| 研究生: |
羅詩淇 Shih-Chi Lo |
|---|---|
| 論文名稱: |
連續柴氏長晶生長過程中質傳的數值模擬 Numerical simulation of mass transfer during continuous CZ crystal growth |
| 指導教授: | 陳志臣 |
| 口試委員: | |
| 學位類別: |
碩士 Master |
| 系所名稱: |
工學院 - 機械工程學系 Department of Mechanical Engineering |
| 論文出版年: | 2021 |
| 畢業學年度: | 109 |
| 語文別: | 中文 |
| 論文頁數: | 110 |
| 中文關鍵詞: | 連續柴氏長晶法 、單晶矽 、隔板深度 |
| 外文關鍵詞: | Continuous Czochralski crystal growth, single crystal silicon, inner crucible depth |
| 相關次數: | 點閱:11 下載:0 |
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連續柴氏長晶法(Continuous Czochralski crystal growth,CCZ)是一種改良自柴氏長晶(Czochralski crystal growth,CZ)的單晶矽生長法。由於多加了隔板的結構,使得在連續添加原料時,不會有未融化的原料參雜進生長中的晶體內,但生長過程中的熱值傳將會受到隔板的影響。本研究將透過數值模擬針對不同坩堝形狀、加熱器、隔板深度、晶體與坩堝的轉速,分析其對長晶法條件之影響。
結果顯示淺坩堝因為能更好的傳遞熱以維持介面形狀,因此總功率較低。且因為與融湯接觸面積較小,可以減少氧雜質的產生,加上隔板底下的縫隙較小較可以阻隔部分氧進入晶體下方之融湯,所以介面處的氧濃度下降。不同的加熱器設計也會影響功率,將側加熱器下移60mm,可以適當的減少功率浪費,並使用側加熱器與底加熱器的功率比(PR)為0.24,如此可以降低的總功率。為了進一步降低氧濃度,隔板深度尤為重要,隔板影響著氧雜質來源和融湯質傳,模擬顯示隨著隔板深度加深,主導氧濃度的程度也會不一樣。考慮到介面偏轉與溫度梯度之於晶體品質,使用隔板深度60mm會較好。不同的轉速也會影響氧濃度,雖然本模型對旋轉很敏感,無法大幅調整,但當晶轉上升到4rpm時,氧濃度會最低。若此時坩堝與晶體改為同向旋轉,雖然氧濃度會上升,但界面氧濃度分布均勻而平坦。
Continuous Czochralski crystal growth (CCZ) is a single crystal silicon growth method modified from Czochralski crystal growth (CZ). Due to the additional structure of the partition, when the feed is continuously added, no unmelted feed will be mixed into the growing crystal. The heat and mass transfer during the growth process will be affected by the presence of partition. This study will analyze the influence of different crucible shapes, heaters, partition depth, crystal and crucible rotation rate on the conditions of the crystal growth method through numerical simulation.
The results show that the shallow crucible can better transfer heat to maintain the shape of the interface, so the total power is lower. And because the contact area with the melt is small, the generation of oxygen impurities can be reduced. In addition, the small gap under the partition can prevent part of the oxygen from entering the melt under the crystal, so the oxygen concentration at the interface decreases. Different heater designs will also affect the power. Moving the side heater down by 60mm can appropriately reduce power waste, and the power ratio (PR) of the side heater to the bottom heater is 0.24, which can reduce the total power. In order to further reduce the oxygen concentration, the depth of the partition is particularly important. The partition affects the source of oxygen impurities and the mass transfer of the melt. The simulation shows that as the depth of the partition deepens, the degree of the dominant oxygen concentration will also be different. Considering the interface deflection and temperature gradient for crystal quality, it is better to use a partition depth of 60mm. Different rotation rate will also affect the oxygen concentration. Although this model is very sensitive to rotation and cannot be adjusted significantly, the oxygen concentration will be the lowest when the crystal rotation rises to 4 rpm. If the crucible and the crystal are rotated in the same direction at this time, although the oxygen concentration will increase, the interface oxygen concentration distribution will be uniform and flat.
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