Analytical Electron Microscopy of Silicon Nitride Nanostructures Synthesized from the Vapor Phase

Silicon nitride, Si3N4 is a covalent compound with excellent physical and chemical properties such as corrosion resistance, low-specific weight and good thermal conductivity at ambient and elevated temperatures. Such properties are very attractive in application as advanced ceramics and in semiconductor devise [1]. Nano sized amorphous silicon nitride powders were synthesized at 300 °C by precipitation from the vapor phase reaction of SiCl4 and NH3 and Ar as carrier gas. Solid ammonium halogenide is formed as by-product, in addition to silicon nitride powder.

Synthesis of Silicon Microspheres

The synthesis of silicon microspheres is of outmost importance, especially for the production of optical and electrical devices due to their unique properties displayed by this material. In this paper, we review the research on the synthesis of silicon microspheres, including one physical method, the drop method and several chemical methods, such as vapor-phase reaction, vapor-solid reaction, liquid phase reaction and magnesio-thermal reduction method. The formation mechanisms for silicon microsphere particles are also summarized.