With 28 nm FeFET Crossbar Array

Müller

Laleni

et al. 2022

IEEE Electron Device Lett.

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A Thousand State Superlattice(SL) FEFET Analog Weight Cell

Cited by 8 publications

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Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Back‐End‐of‐Line Integration of Synaptic Weights using HfO₂/ZrO₂ Nanolaminates

Demonstration of Multiply-Accumulate Operation With 28 nm FeFET Crossbar Array

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A Thousand State Superlattice(SL) FEFET Analog Weight Cell

Cited by 8 publications

References 0 publications

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO2/ZrO2 ferroelectric capacitors towards long endurance and high temperature retention

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO2/ZrO2 ferroelectric capacitors towards long endurance and high temperature retention

Back‐End‐of‐Line Integration of Synaptic Weights using HfO2/ZrO2 Nanolaminates

Demonstration of Multiply-Accumulate Operation With 28 nm FeFET Crossbar Array

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Product

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Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Tunable defect engineering of Mo/TiON electrode in angstrom-laminated HfO₂/ZrO₂ ferroelectric capacitors towards long endurance and high temperature retention

Back‐End‐of‐Line Integration of Synaptic Weights using HfO₂/ZrO₂ Nanolaminates