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The aim of this work was to examine corrosion behaviour of bare and artificial patinated bronzes during exposure to urban outdoor atmosphere. Studies were conducted on copper and two different bronzes in order to evaluate the influence of substrate composition on patina composition and electrochemical behaviour. Additionally, two different patination methods were compared. Corrosion behaviour was examined using electrochemical impedance spectroscopy with gel-electrolyte electrochemical cell. The composition of patina was determined by ATR-FTIR spectroscopy. The obtained results showed that all studied artificial patinas initially decrease the corrosion resistance of copper and bronzes but in time their corrosion resistance improves, and even for certain combinations, artificial patina-bronze corrosion resistance is higher than that of naturally patinated bronze. [ABSTRACT FROM AUTHOR]

The role of nitrogen in improving the interface properties and the reliability of oxynitride/SiGe interfaces and the dielectric properties of oxynitride films has been studied using constraint theory. Ultrathin (<3 nm) oxynitride films were grown using N[sub 2]O followed by N[sub 2] annealing on strained Si[sub 0.82]Ge[sub 0.18] layers. Silicon dioxide films grown on strained Si[sub 0.82]Ge[sub 0.18] layers were also nitrided in N[sub 2]O by rapid thermal processing. The nitrogen distribution in the oxynitride films was investigated by time-of-flight secondary ion mass spectrometry. The interface state density, charge trapping properties, and interface state generation with constant current and voltage stressing were studied. It is observed that dielectric films grown in N[sub 2]O ambient and subsequently annealed in N[sub 2] have excellent electrical properties. A low stress-induced leakage current and a high time dependent dielectric breakdown are also observed in these films. Improvements in the electrical properties are shown to be due to the creation of a large number of strong Si-N bonds both in bulk and in the SiON-Si[sub 1-x]Ge[sub x] interface region of the dielectric. [ABSTRACT FROM AUTHOR]

The oxide growth of rf sputtered polycrystalline Si[sub 1-x]Ge[sub x] films was found not sensitive to the Ge concentration in the films. The infrared results showed that the oxide grown on Si[sub 0.61]Ge[sub 0.39] film mainly contained GeO[sub 2] and the oxide contained Ge–O–Ge and Si–O–Ge bonds when grown on Si[sub 0.73]Ge[sub 0.27] film. X-ray photoelectron spectroscopy results showed the absence of Ge in the bulk of the oxides for Si[sub 1-x]Ge[sub x] films with x<0.27 and no pile-up of Ge at the SiO[sub 2]/Si[sub 1-x]Ge[sub x] interface. The electrical breakdown fields of oxides grown on Si[sub 1-x]Ge[sub x] films were lower than the oxide breakdown field of polysilicon. The D[sub it] and Q[sub f] values of the SiO[sub 2]/Si[sub 1-x]Ge[sub x] system were found to be rather high at ∼2.1–2.6×10[sup 12] eV[sup -1] cm[sup -2] and ∼1.1–2.7×10[sup 12] cm[sup -2], respectively. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Polycrystalline silicon germanium (Si[sub 1-x]Ge[sub x]) films deposited by the rf sputtering technique were characterized using a combination of transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray diffraction (XRD), and Raman spectroscopy techniques. The TEM results showed small grains (10–20 nm) with microtwins, and AFM showed islands of 100–200 nm in the films. The XRD results show that our films consist of Si[sub 1-x]Ge[sub x] alloy with no cluster of Ge or a Ge-rich material embedded in a Si matrix. The smaller grains in our films could be a result of an abundance of nucleating sites or impurities in the films. Raman spectroscopy results indicate that our films were strain free. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy results showed the formation of SiC precipitation in a rapid thermally oxidized (RTO) Si[sub 1-x-y]Ge[sub x]C[sub y] sample with high-C content. The spectroscopic ellipsometry results showed that the E[sub 1] gap increased and E[sub 2] gap decreased as the C concentration increased. For the oxidized samples, the amplitude of the E[sub 2] transitions reduced rapidly and the E[sub 1] transition shifted to a lower energy. The reduction in the E[sub 2] transitions was due to the presence of the oxide layer. A high-Ge content layer and the low-C content in the RTO films accounted for the E[sub 1] shift to lower energy. The electrical measurements showed that RTO at 800 °C did not improve the oxide quality as compared to 1000 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A low-temperature fabrication of Al x Ga1–xN/GaN MISHEMTs on a 200-mm GaN-on-Si substrate using a common metal stack (Ti/Al/NiV) for concurrent source, drain, and gate formation is demonstrated. An ohmic contact resistance of 0.8 \Omega -mm and a specific contact resistivity of 6\times 10^\mathrm -6 \Omega -cm2 are achieved at an annealing temperature of 500 °C. The fabricated MISHEMTs have excellent electrical characteristics: an I\mathrm{\scriptscriptstyle ON}/I\mathrm{\scriptscriptstyle OFF} ratio of nine decades (due to subnanoampere off-state leakage current up to a −15 V gate bias), and a subthreshold swing of 80 mV/decade (by virtue of a relatively low Al0.23Ga0.77N/GaN interface-trap density on the order of 10^11 cm ^\mathrm -2 eV ^\mathrm -1 ). The demonstrated approach is thus a promising alternative toward the gold-free GaN-on-Si integration. [ABSTRACT FROM AUTHOR]