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Abstract

Researchers from Goethe University Frankfurt am Main have developed a portfolio of silylene-based chemistry allowing for the synthesis of defined oligo- and polysilanes from trichlorosilane and hexachlorodisilane. The combination of the new technologies offers an alternative to the conventional energy-consuming silicon chemistry and access to new compounds.

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Background

Silicon represents the essential material in electronic applications, as both the semiconductor and the photovoltaic industry rely on silicon-based devices. Typically, oligo- or polysilanes are used as precursors for vapor deposition dur-ing the manufacturing process. The defined synthesis of these compounds is associated with high energy demands, as usually plasma or thermal processes are involved.

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Solution

The technologies are based on the finding that formal sylilene fragments [:SiCl2] can be generated from trichlorosilane and hexachlorodisilane in the presence of ammonium (R4NCl) or phosphonium chloride (R4PCl). These fragments are utilized as building blocks to construct perhalogenated higher silyl anions. By varying the reaction conditions, linear, cyclic or cagelike oligo- and polysilyl anions are obtained. Especially, length/size and branching of the polysilyl anions can be specifically tuned. Hence, defined polysilyl anions are accessible through simple and energy-saving one-step synthesis. cyclo-Hexasilane [20]Silafullerane Silylcarbanions

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Advantages

• Defined products
• Material properties easily and selectively tunable
• High yields
• Cheap reagents
• Low energy demands

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Scope of application

The new silanes can be used in various contexts, but are especially suited for thin film and vapor deposition of amorphous silicon e.g. for solar energy components. The silylcarbanions exhibit defined Si/C ratios. Hence, they are especially suited for manufacturing of defined silicon carbides. After hydrolysis, the branched C(SiCl3)3 can be employed as crosslinker in silicones.

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Service

Licensing or assignment of the technology is possible as well as a cooperation for further development of the technologies.