Monocrystal-like silicon ingot, preparation method of monocrystal-like silicon ingot, and monocrystal-like silicon ingot furnace

Abstract

The invention discloses a preparation method of a monocrystal-like silicon ingot. The preparation method comprises the following steps: spreading seed crystals in a crucible to form a seed crystal layer; arranging molten silicon on the seed crystal layer, controlling the temperature at the bottom of the crucible to be lower than the melting point of the seed crystals so as to ensure that the seed crystal layer is not completely molten; adjusting a thermal field to form a supercooled state to enable crystal growth of the molten silicon on the basis of the seed crystal layer; in the crystal growth process, continually or discontinuously stirring the molten silicon at the stirring speed of 1 turn / min-60 turns / min; after crystallization of all the molten silicon, performing annealing and cooling to obtain the monocrystal-like silicon ingot. According to the preparation method of the monocrystal-like silicon ingot, the molten silicon is stirred in the crystal growth process to enhance convection of the molten silicon, so that the amount of metal impurities entering the monocrystal-like silicon ingot can be reduced, enrichment of the impurities is reduced, the minority carrier lifetime of the silicon ingot is prolonged, and the monocrystal area of the cast monocrystals is increased. The invention further provides the monocrystal-like silicon ingot prepared according to the preparation method and further provides a monocrystal-like silicon ingot furnace.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a quasi-single crystal silicon ingot, a preparation method thereof and a quasi-single crystal silicon ingot furnace. Background technique [0002] At present, the production process of casting single crystal is mainly to lay single crystal seed crystals on the bottom of the crucible. Taking G5 silicon ingot as an example, the size of the seed crystal is 156mm long and 156mm wide, and the height is 30mm. Way bedding in a crucible with an internal diameter of 840mm long and 840mm wide. Then fill the silicon material above the seed crystal, and control the temperature to melt the silicon material from top to bottom to form a silicon melt. A quasi-single crystal grows on the layer. [0003] In the existing casting single crystal technology, the silicon melt undergoes natural convection, which leads to the accumulation of impurities on the side of the silicon melt at the s...

AI Technical Summary

Problems solved by technology

This will bring the following problems: (1) metal impurities, especially transition metal impurities, easily enter the silicon crystal, which will affect the minority carrier life of the silicon ingot, thereby affecting the electrical properties of the silicon wafer

(2) Solid infusible impurities (silicon nitride, silicon carbide, silicon oxide, etc.) are easy to accumulate at the solid liquid crystal surface and become nucleation centers, thereby producing polycrystals with other crystal orientations, which will affect cast single crystals single crystal area, thus affecting the quality of silicon wafers

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