ArF-line high transmittance attenuated phase shift mask blanks using amorphous Al2O3-ZrO2-SiO2 composite thin films for the 65-, 45- and 32-nm technology nodes

Amorphous (ZrO₂)_x-(SiO₂)_1−x and (Al₂O₃)_x-(ZrO₂)_y-(SiO₂)_1−x−y composite films were prepared using r.f. unbalanced magnetron sputtering in an atmosphere of argon and oxygen at room temperature. The (ZrO₂)_x-(SiO₂)_1−x and (Al₂O₃)_x-(ZrO₂)_y-(SiO₂)_1−x−y composite films were completely oxidized when an O₂/Ar flow rate ratio of 2.0 was used. The optical constants of these thin films depend linearly on the mole fraction of corresponding films. By tuning the (x, y) mole fractions of (Al₂O₃, ZrO₂) in the (Al₂O₃)_x-(ZrO₂)_y-(SiO₂)_1−x−y composite films, the optical constants can meet the optical requirements for a high transmittance attenuated phase shift mask (HT-AttPSM) blank. The n-k values in the quadrangular area in the (x, y) plane, where x and y represent the mole fractions of Al₂O₃ and ZrO₂, respectively, meet the optical requirements for an HT-AttPSM blank with an optimized transmittance of 20 ± 5% in ArF lithography. It is noted that the quadrangular area is bounded by (0, 0.31), (0, 0.62), (0.26, 0) and (0.57, 0). All the films also met the chemical and adhesion requirements for an HT-AttPSM application. One (Al₂O₃)_0.1-(ZrO₂)_0.52-(SiO₂)_0.38 composite film was fabricated with optical properties that meet the optimized optical requirements of ArF-line HT-AttPSM blanks. Combined with these HT-AttPSMs, ArF-line (immersion) lithography may have the potential of reaching 65-, 45-nm and possibly the 32-nm technology nodes for the next three generations.     

A highly stabilized Ni-rich NCA cathode for high-energy lithium-ion batteries

In this study, we have demonstrated that boron doping of Ni-rich Li[Ni_xCo_yAl_1−x−y]O₂ dramatically alters the microstructure of the material. Li[Ni_0.885Co_0.1Al_0.015]O₂ is composed of large equiaxed primary particles, whereas a boron-doped Li[Ni_0.878Co_0.097Al_0.015B_0.01]O₂ cathode consists of elongated particles that are highly oriented to produce a strong, crystallographic texture. Boron reduces the surface energy of the (0 0 3) planes, resulting in a preferential growth mode that maximizes the (0 0 3) facet. This microstructure modification greatly improves the cycling stability; the Li[Ni_0.878Co_0.097Al_0.015B_0.01]O₂ cathode maintains a remarkable 83% of the initial capacity after 1000 cycles even when it is cycled at 100% depth of discharge. By contrast, the Li[Ni_0.885Co_0.1Al_0.015]O₂ cathode retains only 49% of its initial capacity. The superior cycling stability clearly indicates the importance of the particle microstructure (i.e., particle size, particle shape, and crystallographic orientation) in mitigating the abrupt internal strain caused by phase transitions in the deeply charged state, which occurs in all Ni-rich layered cathodes. Microstructure engineering by surface energy modification, when combined with protective coatings and composition modification, may provide a long-sought method of harnessing the high capacity of Ni-rich layered cathodes without sacrificing the cycling stability.     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Simple cubic perovskites as components in R1−yNayBa2Cu3Ox (R=Ce,Pr, Tb)

Simple cubic perovskites derived from RBaO₃ appear in the X-ray diagrams of materials with nominal composition R_1−yNa_yBa₂Cu₃O_x with R = Ce, Pr, Tb. Y_1−yBi_yBa₂Cu₃O_x also contains this structure type. Materials are not superconducting at 77 K. The absence of YBa₂Cu₃O_x type structures in these cases is explained on thermodynamic arguments considering the high stability of phases R⁴⁺Ba²⁺O₃ which dominate the phase diagram.     

Synthesis of Ti3AlC2/Al2O3 nanopowders by mechano-chemical reaction

Ti₃AlC₂/Al₂O₃ nanopowders were synthesized by the combination of mechanically-induce self-propagating reaction (MSR) of Ti, C, Al and TiO₂ powder mixtures and subsequently heat treatment. Effects of high energy milling and heat treatment temperatures on the phase transformation were investigated in detail. X-ray diffraction (XRD) was used to characterize the powders of milled and annealed, respectively. The morphology and microstructure of as fabricated products were also studied by scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). Results show that TiC, Ti_xAl_y and Al₂O₃ transitional phases were formed when the initial powder mixtures were milled for 24 h. The desired Ti₃AlC₂/Al₂O₃ nanopowders with high purity were obtained when annealed the as-milled powders at 1100 °C. SEM image confirmed that the as fabricated Ti₃AlC₂/Al₂O₃ particles has nanocrystalline layered structural matrix of Ti₃AlC₂, and the second phase of nanosized Al₂O₃ disperses uniformly in the Ti₃AlC₂ matrix.     

A comprehensive review on the progress of lead zirconate-based antiferroelectric materials

Lead zirconate (PbZrO₃ or PZ)-based antiferroelectric (AFE) materials, as a group of important electronic materials, have attracted increasing attention for their potential applications in high energy storage capacitors, micro-actuators, pyroelectric security sensors, cooling devices, and pulsed power generators and so on, because of their novel external electric field-induced phase switching behavior between AFE state and ferroelectric (FE) state. The performances of AFE materials are strongly dependent on the phase transformation process, which are mainly determined by the constitutions and the external field. For AFE thin/thick films, the electrical properties are also strongly dependent on their thickness, crystal orientation and the characteristics of electrode materials. Accordingly, various strategies have been employed to tailor the phase transformation behavior of AFE materials in order to improve their performances. Due to their relatively poor electrical strength (low breakdown fields), most PZ-based orthorhombic AFE ceramics are broken down before a critical switching field can be applied. As a consequence, the electric-field-induced transition between AFE and FE phase of only those AFE bulk ceramics, with compositions within tetragonal region near the AFE/FE morphotropic phase boundary (MPB), can be realized experimentally at room temperature. AFE materials with such compositions include (Pb,A)ZrO₃ (A = Ba, Sr), (Pb_1−3/2xLa_x)(Zr_1−yTi_y)O₃ (PLZT x/(1−y)/y), (Pb_0.97La_0.02)(Zr,Sn,Ti)O₃ (PLZST) and Pb_0.99(Zr,Sn,Ti)_0.98Nb_0.02O₃ (PNZST). As compared to bulk ceramics, AFE thin and thick films always display better electric-field endurance ability. Consequently, room temperature electric-field-induced AFE–FE phase transition could be observed in the AFE thin/thick films with orthorhombic structures. Moreover, AFE films are more easily integrated with silicon technologies. Therefore, AFE thin/thick films have been a subject of numerous researches. This review serves to summarize the recent progress of PZ-based AFE materials, focusing on the external field (electric field, hydrostatic pressure and temperature) dependences of the AFE–FE phase transition, with a specific attention to the performances of AFE films for various potential applications, such as high energy storage, electric field induced strains, pyroelectric effect and electrocaloric effect.     

d-Hole localization and the suppression of superconductivity in YBa2(Cu1-xZnx)3O7−y

The temperature and Zn concentration dependence of the electrical resistivity, specific heat, magnetic susceptibility, and electron paramagnetic resonance (EPR) spectra of YBa₂(Cu_1?x Zn _x )₃O_7?y withy～0.1 has been measured forx≤0.16. In addition, the temperature and field dependence of the magnetization has been measured for 2<T<300K and 0<H<9.0T, along with the temperature and quasihydrostatic pressure dependence of the electrical resistivity for selected samples for 0<P<13 GPa. The substitution of Zn for Cu in YBa₂Cu₃O_7?y causes a rapid and nearly linear depression of the superconducting transition temperature,T _c , withT _c going to 0 K forx≥ 0.10. YBa₂(Cu_1?x Zn _x )₃O_7?y retains the YBa₂Cu₃O_7-y orthorhombic structure forx≤0.16 for both the superconducting and nonsuperconducting samples. Initially, the unit cell volume increases nearly linearly with Zn content; however, an abrupt change occurs in the vicinityx=0.8–0.10. Forx<0.10, the temperature dependence of the electrical resistivity,ρ(T), is metallic-like (dρ/dT>0) andρ increases gradually with increasing Zn content. However, forx≥ 0.10,ρ(T) becomes semiconductor-like, with a very rapid increase of the resistivity with increasingx. The electrical resistivity, magnetic susceptibility, EPR spectra, and specific heat all indicate that thed-holes associated with the Cu ions become localized in the nonsuperconducting phase,x>-0.10.     

Electrical properties of Al2O3 and AlPxOy dielectric layers on InP

Al₂O₃ and AlP_xO_y dielectric layers have been deposited on n-type InP substrates and the electrical properties of the interfaces have been evaluated by current-voltage and capacitance-voltage (C-V) measurements on metal- insulator-semiconductor diodes. Layers were deposited by combining trimethyl- aluminum, oxygen and phosphine in a low pressure chemical vapor deposition reactor in which the oxygen was excited in an r.f. plasma prior to mixing with the reactive gases in the deposition zone. The Al₂O₃ layers were invariably too conductive for meaningful C-V measurements; however, the AlP_xO_y layers not only were of high resistivity (? > 10¹⁶ Ω cm) but also exhibited interfacial properties superior to those of SiO₂ layers on InP. The surface potential could be modulated over the full band gap of InP since the surface density was less than 10¹¹ cm^-2 eV^-1 over much of the band gap.     

Magnetic softness and interparticle exchange interactions of (Fe65Co35)1 − x(Al2O3)x (x = 0-0.50) nanogranular films

The effect of Al₂O₃ content on the structure, electrical properties, magnetic properties, and interparticle exchange interactions of (Fe₆₅Co₃₅)_1 − x(Al₂O₃)_x films with Al₂O₃ volume fractions x ranging from 0 to 0.50 was systematically investigated. Among the films with x between 0 and 0.25, the lowest coercivity of 0.56 kA/m was achieved in the (Fe₆₅Co₃₅)_0.82(Al₂O₃)_0.18 film. This is ascribed to the strongest exchange interactions between the Fe₆₅Co₃₅ nanoparticles in this film. Combined with the microstructure analysis of the (Fe₆₅Co₃₅)_1 − x(Al₂O₃)_x films, the modified Herzer's model was extended to interpret the variation of the coercivity with x and analyze the effect of the exchange interactions between the Fe₆₅Co₃₅ nanoparticles on the magnetic softness. The remanence curves confirm the existence of the exchange interactions and reveal the evolution of the exchange interaction strength with Al₂O₃ content.     

Effect of nonstoichiometry on the structure and microwave dielectric properties of cobalt metaniobate

The formation of cobalt metaniobate, CoNb₂O₆, with the columbite structure has been studied, and possible ways of optimizing solid-state synthesis conditions have been examined. Single-phase CoNb_2?y O_6?2.5y has been obtained in the composition range 0 ≤ y ≤ 0.05. The microstructure and microwave dielectric properties of Co_1?x Nb₂O_6?x materials have been investigated. The results indicate that the electrical Q of the nonstoichiometric materials drops sharply for x > 0 because of the presence of Nb₂O₅ as an impurity phase. For x < 0, Q gradually decreases with increasing Co content, which is caused by the rise in lattice strain and presence of Co₄Nb₂O₉ impurity.     

Effect of TiO2 and Al2O3 doping on sintering behavior and microwave dielectric properties of Ba4(Sm0.5Nd0.5)28/3Ti18+xO54+2x ceramics

The effects of TiO₂ and Al₂O₃ doping on the phase formation, the microstructure and microwave dielectric properties of Ba_6?3x (Sm_1?y ,Nd _y )_8+2x Ti₁₈O₅₄ (x = 2/3 and y = 0.5; BSNT) ceramics were investigated. X-ray diffraction patterns showed that the main crystal phase of BSNT + xTiO₂ (x = 0–2) ceramics sintered at 1,280 and 1,300 °C for 5 h was Ba(Sm, Nd)₂Ti₄O₁₂, accompanied by a small number of second phases: Ba₂Ti₉O₂₀ and TiO₂ (x ≥ 1.0), while the new phase BaAl₂Ti₅O₁₄ appeared and the two phases Ba₂Ti₉O₂₀ and TiO₂ disappeared in BSNT ? 2TiO₂ ceramic doped with ≥2 wt% Al₂O₃ successively as identified by scanning electron microscopy and energy dispersive spectroscopy analysis. The TiO₂ and Al₂O₃ working as sintering aids conduced effectively to promote the densification and grain growth, and thus decreasing the sintering temperature, so when the amounts of TiO₂ was increased, Q × f and τ _f values increased continuously. The BSNT ? 2TiO₂ ceramics doped with y wt% Al₂O₃ decreased the density and dielectric constant, increased the Q × f value remarkably and the τ _f values was adjusted from 25.3 to ?7.3 ppm/ °C. When doped with 1.5 wt% Al₂O₃ sintered at 1,260 °C for 5 h, the ceramics obtained the excellent microwave dielectric properties: ε _r  = 74.3, Q × f = 11,928 GHz, and τ _f  = +5.39 ppm/ °C.     

Phase composition of lithium aluminosilicate glass-ceramics

The phase composition of glass-ceramics produced by heat-treating lithium aluminosilicate glass at temperatures from 600 to 1300°C has been determined by x-ray diffraction and electron probe x-ray microanalysis. The materials heat-treated in the range 1000–1230°C have been shown to contain an Si_0.65Al_0.19Ti_0.09Sb_0.013Na_0.032K_0.013Ce_0.008As_0.013O_1.864 glass phase and crystalline solid solutions: tetragonal spodumene-like Li_{1 ? 4x ? 2y} Ti_xZn_yAlSi₃O₈ (x, y ≤ 0.05), sillimanite-based Al_1.92Ti_0.08SiO_5.04, and rutile-based Ti_0.99Sb_0.01O_2.005. The structures and lattice parameters of the crystalline phases have been determined.     

Magnetic properties and NMR studies of the SrAlM hexagonal ferrite system

The magnetic parameters for single crystals of SrAl_xFe_12−xO₁₉ (x=0, 0.8) were measured at 77 and 295 K. The nuclear magnetic resonance (NMR) experimental data of ⁵⁷Fe nuclei in domains of these samples were determined in a wide range of temperatures using the spin-echo technique. Influence of substitution of Fe³⁺ ions by Al³⁺ ions on magnetic properties have been studied with the aid of NMR spectra of ⁵⁷Fe nuclei. It is shown that only 82% of Al³⁺ exist in b-sublattice (site 2a) and 18% of Al³⁺ ions are statistically distributed in the other sublattices for SrAl_xFe_12−xO₁₉. The percentage 82% Al³⁺ in sites 2a experimentally increases the value of anisotropy constant K₁ by 0.60×10⁶ erg cm⁻³. Thus, the contribution of Fe³⁺ ion in the position 2a to the magnetic anisotropy constant of SrFe₁₂O₁₉ in low temperatures is estimated. It is shown that the value K₁(2a)=−0.90×10⁶ erg cm⁻³.     

Elastic properties of lanthanum aluminosilicate glasses

The elastic properties of two series of lanthanum aluminosilicate glasses (15La₂O₃-xAl₂O₃-(85−x)SiO₂ and 25La₂O₃-yAl₂O₃-(75−y)SiO₂, where x, y=15, 20, 25, 30, 35 mol%), were obtained by the ultrasonic pulse-echo technique, at room temperature. The correlation of elastic stiffness, the cross-link density, and the fractal bond connectivity of these glasses are discussed. The derived experimental values of Young’s modulus, bulk modulus, shear modulus and Poisson’s ratio for our glasses are compared with those theoretically calculated values in terms of the Makishima-Mackenzie model.     

Etude de la cinetique d'oxydation de magnetites finement divisees. I - Influence de la substitution par l'aluminium

The kinetics of finely divided, (Fe²⁺Fe³⁺_2?xAl³⁺_x)O₄ type (0 ? x ? 2), substitution magnetites oxidation into metastable phase γ(Fe³⁺_1?yAl³⁺_y)₂O₃ (x = 3y) has been accounted for by means of the law of diffusion, under variable working conditions, of the cationic vacancies generated at solid-gas interface with a diffusion coefficient that decreases when the stoichiometric difference is high. The crystallites size and the trivalent substituant percentage increases, in both cases, slow down the reaction rate.     

Coprecipitation-assisted hydrothermal synthesis of PLZT hollow nanospheres

Lanthanum-modified lead zirconate titanate Pb_1−xLa_x(Zr_1−yTi_y)O₃ (PLZT) hollow nanospheres have been successfully prepared via a template-free hydrothermal method using the well-mixed coprecipitated precursors and the KOH mineralizer. The structure, composition, and morphology of the PLZT hollow nanospheres were characterized by XRD (X-ray diffraction), ICP (inductive coupled plasma emission spectrometer), FTIR (Fourier transform infrared spectra), TG/DTA (thermogravimetric analysis and differential thermal analysis), TEM (transmission electron microscopy) and SEAD (selected area diffraction). The results show that the composition and the morphology control of the PLZT products are determined by the KOH concentration. The PLZT hollow nanospheres with uniform size of about 4 nm were synthesized in the presence of 5 M KOH. The crystalline nanoparticles can be prepared at dilute KOH, in contrast to the amorphous powders prepared at concentrated KOH. Formation mechanisms of the PLZT hollow nanospheres are also discussed.     

Phase equilibria in the system LaMnO3 + δ-SrMnO3-LaFeO3-SrFeO3 − d

We have revealed the formation of a continuous series of orthorhombic LaMn_{1 ? y} Fe_yO₃ solid solutions (0<y<1); La_{1 ? x} Sr_xFeO₃ solid solutions in the composition range 0 < x ≤ 0.8, with an orthorhombic structure at 0 < x ≤ 0.6 and a cubic structure at 0.6 < x ≤ 0.8; and a tetragonal SrMn_{1 ? y} Fe_yO₃ phase in the range 0.6 ≤ y ≤ 1. The composition stability limits of the perovskite phase La_{1 ? x} Sr_xMn_{1 ? y} Fe_yO₃ have been determined, and the 1100°C isotherm of the La₂O₃-SrO-Mn₃O₄-Fe₂O₃ system in air has been constructed.     

Effects of double-doping on physical properties of V2O3-based alloys

The electrical resistivity of several types of (V_1?x?yM_xM′_y)₂O₃ alloys have been investigated, where M and M′ represent Al, Ga, and 3d transition metal elements. It was found that effects previously obtained by incorporation of M = Al, Cr, may be counteracted by use of M′ = Ti or Ga. On the basis of this information 3-dimensional phase diagrams have been sketched out; several sets of critical points have been encountered. The physical characteristics of (Ti_1?yCr_y)₂O₃ have also been determined; the electrical properties of the alloy y = 0.4 and 0.6 are remarkably similar to those of (V_1?xCr_x)₂O₃ with x = 0.02, 0.03.     

Formation of B, Al, Ga, and Si nitrides from their oxides: a reactive laser ablation study

Nitrides such as Si₃N₄ and GaN are made by the reaction of the respective oxide with N₂ or NH₃. In order to understand the mechanism of formation of nitrides, reactive laser ablation of B₂O₃, Al₂O₃, Ga₂O₃, and SiO₂ in pure form, as well as in mixture with carbon, has been carried out in an atmosphere of nitrogen or ammonia in a pulsed supersonic jet. The reaction of N₂ with SiO₂ gives nitridic species such as Si₂N_y (y≤5) in the vapor phase. On reaction with N₂ in the presence of carbon, B₂O₃ and Ga₂O₃ yield species of the type B_xN_y and GaN_y, respectively. Nitridic species are preponderant in the reaction with ammonia only in the case of SiO₂. Al₂O₃ predominantly gives oxynitridic species under the reaction conditions examined.     

Composition dependence of superconductivity in YBa2(Cu3−xAlxOy

Eleven different compositions in the system YBa₂(Cu_3–x Al _x O_y(x=0-0.3) have been synthesized and characterized by electrical resistivity measurements, powder X-ray diffraction, and scanning electron microscopy. The superconducting transition temperature,T _c (onset), was almost unaffected by the presence of alumina due to its limited solubility in YBa₂Cu₃O_7–x . However,T _c(R=0) gradually decreased and the resistive tails became longer with increasing Al₂O₃ concentration. This was probably due to formation of BaAl₂O₄ and other impurity phases from chemical decomposition of the superconducting phase by reaction with Al₂O₃.