Silicon discs esp. for solar cells - hot-pressed from droplet of melted polycrystalline silicon rod

摘要

A method of making disc-shaped silicon objects, particularly for use in solar cells consists of melting a suitable quantity of polycrystalline silicon to produce a droplet; This is then pressed in a mould to produce a disc of the desired size and thickness. Suitably a silicon rod is held obliquely in the path of a laser beam so that its lower end melts to form the droplet. Alternatively, the silicon rod is held vertical and an induction heating coil surrounds its lower end; the mould then operates with a horizontal motion. Used for producing flat silicon discs of the quality required for solar cells, i.e. lower quantity than that for silicon chips.