Technology for directional solidification growth of polycrystalline silicon ingot

The invention discloses a technology for the directional solidification growth of polycrystalline silicon ingot, belonging to the preparation of semiconductor material silicon crystal. In a high-performance quartz crucible mold, treated silicon nitride powder is blended to paste as a mold release agent in an atmosphere of argon and nitrogen by using deionized water as blending material, the mold suspends during melting and supports on a water-cooled lower rotating shaft during solidification, the flow velocity of cooling water is increased while the mold descends so that molten silicon begins directional solidification from the bottom of the mold. With the help of the technology, complete ingot without pores and cracks can be obtained with cylindrical crystalline grains and crystalline width reaching the level of millimeter, the doping is controllable, solar cells manufactured therefrom have excellent performances and the optimal value of full-area conversion efficiency runs up to 11.3%.