Method and Apparatus for Manufacturing Silicon Ingot

An apparatus for manufacturing a silicon ingot, comprising:

• a container to which a vacuum exhaust system and a gas introducing system are connected,
• a crucible set in the container,
• a heating means for heating the crucible to generate, in the crucible, an alloy melt comprising an element which can undergo eutectic reaction with silicon and has a lower eutectic point than the melting point of silicon when made into silicon alloy, and a metallic silicon having a purity of 98% or more,
• a pulling-up means for making a silicon crystal into an ingot form, and
• a liquid surface temperature measuring means for measuring the liquid surface temperature of the alloy melt in the crucible,
• the heating means having a function of heating the region of the liquid surface of the alloy melt generated in the crucible, and other region of the alloy melt at intensities independent of each other, and
• the apparatus having a controlling means for grasping the amount of a fall in the concentration of the silicon in the alloy melt, and further controlling the heating based on the heating means to keep the liquid surface temperature of the alloy melt into temperatures slightly lower than a primary crystallization temperature which corresponds to the grasped silicon concentration in the alloy melt.