Directional solidification furnace with heat preservation part at bottom of side wall of crucible

Abstract

The invention discloses a directional solidification furnace. The directional solidification furnace comprises an upper furnace body, a lower furnace body, a crucible, at least one heater, a crucible retainer, a crucible support, a thermal insulation part, a vent pipe and a heat preservation part, wherein the lower furnace body is matched with the upper furnace body to form a furnace body space; the crucible is arranged in the furnace body space and used for accommodating feedstock; the at least one heater is used for heating the crucible and melting the feedstock accommodated in the crucible; the crucible retainer is used for retaining the crucible and arranged on the crucible support; the thermal insulation part is accommodated in the furnace body space, covers the heater and is used for controlling the directional solidification of the feedstock in the crucible; the vent pipe is connected to an external air source and vertically passes through the thermal insulation part; and the heat preservation part is arranged on the outer side of the bottom of the crucible retainer. The directional solidification furnace improves the crystal quality of polycrystalline ingots, improves production benefit and improves the conversion efficiency of solar cells prepared from the polycrystalline ingots.

Description

technical field [0001] The present invention relates to directional solidification equipment such as monocrystalline ingots or polycrystalline ingots, and in particular to a directional solidification furnace for producing polycrystalline silicon ingots for solar energy by directional solidification technology, and is provided with heat preservation parts at the bottom of crucible side walls. Background technique [0002] When using the directional solidification process to produce polycrystalline silicon ingots for solar energy, since the bottom of the quartz crucible cools faster than other parts, crystallization starts from the bottom first, and then gradually grows upwards. If the shape of the solid / liquid interface can be kept straight or slightly convex, most silicon grains tend to grow vertically upwards, and the grain boundaries are almost kept vertical, thus obtaining a nearly ideal grain arrangement. The quality of the crystal ingot is the best, and the conversion ...

AI Technical Summary

Problems solved by technology

And with the passage of the solid / liquid interface shown in the direction of the arrow in the figure, it can be seen from the kinetic analysis that the obtained polycrystalline ingot near the side wall of the quartz crucible has small and messy crystal grains, poor crystal quality, and low carrier lifetime. Low, and the conversion efficiency of solar cells prepared from this part of polycrystalline ingot is low

Images