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In this letter, a threshold switching (TS) selector with Ag doping-based nano-polycrystalline ZnO switching layer (SL) having (002) preferred orientation has been manifested, without incorporating an active Ag metal layer, using a facile co-sputtering deposition technique. The TS selectors with extremely controlled doping of ~0.14 at. % Ag concentration showed remarkable electroforming (EF)-free selection behavior such as gigantic selectivity (~1011), extreme-low off-current (~10 fA), high on-current density (~1.6 MA/cm2), ultra-steep switching slope (~0.8 mV/decade), satisfactory endurance (>106), fast switch-on speed (~38 ns) and relaxation speed (~64 ns), and high device yield (~90%). Furthermore, selector devices showed reproducible selection behavior with stable threshold voltage (Vth) having merely 8% variances.

Fibre metal laminates (FMLs) are layered materials based on stacking arrangements of metals and fibre reinforced plastic (FRP) composite laminates. These hybrid fibre metal laminates combine the advantages of both metallic materials and the reinforced hard and strong fibrous materials. A series of low velocity impact and tensile tests were carried out on the fabricated hybrid fibre metal laminates with different orientations and stacking sequences. Aluminium metal, carbon and glass fibres were the layers used for fabricating the hybrid composites and the fabrication was done by varying the position and orientation of the laminates and as well as the stacking sequences. The effect of the different stacking sequence of the metal laminates and the fibre layers on the impact and tensile strengths of the hybrid composites are studied. The stress-strain curve analyses were carried out for tensile properties, while the force-time and energy-time curves were analysed for impact charcteristics of the developed composites.

Leakage current, that causes interferences in the read/write operation, arising from neighboring unselected or half-selected memory cells is considered as one of the main hurdles to be overcome to ...

HfxZr1−xO2 (HZO) has been an attractive material for future ferroelectric memory devices because of their high scalability ~10 nm, stable ferroelectricity over a wide Hf:Zr composition range, and compatibility with CMOS manufacturing process. [1] Considering the ferroelectric device manufacturing, the stable ferroelectricity in the thicker film region is required. However, it has been reported that the ferroelectricity of HZO films is generally degraded in the thick ferroelectric film region > 10 nm. [2] To obtain the superior ferroelectricity in the thicker film region, we pay attention to the ferroelectricity of the HZO based thick ferroelectric structures (> 20 nm) with paraelectric HfO2 and anti-ferroelectric ZrO2 layers. In this work, we studied the ferroelectricity and fatigue properties of the thick HZO/ZrO2 and HZO/HfO2 stack structures fabricated using atomic layer deposition (ALD). The TiN/HZO/ZrO2/TiN capacitors were fabricated as follows: An HZO layer was deposited on TiN bottom electrode by ALD at 300 °C using (Hf/Zr)[N(C2H5)CH3]4 (Hf:Zr = 1:1) cocktail precursor and H2O gas. The thickness of the HZO layer were varied from 0 to 10 nm. Next, a 10-nm-thick ZrO2 layer was deposited at 300 °C using (C5H5)Zr[N(CH3)2]3 and H2O gas. After fabrication of HZO/ZrO2 bi-layer, post deposition annealing (PDA) was performed at 600 °C for 1 min in a N2 atmosphere. Finally, TiN top electrode was fabricated by DC sputtering. The capacitors with HZO single layer and HZO/HfO2 bi-layer were also prepared as references. Figure 1 shows the remanent polarization (2P r) of the HZO single layer, HZO/HfO2, and HZO/ZrO2 bi-layers from polarization-electric field (P-E) hysteresis curves as a function of the HZO thickness while the HfO2 and ZrO2 thicknesses were kept at 10 nm. The maximum 2P r (12 µC/cm2) of the HZO single layer was obtained when the thickness of the HZO layer was 10 nm. However, the 2P r of the HZO single layer gradually decreased with the HZO thickness due to the formation of the stable monoclinic phase which shows paraelectricity. [2] The ferroelectric properties of ZrO2 and HfO2 single layers were hardly observed because both layers exhibited anti-ferroelectricity and paraelectricity, respectively. The HZO/HfO2 bi-layer maintained extremely small 2P r regardless of the HZO thickness. On the other hand, the switching properties of HZO/ZrO2 bi-layer were divided into three regions such as anti-ferroelectricity in less than 12.5 nm, mixing phases of anti-ferroelectricity and ferroelectricity in 15 nm, and ferroelectricity in over 17.5 nm. The maximum 2P r of 11 µC/cm2 could be obtained in the 20-nm-thick of HZO/ZrO2 bi-layer, and was approximately 2 times larger than that (6 µC/cm2) of the 20-nm-thick HZO single layer. This superior ferroelectricity of the HZO/ZrO2 bi-layer may be due to the improvement of quality of the HZO layer and the transformation from anti-ferroelectric to ferroelectric phase in the ZrO2 layer. [3, 4] Figure 2 shows endurance properties of HZO (10 nm) single layer, HZO/ZrO2 (20 nm), and HZO/HfO2 (20 nm) bi-layers using positive-up negative-down (PUND) method. For the HZO single layer and the HZO/ZrO2 bi-layer cases, the wake-up effect was observed until 104 cycles, while the HZO/HfO2 bi-layer had small 2P r in the entire switching cycle region. The large difference of 2P r properties between the HZO layer and the HZO/ZrO2 bi-layer was observed in over 104 cycles. Noted that the HZO/ZrO2 bi-layer was larger 2P r than that in pristine condition after 106 cycles, while the 2P r of the HZO single layer was dropped by around 30%. Therefore, it is thought that ZrO2 layer play an important role in preventing the HZO/ZrO2 bi-layer from the degradation of ferroelectricity. In conclusion, the thick HZO/ZrO2 bi-layer exhibited superior ferroelectricity and endurance properties compared to the HZO/HfO2 bi-layer and thin HZO single layer. Based on these results, the HZO/ZrO2 bi-layer using the combination of HZO and ZrO2 layers is one of the promising structures for future ferroelectric devices application. This study was partially supported by JSPS KAKENHI (JP18J22998 and K4H002). The authors thank all staff members of the Nanofabrication Group of NIMS for their support in fabricating the MFM capacitors. [1] J. Müller et al., Nano Lett. 12, 4318 (2012). [2] M. H. Park et al., Appl. Phys. Lett. 102, 242905 (2013). [3] T-.Y. Hsu et al., Smart Mater. Struct. 28, 084005 (2019). [4] S. Shibayama et al., Jpn. J. Appl. Phys. 59, SMMA04 (2020). Figure 1

Hexagonal boron nitride (h-BN) has been considered a promising dielectric for two-dimensional (2D) material-based electronics due to its atomically smooth and charge-free interface with an in-plane lattice constant similar to that of graphene. Here, we report atomic layer deposition of boron nitride (ALD-BN) using BCl3 and NH3 precursors directly on thermal SiO2 substrates at a relatively low temperature of 600 °C. The films were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and transmission electron microscopy wherein the uniform, atomically smooth, and nanocrystalline layered-BN thin film growth is observed. The growth rate is ∼0.042 nm/cycle at 600 °C, a temperature significantly lower than that of h-BN grown by chemical vapor deposition. The dielectric properties of the ALD-BN measured from Metal Oxide Semiconductor Capacitors are comparable with that of SiO2. Moreover, the ALD-BN exhibits a 2-fold increase in carrier mobility of graphene field effect transistors (G-FETs/ALD-BN/SiO2) due to the lower surface charge density and inert surface of ALD-BN in comparison to that of G-FETs fabricated on bare SiO2. Therefore, this work suggests that the transfer-free deposition of ALD-BN on SiO2 may be a promising candidate as a substrate for high performance graphene devices.

Integrating the HfZrO2 (HZO) on silicon have attracted the attention of researches in the development of ferroelectric field effect transistor (FeFETs) for implementation in high-density memories and neuromorphic devices[1][2]. In this work, it has been investigated the thickness scalability of HZO thin films and the reduction of the equivalent-oxide-thickness (EOT) on Silicon using [(CH3)2N]4Hf and [(CH3)2N]4Zr as precursor and H2O and O3 as oxidants by means of atomic layer deposition. A TiN/HZO/Si structure was fabricated where the Si substrate has been prepared with a HF-last clean to remove the native oxide or SC1-last clean process to form a chemical oxide layer of 1.2nm. The EOT vs thickness analysis shows an interesting alteration in the dielectric constant which is understood as a phase formation in the HZO from the amorphous to the ferroelectric o-phase to be found in the 4 to 5nm region when annealed at 400 °C. Also, the interface thickness between silicon and HZO was reduced when the HZO is scaled down below the transition region and it is confirmed by transmission electron microscopy (TEM). This reduction in the interface is expressed as scavenging effects from the TiN top electrode when the samples are annealed at 400 °C. [1] J. Y. Kim, M.-J. Choi, and H. W. Jang, “Ferroelectric field effect transistors: Progress and perspective” APL Mater., 9, 021102 (2021) [2] E. T. Breyer, H. Mulaosmanovic, T. Mikolajick, and S. Slesazeck, “Perspective on ferroelectric, hafnium oxide based transistors for digital beyond von-Neumann computing,” Appl. Phys. Lett, 118, 050501 (2021)

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.

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.

Increasing interest in the development of alternative energy storage technologies has led to efforts being taken to improve the energy density of dielectric capacitors with high power density. However, dielectric polymer materials still have low energy densities because of their low dielectric constant, whereas Pb-based materials are limited by environmental issues and regulations. Here, the energy storage behaviors of atomic layer-deposited Hf1- XZr XO2 ( X = 0-1) thin films (10 nm) and the phase transformation mechanism associated with an enhancement of their energy density are reported using unipolar pulse measurements. Based on electrical and material characterization, the energy density and energy efficiency are dependent on the Zr content, and stress-induced crystallization by the encapsulating Hf1- XZr XO2 films with TiN top electrodes prior to annealing can enhance the energy density (up to 47 J/cm3 at a small voltage value of 3.5 MV/cm) while minimizing energy loss even at low process temperatures (400 °C). This work will facilitate the realization of Hf1- XZr XO2-based capacitors for lead-free electrostatic energy storage applications.

Ferroelectricity in HfO2-based materials, especially Hf0.5Zr0.5O2 (HZO), is today one of the most attractive topics because of its wide range of applications in ferroelectric random-access memory, ferroelectric field-effect transistors, ferroelectric tunneling junctions, steep-slope devices, and synaptic devices. The main reason for this increasing interest is that, when compared with conventional ferroelectric materials, HZO is compatible with complementary metal–oxide–semiconductor flow [even back-end of the line thermal budget] and can exhibit robust ferroelectricity even at extremely thin (

In this work, a nano-polycrystalline Ag-doped ZnO-based threshold switching (TS) selector via a facile co-sputtering technique is investigated without using an Ag active metal layer. The effects of the Ag concentration with respect to OFF-state leakage current (Ioff) were studied, and the results demonstrate that by regulating the Ag doping concentration in the switching layer (SL), an electroforming-free switching with an Ion/Ioff ratio of ∼108 could be achieved, having an extremely low Ioff value of ∼10−13 A. Furthermore, cycling endurance can also be improved as the formation of a laterally thick and stable filament does not happen promptly with consequent measurements when there is a limited amount of Ag in the SL. The selector device performance enhancement is attributed to the doping-based polycrystalline structure that facilitates enhanced control on filament formation due to the restricted availability and anisotropic diffusion of Ag ions in the polycrystalline ZnO SL, thereby trimming down the overall stochasticity during metallic filament growth. The present study demonstrates that a doping-based polycrystalline SL structure can be implemented in a selector device to augment TS characteristics, i.e., device variances and cycling endurance for adoption in ultra-high density memory applications.

In this paper, we investigate the polarization retention of Hf0.5Zr0.5O2 (HZO)-based metal–ferroelectric–insulator–Si (MFIS) capacitors with scaling of the ferroelectric (FE) layer thickness from 5 nm to 20 nm. The capacitors have a constant interface layer capacitance of ∼24 μF/cm2, developed due to the integration of HZO on a degenerated Si as a bottom conducting electrode. It is observed that 20 nm HZO films show a small change (∼5%) in FE polarization (PFE) between short (10 μs) and long (6 s) retention time, while 5-nm-thick films exhibit a large difference (∼90%). The dependence of PFE retention loss on the FE thickness can be understood by the presence of a built-in electric field in the FE layer, generated due to charge continuity between the FE and the interface layers in the ground state without any external bias. A direct experimental observation also confirms that a residual voltage is developed at the node between the metal–ferroelectric–metal and metal–oxide–semiconductor capacitors connected in series, in the ground state with zero external bias. It is expected that a proper understanding of the built-in field developed in the FE layer in an MFIS stack is crucial for FE memory retention characteristics.

The change in the interplanar spacing (d-spacing) including the ferroelectric orthorhombic (O) phase in the low-temperature fabricated HfxZr1−xO2 (HZO) films was studied using synchrotron grazing-incidence wide-angle x-ray scattering analysis. The 10-nm-thick HZO films were fabricated by thermal and plasma-enhanced atomic layer deposition (TH- and PE-ALD) methods using H2O gas and O2 plasma as oxidants, respectively, and a post-metallization annealing (PMA) was performed at 300–400 °C. The d-spacing of the mixture of (111)-, (101)-, and (111)-planes of O, tetragonal (T), and cubic (C) phases, respectively, for the TH- and PE-ALD HZO films increased up to 2.99 Å with an increase in PMA temperature, while the d-spacing estimated by conventional x-ray diffraction was 2.92 Å regardless of the PMA temperature. The remanent polarization (2Pr = Pr+ − Pr−) of the HZO films increased as the PMA temperature increased. It is clear that the 2Pr value satisfied a linear relationship as a function of the d-spacing of O(111)/T(101)/C(111) phases. Furthermore, the wake-up effect was found to depend on the ferroelectric O phase formation. The wake-up effect was significantly reduced in both the TH- and PE-ALD HZO films after the PMA at 400 °C due to the increase in the ferroelectric O phase formation. The leakage current density (J)–electric field properties of the PE-ALD HZO film with the lowest d-spacing were divided into three steps, such as low, middle, and large J values, in the wake-up (103 cycles), pristine (100 cycle), and fatigue (107 cycles) states, respectively. Therefore, an analysis of the ferroelectric O phase is very important for understanding the ferroelectricity including endurance.

The ferroelectricity of metal–ferroelectric–metal capacitors with a ferroelectric HfxZr1−xO2/ZrO2 (HZO/ZO) bilayer thicker than 20 nm formed by atomic layer deposition and postdeposition annealing at 600 °C was investigated. The HZO/ZO capacitors exhibited a higher remanent polarization (2Pr = Pr+ − Pr−) and breakdown voltage (Vbd) than capacitors with a HfxZr1−xO2 (HZO) single layer. In particular, a HZO (15 nm)/ZO(10 nm) (HZ15Z10) capacitor exhibited excellent Vbd and 2Pr values of 6.7 V and 14 μC/cm2, respectively, which are much higher than those (4.3 V and 10 μC/cm2, respectively) for a HZO (15 nm) (HZ15) capacitor. The HZ15Z10 capacitor also exhibited higher endurance, a smaller wake-up effect (∼5%), and superior fatigue properties up to 108 switching cycles, compared to a HZ15 capacitor, which exhibited a large wake-up effect (∼15%) and large 2Pr degradation at 108 cycles. The wake-up behavior is attributed to domain depinning mainly related to the redistribution of oxygen vacancies and transformation from the nonferroelectric phase to the ferroelectric orthorhombic (O) phase during field cycling. The HZO/ZO bilayer grew a larger grain size with the ZO nucleation layer, which is twice as large as that of the HZO single layer, and the former structure exhibited more stable bulk-like ferroelectricity. Although the ferroelectric O phase in HZO decreased with increasing HZO thickness, the HZO/ZO structure had a larger fraction of the O phase than the HZO structure. Considering the manufacturing process of ferroelectric devices, these thick HZO/ZO bilayers are promising ferroelectric materials.

Ferroelectrics have retrieved great interest since the discovery of a ferroelectric phase in HfO2.1 Especially, ferroelectric Hf0.5Zr0.5O2 (HZO) thin films have studied for application as a non-volatile memory and field-effect transistor, due to their high scalability and compatibility with CMOS process.2 In our previous work, we have achieved a low thermal budget process (400 °C) by controlling the tensile stress from the TiN electrode during the annealing process.3 Moreover, the TiN electrode can act as a barrier layer against hydrogen diffusion, therefore, the HZO films using the TiN electrodes can prevent degradation of the ferroelectric properties from hydrogen incorporation. However, during the deposition of HZO film using atomic layer deposition (ALD), the choice of oxygen source can affect the residue in the deposited film. When hydrogen-related substances are used as the oxygen source, the ferroelectric properties can be altered by the residues remaining in the HZO film. In this study, we adopted various oxygen sources such as H2O, deuterium oxide (D2O), and O3, for the investigation of hydrogen effect on the ferroelectric properties of the ALD-HZO films. The HZO films were deposited on the TiN bottom electrode by ALD using Hf[N(CH3)2]4 (TDMA-Hf) and Zr[N(CH3)2]4 (TDMA-Zr) as the precursors of Hf and Zr, while H2O, D2O, or O3 as the oxidant. After the TiN top electrode was deposited, rapid thermal annealing was done, and metal-insulator-metal capacitors were fabricated using a Pd/Au hard mask and wet etch process. The HZO films exhibited the formation of a non-centrosymmetric orthorhombic phase which is origin of the ferroelectricity, without consideration for the oxygen sources.4 However, it was confirmed that the ferroelectricity of the HZO film deposited with the oxygen source including hydrogen such as H2O and D2O, was degraded due to the more incorporation with hydrogen. As a result, the ferroelectric polarization of H2O-, and D2O-based HZO was lower than that of O3-based HZO. Simultaneously, the H2O- and D2O-based HZO exhibited higher leakage current than that of O3-based HZO. The results strongly suggest that the suppression of hydrogen incorporation is important to apply ALD-HZO films for next-generation memory application. This work is supported by the National Research Foundation of Korea (NRF) grant (No. NRF-2019R1F1A1059972), Brain Pool Program (No. 2019H1D3A2A01101691), and the Fostering Global Talents for Innovative Growth Program (No. P0008750). 1 T. S. Böscke, et al., Appl. Phys. Lett. 99, 102903 (2011). 2 S.J. Kim, et al., Appl. Phys. Lett. 113, 182903 (2018). 3 S.J. Kim, et al., Appl. Phys. Lett. 111, 242901 (2017). 4 S.J. Kim, et al., JOM 71, 246 (2019). Figure 1

Increasing interest in the development of alternative energy storage technologies has led to efforts being taken to improve the energy density of dielectric capacitors with high power density. However, dielectric polymer materials still have low energy densities because of their low dielectric constant, whereas Pb-based materials are limited by environmental issues and regulations. Here, the energy storage behaviors of atomic layer-deposited Hf

In this study, we investigated the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) thin films with different thicknesses (5-20 nm) deposited by atomic layer deposition for the development of future ferroelectric random access memory cells. HZO-based capacitors with a thickness of 5 nm exhibited a switching polarization of ~13 μC/cm2 and a ferroelectric saturation voltage of ~1.0 V as extracted from the pulse write/read measurements. Furthermore, we performed fatigue measurements and we found no degradation up to 1010 switching cycles at 1.2 V.

In this study, ferroelectric properties of atomic layer deposited Hf0.5Zr0.5O2 (HZO) thin films have been investigated for the development of future ferroelectric random access memory capacitors. A 10 nm thick HZO sample annealed at 400°C for 60 s in an N2 atmosphere after TiN top electrode deposition showed large switching polarization (~45 μC/cm2) and low ferroelectric saturation voltage (~1.5 V) from pulse write/read measurement. Furthermore, fatigue measurements were performed and no significant degradation was observed until 108 switching cycles at 2 V.

The ferroelectric (FE) properties of 10-nm-thick Hf0.5Zr0.5O2 (HZO) films deposited by an atomic layer deposition technique were improved by adopting O3 as an oxygen source instead of H2O. All HZO films were annealed at 400 °C for 1 min in an N2 atmosphere after TiN top electrode deposition. Regardless of the oxygen source, the HZO films exhibited the formation of a noncentrosymmetric orthorhombic phase, which is responsible for FE behavior with the suppression of the monoclinic phase. However, compared to the O3-based HZO film, it was confirmed that the H2O-based HZO film was more incorporated with hydrogen derived from H2O, thereby degrading FE polarization and leakage behavior. The results indicate that the strategy of using O3 as the oxygen source is useful for the fabrication and integration of FE HZO films for next-generation memory applications.

In this letter, the ferroelectric (FE) properties of 5-nm-thick Hf0.5Zr0.5O2 (HZO) films deposited by atomic layer deposition have been investigated. By reducing the HZO film thickness to 5 nm, low-voltage operation (1.0 V) of the HZO-based capacitor was achieved while maintaining a remnant polarization (Pr) of about 10 μC/cm2 (i.e., 2Pr of 20 μC/cm2). Meanwhile, in order to form an orthorhombic phase, which is responsible for FE properties, a rapid thermal annealing process was performed after TiN top electrode deposition. The FE properties were realized after low temperature annealing (450 °C for 1 min), making them compatible with the back-end of the line. In addition, the low operating voltage and the suppression of an additional monoclinic phase formation by stress-induced crystallization induced a robust endurance (>1010 cycles at 1.2 V) of the 5-nm-thick HZO sample.

We report on the effect of the Hf0.5Zr0.5O2 (HZO) film thickness on the ferroelectric and dielectric properties using pulse write/read measurements. HZO films of thicknesses ranging from 5 to 20 nm were annealed at 400 °C for 1 min in a nitrogen ambient to be compatible with the back-end of the line thermal budget. As the HZO film thickness decreases, low-voltage operation (1.0 V or less) can be achieved without the dead layer effect, although switching polarization (Psw) tends to decrease due to the smaller grain size. Meanwhile, for 20-nm-thick HZO films prepared under the identical stress (similar TiN top electrode thickness and thermal budget), the Psw and dielectric constant are reduced because of additional monoclinic phase formation.

We report on atomic layer deposited Hf0.5Zr0.5O2 (HZO)-based capacitors which exhibit excellent ferroelectric (FE) characteristics featuring a large switching polarization (45 μC/cm2) and a low FE saturation voltage (∼1.5 V) as extracted from pulse write/read measurements. The large FE polarization in HZO is achieved by the formation of a non-centrosymmetric orthorhombic phase, which is enabled by the TiN top electrode (TE) having a thickness of at least 90 nm. The TiN films are deposited at room temperature and annealed at 400 °C in an inert environment for at least 1 min in a rapid thermal annealing system. The room-temperature deposited TiN TE acts as a tensile stressor on the HZO film during the annealing process. The stress-inducing TiN TE is shown to inhibit the formation of the monoclinic phase during HZO crystallization, forming an orthorhombic phase that generates a large FE polarization, even at low process temperatures.