Silicon Feedstock Cost Reduction; Implementation of Fluidized Bed and Microwave Technology

Silicon as a material has become increasingly important in the last years due to the rising demand for Si solar cells. Today, one of the main obstacles in continuing the impressive industrial growth of Si solar cell supply is the availability of Si feedst ock of adequate quality for the solar cell industry. The goal of the project is to reduce the production cost and energy required for the production of solar grade silicon (Si) by decomposition of silane (SiH4) using a combination of the Fluidized Bed (F B) reactor concept and microwaves as an energy source. The use of a FB concept has been shown to reduce energy consumption by 80-90% compared to the traditional Siemens process for decomposition of SiH4. In our opinion, using microwaves has a potential t o reduce this further by improving heat transfer to the seeding particles in the fluidized bed. For the above stated goal to be reached, several sub-goals need to be reached: - Get a complete overview of the options within FB technology and decide which direction to proceed - Carry out modeling of heat transfer (thermodynamics) and particle movement (hydrodynamics) of different designs to evaluate which to use - Design, construct and test a reactor concept that can run continuously and produce Si feedsto ck for both single crystal and multi crystalline Si ingot formation - Determine critical product parameters of the Si material, including material purity, the shapes, sizes and size distributions of the Si particles and the process yield. - Establish the characterization techniques needed to evaluate the abovementioned characteristics Through this project highly skilled personnel will be educated by use of PhDs and Master programs. Additionally, the project will have at its disposition highly qualified research personnel at all involved institutions.