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Showing papers on "Annealing (metallurgy) published in 2001"


Journal ArticleDOI
TL;DR: In this paper, the Curie temperature of Mn-doped GaN films has been obtained by varying the growth and annealing conditions of the GaN and they have been shown to have ferromagnetic behavior with hysteresis curves showing a coercivity of 100−500 Oe.
Abstract: Dilute magnetic semiconductor GaN with a Curie temperature above room temperature has been achieved by manganese doping. By varying the growth and annealing conditions of Mn-doped GaN we have identified Curie temperatures in the range of 228–370 K. These Mn-doped GaN films have ferromagnetic behavior with hysteresis curves showing a coercivity of 100–500 Oe. Structure characterization by x-ray diffraction and transmission electron microscopy indicated that the ferromagnetic properties are not a result of secondary magnetic phases.

635 citations


Journal ArticleDOI
TL;DR: The thermal stability, microstructure, and electrical properties of binary oxides were evaluated to help assess their suitability as a replacement for silicon dioxide gate dielectrics in complementary metal-oxide-semiconductor transistors as discussed by the authors.
Abstract: The thermal stability, microstructure, and electrical properties of xZrO2⋅(100−x)SiO2 (ZSO) and xHfO2⋅(100−x)SiO2 (HSO) (x=15%, 25%, 50%, and 75%) binary oxides were evaluated to help assess their suitability as a replacement for silicon dioxide gate dielectrics in complementary metal–oxide–semiconductor transistors. The films were prepared by chemical solution deposition using a solution prepared from a mixture of zirconium, hafnium, and silicon butoxyethoxides dissolved in butoxyethanol. The films were spun onto SiOxNy coated Si wafers and furnace annealed at temperatures from 500 to 1200 °C in oxygen for 30–60 min. The microstructure and electrical properties of ZSO and HSO films were examined as a function of the Zr/Si and Hf/Si ratio and annealing temperature. The films were characterized by x-ray diffraction, mid- and far-Fourier transform infrared (FTIR), Rutherford backscattering spectroscopy, and Auger electron spectroscopy. At ZrO2 or HfO2 concentrations ⩾50%, phase separation and crystallizatio...

461 citations


Journal ArticleDOI
TL;DR: In this article, the service-exposed Alloy 625 ammonia cracker tubes showed higher strength and lower ductility compared to the virgin material in the solution annealed state, and the dissolution of the Ni2(Cr,Mo)-phase exhibited significant influence upon yield strength (YS) but negligible effect on ductility.

364 citations


Journal ArticleDOI
TL;DR: In this article, the authors measured the variation of the volume fraction of untransformed retained austenite as a function of uniaxial plastic strain and found that the increase of the mechanical stability of retained Austenite is not solely related to the decrease of the M s temperature induced by carbon enrichment.
Abstract: The mechanical stability of dispersed retained austenite, i.e., the resistance of this austenite to mechanically induced martensitic transformation, was characterized at room temperature on two steels which differed by their silicon content. The steels had been heat treated in such a way that each specimen presented the same initial volume fraction of austenite and the same austenite grain size. Nevertheless, depending on the specimen, the retained austenite contained different amounts of carbon and was surrounded by different phases. Measurements of the variation of the volume fraction of untransformed austenite as a function of uniaxial plastic strain revealed that, besides the carbon content of retained austenite, the strength of the other phases surrounding austenite grains also influences the austenite resistance to martensitic transformation. The presence of thermal martensite together with the silicon solid-solution strengthening of the intercritical ferrite matrix can “shield” austenite from the externally applied load. As a consequence, the increase of the mechanical stability of retained austenite is not solely related to the decrease of the M s temperature induced by carbon enrichment.

347 citations


Journal ArticleDOI
TL;DR: In this article, the mechanical properties of commercially pure (CP) Ti at room temperature were investigated and the decreasing grain size in CP Ti leads to significant increases in its hardness and/or strength.

322 citations


Patent
23 May 2001
TL;DR: An atomic layer deposition (ALD) process deposits thin films for microelectronic structures, such as advanced gap and tunnel junction applications, by plasma annealing at varying film thicknesses to obtain desired intrinsic film stress and breakdown film strength as mentioned in this paper.
Abstract: An atomic layer deposition (ALD) process deposits thin films for microelectronic structures, such as advanced gap and tunnel junction applications, by plasma annealing at varying film thicknesses to obtain desired intrinsic film stress and breakdown film strength. The primary advantage of the ALD process is the near 100% step coverage with properties that are uniform along sidewalls. The process provides smooth (R a ˜2 Å), pure (impurities<1 at. %), AlO x films with improved breakdown strength (9–10 MV/cm) with a commercially feasible throughput.

290 citations


Journal ArticleDOI
TL;DR: In this paper, the evolution of the magnetic, electronic, and structural properties of annealed epilayers of Ga1−xMnxAs grown by low temperature molecular beam epitaxy was studied.
Abstract: We have studied the evolution of the magnetic, electronic, and structural properties of annealed epilayers of Ga1−xMnxAs grown by low temperature molecular beam epitaxy. Annealing at the optimal temperature of 250 °C for less than 2 h significantly enhances the conductivity and ferromagnetism, but continuing the annealing for longer times suppresses both. These data indicate that such annealing induces the defects in Ga1−xMnxAs to evolve through at least two different processes, and they point to a complex interplay between the different defects and ferromagnetism in this material.

286 citations


Journal ArticleDOI
TL;DR: In this article, the authors report improvements in the crystallinity of a III-V-based diluted magnetic semiconductor by heat treatment (annealing) after growth at comparatively low temperatures.
Abstract: We report improvements in the crystallinity of a III–V-based diluted magnetic semiconductor (Ga, Mn)As by heat treatment (annealing) after growth at comparatively low temperatures. This method can be used to raise the Curie temperature to 100 K without the need for severe optimization of growth conditions, as well as to adjust the material parameters to desired values.

228 citations


Journal ArticleDOI
TL;DR: In this article, a ZnO thin film was deposited on a Si wafer having an oxidized SiO2 layer using a chemical solution deposition process and was applied to a bottom-gate type thin film transistor (TFT).
Abstract: A ZnO thin film was deposited on a Si wafer having an oxidized SiO2 layer using a chemical solution deposition process and was applied to a bottom-gate type thin film transistor (TFT). The films prepared by combined heating at 600° and 900°C exhibited typical enhancement-type TFT characteristics with electrons as carriers. The low heating temperature around 600°C degraded the insulating properties of the SiO2 layer but high temperature annealing recovered that.

208 citations


Patent
25 Oct 2001
TL;DR: In this article, a method for annealing a high-k gate dielectric layer was proposed, which involves placing a wafer including one or more partially formed transistors in an ambient.
Abstract: A method for annealing a high dielectric constant (high-k) gate dielectric layer includes placing a wafer including one or more partially formed transistors in an ambient. The ambient may include hydrogen and an oxidizing gas or the ambient may include nitrous oxide. Each transistor includes a high-k gate dielectric layer coupled to a substrate. The method further includes heating the high-k gate dielectric layer to a temperature greater than 650° C. while the gate dielectric layer is in the ambient. The ambient prevents or reduces the formation of lower dielectric constant (lower-k) material between the high-k gate dielectric layer and the substrate. Another method for annealing a high-k gate dielectric layer includes the use of an ambient including chemically active oxygen gas. When such an ambient is used, the high-k gate dielectric layer is heated to a temperature not greater than 600° C. while the gate dielectric layer is in the ambient.

206 citations


Patent
Weimin Li1
27 Dec 2001
TL;DR: In this article, a method for forming a material with a low dielectric constant, suitable for electrical isolation in integrated circuits, is described, where methylsilane is reacted with hydrogen peroxide to deposit a silicon hydroxide layer incorporating carbon, then treated by exposure to a plasma containing oxygen, and annealing the layer at a temperature of higher than about 450° C or higher.
Abstract: A method is provided for forming a material with a low dielectric constant, suitable for electrical isolation in integrated circuits. The material and method of manufacture has particular use as an interlevel dielectric between metal lines in integrated circuits. In a disclosed embodiment, methylsilane is reacted with hydrogen peroxide to deposit a silicon hydroxide layer incorporating carbon. The layer is then treated by exposure to a plasma containing oxygen, and annealing the layer at a temperature of higher than about 450° C. or higher.

Journal ArticleDOI
TL;DR: In this paper, the influence of the annealing treatment (atmosphere and temperature) on the properties of zinc oxide thin films (intrinsic and doped with indium and aluminum) prepared by spray pyrolysis is presented.

Journal ArticleDOI
TL;DR: In this article, annealing temperature is found to significantly affect the superelasticity of NiTi shape memory alloy, and the plateau strain of the forward stress-induced transformation increases with increasing annesaling temperature, being 9% for specimens annealed at 600°C.

Journal ArticleDOI
TL;DR: In this article, a novel device and a stepped heating process were used both to eliminate the tensile force and to diminish the thermal expansion of the polymer substrates by sputtering ITO films without any cracking or shrinkage of the polyethersulfone substrates.

Journal ArticleDOI
TL;DR: In this article, the aging behavior of base-metal electrode materials above the temperature of the permittivity maximum (T M ), including the influence of the zirconium content and annealing conditions, is described for the first time.
Abstract: The purpose of the present investigation is to describe the influence of the processing parameters on the dielectric behavior of manganese-doped Ba(Ti 1-x Zr x )O 3 ceramics, particularly variations in the small-signal aging rate, temperature characteristic, and hysteresis. In this paper, the aging behavior of base-metal electrode materials above the temperature of the permittivity maximum (T M ), including the influence of the zirconium content and annealing conditions, is described for the first time. The aging rate at temperatures greater than T M decreases as the oxygen partial pressure increases during annealing and the zirconium content increases, whereas the aging rate exhibits a maximum at temperatures much less than T M . The behavior is explained in terms of a diffuse phase transition. Hysteresis-loop deformation is observed during aging.

Journal ArticleDOI
01 Apr 2001-Carbon
TL;DR: In this article, the authors showed that the desorption energy barrier of a C-O pair from the nanotube edge is 2.48 eV, higher than 0.3∼2.1 eV from an amorphous carbon, confirming the current approach of purification by the selective oxidation.

Journal ArticleDOI
TL;DR: In this paper, the effects of post-annealing between 600 °C and 1000 °C were investigated on the structural and optical properties of the TiO2 films, and it was confirmed that the microstructure of as-deposited films changed from narrow columnar grains into wide columnar ones.
Abstract: Titanium dioxide (TiO2) films with a thickness of 550 nm were deposited on quartz glass at 300 °C by metalorganic chemical vapor deposition. The effects of post-annealing between 600 °C and 1000 °C were investigated on the structural and optical properties of the films. X-ray diffraction patterns revealed that the anatase phase of as-grown TiO2 films began to be transformed into rutile at the annealing temperature of 900 °C. The TiO2 films were entirely changed to the rutile phase at 1000 °C. From scanning electron spectroscopy and atomic force microscopy images, it was confirmed that the microstructure of as-deposited films changed from narrow columnar grains into wide columnar ones. The surface composition of the TiO2 films, which was analyzed by X-ray photoelectron spectroscopy data, was nearly constant although the films were annealed at different temperatures. When the annealing temperature increased, the transmittance of the films decreased, whereas the refractive index and the extinction coefficient calculated by the envelope method increased at high temperature. The values of optical band gap decreased from 3.5 eV to 3.25 eV at 900 °C. This abrupt decrease was consistent with the anatase-to-rutile phase transition.

Journal ArticleDOI
TL;DR: In this article, the authors explored magnetic properties and structural characteristics of Fe/Pt multilayers after annealing at various temperatures in order to clarify the growth process of the ordered Fe-Pt phase in the multi-layer structures.
Abstract: We have explored magnetic properties and structural characteristics of Fe/Pt multilayers after annealing at various temperatures in order to clarify the growth process of the ordered Fe–Pt phase in the Fe/Pt multilayer structures. It is found that rapid diffusion at Fe/Pt interface occurs at temperatures 275–325 °C and the multilayer structure directly transforms to the ordered (fct) phase when Fe and Pt layer thickness is almost equal. The ordering parameter S is evaluated to be 0.50–0.65 after annealing at 300–325 °C, and then is significantly enhanced to ∼1.00 with increasing annealing temperatures. By comparing the thermal processes of these different multilayer structures, it is found that the rapid formation of the fct phase in the multilayers with Fe/Pt≅1 is due to relatively rapid diffusion at the interface.

Journal ArticleDOI
TL;DR: In this article, structural, optical and electronic changes caused by thermal annealing in vacuum and in oxygen atmosphere on evaporated WO 3 films, were investigated by visible and infrared transmission spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectrography (XPS).

Journal ArticleDOI
TL;DR: In this paper, the effect of changing the aluminum-to-zinc ratio from 0 to 5 at.8 at. % and annealing temperature from 0°C to 700°C in air has been investigated.
Abstract: Highly conductive and transparent aluminum-doped zinc oxide thin films have been prepared from the solution of zinc acetate and aluminum nitrate in ethanol by the sol–gel process. The effect of changing the aluminum-to-zinc ratio from 0 to 5 at. % and annealing temperature from 0 °C to 700 °C in air has been investigated. The resistivities of thin films were measured as a function of annealing temperature and also as a function of aluminum dopant concentration in the solution. As-deposited films have high resistivity and high optical transmission. Annealing of the as-deposited films in air leads to a substantial reduction in resistivity. The films have a minimum value of resistivity of 1.5×10−4 Ω cm for 0.8 at. % aluminum-doped zinc oxide and a maximum transmission of about 91% when deposited on glass substrates. X-ray diffraction measurements employing Cu Kα radiation were performed to determine the crystallinity of the ZnO:Al films which showed that the films were polycrystalline with a hexagonal structure when annealed at 500 °C.

Journal ArticleDOI
TL;DR: In this paper, the effect of RF sputtering power and heat treatment on the photoluminescence (PL) and resistivity were studied, and it has been found that increasing RF sputter power improves the PL efficiency, and after heat treatment in argon atmosphere, the crystalline structure of the ZnO film is improved and the (0,0, 0,2) preferred orientation is enhanced.

Journal ArticleDOI
01 Feb 2001-Polymer
TL;DR: In this article, the influence of annealing temperature on the fracture properties of iPP films (one homopolymer and two propylene-ethylene block copolymers) is presented by means of the essential work of fracture (EWF) procedure.

Journal ArticleDOI
TL;DR: In this paper, sheet resistance, x-ray diffraction and transmission electron microscopy were used to study Ni-silicide phase formation with and without a Ti capping layer.
Abstract: Ni-silicide phase formation with and without a Ti capping layer was studied by sheet resistance, x-ray diffraction and transmission electron microscopy. Ni monosilicide is found to be the stable phase in a temperature range from 400 to 600 °C. At lower temperatures the Ni2Si phase is found to be present. For temperatures higher than 700 °C NiSi is converted into NiSi2. Pyramidal NiSi2 precipitates were found to grow epitaxially along the Si〈111〉 planes for annealing temperatures as low as 310 °C. The epitaxial NiSi2 grains were found to disappear when the annealing temperature is increased. Stress buildup during Ni silicidation was measured in situ and could be correlated to the formation of the different Ni-silicide phases. The stress induced by Ni-monosilicide formation compares favorably to the stress induced by Co disilicide and Ti disilicide. The average silicon consumption required to obtain a certain sheet resistance was found to be 35% lower for Ni monosilicide compared for Co disilicide. It was f...

Journal ArticleDOI
TL;DR: In this paper, the effect of Sc and Zr on the resistance to recrystallization in Al-Mg-Sc-Zr alloys has been investigated and the specific behavior of Al 3 Sc phase and its substantial influence on the softening processes and weldability in Sc containing Al alloys have been investigated.

Journal ArticleDOI
TL;DR: In this paper, local thermal analysis and ellipsometry was used to measure the glass transition temperatures (Tg) of supported thin films of poly(4-hydroxystyrene) (PHS) and hydroxy terminated polystyrene (PS-OH).
Abstract: We used local thermal analysis and ellipsometry to measure the glass transition temperatures (Tg) of supported thin films of poly(4-hydroxystyrene) (PHS) and hydroxy terminated polystyrene (PS-OH). The films were spuncast from solution onto silicon oxide substrates and annealed under vacuum at elevated temperatures to graft the polymer to the substrate. Grafting was verified and characterized in terms of the thickness of and the advancing contact angle of water on the residual layer after solvent extraction. For PHS, each segment of the polymer chain was capable of grafting to the substrate. The thickness of the residual layer increased with increasing annealing temperature. For this polymer the critical thickness below which the Tg of the film deviated from the bulk value was nearly 200 nm after annealing at the highest temperature (190 °C); the Tg of films 100 nm thick or less were elevated by more than 50 °C above the bulk value. For PS-OH films the polymer was only capable of grafting at one chain end...

Journal ArticleDOI
TL;DR: In this article, Lanthanum aluminate (LaAlO3) films were deposited on Si(100) substrates by evaporating single-crystal pellets in vacuum using an electron-beam gun.
Abstract: Lanthanum aluminate (LaAlO3) films were deposited on Si(100) substrates by evaporating single-crystal pellets in vacuum using an electron-beam gun. Then, they were annealed in N2 ambience at 700 °C for 10 min using an electric furnace. X-ray diffraction analysis showed that the LaAlO3 films were amorphous even after the annealing process. No hysteretic characteristics were observed in the capacitance–voltage (C–V) measurement and the dielectric constant of the LaAlO3 films was estimated to be 21–25. It was also found that the leakage current density decreased by about three orders of magnitude after the annealing process. On these films, Sr0.8Bi2.2Ta2O9 films with 210 nm thickness were deposited by a sol–gel method. All samples annealed in O2 atmosphere at temperatures ranging from 650 to 750 °C showed hysteretic C–V characteristics, and the memory window width in the sample annealed at 750 °C for 30 min was about 3.0 V for a voltage sweep of ±10 V. It was also found that the capacitance values biased in ...

Journal ArticleDOI
TL;DR: In this article, the authors discuss the possible origin of the high thermal stability of superhard nanocomposites, prepared according to the generic concept for their design published earlier, and they show that in systems which show a strong thermodynamically driven segregation (i.e. they are immiscible), the nanostructure and resulting superhardness (measured at room temperature) remain stable up to high temperatures of ≥1100°C.
Abstract: We discuss the possible origin of the high thermal stability of our superhard nanocomposites, prepared according to the generic concept for their design published earlier. It will be shown that in systems which show a strong thermodynamically driven segregation (i.e. they are immiscible), the nanostructure and resulting superhardness (measured at room temperature) remain stable up to high temperatures of ≥1100°C. Spinodal decomposition which occurs during deposition leads to spontaneous formation of such nanostructures. The latter is fulfilled for plasma CVD of binary nanocomposites, such as nc-TiN/a-Si 3 N 4 , W 2 N/a-Si 3 N 4 , nc-VN/a-Si 3 N 4 and others deposited at a relatively high pressure of ≥1 mbar and high plasma density. In the case of plasma PVD at much lower pressure and temperature, formation of the nanostructure is not fully completed during deposition. Upon annealing, such nanocomposites show a complex structural relaxation, accompanied by an increase of the hardness, after which they remain stable up to a high temperature of ≥1000°C. This will be demonstrated by (Ti 1-x Al x )N/a-Si 3 N 4 nanocomposite coatings. Finally, we discuss the complex issue of the stability of ternary and quaternary nc-TiN/a-Si 3 N 4 / a- and nc-TiSi x nanocomposites.

Journal ArticleDOI
TL;DR: In this article, the silicon-cerium oxide interface was studied using x-ray photoelectron spectroscopy and the oxidation and reduction of species at the interface were examined as a function of annealing temperature both in vacuum and oxygen ambient, in order to determine their relative stabilities.
Abstract: The silicon-cerium oxide interface is studied using x-ray photoelectron spectroscopy. The oxidation and reduction of species at the interface are examined as a function of annealing temperature both in vacuum and oxygen ambient, in order to determine their relative stabilities. By depositing a very thin CeO2 film (similar to 30 Angstrom), the cerium and silicon core level peaks can be monitored simultaneously. The presence of characteristic chemical shifts of the Si 2p peak gives information about any SiOx, layer that may form at the interface. The oxidation state of the cerium can be probed from three different areas of the spectrum. From this information we can infer the oxidation state of both the silicon and the cerium. For the first time a complete picture of the interface is obtained. The implications of these findings on the utility of CeO2 in device applications are discussed.

Journal ArticleDOI
TL;DR: In this paper, the structural behavior and electrical transport properties of epitaxial α-SnO thin films grown on the (1012) α-Al2O3 (sapphire) substrate were studied.
Abstract: We studied the structural behavior and electrical transport properties of epitaxial α-SnO thin films grown on the (1012) α-Al2O3 (sapphire) substrate Hall effect measurements revealed that the epitaxial as-deposited SnO film is a p-type semiconductor In situ x-ray diffraction studies show that the α-SnO phase is metastable and will transform into SnO2 with the rutile type structure when annealed at high temperatures in air The onset of this phase transformation was observed to begin approximately at 300 °C during heating Shortly thereafter, rutile SnO2 was observed to coexist with α-SnO and intermediate products such as Sn and Sn3O4 After being annealed at temperatures above 600 °C, the film then fully transformed into the rutile SnO2 phase Our results show that the α-SnO to SnO2 structural transformation proceeds initially by the localized disproportionate redistribution of internal oxygen at low temperature, followed by the transformation of the remaining SnO phase and intermediate phases into Sn

Journal ArticleDOI
TL;DR: In this article, a method to produce CuSbS 2 thin films through a solid state reaction at 400°C involving thin films of Sb 2 S 3 (0.5μm) and CuS was reported.