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Near-ideal behavior in Schottky contacts to Si-doped AlN was observed as evidenced by a low ideality factor of 1.5 at room temperature. A temperature-independent Schottky barrier height of 1.9 eV was extracted from temperature-dependent I–V measurements. An activation energy of ∼300 meV was observed in the series resistance, which corresponded to the ionization energy of the deep Si donor state. Both Ohmic and Schottky contacts were stable up to 650 °C, with around four orders of magnitude rectification at this elevated temperature. These results demonstrate the potential of AlN as a platform for power devices capable of operating in extreme environments. [ABSTRACT FROM AUTHOR]

A study on frustration caused to users during instances like program crash, inability to open e-mail etc, is discussed. Human-computer interface is explained using episode report methodology.

DC current-switching and power-switching transients of various GaN-based FET structures are investigated. Two different characteristics are compared, namely, thermal and electronic transients. While the thermal transients are mainly reflected in changes in channel carrier mobility, the electronic transients are dominated by charge instabilities caused by the polar nature of the material. The discussion of the electronic transients focuses, therefore, on instabilities caused by polarization-induced image charges. Three structures are discussed, which are: 1) a conventional AlGaN/GaN heterostructure FET; 2) an InGaN-channel FET; and 3) an AlGaN/GaN double-barrier structure. In structures 2) and 3), field-induced image charges are substituted by doping impurities, eliminating this source of related instability. This is indeed observed. Index Terms--GaN, heterostructure field-effect transistors (HFETs), switching experiments, transient analysis.

Epitaxial single crystal and boron-doped diamond layers were exposed to reactive ion etching in Ar/O2 plasma (rf power of 25 W and self-bias of 100 V); and the electrical, structural, and electrochemical characteristics of the exposed surface were investigated. Angle-resolved x-ray photoemission spectroscopy (XPS) measurements revealed a nonuniform layer of amorphous carbon at the exposed surface with an average thickness of approximately 4 nm, as confirmed also by atomic force microscopy profiling of selectively etched areas. On highly boron-doped diamond, the plasma-induced damages resulted also in a nonconductive surface layer. This damaged and insulating surface layer remained resistant to graphite-etching chemicals and to rf oxygen plasma but it was removed completely in microwave hydrogen plasma at 700 °C. The surface characteristics after the H-plasma process followed by wet chemical oxidation were restored back to the initial state, as confirmed by XPS. Such 'recovery' treatment had been applied to an all-diamond submicrometer electrode array initially patterned by an Ar/O2 plasma etching. The electrochemical characteristics of this electrode array were improved by more than two orders of magnitude, approaching theoretical limit for the given geometrical configuration. [ABSTRACT FROM AUTHOR]

Si-doped InN layer by molecular beam epitaxy was subjected to anodic oxidation in 0.1 M potassium hydroxide (KOH) electrolyte and characterized by electrochemical methods to derive carrier profile at the InN surface. The obtained results were compared to the characteristics of a planar resistor structure and vertical metal-oxide-semiconductor (MOS) diodes with Ni-metal contacts on the oxidized InN. Both measurements in electrolyte and in air confirmed the formation of a surface oxide layer after the anodic treatment and depletion of the surface accumulation charge of the as-grown InN. The upward band bending of InN at the oxide interface was also concluded from the analysis of capacitance-voltage characteristics of the MOS diodes. Transmission electron microscopy revealed a nonuniform oxide layer containing porelike structures of a few nanometers in diameter. [ABSTRACT FROM AUTHOR]

It was shown that a strong anodic oxidation of 100-oriented diamond induces the electronic surface states, which pin the surface Fermi level at about 3.6 eV above the valence-band maximum. The characteristics of the electronic surface barrier were evaluated from the analysis of boron-doped diamond electrodes and correlated with the four-point probe measurements of an oxidized diamond resistor with a boron delta-doped channel. The same evaluation procedure applied to the case of a wet chemical oxidation yielded a surface barrier of 1.9 eV, which is consistent with the data in the literature. The characteristics of the 3.6 eV barrier by the anodic oxidation remained stable after subsequent chemical treatments even at elevated temperatures, and were also not degraded in air for a long time. The x-ray photoemission spectroscopy study showed that the anodic oxidation generates complex oxygen functionalities, like polycarbonate groups, and also C-O-C bridging bond structures with possible contribution of an additional chemisorbed layer. [ABSTRACT FROM AUTHOR]