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In this study, the deposition and characteristics of Si- and Ti-series multilayer coatings with respective glass/Si 3 N 4 /NiCr/Ag/NiCr/Si 3 N 4 and glass/TiO 2 /ZnSnO 3 /ZnO/Ag/NiCrO x /ZnSnO 3 /Si 3 N 4 structures were investigated. Experimental analyses were performed, and the optical performance and thermal stability of the coatings were assessed. The as-deposited Si- and the Ti-series samples exhibited optimal shading coefficient of 0.49 and 0.57, respectively. Thermal annealing in air was performed to analyze the thermal stability and oxidation resistance of the samples. The Si- and Ti-series samples prevented the failure of low-emissivity properties at 700 and 600 °C, respectively. In addition to high transparency, the Si-series samples exhibited improved low-emissivity properties, reduced light pollution, and superior thermal stability compared to the Ti-series samples. The use of Si 3 N 4 and NiCr layers effectively prevented the oxidation and cracking of the Ag layer upon heat treatment. This study presents the characteristics of Si- and Ti-series samples for energy-saving building applications. [ABSTRACT FROM AUTHOR]

Zn–Ti–O films were co-sputtered from Zn and Ti targets and then annealed at temperatures ranging from 600 °C to 900 °C for 2 h under an air atmosphere. The [Ti]/([Ti]+[Zn]) ratio decreased from 75.52 to 28.26 as the Zn-target power increased from 25 W to 75 W. The phase transition of the films strongly depended on the [Ti]/([Ti]+[Zn]) ratio. High [Ti]/([Ti]+[Zn]) ratios led to the coexistence of ZnTiO 3 , Zn 2 Ti 3 O 8 , and rutile TiO 2 phases. Zn 2 Ti 3 O 8 gradually became the major crystalline phase as the [Ti]/([Ti]+[Zn]) ratio and rutile TiO 2 and ZnTiO 3 phases decreased. The aforementioned phases disappeared when the [Ti]/([Ti]+[Zn]) ratio was especially low. In their place, Zn 2 TiO 4 and even ZnO phases developed. The dielectric constant of the films increased with increasing [Ti]/([Ti]+[Zn]) ratio. However, extremely high [Ti]/([Ti]+[Zn]) ratios increased the dielectric loss of the films. The film mainly composed of the Zn 2 Ti 3 O 8 phase exhibited optimal dielectric properties, including a dielectric constant and loss equal to 40.1 and 0.0304, respectively, at 1 MHz. [ABSTRACT FROM AUTHOR]

A Cu-deficient Cu(In,Ga)Se2 (CIGS) absorber layer with different deposition time of third stage was fabricated using three-stage co-evaporation process. An appropriate deposition time not only eliminated excess Cu2−xSe but also formed the order defect compound (ODC) phase near the CIGS surface. This ODC surface phase can minimize the recombination rate between absorber and buffer layer. The highest efficiency of 15.82% was achieved when the deposition time was 7 min and bulk [Cu]/([In] + [Ga]) ratio at the end of the three-stage process was 0.98. It indicated that the suitable deposition time of third stage and [Cu]/([In] + [Ga]) ratio could improve the defect concentration, surface properties and recombination of interface between CIGS/CdS. [ABSTRACT FROM AUTHOR]

Indium zinc oxide (IZO) films were grown by direct current magnetron sputtering from vacuum hot-pressed ceramic oxide targets of In 2 O 3 :ZnO with a weight ratio of 7:3 onto glass substrates. No external heating of the substrate was used during deposition. The thickness dependences of the structural, optical, and electrical properties of IZO films were characterized. The IZO film structure remained amorphous with low roughness as its thickness increased but showed an increased degree of short-range order. The thick IZO film contained relatively high carrier concentration and mobility but exhibited low transmittance in the visible region and high reflectance in the IR region. The smallest electrical resistivity was 5.44 × 10 −4 Ω-cm for the 800 nm-thick IZO film. The optical band gap shifted to a higher energy with thickness as the carrier concentration and Urbach energy increased. An inverse linear relation was found between band gap energy and Urbach energy. In consideration of the figure of merit values, the optimized thickness of the IZO film was 800 nm due to the effect of IZO film thickness on sheet resistance. Given its low temperature process and good optoelectronic properties, the IZO film has a wide range of potential applications in various optoelectronic devices. [ABSTRACT FROM AUTHOR]

Cu–Cr–O films were prepared by DC magnetron co-sputtering using Cu and Cr targets on quartz substrates. The films were then annealed at temperatures ranging from 400 °C to 900 °C for 2 h under a controlled Ar atmosphere. The as-deposited and 400 °C-annealed films were amorphous, semi-transparent, and insulated. After annealing at 500 °C, the Cu–Cr–O films contained a mixture of monoclinic CuO and spinel CuCr 2 O 4 phases. Annealing at 600 °C led to the formation of delafossite CuCrO 2 phases. When the annealing was further increased to temperatures above 700 °C, the films exhibited a pure delafossite CuCrO 2 phase. The crystallinity and grain size also increased with the annealing temperature. The formation of the delafossite CuCrO 2 phase during post-annealing processing was in good agreement with thermodynamics. The optimum conductivity and transparency were achieved for the film annealed at approximately 700 °C with a figure of merit of 1.51×10 −8 Ω −1 (i.e., electrical resistivity of up to 5.13 Ω-cm and visible light transmittance of up to 58.3%). The lower formation temperature and superior properties of CuCrO 2 found in this study indicated the higher potential of this material for practical applications compared to CuAlO 2 . [ABSTRACT FROM AUTHOR]

Cu-Cr-O films were prepared by DC magnetron co-sputtering using Cu and Cr targets on fused silica substrates. The as-deposited Cu-Cr-O films were amorphous, semi-transparent, and insulated. After annealing at 800 °C for 30-240 min, the surface roughness and optical transmittances of the resultant films increased, but their electrical resistivity, direct optical band gap (E) values, and compressive residual stress decreased. The as-deposited amorphous Cu-Cr-O films crystallized to the delafossite structure of the CuCrO phase and showed p-type conductivity. The maximum optical transmittance of the films was as high as 80 % at a visible wavelength of 740 nm. In addition, the electrical resistivity of the films decreased from 34.72 to 14.73 Ω cm as annealing time increased from 30 to 120 min but became saturated after 240 min. These results indicate that the CuCrO films obtained in this work show promising optoelectronic properties under a suitable annealing time. [ABSTRACT FROM AUTHOR]

We investigated the effects of sputtering power on the microstructure of direct-current magnetron sputter-deposited TiVCr films on silicon wafer grown at room temperature. When the sputtering power was 100 W, composite structure with amorphous and body-centered cubic (BCC) crystal phases can be observed. When sputtering power was increased to 200 W, the composite structure was almost transformed into crystal columnar structure. Apart from interface region, the amorphous zone was composed of bundles of fine fibrous structure, whereas the BCC crystal zone contained V-shaped columnar structures without significant element segregation. Results indicated that the high sputtering power favored the formation of crystal films and the decrease of intracolumnar voids. However, a significant crack occurred, thereby widening intercolumnar voids. The film deposited at high sputtering power demonstrates slight improvement of mechanical properties. [ABSTRACT FROM AUTHOR]

Si-doped (AlCrMoTaTi)N coatings were deposited onto an Si substrate by radio-frequency magnetron sputtering of an AlCrMoTaTi alloy target under direct current bias in an N 2 /Ar atmosphere. The crystal, microstructural, mechanical, and electrical properties at different Si-target powers were investigated. As the Si content reached 7.51 at.%, the simple NaCl-type face-centered cubic structure of nitride was retained. Significant lattice decline and grain growth were observed in the nitride coatings. The microstructure of coatings transformed from loose columns with rough-faceted surface into dense ones with smooth-domed surface. The solubility of approximately 7.51 at.% Si content was demonstrated. Si incorporation significantly improved the mechanical properties of the coatings, but degraded their electrical properties. The hardness of the coatings increased from 20.7 GPa to 35.5 GPa, and the electrical resistivity increased from 793 μΩ cm to 3872 μΩ cm. [ABSTRACT FROM AUTHOR]

In this study, Cu (In, Ga)Se 2 (CIGS) film was formed using a two-stage process. Bilayer CuGa/In metallic precursors were sequentially deposited using both CuGa alloy and In targets in magnetron sputtering. Then, the Se layer was coated on the sputter-deposited CuGa/In precursors through evaporation. The diffusion behaviors of each element during the post-selenization annealing process were determined based on FESEM, XRD, and SIMS. The higher annealing temperature was proposed to have improved Ga diffusion toward the film surface, and thus, achieved the growth of more uniform, more densely packed, and larger grains. Moreover, Na and O contents were found to be correlated due to the strong affinity between Na and O. The distribution of Na seems to be similar to the Ga profile, which may be ascribed to the diffusion of Ga, which was retarded by Na and O. The CIGS films fabricated by the two-step method consisted of a single chalcopyrite phase, and the efficiency of the cell fabricated by the films was 2.56%. [ABSTRACT FROM AUTHOR]

Abstract: The Kerr intensity versus the Ag thickness for Ag grown on the top of Co/Ir(111) exhibits an oscillating behavior with a period around one monolayer which should be due to the morphological change related electronic structure differences of the Ag layer. From systematical investigations of Ag/Co/Ir(111) films with the Co layer thinner than 4monolayers at temperatures below 900K, a magnetic phase diagram has been established. As the annealing temperature increases for Ag/Co/Ir(111) films, enhancements of the coercive force occur in both the polar and longitudinal configurations due to the intermixing of Ag and Co at the interface and the formation of Co–Ir alloy. The disappearance of ferromagnetism is mainly attributed to the reduced atomic percent of cobalt in Co–Ir alloy, the lowered Curie temperature by a reduction of the thickness of magnetic layers, and the intermixing of Ag and Co at the Ag/Co interface. [Copyright &y& Elsevier]

Abstract: Ti–V–Cr–Al–N films were prepared by dc magnetron co-sputtering by utilizing TiVCr and Al targets. By using glancing incidence X-ray diffraction, a single NaCl solid solution phase with (200) preferred orientation for the Al-doped films was revealed, as opposed to the undoped films that possessed predominantly (111) preferred orientation. This indicates that Al addition can lead to the enhancement of adatom mobility and consequently, to a thermodynamically favorable (200) orientation. This also leads to grain growth and increased surface roughness. However, based on results from transmission electron microscopy, the microstructure morphology seemed independent of the Al concentration, implying that adatom mobility is not sufficient for the barriers present at the grain boundaries. Accordingly, hardness was enhanced by the increase in Al concentration. [Copyright &y& Elsevier]

Abstract: (TiVCrZrHf)N coatings were deposited via reactive radio-frequency (RF) magnetron sputtering at different substrate biases (0 to 200V). The chemical composition, microstructure, and mechanical properties of the coatings were investigated. As the substrate bias increased, the preferred orientation of the (TiVCrZrHf)N coatings changed from (111) to (200). Reduced grain size and surface roughness were also observed. The microstructure obviously changed, from a V-shaped columnar structure with clearly faceted surface features to a highly dense structure with a very smooth surface. Moreover, a continuous variation in the microstructure, from randomly oriented nanograins to columns with a face-centered cubic (FCC) phase, was evident. The hardness of the coatings deposited at 100V or higher was around 32–33GPa. The structural evolution and strengthening mechanism of the coatings were also discussed. [Copyright &y& Elsevier]

Abstract: To fulfill the strict demands for Cu interconnects below 65nm, a 10nm-thick (TiVCr)N film with ternary metallic elements was developed in this study as a candidate diffusion barrier by reactive sputtering in an N2/Ar mixed atmosphere. Barrier properties were examined by annealing over a temperature range of 700–900°C for 30min. From the analyses of diffusion behaviors after thermal annealing at 700°C, the electrical resistance of the Si/(TiVCr)N/Cu film stack remained as low as the as-deposited value. No interdiffusion between the Si substrate and the Cu metallization was found through the (TiVCr)N film at temperatures as high as 700°C. After annealing at 800°C, the penetration of a partial number of Cu atoms through the (TiVCr)N barrier occurred and thus some Cu silicides were formed. With temperature further increased to 900°C, severe interdiffusion of Si and Cu through the layer occurred and induced the formation of a large amount of Cu silicides. This demonstrates that TiVCr ternary refractory metal nitrides have potential use as effective diffusion barriers for copper metallization. [Copyright &y& Elsevier]

Abstract: The present paper reports the influence of growth conditions on the characteristics of (TiVCr)N coatings prepared by dc reactive magnetron sputtering at various N2-to-total (N2 +Ar) flow ratios, R N. The crystal structures, microstructure, and mechanical, electrical and optical properties under the R N were characterized. Results indicate that the TiVCr alloy and nitride coatings exhibited a single body-centered cubic type (BCC) and a face-centered cubic (FCC) solid solution structure, respectively. As the R N increases, the preferred orientation (TiVCr)N coatings changed to (200). The grain size also had a significant increase. The microstructure of the coatings obviously changed from a porous to a compact and dense columnar structure. Accordingly, the physical properties of the coatings were improved due to the densification of the structure. The hardness of the (TiVCr)N was enhanced to about 15GPa, and the electrical resistivity was lowered to 10,000μΩ-cm. [Copyright &y& Elsevier]

Abstract: In this study, 15nm-thick sputter-deposited TiVCr alloy thin films were developed as diffusion barrier layers for Cu interconnects. The TiVCr alloy film tends to form a solid solution and a simple crystal structure from the constituted elements. Under TEM, the 15nm-thick as-deposited TiVCr alloy film was observed to have a dense semi-amorphous or nanocrystalline structure. In conjunction with X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy analyses, the Si/TiVCr/Cu film stack remained stable at a high temperature of 700°C for 30min. The electrical resistance of Si/TiVCr/Cu film stack remained as low as the as-deposited value. These indicated that the mixed TiVCr refractory elements’ alloy barrier layer is very beneficial to prevent Cu diffusion. [Copyright &y& Elsevier]

Abstract: In this study, TiVCr alloy coatings were deposited on Si substrates by magnetron sputtering system at different working pressures (0.33–1Pa). The TiVCr coatings have a composite structure with amorphous and body-centered cubic (bcc) crystal phases comprised of bundles of fine fibrous structures and V-shaped columnar structures, respectively. Compared with the amorphous zone, the crystalline zone has a denser and more compact structure. The coating microstructure became more porous as working pressure increased. Consequently, the crystal zones of the deposited coatings at 0.33Pa obtained higher hardness (11.6GPa) while the deposited coatings at 1Pa achieved lower hardness (4.5GPa). [ABSTRACT FROM AUTHOR]

Abstract: The (TiVCr)N coatings were deposited on Si substrate via rf magnetron sputtering of a TiVCr alloy target under dc bias in a N2/Ar atmosphere. The deposition rate of the coatings gradually decreased with increasing N2-to-total (N2 +Ar) flow ratio, R N. The TiVCr alloy and its nitride coatings exhibited a body-centered cubic (BCC) and a face-centered cubic (FCC) crystal structure, respectively. The preferred orientation of the (TiVCr)N coatings changed from (111) to (200) with increasing R N. In addition, the microstructure of the nitride coatings was also converted from a columnar structure with void boundaries and rough-faceted surface to a very dense structure with a smooth-domed surface. The grain size of the (TiVCr)N coatings decreased as the R N was increased. Accordingly, the hardness of the (TiVCr)N coatings was enhanced from 4.06 to 18.74GPa as the R N was increased. [ABSTRACT FROM AUTHOR]

Abstract: This study reports the influence of growth conditions on the characteristics of (TiVCrZrY)N coatings prepared by reactive magnetron sputtering at various N2-to-total (N2 +Ar) flow ratio, which is RN. The crystal structures, microstructure, and mechanical properties for different RN were characterized by electron spectroscopy for chemical analysis, X-ray diffraction, atomic force microscopy, field-emission-scanning electron microscopy, transmission electron microscopy, and nanoindentation. The results indicate that the TiVCrZrY alloy and nitride coatings have hexagonal close-packed (hcp)-type and sodium chloride (NaCl)-type solid–solution structures, respectively. The voids in the coatings are eliminated and the growth of the columnar crystal structures is inhibited along with an increasing RN. As a consequence, highly packed equiaxed amorphous structures with smooth surfaces are formed. The coatings accordingly achieved a pronounce hardness of 17.5GPa when RN =100%. [ABSTRACT FROM AUTHOR]

Transparent conducting thin films of undoped and Sn-doped zinc oxide films w~re prepared on glass substrate by a dip-coating method using an acidic sot. The effect of metal sources, zinc chloride (ZnCl2) and zinc acetate dihydrate [Zn(OAc)2·2H2O], on the crystalline structure and properties of the films was investigated in detail. X-ray diffraction analysis reveals that the acidic sol leads to ZnO crystals with a hexagonal wurtzite structure after annealing treatment. Transmission electron microscopy results evidence that the Sn-doped ZnO thin films are a mixed phase of wurtzite ZnO and tetragonal Sn2, nanocrystals. Field-emission scanning electron microscopy shows that the morphology of the films is largely affected by the zinc metal sources, and optical and electrical properties of the films are closely related to their microstructure. The undoped films prepared with the zinc chloride source exhibit a lower transmittance in the visible wavelength between 600 and 800 nm, compared with that using the zinc acetate dihydrate source. The electrical resistivity of the undoped films is high (p > 2.0 X 104 Ω cm) but can be reduced by a Sn doping treatment. The optimum electrical resistivity of the Sn-doped films can reach to about 1.5 X 10¹ Ω cm. [ABSTRACT FROM AUTHOR]

Nb-doped titanium oxide (TiO2) thin films were deposited on glass by dc/radio-frequency (dc/rf) magnetron cosputtering, in which dc and rf were utilized for Ti and Nb targets, respectively. The coated samples were postannealed at temperatures ranging from 473 to 773 K for 1 h in ambient air. Glancing incidence X-ray diffraction revealed a polycrystalline phase for the Nb-doped films postannealed at 523 K, in Contrast to the undoped one that has to be annealed at 723 K, indicating that Nb dopant can enhance the crystallization of amorphous TiO2. Furthermore, the as-deposited Nb-doped film postannealed at 673 K was found to have an anatase-dominated phase with a fine-grain microstructure observed by transmission electron microscopy. Heat-treatment also induces a change in the surface morphology of the TiO2 films examined by field-emission scanning electron microscopy. The optical properties of the TiO2 films were characterized by UV/visible spectrophotometry. The average transmittance of the films is higher than 85%, and a small absorbance zone occurs in the visible region. Under visible light irradiation, all the Nb-doped TiO2 films exhibit better photocatalytic activity than that of undoped ones. Among them, the Nb-doped TiO2 film annealed at 673 K shows the best photocatalytic performance. [ABSTRACT FROM AUTHOR]

The anisotropic relaxation behavior of the compressive residual stress of delafossite CuAlO2 film was identified to take place on silicon substrate, on which the film was grown. Experimental results suggest that in order to release the internal compressive residual stress of the CuAlO2 film, CuO hillocks would be favored to grow on the film surface. It was also proposed that because of the structural anisotropic nature associated with the delafossite CuAlO2, the compressive residual stress was released first by breaking the O-Cu-U bonds of the dumbbell layers and subsequently by the diffusion of Cu and O atoms along the a-axis direction on the close-packed Cu layers, suggesting that the c-axis direction across the AlO6 octahedral layers has a greater resistance to compressive residual stress. [ABSTRACT FROM AUTHOR]

Aluminum-doped zinc oxide (AZO) was cosputtered from ZnO and Al targets on glass substrates at room temperature. The effect of Al-target power and annealing atmosphere on structural and optoelectronic properties of AZO films was investigated.[Al]/[Zn] ratio increased to 0.258 when the Al-target power increased to 250 W. At a fixed Al-target power of 200 W, the [Al]/[Zn] ratio was 0.104 and the as-deposited AZO film demonstrated a low resistivity of 3.19 × 10−4 Ω-cm and high transmittance of approximately 90% in the visible region. After annealing at 500 °C in forming gas (5% H2 in Ar) atmosphere, the resistivity of the AZO film can be further reduced to 9.38 × 10−5 Ω-cm. Given its low-temperature process and good optoelectronic properties, sputtered AZO films that use ZnO and Al targets have high potential in various optoelectronic devices. [ABSTRACT FROM AUTHOR]

This letter reports a technique for increasing the carrier concentration and the conductivity of the p-type CuAlO2 through doping the material with nitrogen. The x-ray photoelectron spectroscopy and the optical band gap analyses suggested that the nitrogen atoms occupying the interstitial sites of the delafossite structure provided the p-type CuAlO2 with an impurity energy level in the energy gap. It was also found that the N-doped CuAlO2 film had its optimum conduction properties when the dopant level reached 1.1 at. %. Here, the carrier concentration was raised from 4.81×1016 in the undoped film to 2.13×1017 cm-3 in the doped film, and the corresponding film’s conductivity was increased from 3.8×10-2 to 5.4×10-2 (Ω cm)-1, as compared with the undoped CuAlO2 film. [ABSTRACT FROM AUTHOR]

Abstract: The present paper reports the influence of growth conditions on the characteristics of (TiVCrZrHf)N films prepared by rf reactive magnetron sputtering at various substrate temperatures. The nitrogen content is observed to decrease with increasing substrate temperature. The X-ray diffraction results indicate that all (TiVCrZrHf)N films are simple face centered cubic (FCC) structures. Initially, there is an obvious decrease followed by an increase in grain size with the increase in substrate temperature. The lower part of the microstructure has an amorphous structure. A nano grain structure (size ∼1nm) with a random orientation is also observed above the amorphous structure. The fully dense columnar structure with an fcc crystal phase then starts to develop. Extreme hardness of around 48GPa is obtained in the present alloy design. [Copyright &y& Elsevier]