Silicon oxide

About: Silicon oxide is a research topic. Over the lifetime, 22220 publications have been published within this topic receiving 260986 citations.

In situ imaging of the conducting filament in a silicon oxide resistive switch

Abstract: The nature of the conducting filaments in many resistive switching systems has been elusive. Through in situ transmission electron microscopy, we image the real-time formation and evolution of the filament in a silicon oxide resistive switch. The electroforming process is revealed to involve the local enrichment of silicon from the silicon oxide matrix. Semi-metallic silicon nanocrystals with structural variations from the conventional diamond cubic form of silicon are observed, which likely accounts for the conduction in the filament. The growth and shrinkage of the silicon nanocrystals in response to different electrical stimuli show energetically viable transition processes in the silicon forms, offering evidence for the switching mechanism. The study here also provides insights into the electrical breakdown process in silicon oxide layers, which are ubiquitous in a host of electronic devices.

Nano Si Cluster- SiO x ‐C Composite Material as High-Capacity Anode Material for Rechargeable Lithium Batteries

Abstract: Nanosilicon cluster-SiO x -C composites including nanosize Si particles were prepared by using the disproportionation of silicon mono-oxide and the polymerization of furfuryl alcohol. The applicability of nanosilicon composites as anode material for rechargeable lithium batteries was investigated on the basis of X-ray diffraction measurement, observation by transmission electron microscopy (TEM) and electrochemical studies. TEM analysis showed that Si clusters in the range of 2-10 nm were distributed homogeneously within silicon oxide phases. The nanosilicon composite anode had a large capacity of ca. 700 mAh/g and a long cycle life of >200 cycles. The improvement of cyclability is due to the nanosize Si particles and their uniform dispersion within the silicon oxide phase retained by the carbon matrix, which could effectively suppress the pulverizing of Si particles by the volume change during lithium insertion and extraction.

Oxidation of Nb–Si–Cr–Al in situ composites with Mo, Ti and Hf additions

Abstract: The effects of Mo, Ti and/or Hf additions on the isothermal oxidation behaviour of Nb–Si–Cr–Al-based in situ composites in static air at 800 °C and 1200 °C were studied for the as-cast and heat-treated materials. After heat treatment at 1500 °C, the microstructures of all the alloys consisted only of the niobium solid solution (Nb ss ) and Nb 5 Si 3 phases. The addition of Ti and the decrease of the Mo concentration to 2 at.% improved the oxidation resistance of the alloys at 800 °C dramatically. The Hf addition had no significant effect on the oxidation behaviour of Nb–24Ti–18Si–5Al–5Cr–2Mo–5Hf (at.%) at 800 °C. The oxidation resistance of the alloys was found to be sensitive to the volume fraction of Nb ss . The coarsening and the increase of the volume fraction of the Nb ss phase in the heat-treated alloys were mainly responsible for the degradation of their oxidation resistance. Preferential attack of the Nb ss phase was observed in all the alloys. Pesting oxidation behaviour was exhibited at 800 °C by the Nb–18Si–5Al–5Cr–5Mo (as-cast), Nb–24Ti–18Si–5Al–5Cr–5Mo (as-cast), Nb–24Ti–18Si–5Al–5Cr–2Mo (heat-treated) and Nb–24Ti–18Si–5Al–5Cr–2Mo–5Hf (heat-treated) alloys. Pesting of the alloys occurred due to a combination of the presence of elements that oxidised rapidly and the restricted deformation capability of the scales. Spallation of oxide scales during cooling was observed for the as-cast and heat-treated Nb–24Ti–18Si–5Al–5Cr–2Mo and Nb–24Ti–18Si–5Al–5Cr–2Mo–5Hf alloys at 1200 °C. In the diffusion zones formed in the alloys without Hf addition, the 5–3 silicide was not oxidised. The TiNbO 4 , TiNb 2 O 7 , Ti 2 Nb 10 O 29 and silicon oxide were present in the scales formed on the Nb–24Ti–18Si–5Al–5Cr–2Mo and Nb–24Ti–18Si–5Al–5Cr–2Mo–5Hf alloys at 1200 °C and Hf oxide was also present in the latter alloy. At 1200 °C, in the Ti containing alloys, large Ti oxide particles formed at the Nb ss and 5–3 silicide interface and fine Ti oxide particles formed inside the Nb ss . Needle-like Hf oxide formed inside the 5–3 silicide in the heat-treated Hf containing alloy, which resulted in the degradation of its oxidation resistance. No protective oxide scale was formed on any of the alloys studied in this work.

Enhancement of silicon oxide etch rate and nitride selectivity using hexafluorobutadiene or other heavy perfluorocarbon

Abstract: A plasma etching process, particularly useful for selectively etching oxide over a feature having a non-oxide composition, such as silicon nitride and especially when that feature has a corner that is prone to faceting during the oxide etch. A primary fluorine-containing gas, preferably hexafluorobutadiene (C 4 F 6 ), is combined with a significantly larger amount of the diluent gas xenon (Xe) enhance nitride selectivity without the occurrence of etch stop. The chemistry is also useful for etching oxides in which holes and corners have already been formed, for which the use of xenon also reduces faceting of the oxide. For this use, the relative amount of xenon need not be so high. The invention may be used with related heavy fluorocarbons and other fluorine-based etching gases.