Effects Of Furnace Annealing Research Articles

Effects of furnace annealing on in situ reacted Ti2AlC MAX phase composite coatings deposited by laser cladding

The ability to deposit mm-scale coatings that are metallurgically bonded to substrates shows great promise for the fabrication of components coated with expensive materials, for their resistance to heat, radiation damage or oxidation in extreme environments. Although considered excellent candidates, in situ laser clad MAX phase coatings on metal substrates have found limited success due to the low proportion of MAX phase in the products. In this work, low-purity laser clad MAX phase coatings were subjected to post-deposition furnace annealing at 1350 °C to improve the Ti2AlC purity. Aside from a thin oxide layer on the coating surface, a pure Ti2AlC layer was formed immediately below. In total, the coatings were found to exist as seven microstructurally unique sub-layers due to equilibration of supersaturated phases formed during the laser cladding process. No delamination between any layers was observed. The phase identification and microstructure, as determined using XRD, SEM and EDS, are described in detail. Some unique microstructures were observed, including dendritic Ti2AlC MAX phase grains produced from a topochemical reaction between TiCx and TiyAlz regions, and α-Ti supersaturated with up to 33 at.% C. The kinetically trapped phases produced within the coating using this process may offer a strong combination of material properties which could be advantageous for use in extreme environments.

Effect of thermal annealing on the optical and structural properties of (311)B and (001) GaAsBi/GaAs single quantum wells grown by MBE

The effect of Furnace Annealing (FA) and Rapid Thermal annealing (RTA) on the structural and optical properties of GaAs1 − xBix/GaAs single quantum wells grown on (001) and (311)B substrates by molecular beam epitaxy was investigated. The structural properties were investigated by high-resolution x-ray diffraction (HR-XRD) and Transmission Electron Microscopy. The Bi concentration profiles were determined by simulating the HR-XRD 2θ−ω scans using dynamical scattering theory to estimate the Bi content, lattice coherence, and quality of the interfaces. The Bi composition was found to be similar for both samples grown on (001) and (311)B GaAs substrates. However, the simulations indicate that the Bi composition is not only limited in the GaAsBi quantum well (QW) layer but also extends out of the GaAsBi QW toward the GaAs barrier. Photoluminescence (PL) measurements were performed as a function of temperature and laser power for samples with a nominal Bi composition of 3%. PL spectra showed that (001) and (311)B samples have different peak energies at 1.23 eV and 1.26 eV, respectively, at 10 K. After RTA at 300 °C for 2 min, the PL intensity of (311)B and (001) samples was enhanced by factors of ∼2.5 and 1.75, respectively. However, for the (001) and (311)B FA samples, an enhancement of the PL intensity by a factor of only 1.5 times could be achieved. The enhancement of PL intensity in annealed samples was interpreted in terms of PL activation energies, with a reduction in the alloy disorder and an increase in the Bi cluster.

Effect of Forming Gas Furnace Annealing on the Ferroelectricity and Wake-Up Effect of Hf0.5Zr0.5O2 Thin Films

The effect of furnace annealing on the ferroelectricity, leakage current, and wake-up effect in Hf0.5Zr0.5O2 (HZO) ultrathin film is studied as a function of furnace annealing temperature and gas environment after crystallizing the films with rapid thermal annealing in the presence of a TiN capping electrode. HZO films are deposited using atomic layer deposition in a Ge-HZO-TiN stack with Pt as the top contact electrode. The increment in the remanent polarization (Pr) is higher when the films are furnace annealed in the forming gas ambient. Forming gas furnace annealed films show an order of magnitude less leakage current as compared to the nitrogen annealed films. Dynamic hysteresis current measurements of the HZO ultrathin films show a faster merging of the four switching peaks after cycling the virgin forming gas furnace annealed films. H-incorporation during forming gas furnace annealing does not degrade the ferroelectric properties of HZO ultrathin films unlike conventional ferroelectrics, such as PZT or SBT. Higher Pr, lower leakage current, and an improved wake-up effect of the HZO ultrathin films show its resistance to degradation by forming gas furnace annealing, which makes ferroelectric HfO2 an ideal material for next-generation ferroelectric memory devices.

Effect of furnace annealing on the ferroelectricity of Hf0.5 Zr0.5O2 thin films

The effect of furnace annealing on the ferroelectricity and crystal phase of Hf0.5ZrO2 (HZO) ultrathin films is studied as a function of film thickness. HZO films are deposited using atomic layer deposition (ALD) in a Ge-HZO-TiN stack with Pt as the top contact electrode. Furnace annealing is carried out after crystallizing the films with rapid thermal annealing in the presence of a TiN capping electrode. While furnace annealing did not have much impact on the 108 ALD cycles (~11 nm) film, it enhanced the ferroelectricity of the 44 ALD cycles film (~4.5 nm). Positive-up-negative-down tests provide evidence of ferroelectricity in the 40 ALD cycles (~4 nm) furnace annealed film after cycling the film at higher fields. Grazing incidence X-ray diffraction shows that the non-centrosymmetric orthorhombic phase responsible for ferroelectricity increased after furnace annealing in thinner films, but little change occurred in the 108 ALD cycles film that was rich in orthorhombic phase prior to furnace annealing. An analysis of the HZO films with a tapping mode atomic force microscope shows grain growth in the 44, and 40 ALD cycles films after furnace annealing.

Effects of furnace annealing and hot pressing on the properties of SZO thin films and on the characteristics of SZO-TFTs

Silicon zinc oxide (SZO) thin films were deposited via co-sputtering, while thin-film transistors (TFTfs) with the SZO film as the active layer were fabricated with a bottom gate configuration. Two kinds of post-treatment, furnace annealing and hot pressing, were carried out on the deposited SZO films. The effects of the post-treatment on the crystalline structure, chemical bond, surface roughness, and optical transmittance of the deposited SZO TFTs were analyzed as functions of the post-treatment conditions that were used. It was observed from the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results that the structure of the SZO film became amorphous and the amount of Si-O bonds in the SZO film drastically increased after low-temperature furnace annealing. The on-off current ratio was 1.35× 108 for the TFT after furnace annealing (200°C) and 1.93× 108 for the TFT after hot-pressing (200°C, 2MPa), while that of the as-deposited SZO-TFT was 3.16×106. The experiment results showed that the hot pressing method would be preferable because it could improve the electrical characteristics of the SZO-TFTs, yielding similar results from the case where furnace annealing for about 60min was carried out, in spite of the short process time (about 30s) of the hot pressing method.

Spin Reorientation Transition in Amorphous FeBSi Thin Films Submitted to Thermal Treatments

Magnetic thin films have been obtained by radio-frequency (RF) sputtering on Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> substrates from a Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">78</sub> B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sub> Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sub> target. The samples, with thickness t varying from 25 to 300 nm, are amorphous; crystalline fraction develops only for t ges 300 nm. Static hysteresis loops have been measured at room temperature by means of an alternating gradient magnetometer. Samples having t >80 nm display a two-slope hysteresis loops: first steep magnetization jump followed by a linear behavior between remanence and saturation revealing the occurrence of a spin-reorientation transition (SRT). The magnetic field H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</sub> at which the saturation is reached is connected with the perpendicular anisotropy. Magnetic force microscopy has been performed on all samples, indicating that for t les80 nm the magnetization lies in the film plane, while for larger thickness, it is oriented perpendicularly to the film plane. In this work, SRT has been studied as a function of sample thickness and perpendicular anisotropy. In particular, the effect of furnace annealing on the transition from in-plane to out-of-plane configuration will be studied in details.

The effect of annealing and crystallization on the magnetoelastic properties of Fe-Si-B amorphous wire

The effect of furnace annealing on the magnetic and magnetoelastic properties of amorphous wire of composition Fe77.5Si7.5B15 has been investigated. The field dependence of Young’s modulus and magnetization combined with x-ray analysis and scanning electron microscopy have been used to monitor the effects of annealing. The results indicate that progressive annealing leads first to relief of the radial casting stress with a corresponding reduction in angle between the average easy direction and the wire axis. Further annealing leads to surface crystallization for which it is suggested that the moments take up a circumferential orientation. Annealing still further leads to crystallization of the bulk material which greatly increases the anisotropy and greatly reduces the ΔE effect.

Effects of furnace annealing and simultaneous laser excitation on copper and gold diffusion in amorphous germanium

Abstract Diffusion of Au and Cu in amorphous germanium was produced by CW Ar laser excitation during furnace heating. Comparison with classical furnace annealing shows a lowering of the crystallization temperature and an increase of the diffusion rate. A transmission electron microscopy study (imaging and electronic diffraction) shows the formation of metastable compounds. The results are analyzed in relationship to the transient sequence of the produced metastable phases.

Magnetic domains around annealed shear bands and embrittlement of FeBSi metallic glass

Magnetic domains in the vicinity of shear bands produced by bending were investigated to study the effect of furnace annealing on the domain structures. Domain wall spacings were measured as a function of annealing time at several temperatures. The same specimens were also used to evaluate the degree of embrittlement by measuring the bending fracture strains.

Effect of heat treatment on InGaAs/GaAs quantum wells

We report on the effect of furnace annealing on 60-Å-wide InxGa1−xAs/GaAs single quantum wells (SQWs) in the range of indium composition 0.1≤x≤0.5. Excitonic energy shifts of up to 120 meV were observed after annealing of the samples at 825 °C for 30 min. The fact that these energy shifts were strongly dependent of the indium composition in the well material was consistent with enhancement on the indium diffusion out of the wells associated with the presence of dislocations. The most dramatic changes, as a result of annealing, manifested by strain recovery were observed from the SQW with x=0.3 which as-grown had a low dislocation density (quantum well thickness slightly exceeding the critical layer thickness for formation of dislocations).