Post-deposition Annealing Treatment Research Articles

Annealing Temperature Effect on the Properties of CoCe Thin Films Prepared by Magnetron Sputtering at Si(100) and Glass Substrates

This study explores cobalt–cerium (Co90Ce10) thin films deposited on silicon (Si) (100) and glass substrates via direct current (DC) magnetron sputtering, with thicknesses from 10 nanometer (nm) to 50 nm. Post-deposition annealing treatments, conducted from 100 °C to 300 °C, resulted in significant changes in surface roughness, surface energy, and magnetic domain size, demonstrating the potential to tune magnetic properties via thermal processing. The films exhibited hydrophilic behavior, with thinner films showing a stronger substrate effect, crucial for surface engineering in device fabrication. Increased film thickness reduced transmittance due to photon signal inhibition and light scattering, important for optimizing optical devices. Furthermore, the reduction in sheet resistance and resistivity with increasing thickness and heat treatment highlights the significance of these parameters in optimizing the electrical properties for practical applications.

Experimental analysis of free-standing and substrate-constrained Ga-doped ZnO nanostructured thermoelectric films

Developing thermoelectric films without substrates—free-standing films—eliminates substrate-induced effects on performance and meets the flexibility requirements of emerging wearable thermoelectric applications. This study investigates Gallium-doped Zinc Oxide (GZO), composed of abundant and non-toxic elements, to fabricate a substrate-free GZO film via 3D printing and compares its structural, chemical, and thermoelectric properties with those of a substrate-constrained GZO film produced through chemical deposition. Both films exhibited uniform crystal structures and phase purity; however, the substrate-constrained film displayed additional diffraction peaks, suggesting potential substrate interactions. The 3D-printed free-standing film effectively eliminated the tensile stresses observed in the substrate-constrained film. FE-STEM analysis revealed nanostructures with homogeneous elemental distribution in both films, though the substrate-constrained film showed discontinuities, such as pores, likely caused by post-deposition annealing treatment. XPS analysis highlighted differences in chemical states and elemental compositions between the films, influenced by fabrication methods, substrate-induced stresses, and surface energy mismatches. The free-standing GZO film developed through 3D printing exhibited a more balanced incorporation of Zn and O, as it was not subject to substrate or post-deposition annealing constraints. Consequently, it demonstrated a 14 % increase in electrical conductivity and a 91 % improvement in the Seebeck coefficient compared to the substrate-constrained film, resulting in a higher room-temperature power factor of 261 nW/m·K2. These findings underscore the potential of 3D-printed free-standing GZO films to advance thermoelectric applications, offering a promising alternative to overcome the challenges of substrate-constrained films and further drive innovation in the field.

Corrosion mechanisms of TiO2 photoelectrode coatings in alkaline conditions

The crystal structure of TiO2 has a significant impact on the chemical stability of the protective TiO2 thin films used in photoelectrochemical conditions. By altering the deposition temperature of atomic layer deposition method, and by post-deposition annealing treatments, amorphous, microcrystalline anatase, and Ti3+-rich nanocrystalline rutile structures can be achieved. In this paper, the chemical stability in alkaline solution and failure mechanisms of ALD grown TiO2 thin films on Si(100) were studied by SEM, XPS, EIS, and ellipsometry. The results showed that the electrically conductive Ti3+-rich nanocrystalline rutile thin film was chemically stable, whereas other samples failed within the first 10 h of the test in 1.0 M NaOH. More detailed analysis in 0.1 M NaOH revealed that the anatase sample experienced sudden failure after NaOH solution penetrated the TiO2 via grain boundaries, causing the Si substrate to dissolve. In contrast, the amorphous TiO2 films had more gradual failure as the NaOH solution permeated the TiO2 film, causing it to swell up to three times the initial thickness of the film.

Comparing post-deposition and post-metallization annealing treatments on Al2O3/GaN capacitors for different metal gates

Vertical Metal–Insulator–Semiconductor (MIS) capacitors with an Al2O3 thin film as a gate insulator have been fabricated on homoepitaxial GaN-on-GaN samples. The effect of the annealing treatments on the MIS characteristics has been investigated exploring two different approaches: Post-insulator-Deposition-Annealing (PDA) and Post-gate-Metallization-Annealing (PMA), i.e., annealing on the bare Al2O3 layer and annealing after the gate metallization deposition on Al2O3. The direct comparison between PDA and PMA is crucial to understand the impact of the metal/dielectric interface quality on the behavior of the Al2O3/GaN MIS capacitors. The efficacy of annealing has been monitored as a function of metal gates having different work functions: nickel (Ni), molybdenum (Mo), and tantalum (Ta). It has been found that both PDA and PMA approaches are equally able to improve the Al2O3/GaN interface electrical quality. However, the PMA demonstrates an additional beneficial effect on the metal/Al2O3 interface. In particular, the possible chemical reactions activated by the annealing process at the metal/dielectric interface can perturb the known metal/dielectric dipole responsible for Fermi-level pinning phenomena, causing a positive shift of the flat voltage (VFB), which depends on the metal, and approaching the theoretical value in the case of Mo and Ta.

Improved electrical performance for SiO2/β-Ga2O3 (001) MIS capacitor by post-deposition annealing

In this study, we have fabricated a high-performance SiO2/β-Ga2O3 (001) MIS capacitor and investigated the effect of low-temperature post-deposition annealing (PDA) on its electrical properties. The SiO2/β-Ga2O3 (001) MIS capacitor exhibits improved gate leakage current and breakdown electrical field after the PDA treatment. The high-frequency capacitance-voltage hysteresis curves reveal that the fixed charge density, as well as the fast and deep near-interfacial trapped charge densities, decreases with the PDA process. We achieved an interfacial trapped charge density as low as 1.6 × 1011 cm−2 eV−1 at an energy of 0.6 eV below the conduction band of β-Ga2O3 (001) through 400 °C annealing.

Stable and Highly Active Single Atom Configurations for Photocatalytic H2 Generation.

The employment of single atoms (SAs), especially Pt SAs, as co-catalysts in photocatalytic H2 generation has gained significant attention due to their exceptional efficiency. However, a major challenge in their application is the light-induced agglomeration of these SAs into less active nanosized particles under photocatalytic conditions. This study addresses the stability and reactivity of Pt SAs on TiO2 surfaces by investigating various post-deposition annealing treatments in air, Ar, and Ar-H2 environments at different temperatures. It is described that annealing in an Ar-H2 atmosphere optimally stabilizes SA configurations, forming stable 2D rafts of assembled SAs ≈0.5-1nm in diameter. These rafts not only resist light-induced agglomeration but also exhibit significantly enhanced H2 production efficiency. The findings reveal a promising approach to maintaining the high reactivity of Pt SAs while overcoming the critical challenge of their stability under photocatalytic conditions.

Post-annealing effect of low temperature atomic layer deposited Al2O3 on the top gate IGZO TFT

Electronical properties of top gate amorphous InGaZnO4 thin film transistors (TFTs) could be controlled by post-annealing treatment, which has a great impact on the Al2O3 insulator. To investigate the effect of post-annealing on Al2O3, Al/Al2O3/p-Si MOS capacitoras with Al2O3 films treated under various post-deposition annealing (PDA) temperature were employed to analysis the change of electrical properties, surface morphology, and chemical components by electrical voltage scanning, atomic force microscope (AFM), and x-ray photoelectron spectroscopy (XPS) technologies. After PDA treatment, the top gate TFTs had a mobility about 7 cm2 V−1 s−1 and the minimum subthreshold swing (SS) about 0.11 V/dec, and the threshold voltage (V th) shifted from positive direction to negative direction as the post-annealing temperature increased. Electrical properties of MOS capacitors revealed the existence of positive fixed charges and the variation of trap state density with increasing PDA temperature, and further explained the change of negative bias stress (NBS) stability in TFT. AFM results clarified the increased leakage current, degraded SS, and NBS stability in MOS capacitors and TFTs, respectively. XPS results not only illuminated the origin of fixed charges and the trap density variation with PDA temperatures of Al2O3 films, but also showed the O and H diffusion from Al2O3 into IGZO during post-annealing process, which led to the deviation of V th, the change of current density, and the negative V th shift after positive bias stress in TFTs.

Defect generation and recovery in high-k HfO2/SiO2/Si stack fabrication

The defect generation and recovery are studied in a high-k HfO2/SiO2/Si stack for MOSFETs, at each fabrication step. The stack is fabricated in a well-established manner, via chemical oxidation for a SiO2 interfacial layer and atomic layer deposition for a HfO2 layer, followed by post-deposition annealing (PDA), O2 plasma treatment, and forming gas annealing (FGA). Throughout the fabrication, the carrier lifetime is measured for monitoring the defects in the stack. The measurements indicate that the defects are generated by the HfO2/SiO2 stack formation as well as PDA and O2 plasma treatment, whereas those defects are mostly recovered by FGA.

Sb2(SxSe1-x)3 thin films by electrodeposition: Role of deposition potential on the formation of the solid solution and photovoltaic performance via device simulation

This work presents one-step electrodeposition of antimony sulfide selenide (Sb2(SxSe1-x)3) thin films on fluorine doped SnO2 substrates. Based on the cyclic voltammetry studies the Sb2(SxSe1-x)3 absorber layers were deposited at different potentials in the range of −0.6 to −0.72 V vs. saturated calomel electrode. The deposited films were uniform and well adhered to the substrate. The effects of the deposition potential and the post-deposition annealing treatment on the physical and chemical properties of the films were analyzed using X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and UV–visible–NIR spectroscopy. The films were crystallized in an orthorhombic crystal structure and the formation of ternary material without any impurity phases was clear from the XRD. The optical band gap of Sb2(SxSe1-x)3 decreased with the increase of the Se concentration in the films. The Mott Schottky plot showed negative slope characteristic of p-type materials. A larger carrier concentration was obtained for films deposited at more negative potentials due to their higher Se content. Solar cells modeled on experimental data of Sb2(SxSe1-x)3 thin films were investigated via device simulation using SCAPS-1D software. The FTO/Sb2(SxSe1-x)3/SnS2 structure showed an efficiency of 11.5%, demonstrating the feasibility of SnS2 as a cadmium-free alternative to the traditional CdS buffer layer.

Synthesis, structural and dielectric properties of Ca3Mn2O7 thin films prepared by pulsed laser deposition

Multiferroic Ruddlesden-Popper Ca3Mn2O7 thin films were prepared by laser ablation on SrTiO3 substrates. For low laser fluences and high oxygen pressures, the films assumed the CaMnO3 Pnma orthorhombic structure. However, by increasing fluence and decreasing the oxygen pressure, the Ca3Mn2O7 phase is achieved through a post-deposition annealing treatment. Furthermore, the ferroelectric phase A21am was observed in the films, along with the orthorhombic Acaa phase, with a preferential [111] growth orientation and substrate-induced enhancement of the polar ferroelectric distortion. The dielectric permittivity shows dispersion described by the Havriliak-Negami function, and from fits to the curves, a different behavior was observed in the antiferromagnetic region. Also, the Kohlrausch-Williams-Watts stretched exponential parameter showed an abrupt decrease below ∼110 K, near the Néel temperature. This indicates the presence of magnetoelectric interactions and magnetically induced enhancement of dipolar correlations in the samples, favoring substrate-induced strain to enhance multiferroicity in these films.

A new approach for alkali incorporation in Cu2ZnSnS4 solar cells

The addition of alkali elements has become mandatory for boosting solar cell performance in chalcogenide thin films based on kesterites (Cu2ZnSnS4, CZTS). A novel doping process is presented here, that consists in the incorporation of sodium or lithium during the deposition of the CdS buffer layer, followed by a post-deposition annealing (PDA). As the doping route leads to more efficient devices in comparison with the undoped reference sample, the influence of PDA temperature was also investigated. Compositional profiling techniques, time-of-flight secondary ion mass spectrometry (TOF-SIMS) and glow discharge optical mission spectroscopy (GDOES), revealed a dependence of the alkaline distribution in kesterites with the PDA temperature. Although the doping process is effective in that it increases the alkaline concentration compared to the undoped sample, the compositional profiles indicate that a significant proportion of Li and Na remains ‘trapped’ within the CdS layer. In the 200 °C–300 °C range the alkali profiles registered the higher concentration inside the kesterite. Despite this, an additional alkali accumulation close to the molybdenum/fluorine doped tin oxide substrate was found for all the samples, which is frequently related to alkali segregation at interfaces. The addition of both, lithium and sodium, improves the photovoltaic response compared to the undoped reference device. This is mainly explained by a substantial improvement in the open-circuit potential (V oc) of the cells, with best devices achieving efficiencies of 4.5% and 3% for lithium and sodium, respectively. Scanning-electron microscopy images depicted a ‘bilayer structure’ with larger grains at the top and small grains at the bottom in all samples. Moreover, the calculated bandgap energies of the CZTS films account for changes in the crystallographic order-disorder of the kesterites, more related to the PDA treatment rather than alkali incorporation. Even if further optimization of the absorber synthesis and doping process will be required, this investigation allowed the evaluation of a novel strategy for alkali incorporation in kesterite based solar cells.

Linear and non-linear optical properties of boron carbide thin films

Boron carbide films deposited by PECVD are subjected to post deposition vacuum annealing and plasma treatment for investigation of changes in the structure, linear and non-linear optical properties of the films. Deconvolution of core level XPES spectra of B1s, C1s and O1s indicates changes in the surface chemical states of the constituent atoms after post deposition treatments. Particle size estimated from XRD spectrum is found increasing from 135 to 140 nm after annealing. Envelop method is used to estimate refractive index, extinction co-efficient, and thickness from their measured optical transmission spectra in VIS-NIR region (400–1400 nm). The refractive index value is found to be 1.619, highest for the vacuum annealed boron carbide film. Direct and indirect optical bandgap remains same after vacuum annealing (Eg = 2.84), the plasma treatment causes a slight decrease in the bandgap. 5% decrease in film thickness is observed after post deposition annealing and plasma treatment owing to film densification. Energy loss in the medium measured in terms of tanδ and ELF’s reveals that the vacuum annealing of the film reduces the electromagnetic and electron energy loss in the film. Non-linear refractive index estimated using Ticha and Tichy relation exhibits similar trend as the linear refractive index spectra.

Tailoring interface epitaxy and magnetism in La1−xSrxMnO3/SrTiO3 heterostructures via temperature-driven defect engineering

Defect engineering of La1−xSrxMnO3 (LSMO)—a strongly correlated oxide displaying half metallicity and ferromagnetism above room temperature—has been the focus of a long-standing quest aimed at the exploitation of this material as a functional building block for memory storage and spintronic applications. Here, we discuss the correlation between structural defects and magnetism in La0.74Sr0.26MnO3/SrTiO3 (LSMO/STO) epitaxial heterostructures as a function of growth temperature and post-deposition annealing. Upon increasing the growth temperature from 500 to 700 °C at a fixed oxygen partial pressure of 0.007 mbar, the sputter-deposited epitaxial LSMO films experience a progressive increase in Curie temperature Tc from 110 to 270 K and saturation magnetization Ms from 1.4 to 3.3 μB/u.c. owing to a reduction in oxygen deficiencies. Concurrently, however, growth temperatures above 600 °C trigger the formation of off-stoichiometric, dendritic-like SrMoOx islands at the film/substrate interface as a possible aftermath of temperature-driven diffusion of impurities from the STO substrate. Notably, although the interfacial spurious islands cause an increase in sample surface roughness, the heterostructure still preserves high-quality epitaxy. In general, the best compromise in terms of both structural and magnetic properties, comprising high-quality epitaxy, atomically flat surface, and robust ferromagnetism above room temperature, is obtained for LSMO films grown at a relatively low temperature of about 500–540 °C followed by a post-deposition annealing treatment at 900 °C for 1 h in air. Our study compares effective routes based on temperature-controlled defect engineering to finely tailor the complex interplay between microstructure and magnetism in LSMO thin films.

Planar heterojunction perovskite solar cell with graded energy band architecture via fast-drying spray deposition

The fast-drying spray deposition (FDSD) technique for perovskite solar cells (PSCs) is developed to enable the stacking of perovskite absorbers with different work functions, which allows the creation of an additional built-in electric field at the interface during the fermi level realignment process upon contact. FDSD is functional under high relative humidity (RH) ambiance and by design, deposits dry film without the need for post-deposition annealing treatment. Based on a spray coating process, FDSD is also highly scalable. Leveraging FDSD’s multilayer deposition capability, this work explores the implementation of graded energy band architectures to achieve PSCs with enhanced carrier extraction and photovoltaic performances. To demonstrate the potential benefit of this approach, two triple cation mixed halide perovskite formulas are chosen. The two formulas, when stacked together in correct order, produce a heterojunction PSC device with an extra built-in electric field, which helps drift charge carriers towards desired electrodes. The architecture with the proper energy band alignment therefore exhibits enhanced carrier extraction efficiency and, despite being subjected to over 60–80% RH during fabrication, reaches the mean power conversion efficiency (PCE) of 7.4%, with the maximum value of 9.5%. The average PCE translates to over 9.9% and 10.3% improvements over the devices based on the two constituent formulas individually. FDSD demonstrates great flexibility i.e., in-humid-air fabrication process and requiring no post annealing treatments, thereby enabling extremely robust and scalable stacked architecture PSCs with low cost and good performance.

Manipulating the Distributions of Na and Cd by Moisture‐Assisted Postdeposition Annealing for Efficient Kesterite Cu2ZnSnS4 Solar Cells

Effectively incorporating alkali metals or alternative isovalent cations into Cu2ZnSnS4 (CZTS) is considered one of the most promising strategies for realizing a step‐change improvement in the photovoltaic device performance. Herein, the local distribution of Na and Cd by a moisture‐assisted postdeposition annealing (MAPDA) treatment combined with a subsequent heterojunction heat treatment is manipulated. The MAPDA treatment facilitates the controllable reduction of the Na concentration, thus promoting the spontaneous diffusion of Cd into the heterojunction region. A subsequent 150 °C low‐temperature heterojunction heat treatment after MAPDA treatment enables further modification of Cd and Na distributions, leading to significantly enhanced optoelectronic properties at the CZTS/CdS heterojunction and greatly improved device performance with a peak conversion efficiency of 9.40%. The modified heterojunction significantly improves quasi‐Fermi‐level splitting under low‐photon injection, making CZTS solar cells more feasible in low‐light applications. This work provides an effective approach to simultaneously manipulate the distribution of Na and Cd, enabling pronounced modification of the heterojunction quality of CZTS solar cells and boost of conversion efficiencies. Insights gleaned herein may also be applicable to manipulating other critical trace elements in chalcogenide materials in general.

Influence of post-deposition annealing temperature on morphological, mechanical and electrochemical properties of CrN/CrAlN multilayer coating deposited by cathodic arc evaporation- physical vapor deposition process

CrN/CrAlN multilayer coatings were deposited on AISI 304 stainless steel substrates utilizing the CAE-PVD process. Then the coatings were annealed at 400, 500, 600, and 700 °C for a duration of 1 h in a vacuum condition. The phases identification, surface morphology, mechanical properties, adhesion, and corrosion behavior of the coating before and after post-deposition annealing treatment were characterized using XRD, SEM, nanoindentation test, Rockwell-C adhesion measurements, and EIS assays, respectively. The results indicated that with increasing post-deposition annealing treatment temperature, the phase structures of the multilayer coating vary from a face-centered cubic CrN to a hexagonal Cr 2 N. Moreover, annealing resulted, in the decrease of the macroparticles on the coating surface decreased. The hardness of the multilayer coating decreased from 19 GPa to 17 GPa, which can be ascribed to the increase in crystallite size and the decrease in the residual stress and annihilation of defects as the temperature increased to 700 °C. Based on the EIS results, the sample annealed at 700 °C had the highest corrosion resistance among other samples, which can be attributed to a decrease in the porosities as corrosion initiation sites, the existence of Cr 2 N as corrosion resistance phase, and an increase in the crystallite size of the multilayer coating. • Comprehensive evaluation on the effect of annealing on CrN/CrAlN multilayer coating. • Significant decrease in residual stress and macrostrain. • Crystallite growth resulted in the decrease in the hardness of the coating by 10%. • Enhancement of electrochemical properties through post-deposition annealing.

Comprehensive rear surface passivation of superstrate Sb2Se3 solar cells via post-deposition selenium annealing treatments and the application of an electron blocking layer.

Sb2Se3, a quasi-1D structured binary chalcogenide, has great potential as a solar cell light absorber owing to its anisotropic carrier transport and benign grain boundaries when the absorber layer is properly aligned along the [hk1] direction perpendicular to the substrate. A growth technique with a high deposition rate, such as vapor transport deposition, is preferred to form an [hk1]-oriented Sb2Se3 film. However, the possible decomposition of Sb2Se3 during cooling after the high-temperature deposition appears to result in Se deficiency, accompanied by the formation of deep-level donor-like defects, such as Se vacancies and Sb on Se antisite defects. Here, we present comprehensive passivation strategies for the rear interface of Sb2Se3 solar cells in a superstrate configuration, namely a post-deposition annealing treatment (PAT) under Se, and the introduction of an electron-blocking layer between Sb2Se3 and the rear metal contact. The PAT effectively passivated the defects associated with Se deficiency and greatly improved the open-circuit voltage and fill factor of Sb2Se3 solar cells. With the further introduction of a poly(N,N-bis(4-butylphenyl)-N,N-bis(phenyl)benzidine) electron-blocking layer, the Sb2Se3 solar cell achieved an efficiency of 7.0%.

Wire-fed electron beam directed energy deposition of Ti–6Al–2Zr–1Mo–1V alloy and the effect of annealing on the microstructure, texture, and anisotropy of tensile properties

Wire-fed electron beam directed energy deposition (EB-DED) is gaining increasing attention owing to its significant advantage of producing high-quality, large-scale metallic components. In this study, EB-DED of a near-α titanium alloy (Ti–6Al–2Zr–1Mo–1V) was conducted, and the effect of post-deposition single annealing treatment on the microstructure, texture, and anisotropy of the tensile properties was investigated. Optical microscopy, scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy were employed to study the microstructure and texture characteristics. The tensile properties along the vertical (Z axis) and horizontal (Y axis) directions were evaluated at both room temperature and 500 °C. The results indicated that the prior β grains had a strong < 001 >β texture along the grain growth direction. Although the α variant selection occurred in some micro-regions, the overall α phase texture was weak. In terms of tensile properties, the vertical specimens exhibited lower strength but higher ductility than the horizontal specimens at both room and elevated temperatures. The anisotropic elongation results from the directional columnar prior β grains and continuous grain boundary α phase, which facilitated the intergranular cracking. The tensile strength and ductility were simultaneously enhanced by annealing at 950 °C for 2 h to meet the standard requirements for wrought counterparts. Moreover, the anisotropy of the tensile properties was decreased significantly. The enhanced and isotropic mechanical properties can be attributed to the combined effect of the bi-lamellar microstructure, discontinuous grain boundary α phase, and the weak α texture.

Interface optimization of La-based gate dielectric for molybdenum disulfide field-effect transistors

Two-dimensional (2D) layered materials such as graphene, transition metal dichalcogenides are considered as the promising candidates for new generation electronics and optoelectronics, owing to their unique physical properties and abundant design freedom. However, the problem of heterogeneous integration of two-dimensional materials with gate dielectric materials has not been solved, especially the problem of interface qualities, which limits the development of two-dimensional electronics. Herein, we demonstrate the feasibility of interface optimization through post-deposition annealing process. The proposed La-based oxide MoS2 transistor offers high mobility of 60 cm2/V·s, increased by 136% up to ∼ 50uA/um and low interface trap density after post-deposition annealing treatment. The detailed research results show that N2 atmosphere annealing treatment can not only promote the composition of LaAlO3, but also suppress the Coulomb scattering generated from interface state charge. All these results provide an enhanced fabrication scheme for heterogeneous integration with the optimized interface and offer reference for high-reliability manufacturing of low-power two-dimensional electronic devices.

Importance of Annealing Step on Dielectric Constant of ZrO2 Layer of MIM Capacitors with Al2O3/ZrO2 and ZrO2/Al2O3 Stack Structures

We investigated characteristics of ZrO2/Al2O3 (ZA) and Al2O3/ZrO2 (AZ) insulators after two annealing step such as post-deposition annealing (PDA) at 600°C before TiN top electrode (TE-TiN) deposition and post-metallization annealing (PMA) at 600°C after TE-TiN deposition. The ZrO2 layers (2.9-5.7 nm) and Al2O3 layer (2.0 nm) were deposited by atomic layer deposition at 300°C. ZrO2 layer had a polycrystalline structure while Al2O3 layer had an amorphous structure. The capacitance of the AZ capacitors after PDA or PMA reasonably decreased as ZrO2 thickness increased. On the other hand, the ZA capacitors after PDA (ZA wPDA) exhibited almost similar capacitance while the ZA capacitors after PMA decreased as well as the AZ capacitor. The dielectric constant (k) of the ZA wPDA drastically increased to 44 compared to other capacitors (30-37) in the ZrO2 thickness region of over 4.9 nm. This is because the ZrO2 layer was annealed with an asymmetric structure sandwiched between Al2O3 and TiN with different coefficients of thermal expansion during PDA. Furthermore, the ZA wPDA with the ZrO2 layers (4.9-5.7 nm) exhibited superior characteristics satisfying a high k-value and a high electric filed value at J = 1 × 10-5 Acm-2. These indicated that PDA treatment should perform after 1st-ZrO2/Al2O3 layer deposition to obtain ZrO2 layer with high k-value.