Local optimization of graphite heater to save a power consumption of Czochralski Si ingot grower for PV application

摘要

In Cz process, Reducing heat loss is the simplest and most important way to sustain a company. However, in the ingot grower, this method is very difficult because it requires prediction of the internal thermal distribution and designing the shape of the heater based on the result. We have designed new hot-zone for commercial 8.3 inches diameter ingot growth in S-tech OSG puller. To predict the internal thermal distribution, we used a commercial simulation program, CG-SIM. The simulation results were found reasonably consistent with experimental observations in the power consumption, and oxygen content. The average power reduction is about 1.8 kW, which is similar to the simulation result of 1.5 kW. Despite the inside temperature of grower rises, the concentration of oxygen was suppressed to 19 ppma or less as in a normal heater. And the other three major indicators for the solar-cell performance were all similar. From these results, it can be seen that the ingots have the same quality for PV applications.