The invention discloses a production technology for
polycrystalline silicon. The production technology includes the following steps: 1, a first
coating, a second
coating and a third
coating are sequentially arranged on the surface of a
crucible from inside to outside, and a crystalline
silicone leftover material layer is laid; 2, a small quantity of raw
polycrystalline silicon materials in the melted state is contained in the
crucible, and the temperature of the
crucible is controlled to be lower than the
melting point of the crystalline
silicone leftover material layer to enable the small quantity of melted raw
polycrystalline silicon materials to form a
crystallization protection layer; 3, in the vacuum environment, to-be-processed raw polycrystalline
silicon materials are contained in the crucible, placed in a
melting furnace with an
electron beam generating device and processed through
laser irradiation; 4, high-frequency
induction heating is carried out in the vacuum environment, a
slag forming constituent is added,
plasma heating is carried out, steam-and-
hydrogen-mixed
argon is introduced, and
directional solidification is carried out to obtain the polycrystalline
silicon serving as the target product. By means of the production technology, the
boron content, the phosphorous content and the
metal impurity content can be effectively reduced, the complete polycrystalline
silicon is prepared, long
crystal dislocation is less, grain boundaries are proper, and the conversion rate of a polycrystalline silicon battery is increased.