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標題: | 電區融晶體生長與界面型態的觀察研究 Crystal Growth and Morphology Observation of Electrical Zone Melting Silicon Ribbon |
作者: | Ming-Chang Wu 吳明昌 |
指導教授: | 藍崇文(Chung-Wen Lan) |
關鍵字: | 電區融長晶,少數載子生命,缺陷密度, electric molten zone,dislocation density,lifetime, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | 太陽光電產業快速發展,仍以矽晶電池為主流,而目前太陽能電池晶片的主要成本在於切片,約為長晶成本的兩倍,且切割損失40 %的矽。因此,不需要切片的長晶技術具相當高的應用潛力,然而,現有技術所長出的矽薄片的生長缺陷仍高,且雜質過多,尚難與晶碇鑄造技術的晶片相抗衡。因此,無坩堝污染的電區融法提供了一個相當好的技術平台,沒有雜質的影響,且能精準控制長晶速度與溫梯,適合用來了解矽晶生長模式與其缺陷形成的行為,更可以加以改良,生長高品質的晶片。
為了證明上述概念,吾人選用不同類型矽晶片進行電區融實驗,吾人選用不同類型矽晶片進行電區融實驗,並探討電區融實驗參數對於長晶介面與缺陷生成的影響,包括移動速度、電流大小等。結果顯示電區融晶片的少數載子壽命主要由缺陷密度影響,在電致融區周圍高型變區圍繞著明顯紅區(低少數載子生命週期)與高缺陷密度。而吾人實驗結果顯示出,在區融實驗過程中成核可以藉由晶界釋放熱應力,因此能有較好的晶片品質。。 With the rapid development of photovoltaic industry, silicon solar cell is still the main stream. Although the solar cell price has dropped greatly to $0.4 /Wp, the silicon wafer ($0.25 /Wp) remains the major cost. More than 40 % of high-purity silicon has been thrown away during slicing in the cutting slurry waste. Therefore, the kerf-free ribbon growth technology has attracted much attention in the cost reduction. Due to its contamination-free nature, the electrical molten zone crystallization proposed recently is very promising for high-quality ribbon production. In addition to its potential in applications, it is an ideal process for crystals growth study because the growth rate and the dopant uniformity could be better controlled. In-situ observation is also possible for the study of nucleation, grain competition, and defection formation. To prove concept of that, we choose different type of silicon wafer to do experiments. The different experimental parameters such as applied current and drift velocity are further discussed. The results show that the minor carrier lifetime is influenced by etch pit density (EPD) and low lifetime area (red zone) encloses the electrical molten zone due to highly plastic deformation of silicon caused by high thermal gradient. Nucleation during the EMZC could release thermal stress via grain boundary to obtain better wafer quality. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/18403 |
全文授權: | 未授權 |
顯示於系所單位: | 化學工程學系 |
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ntu-103-1.pdf 目前未授權公開取用 | 5.99 MB | Adobe PDF |
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