回收矽晶圓上製作金氧半結構太陽電池

Abstract

隨著石油的逐漸耗損,能源問題也變成人類關切的議題,太陽電池就這樣孕育而生,尋求新的方式來提高效率和低成本的太陽電池的必要性也逐漸增加。在本篇論文中,我們將以不同的氧化層備製的技術應用在回收矽晶圓上製作金氧半結構太陽電池。我們發現在矽氟酸溶液內成長的氧化層,對於回收矽晶圓製作的太陽能電池的應用上有不錯的特性。在主電極之間沉積一層半透明的薄鋁層,太陽電池的特性可以大幅提升。 第二章我們先以傳統快速熱系統生長氧化層,此方法會有極佳的均勻度,但厚度的控制是比較嚴格的。我們對於新的矽晶圓與回收的矽晶圓的金氧半太陽電池做討論。由實驗觀察得知新的矽晶圓的效率與氧化層平整度都明顯優於回收的矽晶圓,當氧化層厚度超過2 nm時對於兩者的效率都會大為降低。 第三章我們先介紹直流陽極氧化的成長機制,我們將以陽極氧化的方法在純水中成長超薄閘極氧化層,在以低溫熱退火處理對於新與舊的矽晶圓作探討。我們之後討論以陽極氧化法在稀釋的矽氟酸溶液中成長氧化層,在以低溫熱退火處理對於新與舊的矽晶圓作探討。然而對於純水與稀釋的矽氟酸溶液中成長的氧化層,發現在純水中成長的氧化層會有較佳的品質,但對於金氧半太陽電池而言特性越差。此外在矽氟酸溶液實驗中成長氧化層對於新的矽晶圓與回收的矽晶圓所製作的金氧半結構太陽電池擁有相近的轉換效率,對於回收矽晶圓的金氧半太陽電池而言可使成本下降。 第四章我們對於整個研究做一個結論並提出些建議。

Due to the conscious consumption of petroleum, the energy question becomes the main subject in which the humanity concerned much. The solar cell is one of the possible solutions to the about problem. It is of importance to enhance the efficiency and reduce the cost for the solar cell. In this paper, we will investigate the metal-oxide-semiconductor (MOS) structure solar cells by the different methods of oxide preparation in the recycle wafers. We find that the oxides in H2SiF6 solution are useful for MOS solar cells’ application. After the inter-cathode semi-transparent thin Al films deposition, the solar cells’ performance can be improved. In chapter 2, growth models for rapid thermal processing (RTP) of silicon are introduced. This method can provide good uniformity, but the thickness control is citical. We also discuss the MOS structure solar cells on new and recycle silicon wafer. We can find that the oxides’ surface roughness on new wafer is inferior to that on recycle wafer. However, both of the efficiencies for new and recycle wafer will be greatly reduced when the oxide thickness is greater than 2nm. In chapter 3, growth models for DC anodization of silicon are introduced. The ultra-thin gate oxides were prepared by anodization in H2O followed by low temperature annealing on new and recycle wafers. In addition, the ultra-thin gate oxides were also prepared by anodization in dilute H2SiF6 solution followed by low temperature annealing. Although, the oxides prepared in pure water reveal electrical better quality in comparison with those prepared in dilute H2SiF6 solution, the performances of the MOS solar cells are on the contrary. In addition, for the oxides prepared the H2SiF6 solution, it was found that almost the efficiencies of recycle and new silicon wafers are the same. Therefore, the recycle wafers for MOS solar cells are of interest since they are cost-effective. In chapter 4, the conclusion is finally given.