Thickness Scaling of AFE-RAM ZrO<sub>2</sub> Capacitors with High Cycling Endurance and Low Process Temperature

Lomenzo, Patrick D.; Slesazeck, Stefan; Mikolajick, Thomas

doi:10.1109/imw48823.2020.9108146

Cited by 6 publications

(7 citation statements)

References 17 publications

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“…Such reversible electric field-induced phase transitions explain the nonlinear polarization-voltage characteristics so often found in the double-hysteresis loop behavior of ZrO 2 . [19][20][21][22][23][24][25] The first-order nature of the phase transition is predicted by Landau theory and supported by experimental observations of temperatureinduced phase transitions of the ferroelectric o-phase to the nonpolar t-phase. [18,26,27] The electric field-induced phase transitions generating AFE behavior, however, have remained hidden from view despite theoretical and supporting experimental evidence.…”

Section: Introductionmentioning

confidence: 85%

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Lomenzo

Collins

Ganser

et al. 2023

Adv Funct Materials

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The emergence of ferroelectric and antiferroelectric properties in the semiconductor industry's most prominent high‐k dielectrics, HfO2 and ZrO2, is leading to technology developments unanticipated a decade ago. Yet the failure to clearly distinguish ferroelectric from antiferroelectric behavior is impeding progress. Band‐excitation piezoresponse force microscopy and molecular dynamics are used to elucidate the nanoscale electric field‐induced phase transitions present in ZrO2‐based antiferroelectrics. Antiferroelectric ZrO2 is clearly distinguished from a closely resembling pinched La‐doped HfO2 ferroelectric. Crystalline grains in the range of 3 – 20 nm are imaged independently undergoing reversible electric field induced phase transitions. The electrically accessible nanoscale phase transitions discovered in this study open up an unprecedented paradigm for the development of new nanoelectronic devices.

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Section: Introductionmentioning

confidence: 85%

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Lomenzo

Collins

Ganser

et al. 2023

Adv Funct Materials

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“…Ferroelectric HfO 2 is extensively characterized in standard device structures such as MFM, MFS, and metal–ferroelectric–insulator–semiconductor (MFIS). There are several reports in the literature describing the properties of HZO films at various ZrO 2 concentrations in classic MFM structures including the now well-established FE-AFE transition. ,,, By increasing the ZrO 2 concentration, the permittivity of the film is increased, and the thermal processing temperature required is expected to decrease as ZrO 2 has a lower crystallization and transition temperature than HfO 2 . ,, Another promising property for AFE-based memories are relatively low coercive fields E C , enabling lower operating voltages, leading to reduced power consumption and electrical stress, as well as better endurance compared to purely ferroelectric HZO. − In this work, we study HZO-based ferroelectric MFS and MFIS capacitors on InAs with varying ZrO 2 concentrations, where we focus on the FE-AFE transition and the electrical properties, comparing it with that of standard MFM structures. An interfacial layer (IL) of approximately 1.2 nm-thin Al 2 O 3 between the HZO and InAs is included as an insulator in the MFIS structure and compared alongside the MFS devices.…”

Section: Introductionmentioning

confidence: 99%

“… 8 , 17 , 18 Another promising property for AFE-based memories are relatively low coercive fields E C , enabling lower operating voltages, leading to reduced power consumption and electrical stress, as well as better endurance compared to purely ferroelectric HZO. 19 − 21 In this work, we study HZO-based ferroelectric MFS and MFIS capacitors on InAs with varying ZrO 2 concentrations, where we focus on the FE-AFE transition and the electrical properties, comparing it with that of standard MFM structures. An interfacial layer (IL) of approximately 1.2 nm-thin Al 2 O 3 between the HZO and InAs is included as an insulator in the MFIS structure and compared alongside the MFS devices.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric-Antiferroelectric Transition of Hf_1–xZr_xO₂ on Indium Arsenide with Enhanced Ferroelectric Characteristics for Hf_0.2Zr_0.8O₂

Dahlberg

Persson

Athle

et al. 2022

ACS Appl. Electron. Mater.

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The ferroelectric (FE)−antiferroelectric (AFE) transition in Hf 1−x Zr x O 2 (HZO) is for the first time shown in a metal−ferroelectric−semiconductor (MFS) stack based on the III-V material InAs. As InAs displays excellent electron mobility and a narrow band gap, the integration of ferroelectric thin films for nonvolatile operations is highly relevant for future electronic devices and motivates further research on ferroelectric integration. When increasing the Zr fraction x from 0.5 to 1, the stack permittivity increases as expected, and the transition from FE to AFE-like behavior is observed by polarization and current−voltage characteristics. At x = 0.8 the polarization of the InAsbased stacks shows a larger FE-contribution as a more open hysteresis compared to both literature and reference metal−ferroelectric−metal (MFM) devices. By field-cycling the devices, the switching domains are studied as a function of the cycle number, showing that the difference in FE−AFE contributions for MFM and MFS devices is stable over switching and not an effect of wake-up. The FE contribution of the switching can be accessed by successively lowering the bias voltage in a proposed pulse train. The possibility of enhanced nonvolatility in Zr-rich HZO is relevant for device stacks that would benefit from an increase in permittivity and a lower operating voltage. Additionally, an interfacial layer (IL) is introduced between the HZO film and the InAs substrate. The interfacial quality is investigated as frequency-dependent capacitive dispersion, showing little change for varying ZrO 2 concentrations and with or without included IL. This suggests material processing that is independently limiting the interfacial quality. Improved endurance of the InAs-Hf 1−x Zr x O 2 devices with x = 0.8 was also observed compared to x = 0.5, with further improvement with the additional IL for Zr-rich HZO on InAs.

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“…Sub-15nm thick ZrO 2 AFE films spurred on the creation of a new nonvolatile memory (NVM) called antiferroelectric random access memory (AFERAM) that operates identically to FeRAM, has promising endurance properties (>10 10 cycles), and has potential for comparatively lower operating voltages [7]- [11]. An AFE material lacks a remanent polarization (P r ) in a conventional symmetric metal-insulator-metal (MIM) capacitor, which was presumed to exclude AFEs from use in nonvolatile memories.…”

mentioning

confidence: 99%

“…Building on the efforts of the first demonstrations of ZrO 2 AFERAM [8]- [10], a subsequent investigation evaluated backend-of-line (BEOL) compatible processes with a thermal budget as low as 350 • C and a scaled ZrO 2 film thickness down to 4.3 nm [11]. Scaling the ZrO 2 thickness from 10 to 4.3 nm in the BEOL process was required to yield a similar memory window (MW) and operating voltage comparable to the high temperature (800 • C) AFERAM process first reported.…”

mentioning

confidence: 99%

Memory Window Enhancement in Antiferroelectric RAM by Hf Doping in ZrO₂

Lomenzo

Pintilie

et al. 2022

IEEE Electron Device Lett.

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Antiferroelectric random access memory (AFERAM) is one of the newest alternative non-volatile memory technologies to emerge in recent years. ZrO 2 -based antiferroelectric films are exceptionally well-suited for memory applications with very high cycling endurance (>10 10 ) and low operating voltages (<2 V). Lightly alloying ZrO 2 with HfO 2 is performed to assess AFERAM device performance with back-end-of-line compatible thin film Zr 1-x Hf x O 2 (x ≤ 0.13) capacitors. The transition fields associated with antiferroelectric behavior are reduced with more Hf incorporation, yielding a larger magnitude switching polarization and memory window. Cycling endurance beyond 10 10 cycles is conducted on thin film capacitors where wake-up in AFERAM first leads to an increase, then a decrease in the memory window at a cumulative cycle number found to be dependent on the amount of Hf-incorporation. Hf-incorporation into ZrO 2 is demonstrated to be a feasible way to improve the memory window in ZrO 2 -based AFERAM.

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Thickness Scaling of AFE-RAM ZrO₂ Capacitors with High Cycling Endurance and Low Process Temperature

Cited by 6 publications

References 17 publications

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Ferroelectric-Antiferroelectric Transition of Hf_1–xZr_xO₂ on Indium Arsenide with Enhanced Ferroelectric Characteristics for Hf_0.2Zr_0.8O₂

Memory Window Enhancement in Antiferroelectric RAM by Hf Doping in ZrO₂

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Thickness Scaling of AFE-RAM ZrO2 Capacitors with High Cycling Endurance and Low Process Temperature

Cited by 6 publications

References 17 publications

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO2

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO2

Ferroelectric-Antiferroelectric Transition of Hf1–xZrxO2 on Indium Arsenide with Enhanced Ferroelectric Characteristics for Hf0.2Zr0.8O2

Memory Window Enhancement in Antiferroelectric RAM by Hf Doping in ZrO₂

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Thickness Scaling of AFE-RAM ZrO₂ Capacitors with High Cycling Endurance and Low Process Temperature

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Discovery of Nanoscale Electric Field‐Induced Phase Transitions in ZrO₂

Ferroelectric-Antiferroelectric Transition of Hf_1–xZr_xO₂ on Indium Arsenide with Enhanced Ferroelectric Characteristics for Hf_0.2Zr_0.8O₂