The Interpretation of Marker Experiment Conducted during Formation of Higher Oxide on the Surface of Lower Oxide

The marker method in studying the formation mechanism and defect structure of higher oxide during oxidation of lower oxide has been discussed. The approach to this problem needs specific treatment, both in experimental procedure and in the interpretation of results. It has been shown that the correct results of marker experiments in the case of highly defected substrates can be obtained, if these substrates before the marker deposition process are submitted to homogenization under highest oxidant activity, at which they remain stable at a given temperature. In addition, the nonstoichiometry must be considered in formulating appropriate chemical reactions, being the basis for foreseeing the location of markers in the interior of reaction product. The other very important problem consists in the possibility of the formation of reaction product not only on the surface of oxidized substrate but also inside of this substrate. In such a situation, the formulation of final conclusions concerning the crystalline lattice disorder from marker position should be combined with considerations of chemical reactions and transport processes occurring in a given substrate.

Dimensional Effect on DIBL in Silicon Nanowire Transistors

Drain-induced barrier lowering (DIBL) is crucial in many applications of silicon nanowire transistors. This paper determined the effect of the dimensions of nanowires on DIBL. The MuGFET simulation tool was used to investigate the characteristics of the transistors. The transfer characteristics of transistors with different dimensions were simulated. The results show that longer nanowires with smaller diameters and lower oxide thickness decrease DIBL and tend to possess the best transistor characteristics.

Study of Non-Aqueous Passivation on GaSb (100) Surfaces

Due to the high chemical reactivity of GaSb surfaces, many commonly used aqueous sulfide passivation techniques lead to the growth of surface oxides that degrade device performance. We have developed a non-aqueous passivation regime consisting of Na2S/benzene/15-crown-5/oxidant. The use of a non-polar, aprotic organic medium required the addition of a specific chelating agent, i.e. a 15-crown-5 ether, to solubilize sodium sulfide, and organic oxidizing agents, such as anthraquinone and benzophenone, to act as electron acceptors. The surface optical and chemical properties of GaSb surfaces after aqueous and non-aqueous sulfide treatments were compared. Non-aqueous passivation resulted in higher PL intensity, lower oxide content, and a less amount of elemental Sb than aqueous passivation.

Diagramme de phases du système K–K2O et le monooxyde de potassium K2O

Le diagramme de fusion du système K–K2O est obtenu par la technique de l'analyse thermique différentielle. La fusion du monooxyde de potassium K2O se manifeste à 646 + 5 °C. Des transformations cristallines réversibles de l'oxyde sont observées à 317, 372 et 446 °C. La dismutation de l'oxyde en peroxyde et métal apparait à une température approximativement égale à celle de la dernière des transitions. Le diagramme K–K2O comporte un eutectique à une température très proche de la température de fusion du potassium et une monotectie à 600 °C (concentration monotectique: 30.5 % atomique d'oxygène). Aucune existence de sous-oxyde n'est démontrée.The potassium–oxygen phase diagram has been determined up to the composition of K2O by the technique of differential thermal analysis. Potassium monoxide K2O melts at 646 ± 5 °C. Reversible transitions occur in solid K2O at 317, 372, and 446 °C. Disproportion of the monoxide into the peroxide and metal occurs at a temperature identical or very near to that of the last transition. The K–K2O eutectic melts at a temperature very close to the melting temperature of pure K (degenerate eutectic) and the monotectic at 600 °C (monotectic concentration: 30.5 oxygen atomic %). No evidence has been obtained that would indicate the existence of a lower oxide.