The invention relates to a high-efficient process for manufacturing
polycrystalline silicon cast ingots. The process is characterized by comprising the following steps: (1) preparing the following raw materials: 60-70% of native polycrystalline and 30-40% of polycrystal auxiliary materials; (2) washing the raw materials; (3) spraying a layer of
quartz sand with the thickness of 0.5mm on the bottom surface of a
crucible, wherein the particle size of the
quartz sand is 70 meshes; putting the raw materials into the
crucible, putting the
crucible on a DS block of an
ingot furnace, vacuumizing the
ingot furnace and starting leakage detecting when the vacuum degree of the furnace chamber is 0.006mbar, wherein the furnace is qualified if the pressure
recovery is less than 0.015mbar in 5 minutes; (4) carrying out a four-step heating process; (5) carrying out a 8-step melting process; (6) carrying out a 8-step
crystal growing process; (7) annealing, cooling, and when the temperature in the
ingot furnace chamber is below 400 DEG C and the
argon fed in the ingot furnace chamber is up to 980mbar, opening the ingot furnace to obtain the
silicon cast ingots. The process disclosed by the invention has the advantages that
crystal flowers of the crystals are uniform and controlled within a certain range, the
crystal defect is reduced and the minority
carrier lifetime is prolonged, so that the conversion efficiency of the cast ingots is increased.