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The microstructure, optical and electrical properties of sputtering-derived HfGdO high-k gate dielectric thin films as a function of the Gd doping content have been systematically investigated. X-ray diffraction (XRD) measurements have indicated that Gd doping can form a new stable cubic phase. The optical band gap of the HfGdO gate dielectrics increases gradually from 5.82 to 6.14 eV as the Gd doping concentration increases. The electrical properties, such as permittivity, oxide trapped charge density, border trap charge density and leakage current density of samples, are determined using a semiconductor device analyzer. The formation mechanism of leakage current is also discussed in detail. In addition, the interfacial properties of HfGdO/Si gate satcks were tested to establish the electrical properties. The excellent optoelectronic properties, such as the optical band gap of 5.95 eV, leakage current density of 8.33 × 10 −8 A/cm 2 at a bias voltage of 2 V, oxide trapped charge density of −1.06 × 10 12  cm −2 and a border trap charge density of zero and optimized interfacial properties were observed in the HfGdO thin films with sputtering power of 30 W, indicating that it may become a potential high-k gate dielectric in future complementary metal oxide semiconductor (CMOS) devices. [ABSTRACT FROM AUTHOR]

In this work, the interface chemistry and the reduction of GaAs surface species by using (NH 4 ) 2 S solution prior to Gd-doped HfO 2 (HGO) thin film deposition and the removal of Ga Oxides and elemental As by rapid thermal annealing (RTA) have been investigated by X-ray photoelectron spectroscopy (XPS). Additionally, the effect of the surface passivation and rapid thermal annealing on the electrical properties of MOS capacitors based on sputtering-derived HGO as gate dielectric on GaAs substrate has been detected by means of capacitance-voltage ( C-V ) and leakage current density-voltage ( J-V ) measurements. Based on electrical analysis, it can be noted that the constantly improvement of electrical properties, such as the decreases of flat band voltage (V fb ), hysteresis (ΔV fb ), oxide charge density (O ox ), border trapped oxide charge density (N bt ) and leakage current density, have been observed. Especially, the dielectric constant of 16.72, flat band voltage V fb of 1.19 V, hysteresis ΔV fb of 0.04 V, leakage current density of 1.54 × 10 −5 A/cm 2 at bias voltage of 1 V, total positive charge density and border trap charge density of 6.09 × 10 12 cm −2 and 2.54 × 10 11 cm −2 , respectively render 600 °C-annealed HGO thin films, potential high-k gate dielectrics in future CMOS devices. [ABSTRACT FROM AUTHOR]

Abstract Fe-based amorphous alloys with excellent soft magnetic properties always suffer catastrophic annealing embrittlement. The soft magnetic and mechanical properties of a series of Fe 84.3- x Co x Si 2 B 13 Cu 0.7 (x = 0, 2, 4, 6, 8) amorphous alloy ribbons were investigated. With appropriate substitution of Co for Fe, the B S of the alloys shows a slight increase and the H C remains at a low level. From two-point bending tests, a sharp transition from ductility to brittleness can be observed upon annealing. The embrittlement can be attributed to localized shear bands due to shear bands branching during deformation. It is found that the ductile-brittle transition temperature increases slightly by applying cryogenic thermal cycling treatment to annealed ribbons, indicating that the annealing embrittlement can be improved to some extent by cryogenic thermal cycling treatment. According to nanoindentation results, the increased shear transformation zone volume is responsible for the bending ductility increment. Ultimately, a ductile Fe 80.3 Co 4 Si 2 B 13 Cu 0.7 amorphous alloy ribbons with a B S of 1.68 T and a H C of 4.8 A/m were obtained by cryogenic thermal cycling treatment after annealing. Highlights • With appropriate substitution of Co for Fe, the B S shows a slight increase, and the H C remains at a low level. • The bending ductility of the annealed ribbons is recovered to some extent by cryogenic thermal cycling. • The increased shear transformation zone volume is responsible for the bending ductility increment. [ABSTRACT FROM AUTHOR]

Abstract Crystallization is a uniform behavior for amorphous alloys while it can be fairly complex. For Fe-B-C alloys with high Fe content, the precipitation of α-Fe is ahead of the Fe-metalloid compounds with temperature increasing. It is found that the crystallization products of Fe-B-C amorphous alloys with Fe content lower than 82% can be modulated by appropriate annealing. The Fe 82 B 12 C 6 alloy is eutectoidally crystallized with the simultaneous precipitation of α-Fe and Fe-metalloid compounds under conventional annealing. It is a diffusion controlled three-dimensionally growth with a constant nucleation rate. However, only α-Fe nanocrystals with a low volume fraction form under rapid annealing, which is evidenced by the results of X-ray and electron diffractions along with the magnetometry. The transmission electron microscopy bright-field images show that the α-Fe nanocrystals obtained by rapid annealing have two different morphologies. One is dendritic with a large characteristic length and the other is equiaxed-like. Highlights • Single α-Fe phase is obtained under suitable rapid annealing for Fe 82 B 12 C 6 alloy. • The α-Fe nanocrystals obtained by rapid annealing have two different morphologies. • The coercivity is drastically reduced due to the absence of hard magnetic phase. [ABSTRACT FROM AUTHOR]

• The nanoscale structural heterogeneity was analyzed by small-angle X-ray scattering and atomic force microscopy. • The microalloying of Co and Ni exhibits an opposite effect on the nanoscale structural heterogeneity. • The variation of mechanical behavior further proves the evolution of the nanoscale structural heterogeneity with Co and Ni substitution. • The evolution of magnetic properties induced by microalloying can be attributed to the variation of nanoscale structural heterogeneity. Nanoscale structural heterogeneity is a critical parameter for understanding the structure-property relationships in amorphous alloys. Herein, the small-angle X-ray scattering and atomic force microscopy were utilized to quantitatively investigate the nanoscale structural heterogeneity of the Fe 80- x M x Si 9 B 11 (M = Co and Ni; x = 0, 2, 4) amorphous alloys. The results show that the nanoscale structural heterogeneity of the amorphous alloys increases prominently with Ni substitution, but gradually decreases with the increase of Co content. Such evolution of structural heterogeneity was further verified by the changes in mechanical behavior. The microalloying of Ni can increase the plastic deformation ability and reduce the microhardness, whereas an opposite effect is found in the Co-doped alloys. Finally, Mössbauer spectroscopy reveals an enhancement in ferromagnetic exchange interaction and magnetic anisotropy with Co substitution, while the microalloying of Ni leads to a deteriorative result. Such variations in magnetic properties can be attributed to the evolution of nanoscale structural heterogeneity with Co and Ni additions. Our observation serves as a link between the nanoscale structural heterogeneity and magnetic properties, providing a new sight into understanding the structural origin of the changes in magnetic properties of Fe-based amorphous alloys. [ABSTRACT FROM AUTHOR]

Fe-based metallic glasses are known to have excellent soft magnetic properties, but restricted to the disastrous annealing embrittlement. A novel class of Fe 84- x B 14+ x Zr 2 (x = 0, 3, 6) metallic glasses with extraordinary annealing bending ductility and excellent soft magnetic properties were developed. The metallic glasses exhibit a high B S of 1.54–1.64 T and a low H C of 4.1–5.8 A/m. It is noteworthy that the Fe 84 B 14 Zr 2 metallic glass exhibits the highest ductile to brittle transition temperature among all Fe-based metallic glasses reported to date and the ductile to brittle transition temperature decreases with the decrease of Fe content. Moreover, the well-distributed shear bands can still be formed during bending for Fe 84 B 14 Zr 2 metallic glass after 680 K annealing. Pronounced β-relaxation peak has been observed for Fe 84 B 14 Zr 2 metallic glass in its relaxation spectra. We demonstrate that the bending deformation ability is closely correlated to the β-relaxation. The underlying mechanism for the extraordinary bending deformation ability of Fe 84 B 14 Zr 2 metallic glass after annealing can be attributed to the heterogeneous structure with plenty of loosely packed zones as revealed by the pronounced β-relaxation and high resolution transmission electron microscopy. • Fe 84 B 14 Zr 2 MG with good soft magnetic properties exhibits extraordinarily high DBT temperature. • Fe 84 B 14 Zr 2 MG shows pronounced β-relaxation, relating to plenty of loosely packed zones. • The β-relaxation is regarded as an indication for the bending ability of metallic glasses after annealing. [ABSTRACT FROM AUTHOR]

The disastrous annealing embrittlement of Fe-based metallic glasses with excellent soft magnetic properties is a long-standing issue. In order to alleviate the annealing embrittlement without worsening the soft magnetic properties, ferromagnetic elements Co and Ni are introduced to the Fe 84 Si 2 B 13 P 1 metallic glasses. The microstructure, mechanical and magnetic properties are investigated by synchrotron diffraction, two-point bending test and magnetometry. It is found that, in contrast to Co, proper Ni substitution for Fe significantly optimizes the H c of Fe 84 Si 2 B 13 P 1 metallic glasses and keeps the B s at a high level. According to bending tests, the ductile-brittle transition temperature of the metallic glasses increases slightly with Ni substitution and decreases prominently with Co substitution. Ultimately, the ductile Fe 82 Ni 2 Si 2 B 13 P 1 metallic glasses with B s of 1.65 T and H c of 3.4 A/m have been successfully obtained. Macroscopically, the cheerful propensity to form well-distributed shear bands during bending of Ni-substituted annealed alloys contributes to their good ductility. Furthermore, the alteration of ductile-brittle transition temperature can be conducted by the structural change at the medium-range scale as revealed by the pair distribution function measurements. After annealing the compression at atomic scale ranging from 6 Å to 16 Å of Co-substituted metallic glasses may hinder the creation of well-distributed shear bands and give rise to the deterioration of bending ductility. This work provides a perspective to understand the ductile-brittle transition of metallic glasses from the atomic scale. • With proper substitution of Ni for Fe, H c of Fe 84 Si 2 B 13 P 1 alloys decreases and B s keeps at a high level. • The bending ductility of annealed ribbons improves by Ni substitution. • The Ni-substituted alloys show good propensity to form well-distributed shear bands during bending. • Medium-range structure compression of Fe 78 Co 6 Si 2 B 13 P 1 alloy results in its ductility deterioration. [ABSTRACT FROM AUTHOR]

Annealing temperature dependent microstructure, optical and electrical properties of sol-gel-deposited HfGdO high-k gate dielectric thin films on Si substrates are systematically investigated. X-ray spectroscopy (XPS) analyses have confirmed that the interfacial layer at HfGdO/Si interface is mainly silicate and the component increases with increasing the annealing temperature. Moreover, the band offsets for HfGdO/Si gate stack as a function of annealing temperature also have been determined. As a result, it can be noted that increase in valence band offset (Δ E v ) and reduction in conduction band offset (Δ E c ) have been detected. Electrical characterizations have indicated that higher annealing temperature effectively improves the electrical characteristics, such as the increased effective permittivity ( k ) and the decreased flat band voltage shift (Δ V fb ). However, due to the reduced Δ E c and the appearance of crystallization, increased leakage current density has been observed with the increase in annealing temperature. [ABSTRACT FROM AUTHOR]

Metallic glasses are structurally heterogeneous on the atomic and nano scales. However, few investigations have been conducted on how the structural heterogeneities in these two scales co-evolve during annealing. In this work, the atomic and nanoscale structural heterogeneity evolution accompanying the magnetic softness is systematically discussed based on the literature and our previous synchrotron X-ray diffraction and atomic force microscopy results. We revealed the co-evolution mechanism of structural heterogeneities on the atomic and nano scales during annealing via the insight of percolation theory from the point of view of the local five-fold symmetry of the clusters. The results indicate that the reduction of atomic-scale structural heterogeneity during annealing is accompanied by an increase in the degree of local five-fold symmetry of the clusters and an alteration in their connection patterns. As the local five-fold symmetry of clusters in Fe-based metallic glasses reaches the percolation threshold, the nanoscale liquid-like regions tend to transform into solid-like regions. The great degree of percolation causes the pronounced weakening of the nanoscale structural heterogeneity accompanying changes in the shape and number of the liquid-like regions. The reduction of the number of liquid-like regions causes a reduction in vertical anisotropy and magnetic softening due to a more uniform and less free volume within the sub-circular shaped liquid-like region. • The evolution of the atomic/nano scale structural heterogeneity and its relation to the magnetic softness was discussed • The co-evolution mechanism of structural heterogeneities on the atomic and nano scales during relaxation is revealed. • The shape of liquid-like regions tend to become nearly circular during relaxation contributing to magnetic softening. [ABSTRACT FROM AUTHOR]

In this work, the band gap, interfacial properties and electrical properties of Gd doped ZrO 2 high-k gate dielectric films deposited by solution method have been systematically investigated. Results have shown that Gd doping can increase band gap energy from 5.65 to 5.92 eV and effectively restrain the formation of low-k SiO x interfacial layer between dielectric and Si substrate. Moreover, the conduction band offset is increased from 2.57 to 3.06 eV by Gd doping, which effectively reduces the leakage current density to 1.8 × 10 −6 A/cm 2 . [ABSTRACT FROM AUTHOR]

HfAlO/Ge gate stack with Al 2 O 3 passivation layer and different Al 2 O 3 concentration in HfAlO layer has been deposited on Ge substrate by atomic layer deposition. Based on measurements from capacitance-voltage and current density-voltage curves, the evolution of the electrical properties of Ge-based MOS capacitors based on HfAlO/Al 2 O 3 /Ge gate stack has been determined as functions of precursor ratio and annealing temperature. It has been found that high annealing temperature and high Al 2 O 3 incorporation in HfAlO films can obtain improved electrical properties such as low hysteresis, low flat-band, low flat-band shift and low interface-state density. However, the oxide-charge density obviously increases with rising the annealing temperature and decreasing Al 2 O 3 incorporation in HfAlO film. By analysis and calculation, it can be noted that the samples annealed at 500 °C holds the lowest leakage current density and the change of the precursor ratio has no apparent effect in 500 °C-annealed Ge MOS capacitor. To investigate current conduction mechanism of Ge MOS capacitors employing HfAlO/Al 2 O 3 gate stacks, current density-voltage measurements have been carried out as functions of annealing temperature and precursor ratio. The involved leakage current conduction mechanisms of the as-deposited and 500 °C-annealed HfAlO/Al 2 O 3 /Ge MOS capacitors for substrate injection also have been discussed in detail. [ABSTRACT FROM AUTHOR]

In this letter, annealing temperature dependence on the structure, band gap energy and electrical properties of TiO 2 doped ZrO 2 gate dielectrics deposited by sol-gel method at low temperature were systemically investigated. The crystalline temperature of TiO 2 doped ZrO 2 is up to 600 °C. The transmittance and band gap value of the ZrTiO x film were about 75% and 4.0 eV, respectively. 300 °C-annealed ZrTiO x MOS capacitor with high dielectric constant of 34.9, a small hysteresis value of 0.004 and low leakage current density of 2.7 × 10 −4 A/cm 2 were obtained. The dominant conduction mechanisms of Al/ZrTiO 4 / n -Si MOS structures were schottky emission and ohmic conduction in the low electric field and direct tunneling in the high electric field. As a result, it can be concluded that sol-gel derived ZrTiO x gate dielectric displays potential application as is a promising candidate in future MOS electronic devices. [ABSTRACT FROM AUTHOR]

High- k HfO x N y and HfO 2 have been applied to amorphous InGaZnO ( a -IGZO) metal–oxide–semiconductor (MOS) capacitors as high-k gate dielectrics by using radio-frequency sputtering at room temperature. Effects of nitrogen incorporation on the optical band gap, band alignment and electrical properties of HfO x N y /IGZO/Si gate stacks have been systematically investigated by spectroscopic ellipsometry (SE), UV–vis spectroscopy, x-ray photoemission spectroscopy (XPS) and electrical measurements. Experimental results have confirmed the successful incorporation of nitrogen into HfO 2 films and reduction in band gap with the incorporation of nitrogen for HfO x N y thin films. Reduction in valence band offset and increase in conduction band offset have been observed for HfO x N y /IGZO gate stack. Electrical properties measurements for a -IGZO MOS capacitors based on HfO x N y gate dielectrics have indicated that nitrogen incorporation leads to the improved interface quality, increased dielectric constant, reduced hysteresis voltage, and decreased leakage current density. Meanwhile, the leakage current mechanism under gate injection for MOS capacitors based on HfO 2 and HfO x N y high-k gate dielectrics has been investigated systematically. [ABSTRACT FROM AUTHOR]

Abstract: Cations of Y and Sr co-substituting for La and Ca at A site in La2/3Ca1/3MnO3 compound, La2/3−x Y x Ca1/3−y Sr y MnO3, were synthesized successfully by solid-state reaction. X-ray diffraction shows there is only one phase with the dopants of Y and Sr within x ≤0.20 or y ≤0.19. The lattice parameters along a-, b-, and c-direction remain almost unchanged with x ≤0.20. The bond angle of Mnh name="sbnd" />Mn increases from 151.9° for x =0 to 172.7° for x =0.20 monotonically, which indicates that the Jahn–Teller effect in MnO6 octahedron decreases with increasing x. The temperature dependence of resistance with/without magnetic applied were measured and fitted theoretically. The metal-to-insulator transition temperature, T MI, decreases with increasing the Y content with x ≤0.10 while T MI increases slightly with further increasing x. The Y-content dependence of magnetoresistance shows a parabolic behavior. The maximum MR value corresponds to x =0.08–0.10. We attributed these variations in the structure and transportation to the cation disorder due to the cation doping. [Copyright &y& Elsevier]

Abstract: Modulation-doped Al0.22Ga0.78N/GaN heterostructure with 1000Å Si-doped n-Al0.22Ga0.78N barrier (n-AlGaN) were deposited on (0001)-oriented sapphire (α-Al2O3) by means of atmosphere-pressure metal-organic chemical vapor deposition. The reciprocal space mappings of symmetric reflection (0002) and asymmetric reflection (10 4) were measured with high resolution X-ray diffraction. The results indicate that the microstructure and strain status of barrier correlate to that of the underlying i-GaN layer. The barrier holds an “abnormal” strain-relaxation status, which probably results from the internal defects of n-AlGaN and the strain relaxation status at the i-GaN/α-Al2O3 interfaces. The results from grazing incidence X-ray diffraction show that the strain in barrier is nonuniform, which is consistent with the results from the reciprocal space mappings. [Copyright &y& Elsevier]

The structure-property relationships in amorphous alloys are far from being fully understood. Here we show an unusual structural rearrangement occurring over medium-range length scale prior to crystallization for a (Fe 0.5 Co 0.5) 72 Si 4 B 20 Nb 4 amorphous alloy ribbon upon heating by in-situ synchrotron diffraction, whereas the short-range structure shows no anomaly. During the above process, local stress field generates and results in the enlargement of coercivity. This can be further supported by the magnetic force microscopy images showing an enhancement of magnetic phase contrast after annealing the sample at a temperature where the unusual structural change occurs. Moreover, the average grain size derived from the transmission electron microscopy images of the crystallized (Fe 0.5 Co 0.5) 72 Si 4 B 20 Nb 4 ribbon is much smaller than that of (Fe 0.5 Co 0.5) 76 Si 4 B 16 Nb 4 , suggesting the slow crystallization kinetics caused by the local stress field. This work highlights the role of medium-range order in determining the properties of amorphous alloys. • Unusual structural change at medium-range occurs in a Fe-based amorphous alloy. • Coercivity increases drastically due to the enhanced stress-induced anisotropy. • The structural rearrangement results in slow crystallization kinetics. [ABSTRACT FROM AUTHOR]