本研究為將數值模擬技術應用於單方向性成長多晶矽長晶爐製程之參數優化，並進行實驗驗證。本研究使用套裝軟體模擬單方向性成長多晶矽長晶爐製程中爐體內部溫度場，並分析溫度場隨時間的變化得知矽晶錠之凝固速率，以相變態之成核成長理論進行參數及爐體內部保溫材之優化修改，並以爐體內部溫度曲線、固液界面成長高度、晶粒成長方向及數量進行數值模型驗證。
本研究首先建立一熱交換式(Heat Exchange Method, HEM)多晶矽長晶爐之溫度場數值模擬系統，以爐體內部溫度曲線、固液界面成長高度、晶粒成長方向及數量等資訊進行驗證，根據模擬結果可推測得知由於爐體僅為單段式熱閘門設計，在長晶初期，矽熔湯底部溫度過低導致成核數目過多，以致於後期晶粒無法成長至理想尺寸，進而提出藉由爐體熱閘門修改以及參數調整使長晶初期減少熔湯底部熱散失，達到減低成核數之目的。因此針對爐體設計進行修改，由單段式熱閘門進行修改為三段式熱閘門，使長晶初期熱散失較少而減少成核數目，以達到增大多晶矽晶粒尺寸及獲得效率更佳之太陽能電池之目的。

The quality of multi-crystalline silicon ingot from casting process by heat exchange method (HEM) is significantly affected by the cooling condition and the design of the hot-zone. The shape of the liquid-solid interface has great impact on the direction and orientation of grain growth and the occurrence of defects such as dislocations, impurities segregation, and residual thermal stresses. In this study, the temperature variation/distribution of crystallization process of silicon ingot is investigated through numerical simulation and compared with experimental measurements.
In HEM system, the temperature variation/distribution is affected by the adiabatic condition of the furnace and power curves of the heaters and cooling system in the furnace. By modifying the power curve of heaters and changing the design of heat gate, a better cooling condition is realized and experimentally verified. Incorporated with the Cellular Automaton (CA) method, the grain structures are also simulated. The different slices of the practical silicon ingot are then compared with the results of grain growth simulation to verify the accuracy of the numerical system. With the numerical system validated, various designs and operating conditions can then be numerically evaluated to obtain the optimal design and operation.

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