NEWS

Toyo Aluminium, one of the world's largest Aluminium powder, pigments , photovoltaic Al paste and photovoltaic backsheets maker, have succeed in developing simple and cost effective technology to transfer the whole silicon wafer surface area into SiGe layer with Ge concentrations exceeding 30% using its innovation screen-printing paste technology.

The innovation technology will allow the process of forming thick SiGe layers over the large area silicon wafers with reduced threading dislocation densities. "This will allow the fabrication of III-V compounds solar cells on low cost and large area SiGe layers formed on cheap Si wafers. The silicon wafers with the SiGe surface layer may be used as a bottom silicon cell by adjusting the doping species in the SiGe layer to form n+ or p+ regions", said Dr. Marwan Dhamrin, leader of the research group who developed this innovation. The innovation will allow the terrestrial solar cell module application of the III-V compound solar cells similar to conventional large area modules of crystalline silicon.

In addition, the SiGe layers on Silicon developed with this innovation will bring the heterojunction bipolar transistors fabrication cost further cheaper allowing a new horizon for next generation of communication electronics and devices. Conventionally, silicon-germanium as a semiconductor is manufactured on silicon wafers using hazardous liquid gases, complicated and expensive processes such as MOCVD to deposit few nm thick SiGe layers with low Ge concentrations.

*img:SEM and EDX Images of Si/SiGe interface