Post-annealing Temperature Research Articles

Effects of Annealing Temperature on TiN/Hf0.5Zr0.5O2/TiN Ferroelectric Capacitor Prepared by In-Situ Like Consecutive Atomic Layer Deposition

In this letter, the ferroelectric characteristics and reliability of TiN&#x002F;Hf_0.5Zr_0.5O₂&#x002F;TiN Metal-Ferroelectric-Metal (MFM) capacitor fabricated using the <i>&#x2018;&#x2018;in-situ&#x2019;&#x2019;</i> like consecutive atomic layer deposition (<i>C-ALD</i>) and the <i>&#x201C;ex-situ&#x201D;</i> deposition techniques are compared for different post metal annealing (PMA) temperatures. We suggested that <i>C-ALD</i> deposition improves the interface of the ferroelectric HZO film and the higher PMA temperature further improves the crystal quality. We found that <i>wake-up</i> tends to happen for both types of samples with lower PMA temperature, indicating the possible higher dependence of <i>&#x201C;wake-up&#x201D;</i> on crystallinity. Nevertheless, <i>C-ALD</i> and higher PMA temperature are both required to prevent early breakdown. <i>C-ALD</i> samples combined with 600 &#x00B0;C PMA showed the excellent remanent polarization (2P_r) of 53 &#x03BC;C&#x002F;cm², endurance properties of 10¹¹ cycles, and outstanding time-dependent dielectric breakdown (TDDB) characteristics.

Effects of annealing temperature on a ZnO thin film-based ultraviolet photodetector

In this paper, the effects of annealing temperature on the performance of a ZnO thin film-based Metal-Semiconductor-Metal (MSM) type ultraviolet (UV) photodetector is reported. ZnO thin films were grown on a glass substrate using the Pulsed Filtered Cathodic Vacuum Arc Deposition (PFCVAD) technique at room temperature and after the deposition process the samples were annealed at 400, 450 and 550 °C in air condition to investigate the annealing effect on the structural, electrical, and optical properties of the photodetector. ZnO thin films which have grains in nanometer range has an increasing in the diameter of grains from 10.5 to 18.3 nm as a function of annealing temperature results in a red shift in the cut-off wavelength of the photodetector from 3.25 eV (381 nm) to 3.23 eV (383 nm). It is demonstrated that the sensitivity and the speed (rise/fall times) of the ZnO thin film based MSM photodetectors enhances with increasing post growth annealing temperature of ZnO thin film due to the increase in the absorption coefficient and the decrease of the total area of the grain boundaries due to the larger grain sizes formation in ZnO thin films with increasing thermal annealing temperature.

The evolution of nanoscale pores with post-annealing and the structure-electrical property correlation in vanadium oxide thin films

Structure-property correlation in vanadium oxide nanoscale thin films used in uncooled thermal detectors is a crucial question for device performance. The purpose of this work is to investigate the evolution of the nanoscale pores with post-annealing temperature and its correlation to electrical properties. It is observed that the as-deposited film has an amorphous matrix containing nanoscale crystal grains of VO2, V2O5, and V6O13 phases, and additionally nanoscale fibrous-like pores. The film post-annealed at 200 C under high purity N2 atmosphere for 3 h possesses nanoscale crystal grains predominantly with the VO2 phase besides V6O13 and nanoscale spherical pores. After post-annealing at 300 °C, a clear enhancement in crystallinity and diminishing of amorphous structure has been found, and the film contains VO2, V2O3, and V6O13 phases, additionally larger pores and cracks. The electrical resistance and temperature coefficient of resistance increase with increasing temperature, whereas the electrical noise reduces after annealing at 200 °C and increases again at 300 °C. The best combination of values for 1/f noise corner frequency (5.7 kHz), electrical resistance (90 kΩ), and temperature coefficient of resistance (-2.71 %K−1) is obtained for the film after post-annealing at 200 °C, favorable for application.

Crystal-phase-specific near-infrared photoluminescence from Er3+-doped Bi2O3 thin films

Er3+-doped Bi2O3 films were sputter deposited on Si(100) substrates at room temperature with H2O vapor as an oxygen source gas. Crystal phases appearing after postannealing in an O2 atmosphere included single-phases of α-Bi2O3, γ-Bi2O3, and δ-Bi2O3, as well as a mixed phase of α-Bi2O3 and γ-Bi2O3. Selection of the crystal phase was possible in terms of H2O pressure and postannealing temperature. Photoluminescence spectra from Er3+ ions excited at a laser wavelength of 532 nm revealed distinct spectral features specific to the crystal phases. A clear crystal-field splitting feature consisting of eight emission lines was observed in PL spectra from sufficiently oxidized α-Bi2O3:Er films, indicating that Er3+ ions occupied low-symmetry C2v sites of Bi3+. The optimum annealing temperature for optical activation of Er3+ ions was between 400 and 450 °C. The emission intensity of α-Bi2O3:Er deposited with H2O was seven times higher than that of α-Bi2O3:Er deposited with O2 probably because larger numbers of Er3+ could substitute Bi3+ sites under reduced condition. Increasing deposition temperature lowered the emission intensity due to the loss of OH and H species from the as-deposited films. The emission spectra of γ-Bi2O3:Er were featureless and its emission intensity was one order of magnitude lower than that of α-Bi2O3:Er. The low-temperature phase of δ-Bi2O3:Er turned out to be entirely emission inactive. Reactions at the interface between the Bi2O3 film and the Si substrate were promoted upon postannealing at 500 °C. The resulting Bi2SiO5:Er exhibited a weak emission spectrum with four emission lines, which reflected occupation at tetragonal Bi3+ sites in the (Bi2O2)2− layers.

UV sensitivity enhancement in ZnO:Cu films through simple post-annealing treatment

Influence of post-annealing temperature on structural, morphological, optical, and electrical properties of ZnO:Cu films was investigated. The films were deposited using the ultrafast spray pyrolysis technique for 10 s. Post-annealing treatment was then conducted at a temperature range of 400–600 °C under ambient pressures. Structural, morphological, electrical, and optical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), current–voltage (I–V) curve, and UV–Vis spectroscopy, respectively. By increasing the annealing temperature, SEM images show morphology modification from rods to spherical grain due to atomic rearrangement. XRD patterns show significant improvement in crystallinity. From I–V curves, the sensitivity of UV detection is also increased. The increase of annealing temperature provokes both the dark current and photocurrent enhancement. UV–Vis spectroscopy analysis shows the decrease of bandgap by increasing the annealing temperature. Our study is essential to improve the functionality of ZnO:Cu film and realizes mass-scale fabrication with low cost.

Resistive switching characteristics of sol-gel derived La2Zr2O7 thin film for RRAM applications

Amorphous La2Zr2O7 thin films were fabricated using the sol-gel method and the bipolar resistive switching behavior of the metal(Al or Ti)/LZO/ITO devices were systematically investigated. The effect of film thickness, top electrodes, and post-annealing treatment conditions on the RS characteristics of the La2Zr2O7 thin films were also discussed. The film thickness increases significantly as the number of spin-coating layers increases, leading to a higher operation voltage and fewer switching cycle times. In addition, the RS properties of the devices are affected by the work function difference between the top and the bottom electrodes. All devices exhibited similar conduction mechanisms, which are described by the ohmic conduction in the low resistance state and space-charge limited current in the high resistance state. Moreover, the RS performance can be profoundly improved by the post-annealing treatment because of the formation of a thicker AlOx interface layer between the Al and LZO thin films, which was revealed via TEM images. The optimized RRAM performances are 1971 cycle times and high stable retention time for over 105 with a Ron/Roff ratio of around 101 at a post-annealing temperature of 300°C. The multilevel RS performances are also observed. Besides, this device maintained a large enough memory window in the retention test at 85°C thermal stress. The longer life is to be expected.

Enhanced switching ratio of sol–gel-processed Y2O3 RRAM device by suppressing oxygen vacancy formation at high annealing temperatures

Sol–gel-processed Y2O3 films were used as an active-channel layer for resistive switching memory (RRAM) devices. The influence of post-annealing temperature on structural, chemical, and electrical properties was studied. Y2O3-RRAM devices comprising electrochemically active metal electrodes, Ag, and indium tin oxide (ITO) electrodes exhibited the conventional bipolar RRAM device operation. The fabricated Ag/Y2O3/ITO RRAM devices, which included 500 °C-annealed Y2O3 films, exhibited less oxygen vacancy and defect sites, reduced the leakage current, increased the high-/low-resistance state ratio of more than 105, and provided excellent nonvolatile memory properties without significant deterioration for 100 cycles and 104 s.

Hydrothermally synthesized ZnO and Z-rGO nanorods: Effect of post-annealing temperature and rGO incorporation on hydrogen sensing

Hydrothermally synthesized ZnO and Z-rGO nanorods: Effect of post-annealing temperature and rGO incorporation on hydrogen sensing

From coating to doping: Effect of post-annealing temperature on the alumina coating of LiNi0.5Mn1.5O4 cathode material

Spinel LiNi0.5Mn1.5O4 is considered as one of the most promising cathode materials due to high working voltage and high energy density. However, the fast capacity degradation, mainly induced by the instability of electrode/electrolyte interface and bulk structure, heavily prevents its commercial application. To alleviate above two issues, LiNi0.5Mn1.5O4 material was first coated with Al(OH)3 via double hydrolysis reactions between NaAlO2 and AlCl3·6H2O, where the corrosion of LiNi0.5Mn1.5O4 material is avoided by controlling the feeding sequence, and the uniform coating of Al(OH)3 on particle surface is achieved by controlling the feeding rate. The Al(OH)3-coated LiNi0.5Mn1.5O4 material was post-annealed at different temperatures, and the effects of different post-annealing temperatures on the structure, morphology and electrochemical performance of LiNi0.5Mn1.5O4 material were systematically investigated. It is found that the LiNi0.5Mn1.5O4 material after post-annealing treatment at 600 ​°C exhibits the optimal rate and cycling performances, which can be mainly attributed to the synergistic effect of Al2O3 surface coating and doping. The uniform and thin Al2O3 coating layer can avoid the direct contact of electrode with electrolyte, capture corrosive HF and increase oxygen vacancy on particle surface, while Al3+ doping can eliminate LixNi1-xO impurity phase, reduce Mn3+ content, strengthen the spinel structure and make Li+ ions diffusion easier, thus leading to the simultaneous improvement of interfacial and structural stability of LiNi0.5Mn1.5O4 material.

Deposition of the tin sulfide thin films using ALD and a vacuum annealing process for tuning the phase transition

Tin sulfide (SnSx) thin films deposited by atomic layer deposition (ALD) under various deposition conditions have unique properties. Such films have two phases, tin monosulfide (SnS) and tin disulfide (SnS2), that depend on the composition ratio of the thin film, and these materials can be applied to a wide range of technologies, such as solar cells, optical sensors, and transistors. In this study, we deposit amorphous tin sulfide thin films at 100 °C using ALD and perform post annealing at various temperatures to control the phase transition from SnS2 to SnS. The post annealing temperature-dependent phase transition was analyzed through Raman spectroscopy, grazing-incidence X-ray diffraction (GI-XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV–vis) spectroscopy, and ultraviolet photoelectron spectroscopy (UPS). Thermodynamic calculations were performed to determine that the initial temperature of the phase transition correspond to the post annealing temperature of 350 °C. The phases and crystal structures of the films annealed at different temperatures were investigated by Raman and GI-XRD. The chemical bonding of the films was analyzed through XPS, revealing that the binding energy of Sn4+ states shifted to the lower binding energy of Sn2+ states with increasing annealing temperatures. The electronic band structures of the films were calculated by UV–vis and UPS. The band gaps of the 300 °C, 350 °C, 400 °C annealed films were 2.26 eV, 2.05 eV, 1.63 eV, respectively. The tin sulfide thin films had n-type characteristics when annealed at 300 °C, which changed to p-type characteristics when annealed at 350 °C and 400 °C. Through this study, we can investigate phase transition of tin sulfides and correlate fabrication conditions to both n-type and p-type characteristics, which can be applied to synthesize the desired films for application in various devices.

Rapid thermal annealing induced engineering of surface and photoluminescence properties of (K,Na)NbO3 thin films for optoelectronic applications

The present study is focused on understanding the mechanism of luminescence behavior and how it gets affected with post annealing temperature via rapid thermal annealing of (K,Na)NbO3 thin films. The crystalline KNN perovskite structure with preferred (001)-orientation is observed upon annealing at 750 and 800 °C. After annealing, the evolution kinetics of surface features is resulted from the simultaneous evaporation-recondensation and volume diffusion of particles. The volatilization of alkali species after annealing and, in contrast, the lattice oxygen and Nb5+ chemical state of niobium related to KNN is enhanced. Narrowing of optical band gap after annealing is attributed to the generation of shallow defects deep below the conduction band owing to order–disorder and/or distortion in NbO6 octahedra. Photoluminescence (PL) quenching behavior is observed after RTA with 290 nm excitation wavelength. A strong blue emission is observed at 800 °C after exciting with 266 nm wavelength. The kinetics of decay lifetime from time-resolved PL results revealed the enhancement of transitions more likely via radiative states. The RTA induced results specify that KNN can be one of the promising candidates for use in LEDs, smart glass windows, optical switches/sensors, and optoelectronic devices.

Sol-gel-processed amorphous-phase ZrO2 based resistive random access memory

In this study, sol–gel-processed amorphous-phase ZrO2 was used as an active channel material to improve the resistive switching properties of resistive random access memories (RRAMs). ITO/ZrO2/Ag RRAM devices exhibit the properties of bipolar RRAMs. The effect of the post-annealing temperature on the electrical properties of the ZrO2 RRAM was investigated. Unlike the ZrO2 films annealed at 400 and 500 °C, those annealed at 300 °C were in amorphous phase. The RRAM based on the amorphous-phase ZrO2 exhibited an improved high-resistance state (HRS) to low-resistance state ratio (over 106) as well as promising retention and endurance characteristics without deterioration. Furthermore, its disordered nature, which causes efficient carrier scattering, resulted in low carrier mobility and the lowest leakage current, influencing the HRS values.

Annealing Effect on the Contact Angle, Surface Energy, Electric Property, and Nanomechanical Characteristics of Co40Fe40W20 Thin Films

This study investigated Co40Fe40W20 single-layer thin films according to their corresponding structure, grain size, contact angle, and surface energy characteristics. Co40Fe40W20 alloy thin films of different thicknesses, ranging from 10 to 50 nm, were sputtered on Si(100) substrates by DC magnetron sputtering. The thin films were annealed under three conditions: as-deposited, 250 °C, and 350 °C temperatures, respectively. The Scherrer equation was applied to calculate the grain size of Co40Fe40W20 thin films. The results show that the grain size of CoFe(110) increased simultaneously with the increase of post-annealing temperature, suggesting that the crystallinity of Co40Fe40W20 thin films increased with the post-annealing temperature. Moreover, the contact angles of all Co40Fe40W20 thin films were all less than 90°, suggesting that Co40Fe40W20 thin films show changes in the direction of higher hydrophilicity. However, we found that their contact angles decreased as the grain size of CoFe increased. Finally, the Young equation was applied to calculate the surface energy of Co40Fe40W20 thin films. After post-annealing, the surface energy of Co40Fe40W20 thin films increased with the rising post-annealing temperature. This is the highest value of surface energy observed for 350 °C. In addition, the surface energy increased as the contact angle of Co40Fe40W20 thin films decreased. The high surface energy means stronger adhesion, allowing the formation of multilayer thin films with magnetic tunneling junctions (MTJs). The sheet resistance of the as-deposited and thinner CoFeW films is larger than annealed and thicker CoFeW films. When the thickness is from 10 nm to 50 nm, the hardness and Young’s modulus of the CoFeW film also show a saturation trend.

Improvement of transparent conductive indium tin oxide based multilayer films on p-silicon through the inclusion of thin copper-aluminium metals interlayer

The distinguished transparent conductive indium tin oxide (ITO) based multilayer films with thin copper-aluminium (Cu-Al) metals interlayer (ITO/Cu-Al/ITO) were prepared on p-type silicon (Si) by radio frequency and direct current magnetron sputtering methods. The ITO/Cu-Al/ITO (ICAI) films structural, topological, optical and electrical properties coupled with electronic properties of ICAI/p-type Si interface were investigated at different post annealing temperature up to 600 °C. Despite the inclusion of Cu-Al metals interlayer, structural analysis results yielded an amorphous structure for the as-deposited films. The films become polycrystalline with a cubic bixbyite structure after post annealing treatment. Dominant In2O3 (222) and Cu (111) peaks intensities were observed at 500 °C and 600 °C indicating substantial enhancement in the films crystallinity at high moderate temperatures. The ICAI films reveal a smooth surface roughness with improved growth in grain size after post annealing treatment as examined by microscopic equipment.The films optical transmittance promptly increased from 73.2% (for as deposited film) to 88.7% (for annealed film at 600 °C) at 470 nm in the visible region with increasing post annealing temperature. The film annealed at 600 °C exhibits excellent electrical characteristics with a very low electrical resistivity of 2.44 × 10−5 Ω cm and sheet resistance of 3.26 Ω/sq. The ICAI films optoelectronic properties as calculated by figure of merit (FOM) show outstanding performance at 600 °C with a high FOM of 92.47 × 10−3 Ω−1 in spite of the reduced ITO films thickness. In addition, admirable ICAI/p-type Si interface quality was observed after post annealing treatment (at 600 °C) as indicated by current-voltage characteristics results. These improved ICAI multilayer films can be favourable for silicon heterojunction solar cells and other low resistance optoelectronic applications.

An effect of rapid post-annealing temperature on the properties of cupric oxide thin films deposited by a remote plasma sputtering technique

Traditional annealing has limitations of long-treatment time, excessive grain size and energy-intensive, inhibiting the quality and applications of the semiconductor thin films. Herein, an effect of rapid post-annealing (RPA) on the properties of cupric oxide (CuO) thin films deposited by a remote plasma sputtering technique was studied systemically. The chemical composition, microstructure, and the optoelectronic properties, including transmission, absorption, band gap, Urbach energy, carrier concentrations, and hall mobility, etc., were characterized by XRD, Raman, XPS, AFM, SEM TEM, optical transmission/absorption spectra and Hall measurements, correspondingly. The results reveal that the as-deposited and annealed (250, 350 and 450oC for 5 min) films all possess a single monoclinic CuO phase. All films possess compact nanostructures and the surface root-mean-square (RMS) roughness is around 1.5 nm because tiny and plain grains distribute uniformly within the films. The thermal annealing under higher temperature partially removes (or suppresses) the defects and this yields a broader bandgap for the CuO thin film, while the Urbach energy monotonous decreases with the increasing annealing temperature, signifying the minimizing disorder of the thin films. Meanwhile, the annealed CuO thin films possess decreased carrier concentration and enhanced hall mobility with increasing annealing temperature. For the 450oC-annealed CuO thin film, the carrier concentration is of 5.3 × 1015 cm−3 and the Hall mobility is of 2.3 cm2 V−1 s−1. This offers an essential material basis for photonic devices.

Effects of post-annealing temperature and micropillar shape on physical properties of micropillar-type multiferroic composite thin films

Microplate (MP) and microrod (MR)-type CoFe2O4/(Bi3.25Nd0.65Eu0.10)Ti3O12 composite thin films were fabricated by a combination of reactive ion etching and metalorganic chemical vapor deposition. The effects of post-annealing temperature on the structural, magnetic, electrical, and magnetoelectric (ME) properties of the films were investigated. Based on the results, the optimal ferroelectric pillar structure to obtain a large ME voltage coefficient (α ME ) was determined. The electrical insulation properties for the films improved with increasing post-annealing temperature. On the other hand, magnetic and ferroelectric properties were degraded at high-temperature. Judging from the structural, magnetic, electric, and ME properties, the optimum post-annealing temperature was 700 °C. The shape of the ferroelectric layer had a significant influence on the ferroelectric properties and consequently on α ME . The MR shape exhibited a smaller clamping effect than the MP shape, producing a greater ME effect. The α ME for the MR-type film post-annealed at 700 °C was 5.5 mV cm−1 Oe−1.

Structural, Optical, and Electrical Properties of Copper Oxide Films Grown by the SILAR Method with Post-Annealing

Copper oxides are widely used in photocatalysts, sensors, batteries, optoelectronic, and electronic devices. In order to obtain different material properties to meet the requirements of different application fields, varied technologies and process conditions are used to prepare copper oxides. In this work, copper oxide films were grown on glass substrates by a successive ionic layer adsorption and reaction (SILAR) method with subsequent annealing under an atmospheric environment. The films were characterized by using an X-ray diffractometer, Raman spectrometer, Scanning electron microscope, UV-Visible-NIR spectrophotometer, and Hall Effect measurement. The results show that the as-deposited film has a Cu2O crystal structure, which begins to transform into Cu2O-CuO mixed crystal and CuO crystal structure after annealing at 300 °C for a period of time, resulting in the bandgap of being reduced from 1.90 to 1.34 eV. The results show that not only are the crystal structure and bandgap of the films affected by the post-annealing temperature and time, but also the resistivity, carrier concentration, and mobility of the films are varied with the annealing conditions. In addition, the film with a Cu2O-CuO mixed crystal shows a high carrier mobility of 93.7 cm2·V−1·s−1 and a low carrier concentration of 1.8 × 1012 cm−3 due to the formation of a Cu2O-CuO heterojuction.

Universal Strategy for Improving Perovskite Photodiode Performance: Interfacial Built-In Electric Field Manipulated by Unintentional Doping.

Organic–inorganic halide perovskites have demonstrated significant light detection potential, with a performance comparable to that of commercially available photodetectors. In this study, a general design guideline, which is applicable to both inverted and regular structures, is proposed for high‐performance perovskite photodiodes through an interfacial built‐in electric field (E) for efficient carrier separation and transport. The interfacial E generated at the interface between the active and charge transport layers far from the incident light is critical for effective charge carrier collection. The interfacial E can be modulated by unintentional doping of the perovskite, whose doping type and density can be easily controlled by the post‐annealing time and temperature. Employing the proposed design guideline, the inverted and regular perovskite photodiodes exhibit the external quantum efficiency of 83.51% and 76.5% and responsivities of 0.37 and 0.34 A W−1, respectively. In the self‐powered mode, the dark currents reach 7.95 × 10−11 and 1.47 × 10−8 A cm−2, providing high detectivities of 7.34 × 1013 and 4.96 × 1012 Jones, for inverted and regular structures, respectively, and a long‐term stability of at least 1600 h. This optimization strategy is compatible with existing materials and device structures and hence leads to substantial potential applications in perovskite‐based optoelectronic devices.

Optimizing the Properties of La0.8Sr0.2CrO3 Thin Films through Post-Annealing for High-Temperature Sensing.

La0.8Sr0.2CrO3 (0.2LSCO) thin films were prepared via the RF sputtering method to fabricate thin-film thermocouples (TFTCs), and post-annealing processes were employed to optimize their properties to sense high temperatures. The XRD patterns of the 0.2LSCO thin films showed a pure phase, and their crystallinities increased with the post-annealing temperature from 800 °C to 1000 °C, while some impurity phases of Cr2O3 and SrCr2O7 were observed above 1000 °C. The surface images indicated that the grain size increased first and then decreased, and the maximum size was 0.71 μm at 1100 °C. The cross-sectional images showed that the thickness of the 0.2LSCO thin films decreased significantly above 1000 °C, which was mainly due to the evaporation of Sr2+ and Cr3+. At the same time, the maximum conductivity was achieved for the film annealed at 1000 °C, which was 6.25 × 10−2 S/cm. When the thin films post-annealed at different temperatures were coupled with Pt reference electrodes to form TFTCs, the trend of output voltage to first increase and then decrease was observed, and the maximum average Seebeck coefficient of 167.8 µV/°C was obtained for the 0.2LSCO thin film post-annealed at 1100 °C. Through post-annealing optimization, the best post-annealing temperature was 1000 °C, which made the 0.2LSCO thin film more stable to monitor the temperatures of turbine engines for a long period of time.

Influence of post annealing temperature on the thermoelectric properties of bulk ZnSnO

In this manuscript, we have studied the structural, electrical and thermoelectric properties of bulk ZnSnO by post growth annealing method. X-Ray Diffraction data showed that the crystallinity was found to be improved y annealing up to 700oC due to compensation of oxygen vacancy type donor defects. But further annealing forced the oxygen atoms to diffuse into the interstitial sites, therefore causes degradation in the crystal quality. Thermoelectric properties were increased with annealing temperature up to 700oC and then decreased due to further annealing. The sharp enhancement of thermoelectric properties is due to mobility increase of carriers.