Effect of film thickness on the ferroelectric and dielectric properties of low-temperature (400 °C) Hf0.5Zr0.5O2 films

Kim, Si Joon; Mohan, Jaidah; Lee, Jaebeom; Lee, Joy S.; Lucero, Antonio T.; Young, Chadwin D.; Colombo, Luigi; Summerfelt, Scott R.; San, Tamer; Kim, Jiyoung

doi:10.1063/1.5026715

Cited by 128 publications

(118 citation statements)

References 16 publications

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“…In addition, the thickness of each layer, including the HZO film (10 nm) and the TiN top and bottom electrodes (90 nm), was confirmed by cross-sectional transmission electron microscopy (see Figure 1 ). These thickness values were chosen deliberately so as to obtain excellent ferroelectric properties as reported in previous studies [ 2 , 16 ]. Based on this conventional process, the effect of TiN top and bottom electrodes on ferroelectric HZO films was investigated by changing the order of the RTA process and/or performing an additional furnace annealing in hydrogen-containing ambience for 30 min at 400 °C (i.e., FGA).…”

Section: Methodsmentioning

confidence: 99%

A Comprehensive Study on the Effect of TiN Top and Bottom Electrodes on Atomic Layer Deposited Ferroelectric Hf0.5Zr0.5O2 Thin Films

et al. 2020

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The discovery of ferroelectricity in HfO2-based materials in 2011 provided new research directions and opportunities. In particular, for atomic layer deposited Hf0.5Zr0.5O2 (HZO) films, it is possible to obtain homogenous thin films with satisfactory ferroelectric properties at a low thermal budget process. Based on experiment demonstrations over the past 10 years, it is well known that HZO films show excellent ferroelectricity when sandwiched between TiN top and bottom electrodes. This work reports a comprehensive study on the effect of TiN top and bottom electrodes on the ferroelectric properties of HZO thin films (10 nm). Investigations showed that during HZO crystallization, the TiN bottom electrode promoted ferroelectric phase formation (by oxygen scavenging) and the TiN top electrode inhibited non-ferroelectric phase formation (by stress-induced crystallization). In addition, it was confirmed that the TiN top and bottom electrodes acted as a barrier layer to hydrogen diffusion into the HZO thin film during annealing in a hydrogen-containing atmosphere. These features make the TiN electrodes a useful strategy for improving and preserving the ferroelectric properties of HZO thin films for next-generation memory applications.

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Section: Methodsmentioning

confidence: 99%

A Comprehensive Study on the Effect of TiN Top and Bottom Electrodes on Atomic Layer Deposited Ferroelectric Hf0.5Zr0.5O2 Thin Films

et al. 2020

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“…This ratio can be easily realized using common deposition techniques like atomic layer deposition (ALD) with a homogenous concentration throughout the film. 2) The FE properties of HZO films can be achieved at low process temperatures of about 400 °C . This is most likely due to the low crystallization temperature of ZrO 2 compared with other potential high‐k oxides .…”

Section: Introductionmentioning

confidence: 99%

“…It was shown that thin HZO films could be crystallized successfully in the desired FE phase by applying rapid thermal annealing (RTA) at 400 °C and even 300 °C for 30 or 60 s. Furthermore, phase transition kinetics were studied (at prior RTA crystallized films) during supplementary annealing at different temperatures and durations to simulate the thermal profile present during the formation of the interconnects, where high‐temperature processes (up to 400 °C) occur several times and last from some minutes to hours.…”

Section: Introductionmentioning

confidence: 99%

Back‐End‐of‐Line Compatible Low‐Temperature Furnace Anneal for Ferroelectric Hafnium Zirconium Oxide Formation

Lehninger

Olivo

Ali

et al. 2020

Physica Status Solidi (a)

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The discovery of ferroelectricity in thin doped hafnium oxide films revived the interest in ferroelectric (FE) memory concepts. Zirconium‐doped hafnium oxide (HZO) crystallizes at low temperatures (e.g., 400 °C), which makes this material interesting for the implementation of FE functionalities into the back end of line (BEoL). So far, the FE phase of prior amorphous HZO films is achieved by using a dedicated rapit thermal annealing (RTA) treatment. However, herein, it is shown that this dedicated anneal is not needed. A sole furnace treatment given by the thermal budget present during the interconnect formation is sufficient to functionalize even ultrathin 5 nm HZO films. This result helps to optimize the integration sequence of HZO films (e.g., involving a minimum number of BEoL process steps), which saves process time and fabrication costs. Herein, metal–FE–metal capacitors with Hf0.5Zr0.5O2 films of different thicknesses (5–20 nm) are fabricated annealed at 400 °C for various durations within different types of ovens (RTA and furnace). Structural and electrical characterization confirms that all furnace‐annealed samples have similar X‐ray diffraction patterns, remanent polarization, endurances, and thickness dependencies as RTA‐annealed ones. With respect to remanent polarization, leakage current, and endurance, the HZO film of 10 nm thickness shows the most promising results for the integration into the BEoL.

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“…In contrast, the tetrakis[dimethylamino]hafnium (TDMAH) and tetrakis[dimethylamino]zirconium (TDMAZ) precursors, which have also been used to deposit the FE HZO films [21][22][23][24], have only methyl groups in their ligands. Therefore, such an adverse effect might not be serious, although the complete suppression of the thermal decomposition cannot be guaranteed.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study on the Ferroelectric Performances in Atomic Layer Deposited Hf0.5Zr0.5O2 Thin Films Using Tetrakis(ethylmethylamino) and Tetrakis(dimethylamino) Precursors

et al. 2020

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The chemical, physical, and electrical properties of the atomic layer deposited Hf 0.5 Zr 0.5 O 2 thin films using tetrakis(ethylmethylamino) (TEMA) and tetrakis(dimethylamino) (TDMA) precursors are compared. The ligand of the metal-organic precursors strongly affects the residual C concentration, grain size, and the resulting ferroelectric properties. Depositing Hf 0.5 Zr 0.5 O 2 films with the TDMA precursors results in lower C concentration and slightly larger grain size. These findings are beneficial to grow more ferroelectric-phase-dominant film, which mitigates its wake-up effect. From the wake-up test of the TDMA-Hf 0.5 Zr 0.5 O 2 film with a 2.8 MV/cm cycling field, the adverse wake-up effect was well suppressed up to 10 5 cycles, with a reasonably high double remanent polarization value of 40 μC/cm 2. The film also showed reliable switching up to 10 9 cycles with the 2.5 MV/cm cycling field without involving the wake-up effect but with the typical fatigue behavior.

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Effect of film thickness on the ferroelectric and dielectric properties of low-temperature (400 °C) Hf0.5Zr0.5O2 films

Cited by 128 publications

References 16 publications

A Comprehensive Study on the Effect of TiN Top and Bottom Electrodes on Atomic Layer Deposited Ferroelectric Hf0.5Zr0.5O2 Thin Films

A Comprehensive Study on the Effect of TiN Top and Bottom Electrodes on Atomic Layer Deposited Ferroelectric Hf0.5Zr0.5O2 Thin Films

Back‐End‐of‐Line Compatible Low‐Temperature Furnace Anneal for Ferroelectric Hafnium Zirconium Oxide Formation

A Comparative Study on the Ferroelectric Performances in Atomic Layer Deposited Hf0.5Zr0.5O2 Thin Films Using Tetrakis(ethylmethylamino) and Tetrakis(dimethylamino) Precursors

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