IMEC is developing a new method to produce ~50µm thin crystalline silicon wafers for use in solar cells. The process involves mechanically initiating and propagating a crack parallel to the surface of a Si wafer. In this way, Si foils with an area of 25cm² and a thickness of 30-50µm have already been produced. The method makes use of industrially available tools (screen printer, belt furnace) and is potentially kerf-loss free.Adding an ultra-thin wafer or foil of active silicon on top of a low-cost substrate is a promising solution to reduce the amount of high-grade silicon used in solar cells. IMEC is pursuing different paths to produce such foils of crystalline Si at an acceptable cost. One of the promising methods is a lift-off process that only requires the use of a screen printer and a belt furnace; no ion-implanted or porous layer is needed.
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