Annealing Temperature Range Research Articles

Determination of Optimal Recrystallization Annealing Temperature on Structural Hot Dip Galvanized Steel Sheets

The salt-bath annealing was used to study the recrystallization of structural steels as well as the effect of chemical compositions on the microstructure and properties of structural hot dip galvanized steel sheets was investigated in term with the production condition of the No.2 hot dip galvanizing line in Pangang. The optimum annealing temperature range was determined. Experimental results show that the recrystallization temperature of Grade40 and Grade33 is approximately 720°C and 680°C, respectively. Considering the stability of mechanical properties, their optimum annealing temperature are determined to be approximately 720°C. The recrystallization temperature of Grade50 is above 700°C. In order to ensure the margin of strength and the stability of properties of Grade50, the optimum annealing temperature is approximately 780°C.

Defect-mediated resonance shift of silicon-on-insulator racetrack resonators

We present a study on the effects of inert ion implantation of Silicon-On-Insulator (SOI) racetrack resonators. Selective ion implantation was used to create deep-level defects within a portion of the resonator. The resonant wavelength and round-trip loss were deduced for a range of sequential post-implantation annealing temperatures from 100 to 300 °C. As the devices were annealed there was a concomitant change in the resonance wavelength, consistent with an increase in refractive index following implantation and recovery toward the pre-implanted value. A total shift in resonance wavelength of ~2.9 nm was achieved, equivalent to a 0.02 increase in refractive index. The excess loss upon implantation increased to 301 dB/cm and was reduced to 35 dB/cm following thermal annealing. In addition to providing valuable data for those incorporating defects within resonant structures, we suggest that these results present a method for permanent tuning (or trimming) of ring resonator characteristics.

Effect of P on crystallization behavior and soft-magnetic properties of Fe 83.3Si 4Cu 0.7B 12 − x P x nanocrystalline soft-magnetic alloys

The P content dependences of the crystallization behavior, thermal stability and soft-magnetic properties of high Fe content Fe 83.3Si 4Cu 0.7B 12 − x P x (x = 0 to 8) nanocrystalline soft-magnetic alloys were investigated. P addition is very effective in widening the optimum annealing temperature range and refining of bcc-Fe grain size in addition to the increasing of nanocrystalline grain density. Uniform nanocrystalline bcc-Fe grains with average size of about 20 nm and number density of 10 23–10 24 /m 3 were prepared at around x = 6–8 for the annealed Fe 83.3Si 4Cu 0.7B 12 − x P x alloys. The coercivity H c markedly decreases with increasing x and exhibits a minimum at around x = 6–8, while the saturation magnetic flux density B s shows a slight decrease. Fe 83.3Si 4Cu 0.7B 6P 6 nanocrystalline alloy exhibits excellent soft-magnetic properties with a high saturation magnetic flux density B s of 1.77 T, low coercivity H c of 4.2 A/m and high effective permeability μ e of 11,600 at 1 kHz.

Toward a Better Understanding of Ni-Based Ohmic Contacts on SiC

There is still little consensus regarding why low contact resistivity is achieved when Ni on n-type 4H- and 6H-SiC is annealed at temperatures of more than above 950°C. The objective of this paper is to provide an answer concerning to this question. It is has been reported that even Ni-based contacts formed in the n++ region exhibited a steep reduction of contact resistivity in an annealing temperature range > 900°C. This effect reduction cannot be explained by the carbon vacancy induced donor model (Vc model) proposed by Han and his coworkers [Appl. Phys. Lett., Vol. 79, p. 1816 (2001)]. And, it is clarified that It was observed that the surface of substrates annealed at 1000°C was not covered with not Ni2Si but with a thin layer of NiSi. Finally, a plausible model is proposed that as the result of annealing at higher temperatures, results in the formation of the a NiSi/SiC system is builtat the substrate interface, resulting in significant reduction in low causing contact resistivity to be reduced significantly.

Fabrication of SB-MOSFETs on SOI Substrate Using Ni Silicide Containing Er Interlayer

SB-MOSFETs were fabricated on SOI substrates by applying novel Schottky barrier height modulation technique of Er interlayer insertion at the interface of Ni/Si prior to Ni silicidation process. It was found that Er interlayer insertion lowered Schottky barrier height for electrons while no significant increase of the resistivity in the Er interlayer inserted films compare to pure Ni silicide films in the annealing temperature range of 500-750 oC. Effects of Er insertion to the transistor characteristics of SOI SB-MOSFETs are also discussed.

Performance of ZnO-Based Ultraviolet Photodetectors Under Varying Thermal Treatment

This paper reports fabrication, characterization, and testing of the thermal stability of ZnO-based Schottky ultraviolet photodetectors. The ZnO thin film was grown on a p-type Si 〈100〉 substrate by the sol-gel technique. The surface morphological and the structural properties of the thin film were studied by an atomic force microscope (AFM) and a scanning electron microscope (SEM). For the investigation of the surface chemical bonding, X-ray photoelectron spectroscopy (XPS) measurements were also performed. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> characteristics of the Schottky barrier photodetector were studied, and the parameters such as ideality factor, leakage current, and barrier height were extracted from the measured data at room temperature. With applied bias voltages in the range from -3 to 3 V, the contrast ratio, responsivity, detectivity, and quantum efficiency of the photodetectors were measured for an incident optical power of 0.1 mW at 365-nm wavelength. The electrical and optical study revealed that the performance of the device improves with increasing post metal deposition annealing temperature up to 100°C. The device exhibited excellent thermal stability in the annealing temperature range of 100°C to 200°C. For annealing temperatures beyond 200°C, the performance of the device degrades drastically. It was also found that at under 200°C, there is a harmonious correlation between the photoresponse and electrical characteristics of the device. Above this temperature, there is no correlation between the variations of photoresponse and electrical characteristics with increasing annealing temperature. The variation of the electrical and photoresponse properties of the Schottky photodetector subjected to different post-fabrication annealing can be attributed to the combined effects of interfacial reaction and phase transition during the annealing process.

Microstructure, martensitic transformation and superelasticity of Ti 49.6Ni 45.1Cu 5Cr 0.3 shape memory alloy

The aim of this study is to investigate the microstructure, martensitic transformation behavior, shape memory effect and superelastic property of Ti 49.6Ni 45.1Cu 5Cr 0.3 alloy, with Cu and Cr substituting for Ni. After annealing, the alloy showed single step A–M/M–A transformations within the whole annealing temperature range of 623 K to 1273 K even in the presence and Ti 2(Ni, Cu) precipitates. With the increase of the annealing temperature, the transformation temperatures exhibited three stages: increasing from 623 K to 873 K, decreasing from 873 K to 1023 K and unchanging from 1023 K to 1273 K. Meanwhile, the critical stress for stress induced martensitic (SIM) transformation decreased to a minimum value and increased after that, exhibiting a V shape curve. The alloy annealed at 623, 773 and 923 K exhibited shape recovery ratio more than 90% when the deformation strain was below 20%.

Solid phase epitaxial growth of Dy-germanide films on Ge(0 0 1) substrates

Dy thin films are grown on Ge(0 0 1) substrates by molecular beam deposition at room temperature. Subsequently, the Dy film is annealed at different temperatures for the growth of a Dy-germanide film. Structural, morphological and electrical properties of the Dy-germanide film are investigated by in situ reflection high-energy electron diffraction, and ex situ X-ray diffraction, atomic force microscopy and resistivity measurements. Reflection high-energy electron diffraction patterns and X-ray diffraction spectra show that the room temperature growth of the Dy film is disordered and there is a transition at a temperature of 300–330 °C from a disordered to an epitaxial growth of a Dy-germanide film by solid phase epitaxy. The high quality Dy 3Ge 5 film crystalline structure is formed and identified as an orthorhombic phase with smooth surface in the annealing temperature range of 330–550 °C. But at a temperature of 600 °C, the smooth surface of the Dy 3Ge 5 film changes to a rough surface with a lot of pits due to the reactions further.

Crystallization behavior of amorphous Alx(Ge2Sb2Te5)1−x thin films

Crystallization properties of thermally deposited amorphous Alx(Ge2Sb2Te5)1−x (x=0.06 and 0.10) films were investigated. The crystallization was performed by both macroscopic thermal annealing and nanopulse laser illumination (λ=658 nm and beam diameter &amp;lt;2 μm). The Al0.10(Ge2Sb2Te5)0.90 film exhibited a very stable one-step phase transition from amorphous→face-centered cubic (fcc) in the annealing temperature range of 100–300 °C. The Al0.10(Ge2Sb2Te5)0.90 film had a higher sheet resistances (RS) in both the amorphous and crystalline phases compared to the Ge2Sb2Te5 film, resulting in lower set and reset programming currents in the phase-change random-access memory. The crystallization speed (v) of the amorphous films was quantitatively and qualitatively evaluated through the analysis of the surface images and the nanopulse reflection-response curves. Conclusively, the Al atom added into Ge2Sb2Te5 serves as a center for suppression of the fcc-to-hexagonal phase transition and the v-value was largely improved by the proper addition of Al, e.g., v[Al0.10(Ge2Sb2Te5)0.90]&amp;gt;v[Ge2Sb2Te5]. Additionally, the improved v was believed to result from improvements in both the nucleation and growth processes.

Domain wall dynamics during the devitrification ofFe73.5CuNb3Si11.5B11magnetic microwires

We have studied the evolution of domain wall dynamics during the devitrification of amorphous and nanocrystalline ${\text{Fe}}_{73.5}{\text{Cu}}_{1}{\text{Nb}}_{3}{\text{Si}}_{11.5}{\text{B}}_{11}$ microwires. Depending on the annealing temperature range, three different regimes in the domain wall dynamics can be considered for these materials. Annealing below the Curie temperature, ${T}_{\text{c}}$, of the alloy leads to the stabilization of the domain structure and a strong temperature dependence of the domain wall dynamic parameters. However, annealing above ${T}_{\text{c}}$ leads to a destabilization of domain patterns and a decrease in the domain wall damping in one order of magnitude. Finally, annealing above the crystallization temperature, ${T}_{\text{x}}$, leads to the appearance of the nanocrystalline state that is structurally very stable. In this case, the domain wall velocity is very fast due to the lack of magnetic anisotropy and extremely stable with the temperature.

Martensite shear phase reversion-induced nanograined/ultrafine-grained Fe–16Cr–10Ni alloy: The effect of interstitial alloying elements and degree of austenite stability on phase reversion

We describe here an electron microscopy study of microstructural evolution associated with martensitic shear phase reversion-induced nanograined/ultrafine-grained (NG/UFG) structure in an experimental Fe–16Cr–10Ni alloy with very low interstitial content. The primary objective is to understand and obtain fundamental insights on the influence of degree of austenite stability (Fe–16Cr–10Ni, 301LN, and 301 have different austenite stability index) and interstitial elements (carbon and nitrogen) in terms of phase reversion process, microstructural evolution during reversion annealing, and temperature–time annealing sequence. A relative comparison of Fe–16Cr–10Ni alloy with 301LN and 301 austenitic stainless steels indicated that phase reversion in Fe–16Cr–10Ni occurred by shear mechanism, which is similar to that observed for 301, but is different from the diffusional mechanism in 301LN steel. While the phase reversion in the experimental Fe–16Cr–10Ni alloy and 301 austenitic stainless steel occurred by shear mechanism, there were fundamental differences between these two alloys. The reversed strain-free austenite grains in Fe–16Cr–10Ni alloy were characterized by nearly same crystallographic orientation, where as in 301 steel there was evidence of break-up of martensite laths during reversion annealing resulting in several regions of misoriented austenite grains in 301 steel. Furthermore, a higher phase reversion annealing temperature range (800–900 °C) was required to obtain a fully NG/UFG structure of grain size 200–600 nm. The difference in the phase reversion and the temperature–time sequence in the three stages is explained in terms of Gibbs free energy change that considers Ni equivalent and Cr equivalent instead of Ni/Cr ratio and secondary precipitation of carbides/nitrides. Also, described is the evolution of deformation structures in NG/UFG Fe–16Cr–10Ni alloy. A number of deformation mechanisms occur during tensile straining involving dislocation glide and twinning.

Optimization of soft magnetic properties and crystallization in FeAgNbSiB, FeAgNbB and FeAgCoNbB amorphous alloys

In the present paper the influence of 1-h annealing (temperature range from 300 to 800 K) on magnetic, plastic and electrical properties of the Fe 75.75Ag 0.25Nb 2Si 13B 9, Fe 75.75Ag 0.25Nb 2B 22, Fe 74.75Ag 0.25Co 5Nb 2B 18 amorphous alloys were carefully examined. For all the tested alloys the enhancement of magnetic permeability effect was observed—i.e. initial magnetic permeability measured at room temperature for annealed samples shows a sharp maximum. A possible mechanism explaining this effect is discussed in detail. Moreover it was found that at room temperature plastic deformation of the annealed samples depends on the progress of structural relaxation (free volume content). Activation energies and preexponential factors of the first stage of crystallization process were determined from the isochronal resistivity curves measured with different heating rates (Kissinger method). The Curie temperatures from the magnetization curves versus temperature were also determined.

Magnetic anisotropy in IrMn/Co structures with an alternative sequence of deposition of antiferromagnetic and ferromagnetic layers

The preparation conditions and the magnitudes of the uniaxial and unidirectional magnetic anisotropies of IrMn/Co structures with an alternative sequence of deposition of antiferromagnetic and ferromagnetic layers upon heat treatment and cooling in an external magnetic field have been investigated. It has been revealed that the unidirectional anisotropy (exchange bias) arises in the structure with an antiferromagnetic layer deposited on a ferromagnetic layer (TS structure) at an annealing temperature of higher than 100°C. In structures with a ferromagnetic layer deposited on an antiferromagnetic layer (BS structure), the exchange bias does not arise in the annealing temperature range under investigation. The possible factors responsible for this effect and the ratio between the temperature of the appearance of the exchange bias and the Neel temperature have been discussed.

Annealing effects on PECVD-grown Si rich aSiNx thin films

Abstract We report on the effect of the annealing temperature (range 600–1100 °C) on amorphous silicon-rich nitride films deposited by PECVD at 300 °C. The evolution of Raman spectra, room temperature photoluminescence, and optical absorption has been investigated on samples with different stoichiometry. Evidence of partial phase separation, with silicon-rich and nitrogen-rich regions, in the as-grown material has been inferred, with the thermal treatments inducing further reorganization of the two phases. Nucleation of silicon nanocrystals has been detected only after the highest temperature treatment on the sample with larger silicon content.

Highly transparent solution processed In-Ga-Zn oxide thin films and thin film transistors

Highly transparent In-Ga-Zn oxide (IGZO) thin films were fabricated by spin coating using acetate- and chlorate-based precursors, and thin film transistors (TFTs) were further fabricated employing these IGZO films as the active channel layer. The impact of the post-annealing temperature on the physical properties of IGZO films and performance of IGZO TFTs were investigated. Compared to the nitrate-based IGZO precursor, the chlorate-based precursor increases the phase change temperature of IGZO thin films. The IGZO films changed from amorphous to nanocrystalline phase in an annealing temperature range of 600–700 °C. The transparency is more than 90% in the visible region for IGZO films annealed with temperatures higher than 600 °C. With the increase of post-annealing temperature, the carrier concentration of IGZO film decreases, while the sheet resistance increases firstly and then saturates. The bottom-gate TFT with IGZO channel annealed at 600 °C in oxygen showed the best performance, which was operated in n-type enhancement mode with a field effect mobility of 1.30 cm2/V s, a threshold voltage of 10 V, and a drain current on/off ratio of 2.5 × 104.

Structural analyses of thermal annealed SRO/SiO2 superlattices

AbstractNanocrystalline silicon embedded in dielectric matrices is currently studied for Si‐photonics, memory devices and solar cells. A common method for the preparation of silicon nanocrystals embedded in oxides is the phase separation of silicon rich oxide (SRO) in SiO2 and Si via thermal annealing. Phase separation, nucleation and crystallization of SRO are known to depend on the thickness of the SRO layer. Here we investigate the structural changes in a sample consisting of alternated nanometer‐thick SRO and SiO2 layers—a so‐called superlattice (SL)—during thermal annealing. Under a thermal treatment the material undergoes a series of modifications due to sintering, phase separation, crystallization and layer mixing. In this work we investigate these transformations in an SL grown by plasma enhanced chemical vapor deposition (PECVD) with several analytical techniques: XPS, variable angle ellipsometric spectroscopy (VASE), SIMS, and X‐ray reflectivity (XRR). Both SIMS and XRR measurements clearly reveal the periodicity of the samples. XPS analysis reveals that phase separation of SRO in silicon and SiO2 occurs in the annealing temperature range 600–925 °C. The process is accompanied by reduction in overall thickness of the samples (ongoing also at higher temperatures) as evidenced from the ellipsometric spectra. A maximum form birefringence is achieved at 925 °C and stays nearly constant until 1100 °C. Eventually, the form birefringence decreases at the highest annealing temperature of 1150 °C, which according to SIMS measurements is caused by a partial oxidation of silicon in the outermost SRO layer. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Annealing effect on the physical properties of evaporated In 2S 3 films

In 2S 3 films of different thicknesses were deposited onto Corning 7059 glass substrates using close spaced evaporation method, at a constant substrate temperature and growth rate of 300 °C and 30 Å/s, respectively. The deposited layers were then annealed in vacuum at temperatures ( T a ) in the range 100–500 °C for 1 h and changes in the chemical and physical properties of the layers were investigated. The films annealed at T a <300 °C resulted in films that consisted of both cubic and tetragonal phases, while for films annealed at T a ≥300 °C only the tetragonal β-In 2S 3 ph ase was found to be present. A considerable change in morphology was observed for the film thickness of >300 nm and annealing temperature of 300 °C. A highest optical transmittance was found to be 92% in the annealing temperature range, 300 °C<T a <400 °C with a nominal reduction in the energy band gap. The electrical resistivity of the layers was found to decrease with increase of annealing temperature up to 400 °C. The observed changes in the physical properties in relation to the annealing temperature for the films of different thicknesses were reported and discussed.

Physical properties characterization of WO3 films grown by hot-filament metal oxide deposition

WO3 is grown by hot-filament metal oxide deposition (HFMOD) technique under atmospheric pressure and an oxygen atmosphere. By X-ray diffraction obtains that WO3 presents mainly monoclinic crystalline phase. The chemical stoichiometry is obtained by X-ray Photoelectron Spectroscopy (XPS). The IR spectrum of the as-grown WO3 presents broad peaks in the range of 1100 to 3600 cm−1. A broad band in the 2200 to 3600 cm−1 region and the peaks sited at 1645 and 1432 cm−1 are well resolved, which are originated from moisture and are assigned to ν(OH) and δ(OH) modes of adsorbed water and the corresponding tungsten oxide vibrations are in infrared region from 400 to 1453 cm−1 and around 3492 cm−1, which correspond to tungsten–oxygen (W–O) stretching, bending and lattice modes. The Raman spectrum shows intense peaks at 801, 710, 262 and 61 cm−1 that are typical Raman peaks of crystalline WO3 (m-phase) that correspond to stretching vibrations of the bridging oxygen, which are assigned to W–O stretching (ν) and W–O bending (δ) modes, respectively. By transmittance measurements obtains that the WO3 band gap can be varied from 2.92 to 3.13 eV in the investigated annealing temperature range.

Epitaxial growth of Co2MnSi thin films at the vicinal surface of n-Ge(111) substrate

The structure and magnetic properties of Co2MnSi films on n-Ge(111) substrate were investigated for the motivation of spin injection. The 50-nm-thick Co2MnSi films were fabricated on n-Ge(111) substrates by dc sputtering and postannealed about 1 h at the various temperatures ranging from 200–500 °C. In the annealing temperature range of 300–400 °C, the Co2MnSi were grown epitaxially at the vicinal surface of n-Ge(111) substrates. The epitaxial layer of Co2MnSi films was about 18 nm thick at 350 °C and exhibited ferromagnetic behavior. Interestingly, there was no diffusion of Ge inside the epitaxial layer and atomically flat interface was obtained.

Dilatometric Analysis of Anisotropic Dimensional Changes in a 16 Pct Cr Stainless Steel with a Planar Banded Structure

Anisotropic dimensional changes in a 16 pct Cr ferritic stainless steel possessing a banded structure of α + α′ obtained by hot rolling were studied. Considerable anisotropic transformation plasticity was observed during both the austenitization and the martensite formation reactions. Anisotropy was also observed in the case of the coefficient of thermal expansion (CTE), over a wide annealing temperature range. The observations are shown to be due to the geometrical arrangement of the phases, with ferrite acting as a constraint against the in-rolling-plane straining of the pancaked γ, thus encouraging exaggerated dimensional changes along the normal direction (ND). Assuming isotropic dimensional change within the rolling plane and combining the dilatometric results in the rolling and normal directions (NDs), the measured dilatation and CTE can be used to determine the volume fraction of α′. This alternative phase analysis method is shown to have advantages compared to a conventional image analysis method especially at low annealing temperatures where there are still residues of the tempered martensite.